Showing papers in "European Journal of Epidemiology in 2010"
TL;DR: The quality assessment of non-randomized studies is an important component of a thorough meta-analysis of non randomized studies and can dramatically influence the interpretation of meta-analyses, and can even reverse conclusions regarding the effectiveness of an intervention.
Abstract: The quality assessment of non-randomized studies is an important component of a thorough meta-analysis of nonrandomized studies. Low quality studies can lead to a distortion of the summary effect estimate. Recent guidelines for the reporting of meta-analyses of observational studies recommend the assessment of the study quality (MOOSE) [1]. In principal, three categories of quality assessments tools are available: scales, simple checklists, or checklists with a summary judgment (for details see Sanderson et al. 2007 [2]). The results of the quality assessment can be used in several ways such as forming inclusion criteria for the meta-analysis, informing a sensitivity analysis or metaregression, weighting studies, or highlighting areas of methodological quality poorly addressed by the included studies [3]. It has been criticized that the use of summary scores involve inherent weighting of component items including items that may not be related to the validity of the study findings [2]. Sanderson et al. [2] recently identified overall 86 tools for assessing the quality of non-randomized studies. Their review "highlighted the lack of a single obvious candidate tool for assessing quality of observational epidemiological studies" [2]. In the field of randomized trials, it has been shown that the choice of quality scale can dramatically influence the interpretation of meta-analyses, and can even reverse conclusions regarding the effectiveness of an intervention [4]. Wells et al. [5] proposed a scale for assessing the quality of published non-randomized studies in meta-analyses,
10,420 citations
TL;DR: The Generation R Study is a population-based prospective cohort study designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood.
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 during fetal life, childhood and adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. General follow-up rates until the age of 4 years exceed 75%. Data collection in mothers, fathers and preschool children included questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome wide association screen is available in the participating children. Regular detailed hands on assessment are performed from the age of 5 years onwards. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.
838 citations
TL;DR: Case misclassification of AF in national registers is small, indicating feasibility of use in prospective studies, and Hypertension and obesity account for large portions of population risk in middle-aged individuals with low prevalence of manifest cardiac disease.
Abstract: The validity of atrial fibrillation (AF) diagnoses in national registers for use as endpoints in prospective studies has not been evaluated. We studied the validity of AF diagnoses in Swedish national hospital discharge and cause of death registers and the occurrence of and risk factors for AF in a middle-aged Swedish population using these registers. Our study included the 30,447 individuals (age 44-73) who attended baseline visits in 1991-1996 of the Malmo Diet and Cancer study. Individuals with a first AF diagnosis were identified by record linkage with national registers. A subset of cases was randomly selected for validation by examination of electrocardiograms and patient records. Electrocardiograms were available in 98% of the validation sample (95% definitive AF, 3% no AF). The 2% with ECGs unavailable had probable AF. Baseline AF prevalence was 1.3%, higher in men and increased with age. During 11.2 years of follow-up 1430 first AF diagnoses occurred. Risk factors were age, hypertension, BMI, diabetes, history of heart failure, history of myocardial infarction and, in men but not women, current smoking. The strongest risk factors were history of heart failure (hazard ratio men 4.5, women 8.7) and myocardial infarction (hazard ratio men 2.0, women 1.8). The largest population attributable risks were observed for hypertension (men 38%, women 34%) and obesity (men 11%, women 10%). In conclusion, case misclassification of AF in national registers is small, indicating feasibility of use in prospective studies. Hypertension and obesity account for large portions of population risk in middle-aged individuals with low prevalence of manifest cardiac disease.
257 citations
TL;DR: The quality of information provided by the web-based anthropometric questionnaire used in the NutriNet-Santé Study was equal to, or better than, that of the paper version, with substantial logistic and cost advantages.
Abstract: Online data collection could advantageously replace paper-and-pencil questionnaires in epidemiological studies by reducing the logistic burden, the cost and the duration of data processing. However, there is a need for studies comparing these new instruments to traditional ones. Our objective was to compare the web-based version of the NutriNet-Sante self-administered anthropometric questionnaire to the paper-based version. The questionnaire included 17 questions divided into subquestions (55 variables in all) dealing with height, weight, hip and waist circumferences, weight history, restrictive diet and weight self-perception. Both versions of the questionnaire were filled out by 147 volunteers (paper version first, N = 76, or web-based version first, N = 71) participating in the SU.VI.MAX ("Supplementation en VItamines Mineraux et AntioXydants") cohort (age-range: 49-75 years; men: 46.3%). At the end of the test, subjects filled in a "satisfaction" questionnaire giving their opinions and feelings about each version. Agreement was assessed by intraclass correlation coefficients (ICCs) and kappas. We also quantified the number of errors inherent in the paper version. Agreement between the two versions was high. ICCs ranged from 0.86 to 1.00. Kappas ranged from 0.69 to 1.00 for comparable variables. A total of 82 data entry mistakes (1.5% of total entries), 60 missing values (1.1%), 57 inconsistent values (1.1%) and 3 abnormal values (0.1%) were counted in the paper version (non-existent in the web-based version due to integrated controls). The web-based version was preferred by 92.2% of users. In conclusion, the quality of information provided by the web-based anthropometric questionnaire used in the NutriNet-Sante Study was equal to, or better than, that of the paper version, with substantial logistic and cost advantages.
