Ellen A. Struijk

Dairy intake and coronary heart disease or stroke—A population-based cohort study

AIM This study aimed to investigate the relationship between total dairy intake and dairy subtypes (high-fat dairy, low-fat dairy, milk and milk products, cheese and fermented dairy) with incident coronary heart disease (CHD) and stroke. METHODS EPIC-NL is a prospective cohort study among 33,625 Dutch men and women. At baseline (1993-1997), dairy intake was measured with a validated food frequency questionnaire (FFQ). The incidence of both fatal and non-fatal CHD and stroke was obtained by linkage to the national registers. RESULTS During 13 years follow-up, 1648 cases of CHD and 531 cases of stroke were documented. Total dairy intake was not significantly associated with risk of CHD (hazard ratio per standard deviation (SD) increase=0.99; 95%-CI: 0.94-1.05) or stroke (0.95; 0.85-1.05) adjusted for lifestyle and dietary factors. None of the dairy subtypes was to CHD, while only fermented dairy tended to be associated (p=0.07) with a lower risk of stroke (0.92; 0.83-1.01). Hypertension appeared to modify the association of total and low-fat dairy with CHD (p interaction<0.02). Among participants without hypertension, but not among hypertensive participants, total (0.92; 0.85-1.02) and low-fat (0.94; 0.87-1.02) dairy tended to be associated with a lower risk of CHD. CONCLUSION Our results provide no evidence that dairy products are associated with risk of CHD or stroke. High intakes of total and low-fat dairy may be associated with a lower risk of CHD among participants without hypertension, while fermented dairy could be associated with a reduced risk of stroke.

Adherence to dietary guidelines and cardiovascular disease risk in the EPIC-NL cohort

BACKGROUND Global and national dietary guidelines have been created to lower chronic disease risk. The aim of this study was to assess whether greater adherence to the WHO guidelines (Healthy Diet Indicator (HDI)); the Dutch guidelines for a healthy diet (Dutch Healthy Diet-index (DHD-index)); and the Dietary Approaches to Stop Hypertension (DASH) diet was associated with a lower risk of cardiovascular disease (CVD), coronary heart disease (CHD) or stroke. METHODS A prospective cohort study was conducted among 33,671 healthy Dutch men and women aged 20-70 years recruited into the EPIC-NL study during 1993-1997. We used Cox regression adjusted for relevant confounders to estimate the hazard ratios per standard deviation increase in score and 95% confidence intervals (CI) of the associations between the dietary guidelines and CVD, CHD and stroke risk. RESULTS After an average follow-up of 12.2 years, 2752 CVD cases were documented, including 1630 CHD cases and 527 stroke cases. We found no association between the HDI (0.98, 95% CI 0.94; 1.02) or DHD-index (0.96, 95% CI 0.92; 1.00) and CVD incidence. Similar results were found for these guidelines and CHD or stroke incidence. Higher adherence to the DASH diet was significantly associated with a lower CVD (0.92, 95% CI 0.89; 0.96), CHD (0.91, 95% CI 0.86; 0.95), and stroke (0.90, 95% CI 0.82; 0.99) risk. CONCLUSION The HDI and the DHD-index were not associated with CVD risk, while the DASH diet was significantly associated with a lower risk of developing CVD, CHD and stroke.

WHO guidelines for a healthy diet and mortality from cardiovascular disease in European and American elderly: the CHANCES project

Background: Cardiovascular disease (CVD) represents a leading cause of mortality worldwide, especially in the elderly. Lowering the number of CVD deaths requires preventive strategies targeted on the elderly. Objective: The objective was to generate evidence on the association between WHO dietary recommendations and mortality from CVD, coronary artery disease (CAD), and stroke in the elderly aged ≥60 y. Design: We analyzed data from 10 prospective cohort studies from Europe and the United States comprising a total sample of 281,874 men and women free from chronic diseases at baseline. Components of the Healthy Diet Indicator (HDI) included saturated fatty acids, polyunsaturated fatty acids, mono- and disaccharides, protein, cholesterol, dietary fiber, and fruit and vegetables. Cohort-specific HRs adjusted for sex, education, smoking, physical activity, and energy and alcohol intakes were pooled by using a random-effects model. Results: During 3,322,768 person-years of follow-up, 12,492 people died of CVD. An increase of 10 HDI points (complete adherence to an additional WHO guideline) was, on average, not associated with CVD mortality (HR: 0.94; 95% CI: 0.86, 1.03), CAD mortality (HR: 0.99; 95% CI: 0.85, 1.14), or stroke mortality (HR: 0.95; 95% CI: 0.88, 1.03). However, after stratification of the data by geographic region, adherence to the HDI was associated with reduced CVD mortality in the southern European cohorts (HR: 0.87; 95% CI: 0.79, 0.96; I2 = 0%) and in the US cohort (HR: 0.85; 95% CI: 0.83, 0.87; I2 = not applicable). Conclusion: Overall, greater adherence to the WHO dietary guidelines was not significantly associated with CVD mortality, but the results varied across regions. Clear inverse associations were observed in elderly populations in southern Europe and the United States.

