Showing papers in "Occupational and Environmental Medicine in 2005"

The relationship between job satisfaction and health: a meta-analysis

Abstract: Background: A vast number of published studies have suggested a link between job satisfaction levels and health. The sizes of the relationships reported vary widely. Narrative overviews of this relationship have been published, but no systematic meta-analysis review has been conducted. Methods: A systematic review and meta-analysis of 485 studies with a combined sample size of 267 995 individuals was conducted, evaluating the research evidence linking self-report measures of job satisfaction to measures of physical and mental wellbeing. Results: The overall correlation combined across all health measures was r = 0.312 (0.370 after Schmidt- Hunter adjustment). Job satisfaction was most strongly associated with mental/psychological problems; strongest relationships were found for burnout (corrected r = 0.478), self-esteem(r = 0.429), depression (r = 0.428), and anxiety(r = 0.420). The correlation with subjective physical illness was more modest (r = 0.287). Conclusions: Correlations in excess of 0.3 are rare in this context. The relationships found suggest that job satisfaction level is an important factor influencing the health of workers. Organisations should include the development of stress management policies to identify and eradicate work practices that cause most job dissatisfaction as part of any exercise aimed at improving employee health. Occupational health clinicians should consider counselling employees diagnosed as having psychological problems to critically evaluate their work—and help them to explore ways of gaining greater satisfaction from this important aspect of their life.

Phthalates and human health

Abstract: The diesters of 1,2-benzenedicarboxylic acid (phthalic acid), commonly known as phthalates, are a group of man-made chemicals with a wide spectrum of industrial applications (fig 1, table 1). High molecular weight phthalates (for example, di(2-ethylhexyl) phthalate [DEHP], di-isononyl phthalate [DiNP], di-n-octyl phthalate [DnOP]), are primarily used as plasticizers in the manufacture of flexible vinyl which, in turn, is used in consumer products, flooring and wall coverings, food contact applications, and medical devices.1–3 Manufacturers use low molecular weight phthalates (for example, diethyl phthalate [DEP] and dibutyl phthalate [DBP]) in personal-care products (for example, perfumes, lotions, cosmetics), as solvents and plasticizers for cellulose acetate, and in making lacquers, varnishes, and coatings, including those used to provide timed releases in some pharmaceuticals.3–5 View this table: Table 1 Potential sources of exposure and health effects of selected phthalates Figure 1 Generic chemical structure of phthalates diesters and phthalate monoester metabolites. R is an alkyl and/or aryl group: CH3 (dimethyl phthalate), CH2CH3 (diethyl phthalate), CH2CH2CH2CH3 (dibutyl phthalate), CH2CH(CH2CH3)CH2CH2CH2CH3 (di[2-ethylhexyl) phthalate), CH2CH2CH2CH3 and CH2C6H5 (butylbenzyl phthalate). In this paper, we review the uses and metabolism of phthalates, and the studies on health effects of phthalates in human populations published between 1973 and June 2005. The references included in this review were searched using the Web of Science database which provides interactive citation and literature searching of the Institute for Scientific Information’s Science Citation Index Expanded. The database contains data from more than 5000 scientific journals and covers the period from 1980 to present. We also searched the bibliography cited in the selected references for additional relevant citations. Because phthalates are widely used in …

The impact of overtime and long work hours on occupational injuries and illnesses: new evidence from the United States.

Abstract: Aims: To analyse the impact of overtime and extended working hours on the risk of occupational injuries and illnesses among a nationally representative sample of working adults from the United States. Methods: Responses from 10 793 Americans participating in the National Longitudinal Survey of Youth (NLSY) were used to evaluate workers’ job histories, work schedules, and occurrence of occupational injury and illness between 1987 and 2000. A total of 110 236 job records were analysed, encompassing 89 729 person-years of accumulated working time. Aggregated incidence rates in each of five exposure categories were calculated for each NLSY survey period. Multivariate analytical techniques were used to estimate the relative risk of long working hours per day, extended hours per week, long commute times, and overtime schedules on reporting a work related injury or illness, after adjusting for age, gender, occupation, industry, and region. Results: After adjusting for those factors, working in jobs with overtime schedules was associated with a 61% higher injury hazard rate compared to jobs without overtime. Working at least 12 hours per day was associated with a 37% increased hazard rate and working at least 60 hours per week was associated with a 23% increased hazard rate. A strong dose-response effect was observed, with the injury rate (per 100 accumulated worker-years in a particular schedule) increasing in correspondence to the number of hours per day (or per week) in the workers’ customary schedule. Conclusions: Results suggest that job schedules with long working hours are not more risky merely because they are concentrated in inherently hazardous industries or occupations, or because people working long hours spend more total time “at risk” for a work injury. Strategies to prevent work injuries should consider changes in scheduling practices, job redesign, and health protection programmes for people working in jobs involving overtime and extended hours.

Prognostic factors for duration of sick leave in patients sick listed with acute low back pain: a systematic review of the literature

Abstract: Background: The percentages of patients with acute low back pain (LBP) that go on to a chronic state varies between studies from 2% to 34%. In some of these cases low back pain leads to great costs. Aims: To evaluate the evidence for prognostic factors for return to work among workers sick listed with acute LBP. Methods: Systematic literature search with a quality assessment of studies, assessment of levels of evidence for all factors, and pooling of effect sizes. Results: Inclusion of studies in the review was restricted to inception cohort studies of workers with LBP on sick leave for less than six weeks, with the outcome measured in absolute terms, relative terms, survival curve, or duration of sick leave. Of the studies, 18 publications (14 cohorts) fulfilled all inclusion criteria. One low quality study, four moderate quality studies, and nine high quality studies were identified; 79 prognostic factors were studied and grouped in eight categories for which the evidence was assessed. Conclusions: Specific LBP, higher disability levels, older age, female gender, more social dysfunction and more social isolation, heavier work, and receiving higher compensation were identified as predictors for a longer duration of sick leave. A history of LBP, job satisfaction, educational level, marital status, number of dependants, smoking, working more than 8 hour shifts, occupation, and size of industry or company do not influence duration of sick leave due to LBP. Many different constructs were measured to identify psychosocial predictors of long term sick leave, which made it impossible to determine the role of these factors.

