Showing papers in "European Journal of Epidemiology in 2007"

The Rotterdam Study: Objectives and design update

Abstract: The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

The INTERPHONE study: Design, epidemiological methods, and description of the study population

Abstract: The very rapid worldwide increase in mobile phone use in the last decade has generated considerable interest in the possible health effects of exposure to radio frequency (RF) fields. A multinational case-control study, INTERPHONE, was set-up to investigate whether mobile phone use increases the risk of cancer and, more specifically, whether the RF fields emitted by mobile phones are carcinogenic. The study focused on tumours arising in the tissues most exposed to RF fields from mobile phones: glioma, meningioma, acoustic neurinoma and parotid gland tumours. In addition to a detailed history of mobile phone use, information was collected on a number of known and potential risk factors for these tumours. The study was conducted in 13 countries. Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden, and the UK using a common core protocol. This paper describes the study design and methods and the main characteristics of the study population. INTERPHONE is the largest case-control study to date investigating risks related to mobile phone use and to other potential risk factors for the tumours of interest and includes 2,765 glioma, 2,425 meningioma, 1,121 acoustic neurinoma, 109 malignant parotid gland tumour cases and 7,658 controls. Particular attention was paid to estimating the amount and direction of potential recall and participation biases and their impact on the study results.

The Generation R Study Biobank: a resource for epidemiological studies in children and their parents

Abstract: The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health from fetal life until young adulthood. In total, 9,778 mothers were enrolled in the study. Prenatal and postnatal data collection is conducted by physical examinations, questionnaires, interviews, ultrasound examinations and biological samples. Major efforts have been conducted for collecting biological specimens including DNA, blood for phenotypes and urine samples. In this paper, the collection, processing and storage of these biological specimens are described. Together with detailed phenotype measurements, these biological specimens form a unique resource for epidemiological studies focused on environmental exposures, genetic determinants and their interactions in relation to growth, health and development from fetal life onwards.

Early-life and adult socioeconomic status and inflammatory risk markers in adulthood.

Abstract: Background: Associations between childhood and adult socioeconomic status (SES) and adult levels of inflammatory markers (C-reactive protein [CRP], fibrinogen, white blood cell count [WBC], and von Willebrand factor [vWF]) were examined in the Atherosclerosis Risk in Communities (ARIC) Study cohort. Methods: A total of 12,681 white and African-American participants provided information on SES (via education and social class) and place of residence in childhood and adulthood. Residences were linked to census data for neighborhood SES information. Multiple imputation was used to impute missing data. Hierarchical and linear regression were used to estimate the effects of SES and possible mediation by adult cardiovascular disease (CVD) risk factors. Findings: Low childhood social class and education were associated with elevated levels of CRP, fibrinogen, WBC, and vWF (increments of 17%, 2%, 4% and 3% for lowest versus highest education in childhood, respectively) among whites. Findings were less consistent among African-Americans. Adult SES was more strongly associated with inflammation than childhood SES. Individual-level SES measures were more consistently associated with inflammation than neighborhood-level measures. Fibrinogen and WBC showed the most consistent associations with SES; the largest changes in inflammation by SES were observed for CRP. Covariate adjustment strongly attenuated these associations. Mediation of the SES-inflammation associations by BMI, smoking and HDL cholesterol (HDL-C) are suggested by these data. Conclusion: Low individual- and neighborhood-level SES in childhood and adulthood are associated with modest increments in adult inflammatory burden. These associations may operate through the influence of low SES on traditional CVD risk factors, especially BMI, smoking and HDL-C.

Reliability and validity of self-reported physical activity in the Nord-Trøndelag Health Study (HUNT 2)

Abstract: Background To validate the physical activity (PA) questionnaire in Nord-Trondelag Health Study (HUNT 2).

Assessment of physical activity and energy expenditure in epidemiological research of chronic diseases.

Abstract: Physical inactivity has emerged as an important risk factor for a number of diseases, but the typically crude exposure assessments in epidemiological studies, with entailing variation in measurement accuracy, may be a source of heterogeneity contributing to inconsistent results among studies. Consequently, the choice of method for the assessment of physical activity in epidemiological studies is important. Good methods increase our chances of avoiding misclassification and may enhance our understanding of the association between physical activity and health. Since physical activity is also a potential confounder of other lifestyle-health relationships, good methods may enhance our ability to control for confounding. But despite a steadily increasing selection of methods to choose from, no method is suitable for every situation and every population. Although the questionnaire is the most widely used method in epidemiological studies, and laboratory methods are mainly used for validation purposes, improved technology may change our ways of assessing physical activity in the future. This paper describes different methods to measure physical activity and energy expenditure from the epidemiological perspective, and attempts to address the concepts related to the measurement of physical activity.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases.