Dietary patterns in relation to disease burden expressed in Disability-Adjusted Life Years

BACKGROUND Although diet is related to chronic disease risk and mortality, its association with total disease burden is not clear. OBJECTIVE We investigated the minimum impact of different dietary patterns on disability-adjusted life years (DALYs) by using individual longitudinal data. DESIGN A prospective cohort study was conducted in 33,066 healthy men and women aged 20-70 y recruited into the European Prospective Investigation into Cancer and Nutrition-Netherlands study during 1993-1997. We measured adherence to 3 a priori dietary patterns [the modified Mediterranean diet score (mMDS), the WHO-based Healthy Diet Indicator, and the Dutch Healthy Diet index] and 2 a posteriori dietary patterns. Two a posteriori methods were used to extract Western and prudent patterns. Participants were followed until the end of 2007 for the occurrence of and mortality from the most important chronic diseases. The disease burden was expressed in DALYs, which are the sum of Years Lost due to Disability and Years of Life Lost because of premature mortality. The associations between dietary patterns (per SD change in score) and DALYs were estimated by using a 2-part model and adjusted for relevant confounders (sex, age at recruitment, smoking status and intensity, educational level, marital status, job status, energy intake, and physical activity). RESULTS After an average follow-up of 12.4 y, higher adherence to the mMDS or prudent pattern was most strongly associated with healthy survival; per SD higher adherence to the mMDS or prudent pattern, fewer healthy life years were lost [51 d (-0.14 DALYs; 95% CI: -0.21, -0.08 DALYs) and 58 d (-0.16 DALYs; 95% CI: -0.23, -0.09 DALYs), respectively]. CONCLUSION In this Dutch study, of various dietary patterns evaluated, higher adherence to the mMDS or prudent dietary pattern was associated with a lower disease burden as assessed by DALYs.

Association between Lifestyle Factors and Quality-Adjusted Life Years in the EPIC-NL Cohort

The aim of our study was to relate four modifiable lifestyle factors (smoking status, body mass index, physical activity and diet) to health expectancy, using quality-adjusted life years (QALYs) in a prospective cohort study. Data of the prospective EPIC-NL study were used, including 33,066 healthy men and women aged 20–70 years at baseline (1993–7), followed until 31-12-2007 for occurrence of disease and death. Smoking status, body mass index, physical activity and adherence to a Mediterranean-style diet (excluding alcohol) were investigated separately and combined into a healthy lifestyle score, ranging from 0 to 4. QALYs were used as summary measure of healthy life expectancy, combining a persons life expectancy with a weight for quality of life when having a chronic disease. For lifestyle factors analyzed separately the number of years living longer in good health varied from 0.12 year to 0.84 year, after adjusting for covariates. A combination of the four lifestyle factors was positively associated with higher QALYs (P-trend <0.0001). A healthy lifestyle score of 4 compared to a score of 0 was associated with almost a 2 years longer life in good health (1.75 QALYs [95% CI 1.37, 2.14]).

Development of Methodology for Disability-Adjusted Life Years (DALYs) Calculation Based on Real-Life Data

Background Disability-Adjusted Life Years (DALYs) have the advantage that effects on total health instead of on a specific disease incidence or mortality can be estimated. Our aim was to address several methodological points related to the computation of DALYs at an individual level in a follow-up study. Methods DALYs were computed for 33,507 men and women aged 20–70 years when participating in the EPIC-NL study in 1993–7. DALYs are the sum of the Years Lost due to Disability (YLD) and the Years of Life Lost (YLL) due to premature mortality. Premature mortality was defined as death before the estimated date of individual Life Expectancy (LE). Different methods to compute LE were compared as well as the effect of different follow-up periods using a two-part model estimating the effect of smoking status on health as an example. Results During a mean follow-up of 12.4 years, there were 69,245 DALYs due to years lived with a disease or premature death. Current-smokers had lost 1.28 healthy years of their life (1.28 DALYs 95%CI 1.10; 1.46) compared to never-smokers. The outcome varied depending on the method used for estimating LE, completeness of disease and mortality ascertainment and notably the percentage of extinction (duration of follow-up) of the cohort. Conclusion We conclude that the use of DALYs in a cohort study is an appropriate way to assess total disease burden in relation to a determinant. The outcome is sensitive to the LE calculation method and the follow-up duration of the cohort.

