Showing papers in "International Journal of Epidemiology in 2003"

‘Mendelian randomization’: can genetic epidemiology contribute to understanding environmental determinants of disease?

Abstract: Associations between modifiable exposures and disease seen in observational epidemiology are sometimes confounded and thus misleading, despite our best efforts to improve the design and analysis of studies. Mendelian randomization-the random assortment of genes from parents to offspring that occurs during gamete formation and conception-provides one method for assessing the causal nature of some environmental exposures. The association between a disease and a polymorphism that mimics the biological link between a proposed exposure and disease is not generally susceptible to the reverse causation or confounding that may distort interpretations of conventional observational studies. Several examples where the phenotypic effects of polymorphisms are well documented provide encouraging evidence of the explanatory power of Mendelian randomization and are described. The limitations of the approach include confounding by polymorphisms in linkage disequilibrium with the polymorphism under study, that polymorphisms may have several phenotypic effects associated with disease, the lack of suitable polymorphisms for studying modifiable exposures of interest, and canalization-the buffering of the effects of genetic variation during development. Nevertheless, Mendelian randomization provides new opportunities to test causality and demonstrates how investment in the human genome project may contribute to understanding and preventing the adverse effects on human health of modifiable exposures.

Widening socioeconomic inequalities in mortality in six Western European countries

Abstract: OBJECTIVES: During the past decades a widening of the relative gap in death rates between upper and lower socioeconomic groups has been reported for several European countries. Although differential mortality decline for cardiovascular diseases has been suggested as an important contributory factor, it is not known what its quantitative contribution was, and to what extent other causes of death have contributed to the widening gap in total mortality. METHODS: We collected data on mortality by educational level and occupational class among men and women from national longitudinal studies in Finland, Sweden, Norway, Denmark, England/Wales, and Italy (Turin), and analysed age-standardized death rates in two recent time periods (1981-1985 and 1991-1995), both total mortality and by cause of death. For simplicity, we report on inequalities in mortality between two broad socioeconomic groups (high and low educational level, non-manual and manual occupations). RESULTS: Relative inequalities in total mortality have increased in all six countries, but absolute differences in total mortality were fairly stable, with the exception of Finland where an increase occurred. In most countries, mortality from cardiovascular diseases declined proportionally faster in the upper socioeconomic groups. The exception is Italy (Turin) where the reverse occurred. In all countries with the exception of Italy (Turin), changes in cardiovascular disease mortality contributed about half of the widening relative gap for total mortality. Other causes also made important contributions to the widening gap in total mortality. For these causes, widening inequalities were sometimes due to increasing mortality rates in the lower socioeconomic groups. We found rising rates of mortality from lung cancer, breast cancer, respiratory disease, gastrointestinal disease, and injuries among men and/or women in lower socioeconomic groups in several countries. CONCLUSIONS: Reducing socioeconomic inequalities in mortality in Western Europe critically depends upon speeding up mortality declines from cardiovascular diseases in lower socioeconomic groups, and countering mortality increases from several other causes of death in lower socioeconomic groups.

Genders, sexes, and health: what are the connections—and why does it matter?

Abstract: Open up any biomedical or public health journal prior to the 1970s, and one term will be glaringly absent: gender. Open up any recent biomedical or public health journal, and two terms will be used either: (1) interchangeably, or (2) as distinct constructs: gender and sex. Why the change? Why the confusion?-and why does it matter? After briefly reviewing conceptual debates leading to distinctions between 'sex' and 'gender' as biological and social constructs, respectively, the paper draws on ecosocial theory to present 12 case examples in which gender relations and sex-linked biology are singly, neither, or both relevant as independent or synergistic determinants of the selected outcomes. Spanning from birth defects to mortality, these outcomes include: chromosomal disorders, infectious and non-infectious disease, occupational and environmental disease, trauma, pregnancy, menopause, and access to health services. As these examples highlight, not only can gender relations influence expression-and interpretation-of biological traits, but also sex-linked biological characteristics can, in some cases, contribute to or amplify gender differentials in health. Because our science will only be as clear and error-free as our thinking, greater precision about whether and when gender relations, sex-linked biology, both, or neither matter for health is warranted.

The World Health Organization Global Database on Child Growth and Malnutrition: methodology and applications

Abstract: Background: For decades nutritional surveys have been conducted using various definitions indicators and reference populations to classify child malnutrition. The World Health Organization (WHO) Global Database on Child Growth and Malnutrition was initiated in 1986 with the objective to collect standardize and disseminate child anthropometric data using a standard format. Methods: The database includes population-based surveys that fulfil a set of criteria. Data are checked for validity and consistency and raw data sets are analysed following a standard procedure to obtain comparable results. Prevalences of wasting stunting under- and overweight in preschool children are presented using z-scores based on the National Center for Health Statistics (NCHS)/WHO international reference population. New surveys are included on a continuous basis and updates are published bimonthly on the database’s web site. Results: To date the database contains child anthropometric information derived from 846 surveys. With 412 national surveys from 138 countries and 434 sub-national surveys from 155 countries the database covers 99% and 64% of the under 5 year olds in developing and developed countries respectively. This wealth of information enables international comparison of nutritional data helps identifying populations in need evaluating nutritional and other public health interventions monitoring trends in child growth and raising political awareness of nutritional problems. Conclusions: The 15 years experience of the database can be regarded as a success story of international collaboration in standardizing child growth data. We recommend this model for monitoring other nutritional health conditions that as yet lack comparable data. (authors)