Abstract: Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Sodium and potassium intake and risk of cardiovascular events and all-cause mortality : the Rotterdam Study

Abstract: Background Dietary electrolytes influence blood pressure, but their effect on clinical outcomes remains to be established. We examined sodium and potassium intake in relation to cardiovascular disease (CVD) and mortality in an unselected older population. Methods A case–cohort analysis was performed in the Rotterdam Study among subjects aged 55 years and over, who were followed for 5 years. Baseline urinary samples were analyzed for sodium and potassium in 795 subjects who died, 206 with an incident myocardial infarction and 181 subjects with an incident stroke, and in 1,448 randomly selected subjects. For potassium, dietary data were additionally obtained by food-frequency questionnaire for 78% of the cohort. Results There was no consistent association of urinary sodium, potassium, or sodium/potassium ratio with CVD and all-cause mortality over the range of intakes observed in this population. Dietary potassium estimated by food frequency questionnaire, however, was associated with a lower risk of all-cause mortality in subjects initially free of CVD and hypertension (RR = 0.71 per standard deviation increase; 95% confidence interval: 0.51–1.00). We observed a significant positive association between urinary sodium/potassium ratio and all-cause mortality, but only in overweight subjects who were initially free of CVD and hypertension (RR = 1.19 (1.02–1.39) per unit). Conclusion The effect of sodium and potassium intake on CVD morbidity and mortality in Western societies remains to be established.

Major decline of hepatitis C virus incidence rate over two decades in a cohort of drug users

Abstract: Injecting drug users (DU) are at high risk for hepatitis C virus (HCV) and HIV infections. To examine the prevalence and incidence of these infections over a 20-year period (1985-2005), the authors evaluated 1276 DU from the Amsterdam Cohort Studies who had been tested prospectively for HIV infection and retrospectively for HCV infection. To compare HCV and HIV incidences, a smooth trend was assumed for both curves over calendar time. Risk factors for HCV seroconversion were determined using Poisson regression. Among ever-injecting DU, the prevalence of HCV antibodies was 84.5% at study entry, and 30.9% were co-infected with HIV. Their yearly HCV incidence dropped from 27.5/100 person years (PY) in the 1980s to 2/100 PY in recent years. In multivariate analyses, ever-injecting DU who currently injected and borrowed needles were at increased risk of HCV seroconversion (incidence rate ratio 29.9, 95% CI 12.6, 70.9) compared to ever-injecting DU who did not currently inject. The risk of HCV seroconversion decreased over calendar time. The HCV incidence in ever-injecting DU was on average 4.4 times the HIV incidence, a pattern seen over the entire study period. The simultaneous decline of both HCV and HIV incidence probably results from reduced risk behavior at the population level.

New times, new needs; e-epidemiology.

Abstract: The successful and systematic collection of demographic and lifestyle data is central in the process of any epidemiological study. The traditionally used methods such as face-to-face and telephone interviews as well as paper-questionnaires are increasingly failing to produce good qualitative results within financially feasible limits. Tools that are better suited for the present dynamic populations are needed and the Internet presents a powerful alternative for the collection of data with several intrinsic features still unexplored.

Factors associated with mortality in a cohort of Australian prisoners.