Evidence based guidelines for the prevention, identification, and management of occupational asthma

Abstract: Background: Occupational asthma is the most frequently reported work related respiratory disease in many countries. This work was commissioned by the British Occupational Health Research Foundation to assist the Health and Safety Executive in achieving its target of reducing the incidence of occupational asthma in Great Britain by 30% by 2010. Aim: The guidelines aim to improve the prevention, identification, and management of occupational asthma by providing evidence based recommendations on which future practice can be based. Methods: The literature was searched systematically using Medline and Embase for articles published in all languages up to the end of June 2004. Evidence based statements and recommendations were graded according to the Royal College of General Practitioner's star system and the revised Scottish Intercollegiate Guidelines Network grading system. Results: A total of 474 original studies were selected for appraisal from over 2500 abstracts. The systematic review produced 52 graded evidence statements and 22 recommendations based on 223 studies. Discussion: Evidence based guidelines have become benchmarks for practice in healthcare and the process used to prepare them is well established. This evidence review and its recommendations focus on interventions and outcomes to provide a robust approach to the prevention, identification, and management of occupational asthma, based on and using the best available medical evidence. The most important action to prevent cases of occupational asthma is to reduce exposure at source. Thereafter surveillance should be performed for the early identification of symptoms, including occupational rhinitis, with additional functional and immunological tests where appropriate. Effective management of workers suspected to have occupational asthma involves the identification and investigation of symptoms suggestive of asthma immediately they occur. Those workers who are confirmed to have occupational asthma should be advised to avoid further exposure completely and early in the course of their disease to offer the best chance of recovery.

The London Underground: dust and hazards to health

Abstract: Aims: To assess hazards associated with exposure to dust in the London Underground railway and to provide an informed opinion on the risks to workers and the travelling public of exposure to tunnel dust. Methods: Concentrations of dust, as mass (PM2.5) and particle number, were measured at different underground stations and in train cabs; its size and composition were analysed; likely maximal exposures of staff and passengers were estimated; and in vitro toxicological testing of sample dusts in comparison with other dusts was performed. Results: Concentrations on station platforms were 270–480 µg/m3 PM2.5 and 14 000–29 000 particles/cm3. Cab concentrations over a shift averaged 130–200 µg/m3 and 17 000–23 000 particles/cm3. The dust comprised by mass approximately 67% iron oxide, 1–2% quartz, and traces of other metals, the residue being volatile matter. The finest particles are drawn underground from the surface while the coarser dust is generated by interaction of brakes, wheels, and rails. Taking account of durations of exposure, drivers and station staff would have maximum exposures of about 200 µg/m3 over eight hours; the occupational exposure standard for welding fume, as iron oxide, is 5 mg/m3 over an eight hour shift. Toxicology showed the dust to have cytotoxic and inflammatory potential at high doses, consistent with its composition largely of iron oxide. Discussion: It is unjustifiable to compare PM2.5 exposure underground with that on the surface, since the adverse effects of iron oxide and combustion generated particles differ. Concentrations of ultrafine particles are lower and of coarser (PM2.5) particles higher underground than on the surface. The concentrations underground are well below allowable workplace concentrations for iron oxide and unlikely to represent a significant cumulative risk to the health of workers or commuters.

Twenty five year mortality and air pollution: results from the French PAARC survey

Abstract: AIMS AND METHODS: Long term effects of air pollution on mortality were studied in 14,284 adults who resided in 24 areas from seven French cities when enrolled in the PAARC survey (air pollution and chronic respiratory diseases) in 1974. Daily measurements of sulphur dioxide, total suspended particles, black smoke, nitrogen dioxide, and nitric oxide were made in 24 areas for three years (1974-76). Cox proportional hazards models controlling for individual confounders (smoking, educational level, body mass index, occupational exposure) were applied, and frailty models used to take into account spatial correlation. Indicators of air pollution were the mean concentration. RESULTS: Models were run before and after exclusion of six area monitors influenced by local traffic (NO/NO2 >3 in ppb). After exclusion of these areas, analyses showed that adjusted risk ratios (95% CI) for TSP, BS, NO2, and NO for non-accidental mortality were 1.05 (1.02 to 1.08), 1.07 (1.03 to 1.10), 1.14 (1.03 to 1.25), and 1.11 (1.05 to 1.17) for 10 microg/m3 respectively. Consistent patterns for lung cancer and cardiopulmonary causes were observed. CONCLUSIONS: Urban air pollution assessed in the 1970s was associated with increased mortality over 25 years in France.

Regression modelling and other methods to control confounding.