216 citations
TL;DR: A meta-analysis of prospective cohort studies found that individuals with the metabolic syndrome had an increased mortality from all causes and the RR of all-cause mortality associated with metabolic syndrome was higher in studies using the National Cholesterol Education Program Adult Treatment Panel than the revised NCEP criteria.
Abstract: To synthesize the available data on the association between metabolic syndrome and all-cause mortality, we conducted a meta-analysis of prospective cohort studies. We performed a literature search using Medline, EMBASE and Cochrane Library from 2001 to December 2009, with no restrictions. We included studies if they were prospective, had an assessment of metabolic syndrome at baseline and risk of all-cause mortality. We recorded several characteristics for each study. We extracted relative risks (RR) and 95% confidence intervals (CI) and pooled them using fixed or random effects models. We performed sensitivity analysis, and assessed heterogeneity and publication bias. A total of 21 studies including 372,411 participants were included in our meta-analysis. 18,556 deaths from any cause occurred during a mean follow-up of 11.5 years. Individuals with the metabolic syndrome, compared to those without, had an increased mortality from all causes (pooled RR 1.46; 95% CI 1.35-1.57). The RR of all-cause mortality associated with metabolic syndrome was higher in studies using the National Cholesterol Education Program Adult Treatment Panel (NCEP) than the revised NCEP criteria (RR: 1.45 vs. 1.25; P = 0.0002). Metabolic syndrome is an important risk factor for all-cause mortality. The diagnosis and treatment of the underlying risk factors for the metabolic syndrome should be an important strategy for the reduction of all-cause mortality associated with metabolic syndrome in the general population.
196 citations
TL;DR: The aim of this perspective article is to review frequent fallacies and misuses of SST in the biomedical field and to review a potential way out of the fallaciesand misuses associated with SSTs.
Abstract: Since its introduction into the biomedical literature, statistical significance testing (abbreviated as SST) caused much debate. The aim of this perspective article is to review frequent fallacies and misuses of SST in the biomedical field and to review a potential way out of the fallacies and misuses associated with SSTs. Two frequentist schools of statistical inference merged to form SST as it is practised nowadays: the Fisher and the Neyman-Pearson school. The P-value is both reported quantitatively and checked against the α-level to produce a qualitative dichotomous measure (significant/nonsignificant). However, a P-value mixes the estimated effect size with its estimated precision. Obviously, it is not possible to measure these two things with one single number. For the valid interpretation of SSTs, a variety of presumptions and requirements have to be met. We point here to four of them: study size, correct statistical model, correct causal model, and absence of bias and confounding. It has been stated that the P-value is perhaps the most misunderstood statistical concept in clinical research. As in the social sciences, the tyranny of SST is still highly prevalent in the biomedical literature even after decades of warnings against SST. The ubiquitous misuse and tyranny of SST threatens scientific discoveries and may even impede scientific progress. In the worst case, misuse of significance testing may even harm patients who eventually are incorrectly treated because of improper handling of P-values. For a proper interpretation of study results, both estimated effect size and estimated precision are necessary ingredients.
174 citations
TL;DR: The findings of this large observational study provide further evidence that patients with COPD are at increased risk for most cardiovascular diseases.
Abstract: Previous large epidemiological studies reporting on the association between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases mainly focussed on prevalent diseases rather than on the incidence of newly diagnosed cardiovascular outcomes We used the UK-based General Practice Research Database (GPRD) to assess the prevalence and incidence of cardiovascular diseases in COPD patients aged 40-79 between 1995 and 2005, and we randomly matched COPD-free comparison patients to COPD patients In nested-case control analyses, we compared the risks of developing an incident diagnosis of cardiac arrhythmias, venous thromboembolism, myocardial infarction, or stroke between patients with and without COPD, stratifying the analyses by COPD-severity, using COPD-treatment as proxy for disease severity We identified 35,772 patients with COPD and the same number of COPD-free patients Most cardiovascular diseases were more prevalent among COPD patients than among the comparison group of COPD-free patients The relative risk estimates of developing an incident diagnosis of cardiac arrhythmia (OR 119, 95% CI 098-143), deep vein thrombosis (OR 135, 95% CI 097-189), pulmonary embolism (OR 251, 95% CI 162-387), myocardial infarction (OR 140, 95% CI 113-173), or stroke (OR 113, 95% CI 092-138), tended to be increased for patients with COPD as compared to COPD-free controls The findings of this large observational study provide further evidence that patients with COPD are at increased risk for most cardiovascular diseases
150 citations
TL;DR: Groups with low socioeconomic resources in terms of education, occupation, income and civil status are underrepresented in the Danish National Birth Cohort compared to the background population.