Abstract: We examined factors associated with increased mortality in a cohort of 85,203 adults with a history of imprisonment in New South Wales, Australia, between 1988 and 2002. Information on death was collected through linkage to the Australian National Death Index. The influence of demographic and criminological factors on the standardised mortality ratio (SMR) for all-cause mortality, and deaths due to drug overdose and suicide was examined using negative binomial regression models. The number of deaths identified was 5,137 (4,714 men, 423 women, 303 in custody). The overall SMR was 3.7 (3.6-3.8) in men and 7.8 (7.1-8.5) in women. SMRs raised for deaths due to drug overdose (men: 12.8, women: 50.3) and suicide (men: 4.8, women: 12.2). The high SMR was associated with hospitalisation for mental illness, multiple imprisonments, and early stage of follow-up independently of causes of death. Being released from prison increased the SMRs for all-cause and drug-related mortality, but not suicide. For women, significant trends for decreasing risk with increasing age were noted. Minority groups, in particular men, had a lower risk of death than white people. In men a sex or drug offence was associated with a lower risk and a property or violence offence was related to higher mortality. Our results reinforce how disadvantaged prisoners are, measured by mortality as the most fundamental scale of human wellbeing. Certain demographic and imprisonment characteristics are indicators of high mortality among this population. The underlying causes of some of these characteristics such as mental illness or multiple imprisonments are potentially treatable and preventable. Prison health services need to develop interventions targeting high-risk groups to avoid this situation.

Using the European guidelines to evaluate the Norwegian Breast Cancer Screening Program

Abstract: This is an evaluation of selected process indicators achieved during the first 10 years of performance of the Norwegian Breast Cancer Screening Program (NBCSP). The indicators are compared with the recommended levels given in the European Guidelines. The program invites all female residents aged 50-69 years old to two-view mammography biennially. The attendance rate was 76.2%. The recall rates due to positive mammography were 4.6% and 2.6%, and the detection rates were 6.4 and 4.9 per 1,000 screens, in prevalent and subsequent screens, respectively. Mean tumor size was 14.7 mm for screening detected and 21.2 mm for interval cancers. Axillary lymph node metastases were present in 25.4% and 43.8%, respectively. Detection mode (screening detected or interval cancer) was shown to be an independent predictor for axillary lymph node metastases and high-grade (Grade 3) tumors. The NBCSP meets the recommendations given in the European Guidelines for most of the process indicators evaluated in this study. Based on the results, we anticipate a future mortality reduction from breast cancer in women invited to the NBCSP.

Weight change, weight cycling and mortality in the ERFORT Male Cohort study

Abstract: Objective To investigate the effect of weight change and weight fluctuations on all-cause-mortality in men. Methods Within a prospective population-based cohort of 1160 men aged 40–59 years at recruitment, complete weight change patterns from baseline and three follow-up examinations during a period of 15 years of follow-up was used to categorize the 505 men into stable obese, stable non-obese, weight gain, weight loss and weight fluctuation groups. For these men (age range: 55–74 years at start time of survival analysis) further survival was analyzed during the subsequent 15 years. Results Overall, 183 deaths were observed among the 505 men. Only weight fluctuations had a clear significant impact on all-cause mortality. Adjusted hazard rate ratio (HRR (95%-CI)) was 1.86 (1.31–2.66) after adjustment for age group, pre-existing cardiovascular disease or diabetes mellitus, smoking and socio-economic status. The risk rate due to weight loss was borderline significant (HRR = 1.81 (0.99–3.31)). Risk of death due to weight gain (HRR = 1.15 (0.70–1.88)) or stable obesity (HRR = 1.16 (0.69–1.94)), however, were not significantly increased compared to men staying non-obese for the first 15 years after cohort recruitment. Conclusion Weight fluctuations are a major risk factor for all-cause mortality in middle aged men. Moreover, stable obesity does not increase further mortality in men aged 55–74 years in long-term follow-up.

Health-related quality of life as a predictor of mortality among community-dwelling older persons.

Abstract: Health-related quality of life (HRQOL) measures predict cause-specific mortality, but few studies have explored whether generic self-reported HRQOL measures are independently associated with mortality in community-dwelling older persons. We postulated that a general measure of HRQOL, the short form 36-item questionnaire (SF-36), would be independently predictive of mortality among community-dwelling older persons. To evaluate this hypothesis, we followed a fixed cohort of 4,424 community-dwelling older persons recruited from a 2000 population-based survey in Taiwan until 2003 and investigated whether HRQOL was predictive of 3-year mortality, even after adjusting for traditional clinical risk variables. The data were collected via a door-to-door survey, and interviewers collected information on the subjects' demographics, medical history, utilization of health services, functional ability, falls, and self-reported physical and mental symptoms. Of the 6053 eligible subjects, 4,424 residents agreed to participate in the baseline survey and were contacted in 2003. During the 3-year period, the 3-year cumulative mortality rate for the study population was 5%. Mortality was significantly higher among males (5.57% vs. 4.27%, p = 0.049), and cumulative mortality increased with age (chi (2)-test for trend; chi (2) = 7.734, p = 0.001). For all scales except bodily pain, there was a significant relationship between a 10-point lower baseline score and mortality. Our primary multivariate risk model, which included two summary measures of HRQOL and significant clinical variables, demonstrated that a 10-point decrease in either the baseline Physical Component Summary (PCS) score or the baseline Mental Component Summary (MCS) score was associated with higher mortality (PCS: RR: 1.60, 95% CI: 1.39-1.83; p < 0.001; MCS: RR: 1.16, 95% CI: 1.01-1.34; p = 0.036). The findings suggested that low baseline PCS and MCS scores were important independent risk factors for 3-year mortality among community-dwelling older persons, even after adjusting for other risk factors.