Distribution and determinants of sedentary lifestyles in the European Union

Abstract: Background Many studies have shown the health burden of a sedentary lifestyle. The main goal of this study was to determine the prevalence of sedentary lifestyles in the 15 Member States of the European Union (EU) and to identify the main correlates of a sedentary lifestyle. Methods Nationally representative samples (n approximately 1000 subjects in each country; >15 years) completed a questionnaire concerning attitudes to physical activity, body weight, and health; in total 15 239 subjects. Sedentary people were defined in two ways: (1) those expending less than 10% of their leisure time expenditure in activities involving >/=4 metabolic equivalents (MET). (2) Those who did not practice any leisure-time physical activity and who also were above the median in the number of hours spent sitting down during leisure time. Logistic regression models were fitted to analyse the association between sedentary lifestyles and gender, age, body mass index (BMI), educational level, weight change in the last 6 months, and marital and smoking status. Results Percentages of sedentary lifestyles across European countries ranged between 43.3% (Sweden) and 87.8% (Portugal) according to the first definition. According to both definitions, a lower prevalence of sedentary lifestyle was found in Northern countries (especially Scandinavian countries) as compared with Mediterranean countries, whereas the prevalence was higher among older, obese, less educated, widowed/divorced individuals, and current smokers. Similar relative differences between countries and socio-demographic groups were found independently of the method used to define a sedentary lifestyle. Conclusion Prevalence of sedentary lifestyle in the EU is high, especially among inhabitants of some Mediterranean countries, obese subjects, less-educated people, and current smokers. This high prevalence involves important public health burdens and preventive strategies are urgently needed.

Neighbourhood deprivation and health: does it affect us all equally?

Abstract: Background Neighbourhood socioeconomic status (SES) may affect rich and poor residents differentially. Two models are proposed. Model 1: living in a non-deprived neighbourhood is better for health because better collective material and social resources are available. Model 2: being poor (rich) relative to the neighbourhood average is associated with worse (better) health because of the discrepancy between an individual's situation and those around them. Methods Individual data from the Whitehall II study covering health, SES, and perceived status were linked to census data on neighbourhood deprivation. Results Both individual and neighbourhood deprivation increased the risk of poor general and mental health. There was a suggestion that the effect of living in a deprived area was more marked for poorer individuals, although interactions were not statistically significant. Poor people in poor neighbourhoods reported more financial and neighbourhood problems and rated themselves lowest on the ladder of society. Conclusions We found no evidence that personal poverty combined with affluent neighbourhood had negative health consequences. Rather, living in a deprived neighbourhood may have the most negative health effects on poorer individuals, possibly because they are more dependent on collective resources in the neighbourhood.

Suicide by intentional ingestion of pesticides: a continuing tragedy in developing countries

Abstract: Deliberate self-poisoning has become an increasingly common response to emotional distress in young adults,1 and it is now one of the most frequent reasons for emergency hospital admission.2 In industrialised countries, the drugs people commonly take in overdose - analgesics, tranquillisers, antidepressants3- are relatively non-toxic. The estimated case fatality for overdose in England, for example, is around 0.5%.4 Most individuals who self-harm do not intend to die. Studies carried out in industrialised countries have found that only 2% go on to commit suicide in the subsequent 12 months.5 In developing countries the situation is quite different.6 The substances most commonly used for self-poisoning are agricultural pesticides.6,7,8,9,10,11 Overall case fatality ranges from 10% - 20%.12 For this reason, deaths from pesticide poisoning make a major contribution to patterns of suicide in developing nations, particularly in rural areas.6 In rural China, for example, pesticides account for over 60% of suicides.8 Similarly high proportions of suicides are due to pesticides in rural areas of Sri Lanka (71%),13 Trinidad (68%),14 and Malaysia (>90%).10 There is, however, no evidence that levels of suicidal intent associated with pesticide ingestion in these countries are any higher than those associated with drug overdose in industrialised countries, where the drugs taken in overdose are less toxic.