Abstract: Background Low participation at recruitment to the Danish National Birth Cohort (DNBC) has raised concern about non-participation bias. Objective To study the socioeconomic pattern of participation to the DNBC. Methods Independently of the DNBC, we identified the DNBC source population in two geographical areas of Denmark by means of local birth registers with full coverage. Socioeconomic information came from national registers, and the source population consisted of 48,560 births including 15,290 participating women. For every socioeconomic characteristic, we estimated the prevalence ratio [prevalence (participants)/prevalence (source population)] which corresponds to the relative representation of the group (presented in percentages with 95% confidence intervals). Results The overall participation rate was 31%. Women outside the work force or with no further education than compulsory school were underrepresented in the DNBC by 62% (59%; 64%) and 43% (41%; 45%), respectively. Also, women were underrepresented by 18% (13%; 23%) if they were unemployed, by 22% (20%; 24%) if they were in the lowest income group, 38% (35%; 40%) if they received a high proportion of social benefits, and 28% (24%; 31%) if they were singles. Particularly women with low resources according to two socioeconomic factors were strongly underrepresented, typically by 50–67%. Conclusion Groups with low socioeconomic resources in terms of education, occupation, income and civil status are underrepresented in the DNBC compared to the background population. These discrepancies must be taken into account when results from the DNBC and other cohorts of pregnant women are interpreted—especially when descriptive results are presented.
142 citations
TL;DR: The reliability of cause-of-death statistics turned out to be high (>90%) for major causes of death such as cancers and acute myocardial infarction and for chronic diseases, such as diabetes and renal insufficiency, reliability was low (<70%).
Abstract: Cause-of-death statistics are a major source of information for epidemiological research or policy decisions. Information on the reliability of these statistics is important for interpreting trends in time or differences between populations. Variations in coding the underlying cause of death could hinder the attribution of observed differences to determinants of health. Therefore we studied the reliability of cause-of-death statistics in the Netherlands. We performed a double coding study. Death certificates from the month of May 2005 were coded again in 2007. Each death certificate was coded manually by four coders. Reliability was measured by calculating agreement between coders (intercoder agreement) and by calculating the consistency of each individual coder in time (intracoder agreement). Our analysis covered an amount of 10,833 death certificates. The intercoder agreement of four coders on the underlying cause of death was 78%. In 2.2% of the cases coders agreed on a change of the code assigned in 2005. The (mean) intracoder agreement of four coders was 89%. Agreement was associated with the specificity of the ICD-10 code (chapter, three digits, four digits), the age of the deceased, the number of coders and the number of diseases reported on the death certificate. The reliability of cause-of-death statistics turned out to be high (>90%) for major causes of death such as cancers and acute myocardial infarction. For chronic diseases, such as diabetes and renal insufficiency, reliability was low (<70%). The reliability of cause-of-death statistics varies by ICD-10 code/chapter. A statistical office should provide coders with (additional) rules for coding diseases with a low reliability and evaluate these rules regularly. Users of cause-of-death statistics should exercise caution when interpreting causes of death with a low reliability. Studies of reliability should take into account the number of coders involved and the number of codes on a death certificate.
140 citations
TL;DR: A non-attendance analysis evaluating the possible impact of selection bias when investigating the association between education level and cardiovascular risk factors revealed that participants were more likely to be women, have university education, high income, be married and of Nordic origin compared to non-participants.
Abstract: Non-participation in population studies is likely to be a source of bias in many types of epidemiologic studies, including those describing social disparities in health. The objective of this paper is to present a non-attendance analysis evaluating the possible impact of selection bias, when investigating the association between education level and cardiovascular risk factors. Data from the INTERGENE research programme including 3,610 randomly selected individuals aged 25-74 (1,908 women and 1,702 men), in West Sweden were used. Only 42% of the invited population participated. Non-attendance analyses were done by comparing data from official registries (Statistics Sweden) covering the entire invited study population. This analysis revealed that participants were more likely to be women, have university education, high income, be married and of Nordic origin compared to non-participants. Among participants, all health behaviours studied were significantly related to education. Physical activity, alcohol use and breakfast consumption were higher in the more educated group, while there were more smokers in the less educated group. Central obesity, obesity and hypertension were also significantly associated with lower education level. Weaker associations were observed for blood lipids, diabetes, high plasma glucose level and perceived stress. The socio-demographic differences between participants and non-participants indicated by the register analysis imply potential biases in epidemiological research. For instance, the positive association between education level and frequent alcohol consumption, may, in part be explained by participation bias. For other risk factors studied, an underestimation of the importance of low socioeconomic status may be more likely.
130 citations
TL;DR: The authors discuss the importance of an adequate definition of drug exposure in pharmaco-epidemiological research and how this time-varying determinant can be analyzed in cohort studies.
Abstract: In pharmaco-epidemiology, the use of drugs is the determinant of interest when studying exposure-outcome associations. The increased availability of computerized information about drug use on an individual basis has greatly facilitated analyses of drug effects on a population-based scale. It seems likely that many negative findings in the early days of pharmaco-epidemiology can be explained by non-differential misclassification because of too simple (yes/no) exposure measures. In this paper, the authors discuss the importance of an adequate definition of drug exposure in pharmaco-epidemiological research and how this time-varying determinant can be analyzed in cohort studies. To reduce the risk of non-differential misclassification, a precise definition of exposure is mandatory and it is important to distinguish the complete follow-up period of a population into mutually exclusive episodes of non-use, past use and current use for each individual. By analyzing exposure to drugs as a time-dependent variable in a Cox regression model, cohort studies with complete coverage of all filled prescriptions can provide us with valid and precise risk estimates of drug-outcome associations. However, such estimates may be biased in the presence of time-dependent confounders which are themselves affected by prior exposure.