Oral clefts and life style factors — A case-cohort study based on prospective Danish data

Abstract: This study examines the association between oral clefts and first trimester maternal lifestyle factors based on prospective data from the Danish National Birth Cohort. The cohort includes approximately 100,000 pregnancies. In total 192 mothers gave birth to child with an oral cleft during 1997-2003. Information on risk factors such as smoking, alcohol consumption, tea, coffee, cola, and food supplements was obtained during pregnancy for these and 828 randomly selected controls. We found that first trimester maternal smoking was associated with an increased risk of oral clefts (odds ratio (OR): 1.50; 95% confidence interval (CIs): 1.05, 2.14). Although not statistically significant, we also saw associations with first trimester consumption of alcohol (OR: 1.11; CIs: 0.79, 1.55), tea (OR: 1.31; CIs: 0.93, 1.86), and drinking more than 1 l of cola per week (OR: 1.40; CIs: 0.92, 2.12). Furthermore supplementation with > or =400 mcg folic acid daily during the entire first trimester (OR: 0.75; CIs: 0.46, 1.22) suggested an inverse associated with oral clefts, similar to our results on coffee drinking. No effects were found for smaller doses of folic acid, vitamin A, B6 or B12 in this study. The present study found an association between oral clefts and smoking and, although not conclusive, supports an association of oral cleft with alcohol.

Exposure-measurement error is frequently ignored when interpreting epidemiologic study results

Abstract: One important source of error in study results is error in measuring exposures. When interpreting study results, one should consider the impact that exposure-measurement error (EME) might have had on study results. To assess how often this consideration is made and the form it takes, journal articles were randomly sampled from original articles appearing in the American Journal of Epidemiology and Epidemiology in 2001, and the International Journal of Epidemiology between December 2000 and October 2001. Twenty-two (39%) of the 57 articles surveyed mentioned nothing about EME. Of the 35 articles that mentioned something about EME, 16 articles described qualitatively the effect EME could have had on study results. Only one study quantified the impact of EME on study results; the investigators used a sensitivity analysis. Few authors discussed the measurement error in their study in any detail. Overall, the potential impact of EME on error in epidemiologic study results appears to be ignored frequently in practice.

Behavioural risk factors in two generations of non-Western migrants: do trends converge towards the host population?

Abstract: Migrant mortality does not conform to a single pattern of convergence towards prevalence rates in the host population. To understand better how migrant mortality develops, it is necessary to further investigate how the underlying behavioural determinants change following migration. We studied whether the prevalence of behavioural risk factors over two generations of Turkish and Moroccan migrants converge towards the prevalence rates in the Dutch population. From a random sample from the population register of Amsterdam, 291 Moroccan and 505 Turkish migrants, aged 15-30, participated in a structured interview that included questions on smoking, alcohol consumption, physical inactivity and weight/height. Data from the Dutch population were available from Statistics Netherlands. By calculating age-adjusted Odds Ratio's, prevalence rates among both generations were compared with prevalence rates in the host population for men and women separately. We found indications of convergence across generations towards the prevalence rates in the host population for smoking in Turkish men, for overweight in Turkish and Moroccan women and for physical inactivity in Turkish women. Alcohol consumption, however, remained low in all subgroups and did not converge towards the higher rates in the host population. In addition, we found a reversed trend among Turkish women regarding smoking: the second generation smoked significantly more, while the first generation did not differ from ethnic Dutch. In general, behavioural risk factors in two generations of non-Western migrants in the Netherlands seem to converge towards the prevalence rates in the Dutch population. However, some subgroups and risk factors showed a different pattern.