A comparison of a food frequency questionnaire with a 24-hour recall for use in an epidemiological cohort study: results from the biomarker-based Observing Protein and Energy Nutrition (OPEN) study

Abstract: Background Most large cohort studies have used a food frequency questionnaire (FFQ) for assessing dietary intake. Several biomarker studies, however, have cast doubt on whether the FFQ has sufficient precision to allow detection of moderate but important diet-disease associations. We use data from the Observing Protein and Energy Nutrition (OPEN) study to compare the performance of a FFQ with that of a 24-hour recall (24HR). Methods The OPEN study included 484 healthy volunteer participants (261 men, 223 women) from Montgomery County, Maryland, aged 40-69. Each participant was asked to complete a FFQ and 24HR on two occasions 3 months apart, and a doubly labelled water (DLW) assessment and two 24-hour urine collections during the 2 weeks after the first FFQ and 24HR assessment. For both the FFQ and 24HR and for both men and women, we calculated attenuation factors for absolute energy, absolute protein, and protein density. Results For absolute energy and protein, a single FFQ's attenuation factor is 0.04-0.16. Repeat administrations lead to little improvement (0.08-0.19). Attenuation factors for a single 24HR are 0.10-0.20, but four repeats would yield attenuations of 0.20-0.37. For protein density a single FFQ has an attenuation of 0.3-0.4; for a single 24HR the attenuation factor is 0.15-0.25 but would increase to 0.35-0.50 with four repeats. Conclusions Because of severe attenuation, the FFQ cannot be recommended as an instrument for evaluating relations between absolute intake of energy or protein and disease. Although this attenuation is lessened in analyses of energy-adjusted protein, it remains substantial for both FFQ and multiple 24HR. The utility of either of these instruments for detecting important but moderate relative risks (between 1.5 and 2.0), even for energy-adjusted dietary factors, is questionable.

Cholesterol, coronary heart disease, and stroke in the Asia Pacific region.

Abstract: Background Cholesterol levels in many Asian countries are rising. Predictions of the likely effects of this on the incidence of cardiovascular diseases have mostly relied on data from Western populations. Whether the associations between total cholesterol and cardiovascular diseases are similar in Asia is not established.Methods The Asia Pacific Cohort Studies Collaboration (APCSC) is an individual-participant data meta-analysis of prospective studies from the Asia-Pacific region. Cox models were applied to the combined data from 29 cohorts to estimate the region-, sex-, and age-specific hazard ratios of major cardiovascular diseases by the fifths of total cholesterol.Results At baseline, the age/sex-adjusted mean value of total cholesterol was higher in Australia and New Zealand (ANZ) (5.52+/-1.05 mmol/l) than in Asia (4.87+/-1.05 mmol/l). During 2 million person-years of follow-up among 352 033 individuals, 4841 cardiovascular deaths were recorded. The association of total cholesterol with coronary heart disease and stroke was similar in Asian and ANZ cohorts. Overall, each 1-mmol/l higher level of total cholesterol was associated with 35% (95% CI: 26-44%) increased risk of coronary death, 25% (95% CI: 13-40%) increased risk of fatal or non-fatal ischaemic stroke, and 20% (95% CI: 8-30%) decreased risk of fatal haemorrhagic stroke.Conclusions In both Asian and non-Asian populations in the Asia-Pacific region, total cholesterol is similarly strongly associated with the risk of CHD and ischaemic, but not haemorrhagic, stroke. Rising population-wide levels of cholesterol would be expected to contribute to a substantial increase in the overall burden of cardiovascular diseases in this region.

Association of the metabolic syndrome with both vigorous and moderate physical activity

Abstract: Results The odds ratios (95% CI) for having the metabolic syndrome in the top categories of vigorous and moderate activity were 0.52 (95% CI: 0.40, 0.67) and 0.78 (95% CI: 0.63, 0.96) respectively, adjusted for age, sex, smoking, alcohol intake, socioeconomic status, and other activity. Adjustment for BMI and resting HR substantially attenuated both of the above associations. Conclusions Moderate and vigorous physical leisure-time activity are each associated with reduced risk of being classified with MS independently of age, smoking, and high alcohol intake. Both vigorous and moderate activities may be beneficial to the MS cluster of risk factors among middle-aged populations. Reduced BMI and increased cardiovascular fitness may be important mediators of this association for both intensities of activity.

Determinants of aflatoxin exposure in young children from Benin and Togo, West Africa: the critical role of weaning

Abstract: Background: Dietary exposure to high levels of the fungal toxin aflatoxin occurs in West Africa where long-term crop storage facilitates fungal growth. Methods: We conducted a cross-sectional study in Benin and Togo to investigate aflatoxin exposure in children around the time of weaning and correlated these data with food consumption socioeconomic status agro-ecological zone of residence and anthropometric measures. Blood samples from 479 children (age 9 months to 5 years) from 16 villages in four agro-ecological zones were assayed for aflatoxinalbumin adducts (AF-alb) as a measure of recent past (2–3 months) exposure. Results: Aflatoxin-albumin adducts were detected in 475/479 (99%) children (geometric mean 32.8 pg/mg 95% CI: 25.3–42.5). Adduct levels varied markedly across agro-ecological zones with mean levels being approximately four times higher in the central than in the northern region. The AF-alb level increased with age up to 3 years and within the 1–3 year age group was significantly (P = 0.0001) related to weaning status; weaned children had approximately twofold higher mean AF-alb adduct levels (38 pg AF-lysine equivalents per mg of albumin [pg/mg]) than those receiving a mixture of breast milk and solid foods after adjustment for age sex agro-ecological zone and socioeconomic status. A higher frequency of maize consumption but not groundnut consumption by the child in the preceding week was correlated with higher AF-alb adduct level. We previously reported that the prevalence of stunted growth (height for age Z-score HAZ) and being underweight (weight for age Z-score WAZ) were 33% and 29% respectively by World Health Organziation criteria. Children in these two categories had 30–40% higher mean AF-alb levels than the remainder of the children and strong dose– response relationships were observed between AF-alb levels and the extent of stunting and being underweight. Conclusions: Exposure to this common toxic contaminant of West African food increases markedly following weaning and exposure early in life is associated with reduced growth. These observations reinforce the need for aflatoxin exposure intervention strategies within high-risk countries possibly targeted specifically at foods used in the post-weaning period. (authors)