TL;DR: The results do not support an association between shift-work and cardiovascular morbidity, and the results were essentially similar after full adjustments for all covariates.
Abstract: Studies on the association between shift-work and cardiovascular disease (CVD), in particular coronary heart disease (CHD), have given conflicting results. In this prospective population-based study we assessed the association of shift-work with three endpoints: CHD mortality, disability retirement due to CVD, and incident hypertension. A cohort of 20,142 adults (the Finnish Twin Cohort) was followed from 1982 to 2003. Type of working time (daytime/nighttime/shift-work) was assessed by questionnaires in 1975 (response rate 89%) and in 1981 (84%). Causes of death, information on disability retirement and hypertension medication were obtained from nationwide official registers. Cox proportional hazard models were used to obtain hazard ratios (HR) for each endpoint by type of working time. Adjustments were made for 14 socio-demographic and lifestyle covariates. 76.9% were daytime workers and 9.5% shift-workers both in 1975 and in 1981. During the follow-up, 857 deaths due to CHD, 721 disability retirements due to CVD, and 2,642 new cases of medicated hypertension were observed. However, HRs for shift-work were not significant (mortality HR men 1.09 and women 1.22; retirement 1.15 and 0.96; hypertension 1.15 and 0.98, respectively). The results were essentially similar after full adjustments for all covariates. Within twin pairs, no association between shift work and outcome was observed. Our results do not support an association between shift-work and cardiovascular morbidity.
TL;DR: The results show that obesity and physical in activity interact on an additive scale, which means that prevention of either obesity or physical inactivity, not only reduces the risk of diabetes by taking away the independent effect of this factor, but also by preventing the cases that were caused by the interaction between both factors.
Abstract: Obesity and physical inactivity are both risk factors for type 2 diabetes. Since they are strongly associated, it has been suggested that they might interact. In this study, we summarized the evidence on this interaction by conducting a systematic review. Two types of interaction have been discerned, statistical and biological interaction, which could give different results. Therefore, we calculated both types of interaction for the studies in our review. Cohort studies, published between 1999 and 2008, that investigated the effects of obesity and physical activity on the risk of type 2 diabetes were included. We calculated both biological and statistical interaction in these studies. Eight studies were included of which five were suitable to calculate interaction. All studies showed positive biological interaction, meaning that the joint effect was more than the sum of the individual effects. However, there was inconsistent statistical interaction; in some studies the joint effect was more than the product of the individual effects, in other studies it was less. The results show that obesity and physical inactivity interact on an additive scale. This means that prevention of either obesity or physical inactivity, not only reduces the risk of diabetes by taking away the independent effect of this factor, but also by preventing the cases that were caused by the interaction between both factors. Furthermore, this review clearly showed that results can differ depending on what method is used to assess interaction.
TL;DR: Consistent sex differentials in survival and physical health, self-rated health and cognition at older ages are revealed, whereas the pattern of sex differences in depressive symptoms was country-specific.
Abstract: The present study aims to compare the direction and magnitude of sex differences in mortality and major health dimensions across Denmark, Japan and the US. The Human Mortality Database was used to examine sex differences in age-specific mortality rates. The Danish twin surveys, the Danish 1905-Cohort Study, the Health and Retirement Study, and the Nihon University Japanese Longitudinal Study of Aging were used to examine sex differences in health. Men had consistently higher mortality rates at all ages in all three countries, but they also had a substantial advantage in handgrip strength compared with the same-aged women. Sex differences in activities of daily living (ADL) became pronounced among individuals aged 85+ in all three countries. Depression levels tended to be higher in women, particularly, in Denmark and the HRS, and only small sex differences were observed in the immediate recall test and Mini-Mental State Exam. The present study revealed consistent sex differentials in survival and physical health, self-rated health and cognition at older ages, whereas the pattern of sex differences in depressive symptoms was country-specific.
TL;DR: An overview of published data on CAG incidence (overall and according to risk factors) from follow-up studies is provided to provide comparable estimates of incidence and the impact of risk factors in the development of CAG.
Abstract: Chronic atrophic gastritis (CAG) is an important precursor lesion of intestinal gastric cancer. As it is typically asymptomatic, epidemiological data on the incidence of CAG are sparse. We aimed to provide an overview of published data on CAG incidence (overall and according to risk factors) from follow-up studies. Articles with information on incidence of CAG published in English until 26th of July 2009 were identified through a systematic MEDLINE and EMBASE search. Data extracted include study characteristics and key findings regarding the incidence of CAG. A meta-analysis was performed on the association between Helicobacter pylori infection and CAG incidence. Overall, data on CAG incidence were available from 14 studies, in 7 studies incidence could be estimated according to H. pylori infection. Most studies were conducted in symptomatic or high risk populations and the maximum number of incident cases was 284. Incidence estimates ranged from 0 to 11% per year and were consistently below 1% in patients not infected with H. pylori. The highest incidence was observed in a special study conducted on ulcer patients treated by proximal gastric vagotomy. Rate ratios for the association between H. pylori infection and CAG incidence ranged from 2.4 to 7.6 with a summary estimate of 5.0 (95% confidence interval: 3.1-8.3). Incidence of CAG is very low in the absence of H. pylori infection. There is a need for more population-based studies to provide comparable estimates of incidence and the impact of risk factors in the development of CAG.