Secular trends of nasopharyngeal carcinoma incidence in Singapore, Hong Kong and Los Angeles Chinese populations, 1973-1997.

Abstract: Nasopharyngeal carcinoma (NPC) is a rare cancer in most parts of world, but rather common in Southern China and Southeast Asia. This study used IARC published datasets to explore the secular trends of incidence rates of NPC among different Chinese populations in Singapore, Hong Kong and Los Angeles, over the time period 1973–1997. We observed great disparity in the risks and time trends of NPC in those selected Chinese populations. The highest risk was in Hong Kong where the incidence rates have declined rapidly throughout the whole study period in both males and females. For Singapore Chinese, the incidence rates also dropped recently in both genders, but the low incidence rates in Los Angeles Chinese have remained essentially unchanged over time. We further assessed the contribution of period and cohort effects to the observed trends in Hong Kong and Singapore populations through age-period-cohort modeling and found that an age-cohort model provided the best fit to the data in both populations, although for Singapore females a simple age-drift model fit the data well. There was a statistically significant decrease in the drop in incidence of NPC for cohorts born around 1940 in Hong Kong and 1958 in Singapore. This indicates that environmental and lifestyle changes play an important role in the declining incidence of NPC over time.

EPIC-Heart: The cardiovascular component of a prospective study of nutritional, lifestyle and biological factors in 520,000 middle-aged participants from 10 European countries

Abstract: EPIC-Heart is the cardiovascular component of the European Prospective Investigation into Cancer and Nutrition (EPIC), a multi-centre prospective cohort study investigating the relationship between nutrition and major chronic disease outcomes. Its objective is to advance understanding about the separate and combined influences of lifestyle (especially dietary), environmental, metabolic and genetic factors in the development of cardiovascular diseases by making best possible use of the unusually informative database and biological samples in EPIC. Between 1992 and 2000, 519,978 participants (366,521 women and 153,457 men, mostly aged 35-70 years) in 23 centres in 10 European countries commenced follow-up for cause- specific mortality, cancer incidence and major cardiovascular morbidity. Dietary information was collected with quantitative questionnaires or semi-quantitative food frequency questionnaires, including a 24-h dietary recall sub-study to help calibrate the dietary measurements. Information was collected on physical activity, tobacco smoking, alcohol consumption, occupational history, socio-economic status, and history of previous illnesses. Anthropometric measurements and blood pressure recordings were made in the majority of participants. Blood samples were taken from 385,747 individuals, from which plasma, serum, red cells, and buffy coat fractions were separated and aliquoted for long-term storage. By 2004, an estimated 10,000 incident fatal and non-fatal coronary and stroke events had been recorded. The first cycle of EPIC-Heart analyses will assess associations of coronary mortality with several prominent dietary hypotheses and with established cardiovascular risk factors. Subsequent analyses will extend this approach to non-fatal cardiovascular outcomes and to further dietary, biochemical and genetic factors.

Associations between overall physical activity level and cardiovascular risk factors in an adult population.

Abstract: Background It is well established that physical activity level is inversely associated with cardiovascular morbidity and mortality, and with all-cause mortality. However, the dose–response relationship between physical activity and other cardiovascular disease risk factors is not fully understood. The aim of the present study was to explore the dose–response relationship between daily physical activity, as measured by a metabolic equivalent score, and BMI, waist circumference, waist hip ratio, total cholesterol, HDL, LDL, triglycerides, systolic and diastolic blood pressure.

Modified Mediterranean diet and survival after myocardial infarction: the EPIC-Elderly study

Abstract: Mediterranean diet is associated with lower incidence of coronary heart disease, and two randomised trials indicated that it improves prognosis of coronary patients. These trials, however, relied on a total of 100 deaths and evaluated designer diets in the clinical context. We have evaluated the association of adherence to the modified Mediterranean diet, in which unsaturates were substituted for monounsaturates, with survival among elderly with previous myocardial infarction within the European Prospective Investigation into Cancer and nutrition (EPIC) study. As of December 2003, after a median follow-up of 6.7 years, 2671 EPIC participants from nine countries were 60 years or older and had prevalent myocardial infarction but no stroke or cancer at enrolment, complete information on dietary intakes and important covariates and known survival status. Adherence to the modified Mediterranean diet was assessed through a 10-unit-scale. Mortality ratio in relation to modified Mediterranean diet was estimated through Cox regression controlling for possible confounding. Increased adherence to modified Mediterranean diet by two units was associated with 18% lower overall mortality rate (95% confidence interval 7-27%, fixed effects model). There was no significant heterogeneity by sex, age at enrolment, or country, although the association tended to be less evident among northern Europeans. Associations between food groups contributing to the modified Mediterranean diet and mortality were generally weak. A diet inspired by the Mediterranean pattern that can be easily adopted by Western populations is associated with substantial reduction of total mortality of coronary patients in the community.