Abstract: Confounding is a major concern in causal studies because it results in biased estimation of exposure effects. In the extreme, this can mean that a causal effect is suggested where none exists, or that a true effect is hidden. Typically, confounding occurs when there are differences between the exposed and unexposed groups in respect of independent risk factors for the disease of interest, for example, age or smoking habit; these independent factors are called confounders. Confounding can be reduced by matching in the study design but this can be difficult and/or wasteful of resources. Another possible approach—assuming data on the confounder(s) have been gathered—is to apply a statistical “correction” method during analysis. Such methods produce “adjusted” or “corrected” estimates of the effect of exposure; in theory, these estimates are no longer biased by the erstwhile confounders. Given the importance of confounding in epidemiology, statistical methods said to remove it deserve scrutiny. Many such methods involve strong assumptions about data relationships and their validity may depend on whether these assumptions are justified. Historically, the most common statistical approach for dealing with confounding in epidemiology was based on stratification ; the standardised mortality ratio is a well known statistic using this method to remove confounding by age. Increasingly, this approach is being replaced by methods based on regression models . This article is a simple introduction to the latter methods with the emphasis on showing how they work, their assumptions, and how they compare with other methods. Before applying a statistical correction method, one has to decide which factors are confounders. This sometimes1–4 complex issue is not discussed in detail and for the most part the examples will assume that age is a confounder. However, the use of automated statistical procedures for choosing variables to include in a regression model …

Health impact assessment

Abstract: A person’s health status is largely determined by factors outside the control of the healthcare sector. While some of these are fixed, such as inheritance, many are environmental in the broadest sense of the term. These operate through such socioeconomic sectors as employment, education, housing and transport, which structure the health risks and opportunities of individuals. Typically the structuring is unequal—sometimes referred to as clustering of disadvantage—so that those who are less well placed socioeconomically also have worse health outcomes, contributing to socioeconomic inequalities in health. The health impacts of these sectors can be influenced by interventions, whether or not these are primarily motivated by health considerations. For example, a policy or other intervention to improve educational status can raise the socioeconomic standard, thereby improving health. Such interventions have the potential to increase or decrease inequalities. Health impact assessment (HIA) is concerned with the health of populations.1 It generally attempts to predict the future health consequences—both positive and negative impacts—of an intervention such as a policy,2 programme, or project3 (hereafter collectively referred to as a “proposal”).1,4,5 There are several definitions of HIA in the literature; for example, “a combination of procedures, methods and tools by which a policy, program or project may be judged as to its potential effects on the health of a population and the distribution of effects within the population”.6 The overall aim when conducting an HIA is to influence decision making to minimise the harm and maximise the health benefit of proposals.7 This might happen in three ways: (1) by raising the general awareness among decision makers that their actions affect health; (2) by informing decision makers of the likely specific impacts of particular decisions; and (3) by helping those potentially affected by decisions to participate in proposal …

A comparison of self-reported sickness absence with absences recorded in employers' registers: evidence from the Whitehall II study

Abstract: Aim: To compare self-reported sickness absence days in the last 12 months with recorded absences from the employers’ registers for the same period. Methods: Self-reported sickness absence data over the 12 months preceding baseline (1985–88) were compared with absence records from the employers’ registers over the same period for 2406 women and 5589 men, participants in the Whitehall II study of British civil servants. Associations with self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease at baseline were determined. Results: In general, women reported less sickness absence over the last year than was recorded in the employers’ registers, while men, with the exception of those in the lower employment grades, reported more. Agreement between self-reported and recorded absence days decreased as the total number of days increased. After adjustment for employment grade and the average number of recorded and self-reported absence days, the total number of self-reported absence days was within two days of the recorded number of days for 63% of women and 67% of men. Associations between annual self-reported sickness absence days and self-rated health, longstanding illness, minor psychiatric disorder, physical illness, and prevalent coronary heart disease were as strong as those for recorded absence days. Conclusion: These findings suggest that agreement between the annual number of self-reported and the annual number of recorded sickness absence days is relatively good in both sexes and that associations with health are equivalent for both measures.

Eye complaints in the office environment: precorneal tear film integrity influenced by eye blinking efficiency

Abstract: To achieve a common base for understanding work related eye complaints in the office environment, it is necessary to merge approaches from indoor air science, occupational health, and ophthalmology. Based on database searches, it is concluded that precorneal tear film (PTF) alteration leads to eye complaints that may be caused by: (1) thermal factors (low relative humidity; high room temperature); (2) demanding task content (attention decreases blinking and widens the exposed ocular surface area); and (3) individual characteristics (for example, tear film alterations, blinking anomalies, gland dysfunctions, and use of contact lenses). These factors and conditions are able to progressively increase water evaporation and faster thinning of the PTF, which causes dryness and dry spot formation on the cornea, possibly followed by corneal and conjunctiva epithelial alterations and eye complaints. Another possible cause of eye complaints is certain irritating chemical compounds, in addition to oxidation mixtures that are formed in reactions between ozone and unsaturated organic compounds (alkenes). The effect may be exacerbated by low relative humidity.

Acoustics and psychosocial environment in intensive coronary care

Abstract: Aims: To examine the influence of different acoustic conditions on the work environment and the staff in a coronary critical care unit (CCU). Method: Psychosocial work environment data from start and end of each individual shift were obtained from three shifts (morning, afternoon, and night) for a one-week baseline period and for two four-week periods during which either sound reflecting or sound absorbing tiles were installed. Results: Reverberation times and speech intelligibility improved during the study period when the ceiling tiles were changed from sound reflecting tiles to sound absorbing ones of identical appearance. Improved acoustics positively affected the work environment; the afternoon shift staff experienced significantly lower work demands and reported less pressure and strain. Conclusions: Important gains in the psychosocial work environment of healthcare can be achieved by improving room acoustics. The study points to the importance of further research on possible effects of acoustics in healthcare on staff turnover, quality of patient care, and medical errors.