TL;DR: The results highlight night and early morning working associations with an adverse profile of CVD risk factors, which are partly explained by socioeconomic, other occupational factors and health behaviours.
Abstract: This study examined associations between exposure to shift-work and risk factors for cardiovascular disease (CVD) and whether the associations are explained by socio-economic circumstances, occupational factors or health behaviours. Biological risk factors for CVD were measured in 7,839 participants of the 1958 British birth cohort at age 45 years who were in paid employment. Regular (>or=1/week) shift-workers included 46% working evenings (1800-2200), 28% weekends, 13% nights (2200-0400) and 14% early mornings (0400-0700). Adverse levels of several CVD risk factors were found in association with increasing participation in any shift-work. Men regularly working all four shift-work types had increased CVD risk factors of approximately 0.1-0.2 standard deviations (e.g. 0.8 kg/m(2) for body mass index; 1.2 cm for waist circumference) than those not regularly working shifts; for women, there was a positive linear trend for triglyceride levels, but a negative trend for diastolic blood pressure. Separate analyses of shift-work types showed associations primarily for night/morning working rather than evening/weekend working. Men had adverse levels of all CVD risk factors except blood pressure and total-cholesterol in association with night or early morning work and women had adverse triglyceride levels. Adjustment for socioeconomic, occupational factors and health behaviours explained most associations except for adiposity and C-reactive protein. Our results highlight night and early morning working associations with an adverse profile of CVD risk factors, which are partly explained by socioeconomic, other occupational factors and health behaviours.
TL;DR: Evidence is provided that both passive and active smoking is associated with type 2 diabetes, and that exposure to environmental tobacco smoke is also associated with T2DM.
Abstract: Active smoking is a risk factor for type 2 diabetes (T2DM), but it is unclear whether exposure to environmental tobacco smoke (ETS) is also associated with T2DM. The effect of passive and active smoking on the 7-year T2DM incidence was investigated in a population-based cohort in Southern Germany (KORA S4/F4; 1,223 subjects aged 55–74 years at baseline in 1999–2001, 887 subjects at follow-up). Incident diabetes was identified by oral glucose tolerance tests or by validated physician diagnoses. Among never smokers, subjects exposed to ETS had an increased diabetes risk in the total sample (odds ratio (OR) = 2.5; 95% confidence interval (CI): 1.1, 5.6) and in a subgroup of subjects having prediabetes at baseline (OR = 4.4; 95% CI: 1.5, 13.4) after adjusting for age, sex, parental diabetes, socioeconomic status, and lifestyle factors. Active smoking also had a statistically significant effect on diabetes incidence in the total sample (OR = 2.8; 95% CI: 1.3, 6.1) and in prediabetic subjects (OR = 7.8; 95% CI: 2.4, 25.7). Additional adjustment for components of the metabolic syndrome including waist circumference did not attenuate any of these associations. This study provides evidence that both passive and active smoking is associated with T2DM.
TL;DR: In conclusion, nonfasting triglycerides were associated with increased risk of CVD death for both women and men, and adjustment for major cardiovascular risk factors attenuated the effect.
Abstract: The association between nonfasting triglycerides and cardiovascular disease (CVD) has recently been actualized The aim of the present study was to investigate nonfasting triglycerides as a predictor of CVD mortality in men and women A total of 86,261 participants in the Norwegian Counties Study 1974–2007, initially aged 20–50 years and free of CVD were included We estimated hazard ratios (HRs) for deaths from CVD, ischemic heart disease (IHD), stroke and all causes by level of nonfasting triglycerides Mean follow-up was 270 years A total of 9,528 men died (3,620 from CVD, 2,408 IHD, 543 stroke), and totally 5,267 women died (1,296 CVD, 626 IHD, 360 stroke) After adjustment for CVD risk factors other than HDL-cholesterol, the HRs (95% CI) per 1 mmol/l increase in nonfasting triglycerides were 116 (113–120), 120 (114–127), 126 (119–134) and 109 (096–123) for all cause mortality, CVD, IHD, and stroke mortality in women Corresponding figures in men were 103 (101–104), 103 (100–105), 103 (100–106) and 099 (092–107) In a subsample where HDL-cholesterol was measured (n = 40,144), the association between CVD mortality and triglycerides observed in women disappeared after adjustment for HDL-cholesterol In a model including the Framingham CHD risk score the effect of triglycerides disappeared in both men and women In conclusion, nonfasting triglycerides were associated with increased risk of CVD death for both women and men Adjustment for major cardiovascular risk factors, however, attenuated the effect Nonfasting triglycerides added no predictive information on CVD mortality beyond the Framingham CHD risk score in men and women
TL;DR: The risk of ischemic stroke is strongly increased shortly after the diagnosis of heart failure but returns to normal within 6 months after onset ofheart failure.