Life course determinants for early disability pension: a follow-up of Norwegian men and women born 1967-1976.

Abstract: Most studies on disability pension (DP) have focused on work conditions, socio-economic status and other contemporary factors. We wanted to study possible determinants of an early DP with a life course perspective within a large register-based cohort, with a main focus on the biological and social factors from childhood. We established a longitudinal, population-based cohort of all persons liveborn in Norway between 1967 and 1976. Through linkage between several national registers we obtained personal data on biological/health related as well as social background factors. After excluding persons who died, emigrated or were granted a DP before age 20 years (at which age follow-up started) and persons who did not become gainfully employed during the study period, the study population consisted of 595,393 persons. They were categorized into four strata according to gender and educational attainment. Adjusted hazard ratios (HR) for granting a DP until the end of 2003 and the corresponding population attributable risks (PAR) were computed. A total of 9,649 persons (1.6%) were granted a DP during follow-up. The disability risk was slightly higher among women than among men (1.7% vs. 1,5%). The following PARs were found: birth weight below the mean 5.7%, chronic childhood disease 6.8%, maternal marital status 4.4% and parental disability 8.8%. Low educational achievement was highly associated with DP, with a PAR more than twice as high as the overall PAR for the childhood factors. Early DP is associated with several biological and social background factors from childhood. It also shows a strong dependency on educational achievement.

Blood pressure, hypertension and mortality from circulatory disease in men and women who survived the siege of Leningrad

Abstract: The population of Leningrad suffered from severe starvation, cold and psychological stress during the siege in 1941-1944. We investigated long-term effects of the siege on cardiovascular risk factors and mortality in surviving men and women. 3905 men born 1916-1935 and 1729 women born 1910-1940, resident in St Petersburg (formerly Leningrad) between 1975 and 1982, of whom a third experienced the siege as children, adolescents or young adults, were examined for cardiovascular risk factors in 1975-1977 and 1980-1982 respectively and followed till end 2005. Effects of siege exposure on blood pressure, lipids, body size, and mortality were studied in multivariate analysis stratified by gender and period of birth, adjusted for age, smoking, alcohol and social characteristics. Women who were 6-8 years-old and men who were 9-15 years-old at the peak of starvation had higher systolic blood pressure compared to unexposed subjects born during the same period of birth (fully adjusted difference 8.8, 95% CI: 0.1-17.5 mm Hg in women and 2.9, 95% CI: 0.7-5.0 mm Hg in men). Mean height of women who were exposed to siege as children appeared to be greater than that of unexposed women. Higher mortality from ischaemic heart disease and cerebrovascular disease was noted in men exposed at age 6-8 and 9-15, respectively. The experience of severe stress and starvation in childhood and puberty may have long-term effects on systolic blood pressure and circulatory disease in surviving men and women with potential gender differences in the effect of siege experienced at pre-pubertal age.

Feasibility of recruiting a birth cohort through the Internet: the experience of the NINFEA cohort.

Abstract: The NINFEA cohort is an Italian birth cohort aiming at recruiting pregnant women through the Internet and following-up their children To understand whether Internet-based recruitment was feasible we started a pilot in July 2005 targeted to pregnant women visiting the hospitals of the city of Turin (900,000 inhabitants), where we advertised the study For this purpose we constructed a website (wwwprogettoninfeait), with on-line questionnaires to be completed during pregnancy and at 6 and 18 months after delivery Participants' characteristics were compared with those of women giving birth in Turin, which are routinely released as individual anonymous records We also compared complete with partial respondents We also carried out a survey of 122 women giving birth in the main Turin obstetric hospital to estimate the proportion of pregnant women with access to the Internet and awareness of the NINFEA cohort By December 2006, we had recruited 670 women Participation was associated with being older, a university graduate, primiparous and born in Italy Complete response (n = 633) was associated with being primiparous and participation after the first trimester In the survey, 66% (95% confidence interval: 56-74%; n = 80) of the women had access to the Internet and 42% (33-51%; n = 51) were aware of the study; 65% (29-125%; n = 8) had participated in the NINFEA cohort Our study indicates that recruitment of an Internet-based birth cohort is feasible As with many other types of birth cohort study, the participants are a self-selected sample To minimise selection bias analyses should therefore be limited to internal comparisons