Asthma, chronic bronchitis, and exposure to irritant agents in occupational domestic cleaning: a nested case-control study

Abstract: Background: Women employed in domestic cleaning are at increased risk for symptoms of obstructive lung disease, but the agents responsible are unknown. Aims: To investigate common tasks and products in occupational domestic cleaning in relation to respiratory morbidity. Methods: Case-control study in domestic cleaning women nested within a large population based survey of women aged 30–65 years; 160 domestic cleaning women with asthma symptoms, chronic bronchitis symptoms, or both and 386 without a history of respiratory symptoms were identified. Detailed exposures were evaluated for 40 cases who reported still having symptoms at the recruitment interview, and 155 controls who reported not having symptoms. All tasks performed and products used when cleaning houses were determined in a face-to-face interview. Lung function, methacholine challenge, and serum IgE testing were performed. Personal exposure measurements of airborne chlorine and ammonia were performed in a subsample. Associations between asthma, chronic bronchitis, and cleaning exposures were evaluated using multiple logistic regression analysis. Results: Airborne chlorine (median level 0–0.4 ppm) and ammonia (0.6–6.4 ppm) were detectable during occupational domestic cleaning activities. Cases used bleach more frequently than controls; adjusted odds ratio (OR) for intermediate exposure was 3.3 (95% CI 0.9 to 11) and for high exposure 4.9 (1.5 to 15). Other independent associations included accidental inhalation of vapours and gases from cleaning agents and washing dishes. These associations were more pronounced for cases with asthma symptoms than for those with symptoms of chronic bronchitis, but were not related to sensitisation to common allergens. Conclusions: Asthma symptoms in domestic cleaning women are associated with exposure to bleach and possibly other irritant agents. The public health impact of the use of irritant cleaning products could be widespread since the use of these products is common both in the workplace and at home.

Intervention studies in occupational epidemiology

Abstract: The proportion of intervention studies in occupational epidemiology has been growing rapidly in recent years. This is a positive trend, which makes it necessary to discuss a number of theoretical, methodological, and practical issues. The aim of this paper is to summarise the specific features of occupational intervention research, to suggest solutions to some of the special problems, and to propose ways of developing worksite intervention studies in the future. Occupational intervention studies are in this paper defined as “studies in which the effects of planned activities at the worksites with the aim of improving the working conditions and/or the health of the workers are being evaluated with research methods”. The goals of these activities are usually improved health and wellbeing of the workers, reduced absence or turnover, or increased motivation and job satisfaction. In some cases these goals are combined with other objectives such as increased product quality, increased productivity, or increased customer satisfaction. The present article will focus on interventions with a behavioural, organisational, or psychosocial element. This leaves out purely engineering interventions where, for example, one chemical is substituted with another or one machine with another without changes in employee behaviour. The scope of the article is still very broad since it includes such diverse fields as ergonomics, accidents, psychosocial factors, health promotion, physical and chemical factors, and secondary prevention of occupational diseases and injuries. Why is occupational intervention research so important? The simple answer is that we want to know whether or not interventions at the worksites have the desired effect. This is by no means a matter of course. Some interventions have no effects while others have negative effects in spite of the good intentions of everyone involved. Going one step further, we can identify at least four good reasons for doing intervention research:

Construction work and risk of occupational disability : a ten year follow up of 14 474 male workers

Abstract: Aims: Most industrialised countries have public income maintenance programmes to protect workers in case of disability but studies addressing disability risk of specific professional groups are rare. The objective of this study was to establish a detailed pattern of the nature and extent of occupational disability among construction workers. Methods: A cohort study was set up including 14 474 male workers from the construction industry in Wurttemberg (Germany) aged 25–64 years who underwent occupational health exams between 1986 and 1992. The cohort was linked to the regional pension register of the manual workers’ pension insurance institution to identify workers who were granted a disability pension during the 10 year follow up. All-cause and cause specific standardised incidence ratios (SIR) and 95% confidence intervals (CI) were calculated using disability rates from the general workforce and from all blue collar workers in Germany as references. Results: In total, 2247 (16%) members of the cohort were granted a disability pension. Major causes of disability were musculoskeletal (45%) and cardiovascular diseases (19%). In comparison with the general workforce, construction workers experienced a higher risk of disability from cancer (SIR = 1.26; 95% CI 1.08 to 1.47), respiratory diseases (SIR = 1.27; 95% CI 1.03 to 1.55), musculoskeletal diseases (SIR = 2.16; 95% CI 2.03 to 2.30), injuries/poisoning (SIR = 2.52; 95% CI 2.06 to 3.05), and all causes combined (SIR = 1.47; 95% CI 1.41 to 1.53). When compared with the blue collar reference group, increased risks of disability among construction workers were found for musculoskeletal diseases (SIR = 1.53; 95% CI 1.44 to 1.63), injury/poisoning (SIR = 1.83; 95% CI 1.50 to 2.21), and all causes combined (SIR = 1.11; 95% CI 1.07 to 1.16). Conclusions: Musculoskeletal diseases and external causes are major factors limiting the work capability of construction workers and lead to an increased proportion of occupational disability.

Relationship between chemical structure and the occupational asthma hazard of low molecular weight organic compounds.