Morbidity profile and its relationship with disability and psychological distress among elderly people in Northern India

Abstract: Background Morbidity among elderly people has an important influence on their physical functioning and psychological well-being. Evaluation of the morbidity profile and its determinants, which have implications for elderly people, are not available. The objective of this study is to assess morbidity, co-morbidity, and patterns of treatment seeking, and to determine relationship of morbidity with disability, psychological distress, and socio-demographic variables among the elderly population in northern India. Methods A cross-sectional survey of 200 subjects over 60 years old (100 each from the urban population of Chandigarh City and the rural population of Haryana State of India) was carried out using a cluster sampling technique. The study period was July 1999‐April 2000. Various socio-demographic characteristics were recorded at baseline. A clinical diagnosis was made by a physician based on reported illness, clinical examination, and cross-checking of medical records and medications held by the subjects. Psychological distress and disability was assessed using the PGI-Health Questionnaire-N-1 and the Rapid Disability Rating Scale-2, respectively. ANOVA, Kruskal‐Wallis H test, correlation coefficient, and multivariate analysis were used to assess the relationship and association of morbidity with other variables. Results Of the total sample, 88.9% reported illness based on their perception, and of these 43.5% were seeking treatment and actually taking medicines, and 42.5% were diagnosed as having 4‐6 morbidities. The mean number of morbidities among elderly people was 6.1 (SD 2.9). A total of 87.5% had minimal to severe disabilities and 66% of elderly people were distressed physically, psychologically, or both. The most prevalent morbidity was anaemia, followed by dental problems, hypertension, chronic obstructive airway disease (COAD), cataract, and osteoarthritis. Morbidities like asthma, COAD, hypertension, osteoarthritis, gastrointestinal disorders, anaemia, and eye and neurological problems were significantly associated with disability and distress. Higher number of morbidities was associated with greater disability and distress. In univariate analysis, socio-demographic variables like age, locality, caste, education, occupation, and income were important determinants of morbidity. Multivariate analysis was undertaken to find out the independent relationship of socio-demographic variables with morbidity. Morbidity was significantly associated with age (b value 0.06, 95% CI: 0.01, 0.12), sex (b value 1.03, 95% CI: 0.02, 2.05), and occupation (b value 0.20, 95% CI: 0.07, 0.33). Conclusions A high mean number of morbidities (6.1, SD 2.9) was observed. Elderly subjects with higher morbidity had increasing disability and distress. Age, sex, and occupation were important determinants of morbidity. Assessment of the morbidity profile and its determinants will help in the application of interventions, both

Relationship between body mass and gastro-oesophageal reflux symptoms: The Bristol Helicobacter Project

Abstract: Main Relationship between overweight (body mass index [BMI] � 25 kg/m 2 and outcome � 30 kg/m 2 ) or obesity (BMI � 30 kg/m 2 ) and frequency and severity of heartburn measure and acid regurgitation. Results Body mass index was strongly positively related to the frequency of symptoms of gastro-oesophageal reflux. The adjusted odds ratios (OR) for frequency of heartburn and acid regurgitation occurring at least once a week in overweight participants compared with those of normal weight were 1.82 (95% CI: 1.33‐2.50) and 1.50 (95% CI: 1.13‐1.99) respectively. Corresponding OR (95% CI) relating to obese patients were 2.91 (95% CI: 2.07‐4.08) and 2.23 (95% CI: 1.44‐3.45) respectively. The OR for moderate to severe reflux symptoms were raised in overweight and obese subjects but not to the same extent as frequency of symptoms and only the relationship between obesity and severity of heartburn reached conventional statistical significance: OR = 1.19; 95% CI: 1.07‐1.33.

The detection of gene–environment interaction for continuous traits: should we deal with measurement error by bigger studies or better measurement?