Abstract: Patients with heart failure used to have an increased risk of stroke, but this may have changed with current treatment regimens. We assessed the association between heart failure and the risk of stroke in a population-based cohort that was followed since 1990. The study uses the cohort of the Rotterdam Study and is based on 7,546 participants who at baseline (1990–1993) were aged 55 years or over and free from stroke. The associations between heart failure and risk of stroke were assessed using time-dependent Cox proportional hazards models, adjusted for cardiovascular risk factors (smoking, diabetes mellitus, BMI, ankle brachial index, blood pressure, atrial fibrillation, myocardial infarction and relevant medication). At baseline, 233 participants had heart failure. During an average follow-up time of 9.7 years, 1,014 persons developed heart failure, and 827 strokes (470 ischemic, 75 hemorrhagic, 282 unclassified) occurred. The risk of ischemic stroke was more than five-fold increased in the first month after diagnosis of heart failure (age and sex adjusted HR 5.79, 95% CI 2.15–15.62), but attenuated over time (age and sex adjusted HR 3.50 [95% CI 1.96–6.25] after 1–6 months and 0.83 [95% CI 0.53–1.29] after 0.5–6 years). Additional adjustment for cardiovascular risk factors only marginally attenuated these risks. In conclusion, the risk of ischemic stroke is strongly increased shortly after the diagnosis of heart failure but returns to normal within 6 months after onset of heart failure.
TL;DR: Modification of lifestyle factors apparently reduces type 2 diabetes risk, especially in persons with normal blood pressure.
Abstract: Lifestyle factors predict type 2 diabetes occurrence, but their effect in high- and low-risk populations is poorly known. This study determines the prediction of low-risk lifestyle on type 2 diabetes in those with and without metabolic syndrome in a pooled sample of two representative Finnish cohorts, collected in 1978-1980 and 2000-2001. Altogether 8,627 individuals, aged 40-79 years, and free of diabetes and cardiovascular disease at baseline were included in this study. A low-risk lifestyle was defined based on body mass index, exercise, alcohol consumption, smoking, and serum vitamin D concentration. The metabolic syndrome was defined according to the International Diabetes Federation including obesity, blood pressure, serum HDL cholesterol, serum triglycerides, and fasting glucose. During a 10-year follow-up, altogether 226 type 2 diabetes cases occurred. Overweight was the strongest predictor of type 2 diabetes (population attributable fraction (PAF) = 77%, 95% confidence interval (CI): 53, 88%). Together with lack of exercise, unsatisfactory alcohol consumption, smoking, and low vitamin D concentration it explained 82% of the cases. Altogether 62% (CI: 47, 73%) of the cases were attributable to the metabolic syndrome and 92% (CI: 67, 98%) to the most unfavourable combination of its components. The metabolic syndrome did not modify the prediction of lifestyle factors but persons with normal blood pressure benefited more from positive changes in exercise, alcohol consumption, and smoking than those with elevated blood pressure (P for interaction = 0.01). In conclusion, modification of lifestyle factors apparently reduces type 2 diabetes risk, especially in persons with normal blood pressure.
TL;DR: Prison inmates were at high risk of HCV infection, despite some reduction in high-risk behaviours and access to prevention services and to prevent HCV transmission in prisons, better prevention strategies are required.
Abstract: To determine hepatitis C incidence and the demographic and behavioural predictors in seronegative drug injecting prisoners. Prisoners in New South Wales, Australia who: were aged 18 years and over; reported IDU; had been continuously imprisoned; had a documented negative HCV antibody test result in prison in the last 12 months; provided written informed consent. Subjects were interviewed about their demographic characteristics and detailed risk factors for transmission prior to, and since, imprisonment. A blood sample was collected to screen for HCV antibodies by ELISA and RNA by PCR. Of 253 inmates recruited, 120 were continuously imprisoned and included in this analysis. Sixteen acquired HCV infection indicating an incidence of 34.2 per 100 person years (CI: 19.6-55.6). Risk factors for transmission included prior imprisonment, methadone treatment and greater than 10 years of education. Although the frequency of injecting was reduced in prison, 33.6% continued to inject drugs, most commonly methamphetamine, and 90% of these reported sharing injecting equipment. Prison inmates were at high risk of HCV infection, despite some reduction in high-risk behaviours and access to prevention services. To prevent HCV transmission in prisons, better prevention strategies are required.
TL;DR: The successful conduct of this pilot study suggests that the internet may be a useful tool to recruit and follow subjects in prospective cohort studies.
Abstract: The attraction of being able to use the internet for the recruitment of an epidemiologic cohort stems mainly from cost efficiency and convenience. The pregnancy planning study (‘Snart-Gravid’)—a prospective cohort study of Danish women planning a pregnancy—was conducted to evaluate the feasibility and cost efficiency of using internet-based recruitment and follow-up. Feasibility was assessed by examining patient accrual data over time, questionnaire-specific response rates and losses to follow-up. The relative cost efficiency was examined by comparing the study costs with those of an alternative non internet-based study approach. The target recruitment of 2,500 participants over 6 months was achieved using advertisements on a health-related website, supported by a coordinated media strategy at study initiation. Questionnaire cycle-specific response rates ranged from 87 to 90% over the 12-month follow-up. At 6 months, 87% of women had a known outcome or were still under follow-up; at 12 months the figure was 82%. The study cost of $400,000 ($160 per enrolled subject) compared favorably with the estimated cost to conduct the same study using a conventional non-internet based approach ($322 per subject). The gain in efficiency with the internet-based approach appeared to be even more substantial with longer follow-up and larger study sizes. The successful conduct of this pilot study suggests that the internet may be a useful tool to recruit and follow subjects in prospective cohort studies.