Abstract: Aims: To investigate quantitatively, relationships between chemical structure and reported occupational asthma hazard for low molecular weight (LMW) organic compounds; to develop and validate a model linking asthma hazard with chemical substructure; and to generate mechanistic hypotheses that might explain the relationships. Methods: A learning dataset used 78 LMW chemical asthmagens reported in the literature before 1995, and 301 control compounds with recognised occupational exposures and hazards other than respiratory sensitisation. The chemical structures of the asthmagens and control compounds were characterised by the presence of chemical substructure fragments. Odds ratios were calculated for these fragments to determine which were associated with a likelihood of being reported as an occupational asthmagen. Logistic regression modelling was used to identify the independent contribution of these substructures. A post-1995 set of 21 asthmagens and 77 controls were selected to externally validate the model. Results: Nitrogen or oxygen containing functional groups such as isocyanate, amine, acid anhydride, and carbonyl were associated with an occupational asthma hazard, particularly when the functional group was present twice or more in the same molecule. A logistic regression model using only statistically significant independent variables for occupational asthma hazard correctly assigned 90% of the model development set. The external validation showed a sensitivity of 86% and specificity of 99%. Conclusions: Although a wide variety of chemical structures are associated with occupational asthma, bifunctional reactivity is strongly associated with occupational asthma hazard across a range of chemical substructures. This suggests that chemical cross-linking is an important molecular mechanism leading to the development of occupational asthma. The logistic regression model is freely available on the internet and may offer a useful but inexpensive adjunct to the prediction of occupational asthma hazard.

The lagged effect of cold temperature and wind chill on cardiorespiratory mortality in Scotland.

Abstract: Aims: To investigate the lagged effects of cold temperature on cardiorespiratory mortality and to determine whether "wind chill" is a better predictor of these effects than "dry bulb" temperature. Methods: Generalised linear Poisson regression models were used to investigate the relation between mortality and "dry bulb" and "wind chill" temperatures in the three largest Scottish cities (Glasgow, Edinburgh, and Aberdeen) between January 1981 and December 2001. Effects of temperature on mortality (lags up to one month) were quantified. Analyses were conducted for the whole year and by season (cool and warm seasons). Main results: Temperature was a significant predictor of mortality with the strongest association observed between temperature and respiratory mortality. There was a non-linear association between mortality and temperature. Mortality increased as temperatures fell throughout the range, but the rate of increase was steeper at temperatures below 11°C. The association between temperature and mortality persisted at lag periods beyond two weeks but the effect size generally decreased with increasing lag. For temperatures below 11°C, a 1°C drop in the daytime mean temperature on any one day was associated with an increase in mortality of 2.9% (95% CI 2.5 to 3.4), 3.4% (95% CI 2.6 to 4.1), 4.8% (95% CI 3.5 to 6.2) and 1.7% (95% CI 1.0 to 2.4) over the following month for all cause, cardiovascular, respiratory, and "other" cause mortality respectively. The effect of temperature on mortality was not observed to be significantly modified by season. There was little indication that "wind chill" temperature was a better predictor of mortality than "dry bulb" temperature. Conclusions: Exposure to cold temperature is an important public health problem in Scotland, particularly for those dying from respiratory disease.

Retirement on grounds of ill health.

Abstract: Today, most modern welfare states face the challenge of an aging population and decreasing rates of labour force participation among older people. Despite increased life expectancy, improved living conditions, and better health status, the average time people spend in paid work is decreasing in most European countries.1–3 This rather paradoxical development is partly due to a delay of young people entering the labour market; however, even more important is that older workers are exiting the labour market in greater numbers. In most countries, the average age of permanent departure from paid labour is well below the statutory pension age. This development, the “early exit trend”, has been called “one of the most profound structural changes in the past 25 years”,1 a trend that is hardly sustainable because of growing financial pressure on governments. This trend is incompatible with anticipated labour shortages in the near future. Consequently, researchers and policy makers all over Europe are involved in studies and debates to find ways to “shift the vicious circle of early exit to the virtuous circle of active aging”.4 Leaving the labour market before old age pension requires alternative sources of income. Across Europe, there are many ways to bridge the time between early exit and old age pension. Depending on the configuration, availability, and generosity of such pathways, countries use different strategies of externalisation and integration of older and/or disabled workers. Integration strategies support employment among these groups, whereas externalisation strategies transfer the risk of old or sick employees to the social security system. Because of generous entering conditions in different social security programmes, many countries have adopted such an externalisation strategy. As a result, the number of premature labour market withdrawals has increased dramatically. To a very high degree, this also applies to the social security …

Self-reported workplace related ergonomic conditions as prognostic factors for musculoskeletal symptoms: the “BIT” follow up study on office workers

Abstract: Aims: To identify prognostic ergonomic and work technique factors for musculoskeletal symptoms among office workers and in a subgroup with highly monotonous repetitive computer work. Methods: A baseline questionnaire was delivered to 5033 office workers in 11 Danish companies in the first months of 1999, and a follow up questionnaire was mailed in the last months of 2000 to 3361 respondents. A subgroup with highly monotonous repetitive computer work was formed including those that were repeating the same movements and/or tasks for at least 75% of the work time. The questionnaire contained questions on ergonomic factors and factors related to work technique. The outcome variables were based on the frequency of musculoskeletal symptoms during the last 12 months. Logistic regression analyses were used to identify prognostic factors for symptoms in the three body regions. Results: In total, 39%, 47%, and 51% of the symptomatic subjects had a reduced frequency of symptom days in the neck/shoulder, low back, or elbow/hand region, respectively. In all regions more men than women had reduced symptoms. In the multivariate logistic regression analyses, working no more than 75% of the work time with the computer was a prognostic factor for musculoskeletal symptoms in the neck/shoulder and elbow/hand, and a high influence on the speed of work was a prognostic factor for symptoms in the low back. In the subgroup with highly monotonous repetitive computer work, the odds ratios of the prognostic factors were similar to those for the whole group of office workers. Conclusion: When organising computer work it is important to allow for physical variation with other work tasks, thereby avoiding working with the computer during all the work time, and further to consider the worker’s own influence on the speed of work.