Ten-year change in serum uric acid and its relation to changes in other metabolic risk factors in young black and white adults: the CARDIA study

Abstract: Elevated serum uric acid is commonly seen in association with obesity, glucose intolerance, hypertension and dyslipidemia. There is currently no satisfactory explanation for the relation of uric acid and the metabolic syndrome (MetSyn). This study aimed to evaluate the relations of change in serum uric acid with changes in components of the MetSyn in young adults. We studied 1,249 male and 1,362 female black and white subjects aged 17-35 years (baseline) from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, which attended a 10-year follow-up. Metabolic factors assessed at both time periods included BMI, waist circumference, blood pressure, fasting glucose, insulin, and lipids. Confounders examined (baseline and change variables) were serum creatinine, alcohol, smoking, physical activity, and oral contraceptives. Mean uric acid increased the most in black males (+0.5 mg/dl), followed by white males (+0.3 mg/dl) and black females (+0.2 mg/dl) (all P < 0.01), with the least change among white females (+0.1 mg/dl) (ns). Although change in all of the metabolic factors was associated with change in uric acid in the anticipated directions, in multivariable analyses only BMI and triglycerides had a significant independent association with uric acid in all race-sex-groups. Among confounders, only change in serum creatinine showed a strong independent association with uric acid. In conclusion, besides weight gain and renal excretion, increasing uric acid concentrations in young adults are strongly related to corresponding changes in triglycerides. The correlation of uric acid and triglycerides was found within the normal range and could not be explained by obesity.

Individual-level measures of social capital as predictors of all-cause and cardiovascular mortality: a population-based prospective study of men and women in Finland

Abstract: Individual-level social capital was assessed for prediction of mortality in a nationally representative study population aged 30-99 years at the baseline. A total of 90% of the original sample had participated in a comprehensive health examination (Mini-Finland Health Survey) in 1978-1980. After the first 5 years of the 24-year follow-up period, 1,196 of 3,014 men and 1,280 of 3,689 women died. Individual-level social capital was determined by factor analysis that revealed three factors: residential stability, leisure participation and interpersonal trust. Factor analysis showed a gender difference in leisure social participation. All-cause mortality and cardiovascular mortality were analyzed using Cox proportional hazard models. Adjusted for demographic, life style and biological risk factors, and for health and socio-economic status, leisure participation was associated with reduced all-cause mortality in men (hazard ratio, HR: 0.94; 95% confidence interval, CI: 0.89-1.00). This association seems to be related to economic status in men. Age modifies the effect of interpersonal trust on all-cause mortality in men. In women, leisure participation (HR: 0.96; 95% CI: 0.91-1.00) and interpersonal trust (HR: 0.69; 95% CI: 0.51-0.93) predicted all-cause mortality, and the latter also cardiovascular mortality (HR: 0.93; 95% CI: 0.86-1.00). The associations between individual-level social capital and mortality are gender- and age-related. Understanding the gender and age perspectives appears to be essential for better insight into the interrelations between social capital and health.

Case-control study of environmental and social factors influencing cryptosporidiosis

Abstract: We report on the first case-control study to investigate the role of wider environmental and socioeconomic factors upon human cryptosporidiosis. Using GIS the detailed locations of 3368 laboratory-confirmed cases were compared to the locations of an equal number of controls. All cases were genotyped enabling Cryptosporidium hominis and Cryptosporidium parvum to be examined separately. When all cryptosporidiosis cases were analyzed, several location variables were strongly associated with illness: areas with many higher socioeconomic status individuals, many individuals aged less than 4 years, areas with a high estimate of Cryptosporidium applied to land from manure, and areas with poorer water treatment. For C. hominis cases, the strongly significant risk factors were areas with many higher socioeconomic status individuals, areas with many young children and urban areas. Socioeconomic status and areas with many individuals aged less then 4 years had a greater impact for infection with C. hominis than for C. parvum. Policy implications are discussed.