Abstract: Background The search for biologically relevant gene-environment interactions has been facilitated by technological advances in genotyping. The design of studies to detect interactions on continuous traits such as blood pressure and insulin sensitivity is attracting increasing attention. We have previously described power calculations for such studies, and this paper describes the extension of those calculations to take account of measurement error. Methods The model considered in this paper is a simple linear regression relating a continuous outcome to a continuously distributed exposure variable in which the ratio of slopes for each genotype is considered as the interaction parameter. The classical measurement error model is used to describe the uncertainty in measurement in the outcome and the exposure. The sample size to detect differing magnitudes of interaction with varying frequencies of the minor allele are calculated for a given main effect observed with error both in the exposure and the outcome. The sample size to detect a given interaction for a given minor allele frequency is calculated for differing degrees of measurement error in the assessment of the exposure and the outcome. Results The required sample size is dependent upon the magnitude of the interaction, the allele frequency and the strength of the association in those with the common allele. As an example, we take the situation in which the effect size in those with the common allele was a quarter of a standard deviation change in the outcome for a standard deviation change in the exposure. If a minor allele with a frequency of 20% leads to a doubling of that effect size, then the sample size is highly dependent upon the precision with which the exposure and outcome are measured. rho(Tx) and rho(Ty) are the correlation between the measured exposure and outcome, respectively and the true value. If poor measures of the exposure and outcome are used, (e.g. rho(Tx) = 0.3, rho(Ty) = 0.4), then a study size of 150 989 people would be required to detect the interaction with 95% power at a significance level of 10(-4). Such an interaction could be detected in study samples of under 10 000 people if more precise measurements of exposure and outcome were made (e.g. rho(Tx) = 0.7, rho(Ty) = 0.7), and possibly in samples of under 5000 if the precision of estimation were enhanced by taking repeated measurements. Conclusions The formulae for calculating the sample size required to study the interaction between a continuous exposure and a genetic factor on a continuous outcome variable in the face of measurement error will be of considerable utility in designing studies with appropriate power. These calculations suggest that smaller studies with repeated and more precise measurement of the exposure and outcome will be as powerful as studies even 20 times bigger, which necessarily employ less precise measures because of their size. Even though the cost of genotyping is falling, the magnitude of the effect of measurement error on the power to detect interaction on continuous traits suggests that investment in studies with better measurement may be a more appropriate strategy than attempting to deal with error by increasing sample sizes.

Indoor air pollution from biomass combustion and acute respiratory illness in preschool age children in Zimbabwe

Abstract: Background Reliance on biomass for cooking and heating exposes many women and young children in developing countries to high levels of air pollution indoors. This study investigated the association between household use of biomass fuels for cooking and acute respiratory infections (ARI) in preschool age children (� 5 years) in Zimbabwe. Methods Analysis is based on 3559 children age 0‐59 months included in the 1999 Zimbabwe Demographic and Health Survey (ZDHS). Children who suffered from cough accompanied by short, rapid breathing during the 2 weeks preceding the survey were defined as having suffered from ARI. Logistic regression was used to estimate the odds of suffering from ARI among children from households using biomass fuels (wood, dung, or straw) relative to children from households using cleaner fuels (liquid petroleum gas [LPG]/natural gas, or electricity), after controlling for potentially confounding factors. Results About two-thirds (66%) of children lived in households using biomass fuels and 16% suffered from ARI during the 2 weeks preceding the survey interview. After adjusting for child’s age, sex, birth order, nutritional status, mother’s age at childbirth, education, religion, household living standard, and region of residence, children in households using wood, dung, or straw for cooking were more than twice as likely to have suffered from ARI as children from households using LPG/natural gas or electricity (OR = 2.20; 95% CI: 1.16, 4.19). Conclusions Household use of high pollution biomass fuels is associated with ARI in children in Zimbabwe. The relationship needs to be further investigated using more direct measures of smoke exposure and clinical measures of ARI.

Socioeconomic differentials in the temperature–mortality relationship in São Paulo, Brazil

Abstract: Background: We investigated the impact of environmental temperature on mortality in Sao Paulo Brazil and examined differences in the temperature–mortality relationship with respect to cause age group and socioeconomic position (SEP). Methods: Generalized additive Poisson regression models adjusted for non-temperature related seasonal factors (including air pollution) were used to analyse daily mortality counts for selected causes from 1991 to 1994. Individuals were classified by the aggregate SEP of their area of residency. These were analysed as potential modifiers of the temperature–mortality relationship. Results: Among the elderly we observed a 2.6% increase in all-cause mortality per degree increase in temperature above 20°C and a 5.5% increase per degree drop in temperature below 20°C after adjustment for confounding. Relationships were similar in children but somewhat weaker in adults. Cold effects were present for deaths due to cardiovascular disease (CVD) respiratory and other causes with effects being greatest in the respiratory group. Heat effects were not found for CVD deaths in adults but otherwise varied little by cause of mortality. There was little evidence for a modification of the mortality effects of cold or heat by SEP. Conclusions: These findings show that the U-shaped pattern of the temperature–mortality relationship found in cooler northern countries occurs also in a sub-tropical city. In addition the relative effects of temperature were similar in each socioeconomic grouping. (authors)

Gender-related differences in the association between socioeconomic status and self-reported diabetes

Abstract: Background The prevalence of diabetes has been steadily increasing in Western countries. We investigated the impact of socioeconomic status (SES) on the prevalence of self-reported diabetes, and its differences between genders. Methods Data for this investigation were derived from the second cycle of the National Population Health Survey conducted in 1996-1997. A total of 39 021 subjects (17 730 males and 21 291 females) >/=40 years of age who answered the question about diabetes were included in the present analysis. Educational attainment and income adequacy were used as indicators of SES. Multiple logistic regression models were constructed for men and women separately to assess the effects of SES on the prevalence of diabetes after adjustment for age, area of residence, body mass index, and physical activity. Results and The prevalence of diabetes was 6.6% among men and 5.5% among women. The Conclusions prevalence increased with decreasing income category and educational attainment in both genders. The odds ratios for income and education in relation to diabetes after adjustment remained significant in women, but attained unity in men. Canadian women >/=40 years of age of low SES have a relatively high prevalence of diabetes, independent of age, area of residence, obesity, and physical inactivity.