Rapidly progressive coal workers' pneumoconiosis in the United States: geographic clustering and other factors.

Abstract: Background: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers' pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue to occur among coal miners. Aims: To identify US miners with rapidly progressive CWP and to describe their geographic distribution and associated risk factors. Methods: Radiographic evidence of disease progression was evaluated for underground coal miners examined through US federal chest radiograph surveillance programmes from 1996 to 2002. A case of rapidly progressive CWP was defined as the development of PMF and/or an increase in small opacity profusion greater than one subcategory over five years. County based prevalences were derived for both CWP and rapidly progressive cases. Results: A total of 886 cases of CWP were identified among 29 521 miners examined from 1996 to 2002. Among the subset of 783 miners with CWP for whom progression could be evaluated, 277 (35.4%) were cases of rapidly progressive CWP, including 41 with PMF. Miners with rapidly progressive CWP were younger than miners without rapid progression, were more likely to have worked in smaller mines (<50 employees), and also reported longer mean tenure in jobs involving work at the face of the mine (in contrast to other underground mining jobs), but did not differ with respect to mean underground tenure. There was a clear tendency for the proportion of cases of rapidly progressive CWP to be higher in eastern Kentucky, and western Virginia. Conclusions: Cases of rapidly progressive CWP can be regarded as sentinel health events, indicating inadequate prevention measures in specific regions. Such events should prompt investigations to identify causal factors and initiate appropriate additional measures to prevent further disease.

Associations between ambient, personal, and indoor exposure to fine particulate matter constituents in Dutch and Finnish panels of cardiovascular patients.

Abstract: Aims: To assess the relation between ambient, indoor, and personal levels of PM2.5 and its elemental composition for elderly subjects with cardiovascular disease. Methods: In the framework of a European Union funded study, panel studies were conducted in Amsterdam, the Netherlands and Helsinki, Finland. Outdoor PM2.5 concentrations were measured at a fixed site. Each subject's indoor and personal PM2.5 exposure was measured biweekly for six months, during the 24 hour period preceding intensive health measurements. The absorbance of PM2.5 filters was measured as a marker for diesel exhaust. The elemental content of more than 50% of the personal and indoor samples and all corresponding outdoor samples was measured using energy dispersive x ray fluorescence. Results: For Amsterdam and Helsinki respectively, a total of 225 and 238 personal, and 220 and 233 indoor measurements, were analysed from 36 and 46 subjects. For most elements, personal and indoor concentrations were lower than and highly correlated with outdoor concentrations. The highest correlations (median r.0.9) were found for sulfur and particle absorbance, which both represent fine mode particles from outdoor origin. Low correlations were observed for elements that represent the coarser part of the PM2.5 particles (Ca, Cu, Si, Cl). Conclusions: The findings of this study provide support for using fixed site measurements as a measure of exposure to particulate matter in time series studies linking the day to day variation in particulate matter to the day to day variation in health endpoints, especially for components of particulate matter that are generally associated with fine particles and have few indoor sources. The high correlation for absorbance of PM2.5 documents that this applies to particulate matter from combustion sources, such as diesel vehicles, as well.

Short term effects of particulate matter on cause specific mortality: effects of lags and modification by city characteristics

Abstract: Background: Consistent evidence has shown increased all-cause mortality, and mortality from broad categories of causes associated with airborne particles. Less is known about associations with specific causes of death, and modifiers of those associations. Aims: To examine these questions in 20 US cities, between 1989 and 2000. Methods: Mortality files were obtained from the National Center for Health Statistics. Air pollution data were obtained from the Environmental Protection Agency website. The associations between daily concentrations of particulate matter of aero-diameter ⩽10 μm (PM10) and daily mortality from all-cause and selected causes of death, were examined using a case-crossover design. Temporal effects of PM10 were examined using lag models, in first stage regressions. City specific modifiers of these associations were examined in second stage regressions. Results: All-cause mortality increased with PM10 exposures occurring both one and two days prior the event. Deaths from heart disease were primarily associated with PM10 on the two days before, while respiratory deaths were associated with PM10 exposure on all three days. Analyses using only one lag underestimated the effects for all-cause, heart, and respiratory deaths. Several city characteristics modified the effects of PM10 on daily mortality. Important findings were seen for population density, percentage of primary PM10 from traffic, variance of summer temperature, and mean of winter temperature. Conclusions: There was overall evidence of increased daily mortality from increased concentrations of PM10 that persisted across several days, and matching for temperature did not affect these associations. Heterogeneity in the city specific PM10 effects could be explained by differences in certain city characteristics.

Evidence based guidelines for the prevention, identification, and management of occupational asthma.

Abstract: Commentary on the paper by Nicholson et al (see page 290) The article by Nicholson et al in this issue of OEM has an ambitious aim: to assist the Health and Safety Executive in the reduction of occupational asthma by 30% in the next five years.1 The article is very well written and timely. Occupational asthma (OA) as noted by the authors is the most common chronic occupational lung disease now in most industrialised countries and most reported rates have not shown a decline in recent years. However, it is not clear as to what database will be used (both to establish baseline incidence and in the future) to determine changes in incidence of OA which may result from these guides—the SWORD scheme, compensation claims, or a new database? Is there knowledge which could be implemented to produce a decline of the magnitude stated? Preventive measures for OA designated by the authors as having a hypersensitivity cause, have been well described, and recently reviewed.2,3 Primary prevention can have dramatic effects when it is feasible. It can be achieved by preventing the exposures which lead to sensitisation and asthma. When an allergenic agent can be removed from a workplace, be substituted with a safe alternative, or be completely enclosed so that inhalation exposure does not occur, then rates of occupational asthma from that allergen in that setting should fall by 100%. This has been the observation when natural rubber latex (NRL) gloves are replaced in healthcare settings with non-NRL gloves, and also when enzymes in a workplace are encapsulated as part of a controlled programme. Even when exposure is markedly reduced, such as use of NRL gloves which have a low protein content and are powder-free, NRL occupational asthma rates fall to close to zero. Similarly estimates …

Impact of ambient air pollution on birth weight in Sydney, Australia.