Commuting physical activity is favourably associated with biological risk factors for cardiovascular disease.

Abstract: Background Little is known about the effects of commuting physical activity on biological cardiovascular risk factors although such knowledge may form an important basis for interventions aimed at reducing cardiovascular disease (CVD) by increasing physical activity. We examined the associations between commuting, leisure time and total physical activity and biological risk factors for CVD. Design A cross-sectional study of men and women, who participated in a health screening programme. Methods The study population comprised persons aged 30–60 years from a population-based random sample, response rate 53% (n = 6,906). Weight, height, waist circumference and blood pressure were measured and blood samples were collected. Physical activity was assessed by a self-administered questionnaire. Results Time spent on commuting, leisure time and total physical activity was positively associated with high-density lipoprotein cholesterol and negatively associated with low-density lipoprotein cholesterol, triglycerides, waist circumference and body mass index. Time spent on total physical activity was negatively associated with total cholesterol and diastolic blood pressure. Among men there was no relationship between time spent on physical activity and systolic blood pressure. Time spent on commuting physical activity and total physical activity was negatively associated with systolic blood pressure among women. Conclusion Commuting physical activity, independent of leisure time physical activity, was associated with a healthier level of most of the cardiovascular risk factors. An increase in commuting physical activity in the population may therefore reduce the incidence of CVD.

Adult socioeconomic position, C-reactive protein and interleukin-6 in the Whitehall II prospective study

Abstract: Background Prior studies on the association of inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), with socioeconomic position (SEP) have been cross-sectional. Thus, the question of whether socioeconomic differences in CRP and IL-6 change over time remains unanswered. We examined the relationship between SEP and changes over 12 years in CRP and IL-6. Methods Data were for 4,750 middle-aged (mean 49.0 years, SD 5.9) civil servants from phases 3 and 7 of the Whitehall II study. Adult SEP was based on last known Civil Service employment grade. Covariates included sociodemographics, behavioural and biological risk factors, presence of diseases/illnesses, prescribed medications, work-related factors, labour market status and early life factors. Results Steep socioeconomic gradients observed at Phase 3 (p < 0.001) persisted in both CRP and IL-6 12 years later after adjustment for other risk factors. Adjustment for behavioural (diet and smoking), biological (mainly body mass index and total : HDL cholesterol ratio) and early life factors resulted in considerable attenuation but the inverse socioeconomic gradients remained statistically significant. Although CRP and IL-6 concentrations increased substantially over the 12-year period at every level of SEP, CRP and IL-6 did not change differentially according to SEP. Conclusion Despite overall increases in CRP and IL6, relative differences by SEP remained unchanged so that socioeconomic gradients in both sexes persisted over the period observed.

The Paris prospective birth cohort study: which design and who participates?

Abstract: The Paris prospective birth cohort study was implemented in 2003 to assess environmental/behavioural factors associated with respiratory and allergic disorder occurrence in early childhood. This paper describes the design and sociodemographic features of eligible/enrolled families. Full-term newborns without any medical problem at birth were recruited in five Paris maternity hospitals. They resided in the Paris area and had French speaking mothers. Sample size is at least 3500 infants, and children are followed-up until their sixth birthday. Data collection is based on regular medical and environmental self-administered questionnaires to parents. Information on dwellings is gathered by means of phone questionnaires, and standardized medical examinations are carried out at 18 months and 6 years. Exposure to traffic-related pollution is modelled. At inclusion, some information concerning refusals is gathered in order to describe sociodemographic features of participating families as compared with eligible children. 4115 (63%) out of the 6493 eligible infants are now participating in this study. Participation rate is higher in parents with a high SES (socioeconomic status), for French and European parents, and for ≥25-year-old mothers, but decreases with sibship size. Similar determinants are associated with the distribution of reasons for non-participation. The participation rate in the Paris study is comparable with other similar studies. Finally, giving detailed explanation of the study aims at inclusion, establishing regular mailed and phoned contacts with families, offering free complete medical examinations for the participant child and re-sent missing questionnaires are very important to improve participation at inclusion and during follow-up.