Women’s perception of the benefits of mammography screening: population-based survey in four countries

Abstract: Misconceptions were widespread: a majority of women believed that screening prevents or reduces the risk of contracting breast cancer (68%), that screening at least halves breast cancer mortality (62%), and that 10 years of regular screening will prevent 10 or more breast cancer deaths per 1000 women (75%). In multivariate analysis higher number of correct answers was positively associated with higher educational status (odds ratio [OR] = 1.44, 95% CI: 1.25, 1.66) and negatively with having had a mammography in the last 2 years (OR = 0.86, 95% CI: 0.73, 1.01). Compared with US women (reference group) and Swiss women (OR = 0.98, 95% CI: 0.82, 1.18) respondents in Italy (OR = 0.61, 95% CI: 0.50, 0.74) and the UK (OR = 0.73, 95% CI: 0.60, 0.88) gave fewer correct answers. Conclusion In the US and three European countries a high proportion of women overestimated the benefits that can be expected from screening mammography. This finding raises doubts on informed consent procedures within breast cancer screening programmes.

Intake of animal products and stroke mortality in the Hiroshima/Nagasaki Life Span Study

Abstract: Results During the follow-up period, 1462 stroke deaths occurred. Four animal products comprising eggs, dairy products, fish, and broiled fish were independently associated with a decreased risk of stroke mortality; while beef/pork, chicken, ham/ sausage, and milk consumption were not associated with stroke death. A composite measure of eggs, dairy products, fish, and broiled fish intake was calculated, and the highest tertile was significantly inversely associated with total stroke mortality (Hazards Ratio [HR] = 0.80, 95% CI: 0.68, 0.93) compared with the lowest tertile. The protective effect of animal product intake on total stroke death was largely confined to intracerebral haemorrhage death; the RH of intracerebral haemorrhage death for the highest tertile of consumption was 0.72 (95% CI: 0.53‐0.98) compared with the lowest tertile; animal products intake was not related to cerebral infarction mortality (HR = 0.84; 95% CI: 0.67‐1.06). Conclusions Intake of animal products such as eggs, dairy products, and fish may be protective against intracerebral haemorrhage, but is not related to cerebral infarction mortality.

The evolving pattern of avoidable mortality in Russia

Abstract: BACKGROUND: Life expectancy at birth in Russia is over 12 years less than in western Europe. This study explores the possible role of medical care in explaining this gap by examining the evolving pattern of mortality amenable to timely and effective medical care in Russia compared with Estonia, Latvia, and Lithuania, and the UK. METHODS: Analysis of standardized death rates from causes amenable to health care (treatable) or inter-sectoral health policies (preventable) in all regions and decomposition of differences in life expectancy between Russia and the UK by age, sex, and cause of death for the period 1965-1999/2000. RESULTS: Death rates from treatable causes remained stable between the mid-1960s and mid-1980s in Russia and the Baltic republics while steadily falling in the UK to less than half the rate in Russia. In the 1990s, rates increased in the former Soviet republics, reaching a peak in 1994 but reversing again in Russia in 1998. Deaths from causes amenable to inter-sectoral health interventions were higher in the UK in 1965 than in the Soviet Union but subsequently fell steadily while they increased in the East. Between 1965 and 1999, the male life expectancy gap between Russia and the UK rose from 3.6 to 15.1 years (women: 1.6 and 7.4 years). Treatable causes became an increasingly important contributor to this gap, accounting for almost 3 years by the end of the 1990s in men and 2 years in women. In Russia, elimination of treatable causes of death would have increased life expectancy by 2.9 years in men in 1995/99 compared with 1.2 years in the UK (women: 3.3 and 1.8 years), suggesting that, were the outcomes of health care achieved in the UK to be obtained in Russia, life expectancy for men might improve by about 1.7 years and for women by about 1.5 years. CONCLUSIONS: Our findings suggest that the Soviet health care system has failed to match the achievements of the West over the past three decades, highlighting the need to establish a system that provides effective and equitable care for the Russian population.