Abstract: Background: Studies in Asia, Europe, and the Americas have provided evidence that ambient air pollution may have an adverse effect on birth weight, although results are not consistent. Methods: Average exposure during pregnancy to five common air pollutants was estimated for births in metropolitan Sydney between 1998 and 2000. The effects of pollutant exposure in the first, second, and third trimesters of pregnancy on risk of "small for gestational age" (SGA), and of pollutant exposure during pregnancy on birth weight were examined. Results: There were 138 056 singleton births in Sydney between 1998 and 2000; 9.7% of babies (13 402) were classified as SGA. Air pollution levels in Sydney were found to be quite low. In linear regression models carbon monoxide and nitrogen dioxide concentrations in the second and third trimesters had a statistically significant adverse effect on birth weight. For a 1 part per million increase in mean carbon monoxide levels a reduction of 7 (95% CI –5 to 19) to 29 (95% CI 7 to 51) grams in birth weight was estimated. For a 1 part per billion increase in mean nitrogen dioxide levels a reduction of 1 (95% CI 0 to 2) to 34 (95% CI 24 to 43) grams in birth weight was estimated. Particulate matter (diameter less than ten microns) in the second trimester had a small statistically significant adverse effect on birth weight. For a 1 microgram per cubic metre increase in mean particulate matter levels a reduction of 4 grams (95% CI 3 to 6) in birth weight was estimated. Conclusion: These findings of an association between carbon monoxide, nitrogen dioxide, and particulate matter, and reduction in birth weight should be corroborated by further study.

A randomised controlled trial of postural interventions for prevention of musculoskeletal symptoms among computer users

Abstract: Aims: To examine the effect of two workstation and postural interventions on the incidence of musculoskeletal symptoms among computer users. Methods: Randomised controlled trial of two distinct workstation and postural interventions (an alternate intervention and a conventional intervention) among 376 persons using computer keyboards for more than 15 hours per week. The incidence of neck/shoulder symptoms and hand/arm symptoms during six months of follow up among individuals in the intervention groups was compared to the incidence in computer users who did not receive an intervention (comparison group). For individuals in the intervention groups, study staff adjusted workstations, where possible, and trained individuals to assume the intervention postures. Individuals reported musculoskeletal symptoms in a weekly diary. Participants who reported discomfort intensity of 6 or greater on a 0–10 visual analogue scale or who reported musculoskeletal symptoms requiring use of analgesic medication were considered symptomatic. Results: There were no significant differences in the incidence of musculoskeletal symptoms among the three intervention groups. Twenty two (18.5%) participants in the alternate intervention group, 25 (20.2%) in the conventional intervention group, and 25 (21.7%) in the comparison group developed incident arm or hand symptoms. Thirty eight (33.3%) participants in the alternate intervention group, 36 (31.0%) in the conventional intervention group, and 33 (30.3%) in the comparison group developed incident neck or shoulder symptoms. Compliance with all components of the intervention was attained for only 25–38% of individuals, due mainly to the inflexibility of workstation configurations. Conclusions: This study provides evidence that two specific workplace postural interventions are unlikely to reduce the risk of upper extremity musculoskeletal symptoms among computer users.

Serum DDT, age at menarche, and abnormal menstrual cycle length

Abstract: Background: Although dichlorodiphenyl trichloroethane (DDT) exposure is known to affect human endocrine function, few previous studies have investigated the effects of DDT exposure on age at menarche or menstrual cycle length. Methods: A cross sectional study was conducted to study the effects of DDT exposure on age at menarche and menstrual cycle length among 466 newly married, nulliparous female Chinese textile workers aged 20–34 years enrolled between 1996 and 1998. Serum was analysed for DDT and its major metabolites. Multivariate linear regression was used to estimate DDT exposure effects on age at menarche and multivariate logistic regression was used to estimate DDT exposure effects on odds of experiencing short or long cycles. Results: Relative to those in the lowest DDT quartile, the adjusted mean age at menarche was younger in those in the fourth quartile (–1.11 years). Modeled as a continuous variable, a 10 ng/g increase in serum DDT concentration was associated with an adjusted reduction in age at menarche of 0.20 years. Relative to those in the lowest DDT quartile, odds of any short cycle ( 40 days). Conclusion: Results suggest that DDT exposure was associated with earlier age at menarche and increased risk of experiencing a shortened menstrual cycle.

Incidence by occupation and industry of acute work related respiratory diseases in the UK, 1992-2001.