TL;DR: The hypothesis that short-term exposure to traffic-related particles might lead to detrimental cardiovascular health effects via an inflammatory mechanism is supported.
Abstract: Daily to monthly variations in fine particulate matter have been linked to systemic inflammatory responses. It has been hypothesized that smaller particles resulting from combustion processes confer higher toxicity. We aim to analyze the association between short-term exposure to ultrafine and fine particles and systemic inflammation. We use baseline data (2000-2003) of the Heinz Nixdorf Recall Study, a population-based cohort study of 4,814 participants in the Ruhr Area in Germany. A chemistry transport model was applied to model daily surface concentrations of particulate air pollutants on a grid of 1 km(2). Exposure included particle number (PN) and particulate matter mass concentration with an aerodynamic diameter < or = 2.5 microm (PM(2.5)) and < or = 10 microm (PM(10)). Generalized additive models were used to explore the relation of air pollutants using single day lags and averaging times of up to 28 days with high-sensitivity C-reactive protein (hs-CRP). We adjusted for meteorology, season, time trend, and personal characteristics. Median hs-CRP level in the 3,999 included participants was 1.5 mg/l. Median daily concentration of PN was 8,414 x 10(4)/ml (IQR 4,580 x 10(4)/ml), of PM(2.5) 14.5 microg/m(3) (IQR 11.5 microg/m(3)) and of PM(10) 18.5 microg/m(3) (IQR 13.9 microg/m(3)). A positive association between PN and hs-CRP could be observed only for single day lags and for averaged PN concentrations with higher estimates for longer averaging times. The highest hs-CRP-increase of 7.1% (95%-CI: 1.9, 12.6%) was found for the 21-day average. These results support the hypothesis that short-term exposure to traffic-related particles might lead to detrimental cardiovascular health effects via an inflammatory mechanism.
TL;DR: This is one of the first studies that investigated an association between exposure to mobile telecommunication networks and mental health behaviour more studies using personal dosimetry are warranted to confirm these findings.
Abstract: Only few studies have so far investigated possible health effects of radio-frequency electromagnetic fields (RF EMF) in children and adolescents, although experts discuss a potential higher vulnerability to such fields. We aimed to investigate a possible association between measured exposure to RF EMF fields and behavioural problems in children and adolescents. 1,498 children and 1,524 adolescents were randomly selected from the population registries of four Bavarian (South of Germany) cities. During an Interview data on participants' mental health, socio-demographic characteristics and potential confounders were collected. Mental health behaviour was assessed using the German version of the Strengths and Difficulties Questionnaire (SDQ). Using a personal dosimeter, we obtained radio-frequency EMF exposure profiles over 24 h. Exposure levels over waking hours were expressed as mean percentage of the reference level. Overall, exposure to radiofrequency electromagnetic fields was far below the reference level. Seven percent of the children and 5% of the adolescents showed an abnormal mental behaviour. In the multiple logistic regression analyses measured exposure to RF fields in the highest quartile was associated to overall behavioural problems for adolescents (OR 2.2; 95% CI 1.1-4.5) but not for children (1.3; 0.7-2.6). These results are mainly driven by one subscale, as the results showed an association between exposure and conduct problems for adolescents (3.7; 1.6-8.4) and children (2.9; 1.4-5.9). As this is one of the first studies that investigated an association between exposure to mobile telecommunication networks and mental health behaviour more studies using personal dosimetry are warranted to confirm these findings.
TL;DR: For children born with birthweight ≥2,500 g, the prevalence of CP in Europe was stable in spite of changes by subtype and a significant decrease in neonatal mortality.
Abstract: Time trends for cerebral palsy (CP) prevalence in children born ≥2,500 g vary across studies and scarce data exist on trends by subtype of CP. The objective of this study was to describe changes in prevalence of CP in infants born ≥2,500 g between 1980 and 1998 in Europe. Data were collated from the SCPE (Surveillance of Cerebral Palsy in Europe collaboration) common database. Poisson regression was used to test for change in prevalence over time. Birth year and register effects were explored and trends in prevalence were estimated by CP subtype and severity. Four thousand and two children with CP and birthweight ≥2,500 g were recorded in 15 population based-registers. The overall prevalence of CP was 1.16 per 1,000 live births (99% CI, 0.88–1.48) in 1980 and 0.99 (CI, 0.80–1.20) in 1998. The trend was not significant (P = .14), except in two registers. However, there were significant changes in the prevalence of spastic CP subtypes, with a decrease in the bilateral spastic form (P < .001), and an increase in the unilateral spastic form (P = .004). There was a concurrent reduction in neonatal mortality of children with birthweight ≥2,500 g: from 1.7 (CI, 1.4–2.1) to 0.9 (CI, 0.7–1.1) per 1,000 live births. In conclusion, for children born with birthweight ≥2,500 g, the prevalence of CP in Europe was stable in spite of changes by subtype and a significant decrease in neonatal mortality.
TL;DR: Several strong predictors are available to predict 60 day case-fatality in aSAH patients who survived the early stage up till a treatment decision; after external validation these predictors could eventually be used in clinical decision making.