Predicting the distribution of under-five deaths by cause in countries without adequate vital registration systems

Abstract: BACKGROUND: The absence of complete vital registration and atypical nature of the locations where epidemiological studies of cause of death in children are conducted make it difficult to know the true distribution of child deaths by cause in developing countries. A credible method is needed for generating valid estimates of this distribution for countries without adequate vital registration systems. METHODS: A systematic review was undertaken of all studies published since 1980 reporting under-5 mortality by cause. Causes of death were standardized across studies, and information was collected on the characteristics of each study and its population. A meta-regression model was used to relate these characteristics to the various proportional mortality outcomes, and predict the distribution in national populations of known characteristics. In all, 46 studies met the inclusion criteria. RESULTS: Proportional mortality outcomes were significantly associated with region, mortality level, and exposure to malaria; coverage of measles vaccination, safe delivery care, and safe water; study year, age of children under surveillance, and method used to establish definitive cause of death. In sub-Saharan Africa and in South Asia, the predicted distribution of deaths by cause was: pneumonia (23% and 23%), malaria (24% and <1%), diarrhoea (22% and 23%), 'neonatal and other' (29% and 52%), measles (2% and 1%). CONCLUSIONS: For countries without adequate vital registration, it is possible to estimate the proportional distribution of child deaths by cause by exploiting systematic associations between this distribution and the characteristics of the populations in which it has been studied, controlling for design features of the studies themselves.

Modelling hepatitis C virus incidence, prevalence and long-term sequelae in Australia, 2001

Abstract: Background To plan an appropriate public health response to the hepatitis C virus (HCV) epidemic requires that estimates of HCV incidence and prevalence, and projections of the long-term sequelae of infection, are as accurate as possible. In this paper, mathematical models are used to synthesize data on the epidemiology and natural history of HCV in Australia to estimate HCV incidence and prevalence in Australia to end 2001, and project future trends in the long-term sequelae of HCV infection. Methods Mathematical models of the HCV epidemic in Australia were developed based on estimates of the pattern of injecting drug use. Estimates of HCV infections due to injecting drug use were then adjusted to allow for HCV infections resulting from other transmission routes. Projections of the long-term sequelae of HCV infection were obtained by combining modelled HCV incidence with estimates of the progression rates to these outcomes. Results It was estimated that there were 210 000 (lower and upper limits of 157 000 and 252 000) people in Australia living with HCV antibodies at the end of 2001, with HCV incidence in 2001 estimated to be 16 000 (11 000‐19 000). It was estimated that 6500 (5000‐8000) people were living with HCV-related cirrhosis in 2001, that 175 (130‐210) people developed HCV-associated liver failure, and that there were 50 (40‐60) incident cases of HCV-related hepatocellular carcinoma (HCC). It was estimated that in 2001 22 500 quality adjusted life years were lost to chronic HCV infection, the majority (77%) in people with early (stage 0/1) liver disease. Discussion Model-based estimates were broadly consistent with other sources of information on the HCV epidemic in Australia. These models suggest that the prevalence of HCV-related cirrhosis and the incidence of HCV-related liver failure and HCC will more than triple in Australia by 2020.

Mobility and the spread of human immunodeficiency virus into rural areas of West Africa

Abstract: Background In eastern and southern Africa, the human immunodeficiency virus (HIV) epidemic appeared first in urban centres and then spread to rural areas. Its overall prevalence is lower in West Africa, with the highest levels still found in cities. Rural areas are also threatened, however, because of the population’s high mobility. We conducted a study in three different communities with contrasting infection levels to understand the epidemiology of HIV infection in rural West Africa. Method A comparative cross-sectional study using a standardized questionnaire and biological tests was conducted among samples in two rural communities of Senegal (Niakhar and Bandafassi, 866 and 952 adults, respectively) and a rural community of Guinea-Bissau (Caio, 1416 adults). We compared the distribution of population characteristics and analysed risk factors for HIV infection in Caio at the individual level. Results The level of HIV infection was very low in Niakhar (0.3%) and Bandafassi (0.0%), but 10.5% of the adults in Caio were infected, mostly with HIV type 2 (HIV-2). Mobility was very prevalent in all sites. Short-term mobility was found to be a risk factor for HIV infection among men in Caio (adjusted odds ratio (aOR) = 2.06; 95% CI: 1.06‐3.99). Women from Caio who reported casual sex in a city during the past 12 months were much more likely to be infected with HIV (aOR = 5.61 95% CI: 1.56‐20.15). Short-term mobility was associated with risk behaviours at all sites. Conclusions Mobility appears to be a key factor for HIV spread in rural areas of West Africa, because population movement enables the virus to disseminate and also because of the particularly risky behaviours of those who are mobile. More prevention efforts should be directed at migrants from rural areas who travel to cities with substantial levels of HIV infection.