Abstract: Aims: To summarise incidence rates and epidemiological characteristics of new cases of work related respiratory disease reported by specialist physicians in thoracic and occupational medicine, with particular reference to occupation, industry, and causal agents for asthma, inhalation accidents, and allergic alveolitis. Methods: Cases reported 1992–2001 to the SWORD and OPRA national surveillance schemes, in which almost all UK chest and occupational physicians participate, were analysed by age, sex, cause, occupation, and industry, with incidence rates calculated against appropriate denominators. Results: Excluding diseases of long latency, infrequently seen by occupational physicians, the distribution of diagnoses in the two specialties was similar, but with rates generally much higher in occupational than chest physicians. Occupational asthma was responsible for about 25% of cases overall, affecting mainly craft related occupations and machinists, and most often attributed to isocyanates, metals, grains, wood dusts, solders, and welding fume. These same occupations were those at highest risk from inhalation injuries, most frequently caused by irritant gases, vapours, and fume. Among medical technicians and nurses, however, glutaraldehyde and latex were the main causes of occupational asthma. Allergic alveolitis was seldom reported, with almost all cases in agriculture, forestry, and fishing. Conclusion: During the 10 year period studied, there were few changes in level of reported incidence, apart from some decline in occupational asthma and inhalation injuries. These results and their implications should be distinguished from much higher estimates of asthma made worse by work derived from population surveys, based on prevalence rather than incidence, and self-reported symptoms rather than diagnoses made by specialist physicians. Even so, the reported incidence of new cases of acute respiratory illness caused by work remains substantial.

Primary osteoarthritis of hip, knee, and hand in relation to occupational exposure

Abstract: Aim: To identify occupations with excess prevalence of osteoarthritis of the knee, hip, and hand in a nationwide survey and to compare occupations with and without excess prevalence with regard to biomechanical stresses and severity of osteoarthritis. Methods: Patients presenting with osteoarthritis of the knee, hip, or hand were recruited throughout France by their treating physician who collected information on history, including age at onset, occupation, and occupational stresses to joints. Severity was assessed using joint specific functional status questionnaires: Lequesne for the hip and knee and Dreiser for the hand. The distribution of osteoarthritis patients by occupation was compared with the distribution of occupations in all workers in France to obtain prevalence rate ratios. Results: Occupations with the greatest prevalence rate ratio were female cleaners (6.2; 95% CI 4.6 to 8.0), women in the clothing industry (5.0; 95% CI 3.9 to 6.3), male masons and other construction workers (2.9; 95% CI 2.6 to 3.3), and agriculture male and female workers (2.8; 95% CI 2.5 to 3.2). A twofold greater prevalence rate was observed within certain occupations between self-employed and salaried workers. Early onset of osteoarthritis was seen in the more heavy labour jobs with almost 40% of patients reporting their first symptoms before the age of 50. Conclusion: The early onset and severity of osteoarthritis in certain occupations warrants an urgent need for occupation specific studies for the development and evaluation of preventive strategies in this leading cause of disability in Western countries.

Atrazine in municipal drinking water and risk of low birth weight, preterm delivery, and small-for-gestational-age status

Abstract: Background: Atrazine is a herbicide used extensively worldwide. Bioassays have shown that it is embryotoxic and embryolethal. Evidence of adverse reproductive outcomes from exposure in the general population is sparse. Aims: To evaluate the association between atrazine levels in municipal drinking water and the following adverse reproductive outcomes: increased risk of preterm delivery, low birth weight (LBW), and small-for-gestational-age (SGA) status. Methods: A total of 3510 births that took place from 1 October 1997, to 30 September 1998 were analysed. Atrazine measurements were available for 2661 samples from water treatment plants over the past decade. A seasonal pattern was identified, with atrazine peaking from May to September. The geometric mean of the atrazine level for this period was calculated for each water distribution unit and merged with the individual data by municipality of residence. Results: Atrazine levels in water were not associated with an increased risk of LBW or SGA status and were slightly associated with prematurity. There was an increased risk of SGA status in cases in which the third trimester overlapped in whole or in part with the May–September period, compared with those in which the third trimester occurred totally from October to April (OR = 1.37, 95% CI 1.04 to 1.81). If the entire third trimester took place from May to September, the OR was 1.54 (95% CI 1.11 to 2.13). Conclusions: Low levels of atrazine, a narrow exposure range, and limitations in the exposure assessment partly explain the lack of associations with atrazine. Findings point to the third trimester of pregnancy as the potential vulnerable period for an increased risk of SGA birth. Exposures other than atrazine and also seasonal factors may explain the increased risk.

Air samples versus biomarkers for epidemiology

Abstract: Background: It has been speculated on theoretical grounds that biomarkers are superior surrogates for chemical exposures to air samples in epidemiology studies. Methods and Results: Biomarkers were classified according to their position in the exposure-disease continuum—that is, parent compound, reactive intermediate, stable metabolite, macromolecular adduct, or measure of cellular damage. Because airborne exposures and these different biomarkers are time series that vary within and between persons in a population, they are all prone to measurement error effects when used as surrogates for true chemical exposures. It was shown that the attenuation bias in the estimated slope characterising a log exposure-log disease relation should decrease as the within- to between-person variance ratio of a given set of air or biomarker measurements decreases. To gauge the magnitudes of these variance ratios, a database of 12 077 repeated observations was constructed from 127 datasets, including air and biological measurements from either occupational or environmental settings. The within- and between-person variance components (in log scale, after controlling for fixed effects of time) and the corresponding variance ratios for each set of air and biomarker measurements were estimated. It was shown that estimated variance ratios of biomarkers decreased in the order short term (residence time (2 days) . intermediate term (2 days , residence time (2 months) . long term biomarkers (residence time .2 months). Overall, biomarkers had smaller variance ratios than air measurements, particularly in environmental settings. This suggests that a typical biomarker would provide a less biasing surrogate for exposure than would a typical air measurement. Conclusion: Epidemiologists are encouraged to consider the magnitudes of variance ratios, along with other factors related to practicality and cost, in choosing among candidate surrogate measures of exposure.