Abstract: Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating event with substantial case-fatality. Our purpose was to examine which clinical and neuro-imaging characteristics, available on admission, predict 60 day case-fatality in aSAH and to evaluate performance of our prediction model. We performed a secondary analysis of patients enrolled in the International Subarachnoid Aneurysm Trial (ISAT), a randomised multicentre trial to compare coiling with clipping in aSAH patients. Multivariable logistic regression analysis was used to develop a prognostic model to estimate the risk of dying within 60 days from aSAH based on clinical and neuro-imaging characteristics. The model was internally validated with bootstrapping techniques. The study population comprised of 2,128 patients who had been randomised to either endovascular coiling or neurosurgical clipping. In this population 153 patients (7.2%) died within 60 days. World Federation of Neurosurgical Societies (WFNS) grade was the most important predictor of case-fatality, followed by age, lumen size of the aneurysm and Fisher grade. The model discriminated reasonably between those who died within 60 days and those who survived (c statistic = 0.73), with minor optimism according to bootstrap re-sampling (optimism corrected c statistic = 0.70). Several strong predictors are available to predict 60 day case-fatality in aSAH patients who survived the early stage up till a treatment decision; after external validation these predictors could eventually be used in clinical decision making.
TL;DR: People with MetS had significantly higher HOMA-IR scores, lower adiponectin levels, and higher CRP levels and were associated with poorer executive function in women.
Abstract: While type 2 diabetes is well-known to be associated with poorer cognitive performance, few studies have reported on the association of metabolic syndrome (MetS) and contributing factors, such as insulin-resistance (HOMA-IR), low adiponectin-, and high C-reactive protein (CRP)- levels. We studied whether these factors are related to cognitive function and which of the MetS components are independently associated. The study was embedded in an ongoing family-based cohort study in a Dutch population. All participants underwent physical examinations, biomedical measurements, and neuropsychological testing. Linear regression models were used to determine the association between MetS, HOMA-IR, adiponectin levels, CRP, and cognitive test scores. Cross-sectional analyses were performed in 1,898 subjects (mean age 48 years, 43% men). People with MetS had significantly higher HOMA-IR scores, lower adiponectin levels, and higher CRP levels. MetS and high HOMA-IR were associated with poorer executive function in women (P = 0.03 and P = 0.009). MetS and HOMA-IR are associated with poorer executive function in women.
TL;DR: No substantial effect modification is found between different measures of adiposity and physical activity—physical inactivity and obesity seem to increase total mortality risk independently and additively.
Abstract: The health benefits of physical activity (PA) have been well documented. However, there is less research investigating whether or not these health benefits might differ among males and females or among subjects characterized by different levels of body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC). Baseline total PA, BMI, WHR and waist circumference were measured in 14,585 men and 26,144 women who participated in the Swedish National March. Their effects on all-cause mortality were analyzed with a follow-up time of almost 10 years. Sedentary men with a BMI ≥ 30 had a 98% (95% CI: 30–201%) increased risk of mortality compared to normal weight men with a high level of total PA. The same trend was observed for sedentary men with high WHR or waist circumference, compared to lean and highly active men. Sedentary women with a waist circumference of 88 cm or more had almost doubled, i.e. 97% (95% CI: 35–189%) increased mortality risk compared to physically active women with a waist circumference below 80 cm. BMI in men, but waist circumference in women better forecast all-cause mortality. We found no substantial effect modification between different measures of adiposity and physical activity—physical inactivity and obesity seem to increase total mortality risk independently and additively.
TL;DR: Differences in the utilization and effectiveness of medical rehabilitation between Germans and foreign nationals cannot be explained only by socio-economic differences or poorer health before rehabilitation, and factors such as the ability of the rehabilitative care system to accommodate clients with differing expectations seem to play a role.
Abstract: In Germany, the proportion of foreign national residents receiving an invalidity pension is higher than that of Germans. Lower utilization and effectiveness of medical rehabilitation are presumed to be the main reasons. We aimed to examine whether differences in utilization and effectiveness of medical rehabilitation between Germans and foreign nationals are attributable to differences in socio-demography, socio-economic background and health status. Utilization of rehabilitation was analyzed for household members aged 18 years or above enrolled in the German Socio-Economic Panel in 2002-2004 (n = 19,521). Effectiveness of rehabilitation was defined by the occupational performance at the end of rehabilitation. It was examined by using an 80% random sample of all completed medical rehabilitations in the year 2006 funded by the German Statutory Pension Insurance Scheme (n = 634,529). Our study shows that foreign nationals utilize medical rehabilitation less often than Germans (OR = 0.68; 95%-CI = 0.50; 0.91). For those who do, medical rehabilitation is less effective (OR for low occupational performance = 1.50; 95%-CI = 1.46; 1.55). Both findings are only partially attributable to socio-demographic, socio-economic and health characteristics: After adjusting for these factors, ORs for utilization and low occupational performance were 0.66 (95%-CI = 0.49; 0.90) and 1.20 (95%-CI = 1.16; 1.24), respectively. It can be concluded that differences in the utilization and effectiveness of medical rehabilitation between Germans and foreign nationals cannot be explained only by socio-economic differences or poorer health before rehabilitation. In addition, factors such as the ability of the rehabilitative care system to accommodate clients with differing expectations, and migrant-specific characteristics such as cultural differences, seem to play a role.