Airborne infectious diseases during infancy and mortality in later life in southern Sweden, 1766–1894

Abstract: Background: The importance of early life conditions and current conditions for mortality in later life was assessed using historical data from four rural parishes in southern Sweden. Both demographic and economic data are valid. Methods: Longitudinal demographic and socioeconomic data for individuals and household socioeconomic data from parish registers were combined with local area data on food costs and disease load using a Cox regression framework to analyse the 55–80 year age group mortality (number of deaths = 1398). Results: In a previous paper, the disease load experienced during the birth year, measured as the infant mortality rate, was strongly associated with old-age mortality, particularly the outcome of airborne infectious diseases. In the present paper, this impact persisted after controlling for variations in food prices during pregnancy and the birth year, and the disease load on mothers during pregnancy. The impact on mortality in later life stems from both the short-term cycles and the long-term decline in infant mortality. An asymmetrical effect and strong threshold effects were found for the cycles. Years with very high infant mortality, dominated by smallpox and whooping cough, had a strong impact, while modest changes had almost no impact at all. The effects of the disease load during the year of birth were particularly strong for children born during the winter and summer. Children severely exposed to airborne infectious diseases during their birth year had a much higher risk of dying of airborne infectious diseases in their old age. Conclusions: This study suggests that exposure to airborne infectious diseases during the first year of life increases mortality at ages 55–80. (Less)

Food insecurity, food choices, and body mass index in adults: nutrition transition in Trinidad and Tobago

Abstract: Background: This study evaluated whether food insecurity and obesity were associated in a population sample in Trinidad. Methods: A sample was drawn of 15 clusters of households in north central Trinidad. Resident adults were enumerated. A questionnaire was administered including the short form Household Food Security Scale (HFSS). Heights and weights were measured. Analyses were adjusted for age sex and ethnic group. Results: Data were analysed for 531/631 (84%) of eligible respondents including 241 men and 290 women with a mean age of 47 (range 24–89) years. Overall 134 (25%) of subjects were classified as food insecure. Food insecurity was associated with lower household incomes and physical disability. Food insecure subjects were less likely to eat fruit (food insecure 40% food secure 55%; adjusted odds ratio [OR] = 0.60 95% CI: 0.36–0.99 P = 0.045) or green vegetables or salads (food insecure 28% food secure 51%; adjusted OR = 0.46 95% CI: 0.27–0.79 P = 0.005) on >/= 5–6 days per week. Body mass index (BMI) was available for 467 (74%) subjects of whom 41 (9%) had BMI<_20 kg/m2 157 (34%) had BMI 25–29 kg/m2 and 120 (26%) had BMI <30 kg/m2. Underweight (OR = 3.21 95% CI: 1.17–8.81) was associated with food insecurity but obesity was not (OR = 1.08 95% CI: 0.55–2.12). Conclusions: Food insecurity was frequent at all levels of BMI and was associated with lower consumption of fruit and vegetables. Food insecurity was associated with underweight but not with present obesity. (authors)

Education, income, and functional limitation transitions among American adults: contrasting onset and progression

Abstract: Background Although a robust association between socioeconomic status and health has been shown in past research, the processes that explain the connection are not well understood. This paper seeks to advance such understanding in two ways, first by attending to the distinction between onset of a functional health problem and its progression, and second by addressing whether and how education and income relate differently to the onset versus progression of functional health problems. Methods Data come from the Americans' Changing Lives survey (n = 3617). The baseline was conducted in 1986 and outcome status measured in 1994. Activity limitations are categorized into none, mild, moderate, severe. Onset is defined as having no limitation at origin and a limitation at outcome. Progression is defined as limitation of a particular severity at origin and improving, staying the same, or getting worse with respect to the severity. Multinomial regressions determine transition probabilities related to onset and progression. Results Those with higher income and education are less likely to experience an onset. Only income associates with progression. Those with the highest income are most likely to improve and least likely to get worse in comparison to those with the lowest income. Conclusions Education, being determined early in life and influencing psychosocial mechanisms throughout life, may have a greater impact on prevention of activity and functional disorders. Income's role may be both as a prevention factor and as a mechanism for management of health problems.

Hormonal factors and risk of lung cancer among women

Abstract: Background Gender differences in the histological distribution of lung carcinoma and a possibly greater susceptibility of women than men to tobacco carcinogens, suggest a possible influence of sex-specific hormones. This study examines endocrine factors and risk of lung cancer among women by smoking status and histology. Methods We used data of a case-control study on lung cancer conducted from 1990 to 1996 in Germany, including 811 histologically confirmed female cases and 912 female population controls. Information on various menstrual and reproductive factors, use of oral contraceptives (OC), hormone replacement therapy (HRT), and smoking was gathered through personal interviews using a structured questionnaire. Odds ratios (OR) and 95% CI adjusted for age, region, smoking, and education were calculated via logistic regression. Results A reduction in lung cancer risk was observed with the use of OC (OR = 0.69; 95% CI: 0.51-0.92), but no trend in risk with increasing duration of use, age at first use, or calendar year of first use was present. A history of HRT was associated with a reduced risk (OR = 0.83; 95% CI: 0.64-1.09), particularly after long duration (>/=7 years) (OR = 0.59; 95% CI: 0.37-0.93). No clear association was found with regard to age at menarche, length of menstrual cycle, number of live-births, and age at menopause. Overall results did not differ much by histological cell subtype. The reduction in lung cancer risk associated with the use of exogenous hormones was primarily seen among smoking women. Conclusions Our data provide evidence for a possible role of hormonal factors in the aetiology of lung cancer in women.

Estonia 1989–2000: enormous increase in mortality differences by education

Abstract: Social disruption and increasing inequalities in wealth can be considered main recent determinants; however, causal processes, shaped decades before recent reforms, also contribute to this widening ...