Modifiable causes of premature death in middle-age in Western Europe: Results from the EPIC cohort study

BackgroundLife expectancy is increasing in Europe, yet a substantial proportion of adults still die prematurely before the age of 70 years. We sought to estimate the joint and relative contributions of tobacco smoking, hypertension, obesity, physical inactivity, alcohol and poor diet towards risk of premature death.MethodsWe analysed data from 264,906 European adults from the EPIC prospective cohort study, aged between 40 and 70 years at the time of recruitment. Flexible parametric survival models were used to model risk of death conditional on risk factors, and survival functions and attributable fractions (AF) for deaths prior to age 70 years were calculated based on the fitted models.ResultsWe identified 11,930 deaths which occurred before the age of 70. The AF for premature mortality for smoking was 31 % (95 % confidence interval (CI), 31–32 %) and 14 % (95 % CI, 12–16 %) for poor diet. Important contributions were also observed for overweight and obesity measured by waist-hip ratio (10 %; 95 % CI, 8–12 %) and high blood pressure (9 %; 95 % CI, 7–11 %). AFs for physical inactivity and excessive alcohol intake were 7 % and 4 %, respectively. Collectively, the AF for all six risk factors was 57 % (95 % CI, 55–59 %), being 35 % (95 % CI, 32–37 %) among never smokers and 74 % (95 % CI, 73–75 %) among current smokers.ConclusionsWhile smoking remains the predominant risk factor for premature death in Europe, poor diet, overweight and obesity, hypertension, physical inactivity, and excessive alcohol consumption also contribute substantially. Any attempt to minimise premature deaths will ultimately require all six factors to be addressed.

Dietary patterns in relation to quality-adjusted life years in the EPIC-NL cohort.

BACKGROUND Dietary patterns have been associated with the incidence or mortality of individual non-communicable diseases, but their association with disease burden has received little attention. OBJECTIVE The aim of our study was to relate dietary patterns to health expectancy using quality-adjusted life years (QALYs) as outcome parameter. METHODS Data from the EPIC-NL study were used, a prospective cohort study of 33,066 healthy men and women aged 20-70 years at recruitment. A lifestyle questionnaire and a validated food frequency questionnaire were administered at study entry (1993-1997). Five dietary patterns were studied: three a priori patterns (the modified Mediterranean Diet Score (mMDS), the WHO-based Healthy Diet Indicator (HDI) and the Dutch Healthy Diet index (DHD-index)) and two a posteriori data-based patterns. QALYs were used as a summary health measure for healthy life expectancy, combining a persons life expectancy with a weight reflecting loss of quality of life associated with having chronic diseases. RESULTS The mean QALYs of the participants were 74.9 (standard deviation 4.4). A higher mMDS and HDI were associated with a longer life in good health. Participants who had a high mMDS score (6-9) had 0.17 [95% CI, 0.05; 0.30] more QALYs than participants with a low score (0-3), equivalent to two months longer life in good health. Participants with a high HDI score also had more QALYs (0.15 [95% CI, 0.03; 0.27]) than participants with a low HDI score. CONCLUSION A Mediterranean-type diet and the Healthy Diet Indicator were associated with approximately 2months longer life in good health.

Mortality and cancer incidence in the EPIC-NL cohort : impact of the healthy volunteer effect

BACKGROUND Prospective cohort studies recruit relatively healthy population samples, resulting in lower morbidity and mortality rates than in the source population. This is known as the healthy volunteer effect. The aim of this study was to define the magnitude and the development over time of the healthy volunteer effect in the EPIC-NL cohort. METHODS We studied mortality rates in the EPIC-NL cohort, which comprises 37 551 men and women aged 20-70 years at recruitment in 1993-97. The date and cause of death of deceased participants until 2010 were obtained through linkage with the municipal registry and Statistics Netherlands. Standardized mortality ratios (SMRs) were computed by dividing the observed number of deaths by the number of deaths expected from the general Dutch population. Additionally, standardized incidence ratios were calculated to compare cancer incidence. RESULTS After an average follow-up of 14.9 years, 3029 deaths were documented. Overall mortality in men [SMR 73.5%, 95% confidence interval (CI): 68.1-79.3] and women (SMR 65.9%, 95% CI: 63.2-68.6) was lower compared with the general population for the whole follow-up period. The SMRs clearly increased over the follow-up period. Among women, the SMR was lower for death due to cardiovascular diseases than death due to cancer. Cancer incidence was also lower in EPIC-NL than in the general population (SMR 78.3 and 82.7% for men and women, respectively). CONCLUSION The results show a healthy volunteer effect in the EPIC-NL cohort, which tapers off with longer follow-up. Therefore, in the first years of follow-up, power might not be sufficient to detect small associations.

The Association between Dietary Energy Density and Type 2 Diabetes in Europe: Results from the EPIC-InterAct Study

Background Observational studies implicate higher dietary energy density (DED) as a potential risk factor for weight gain and obesity. It has been hypothesized that DED may also be associated with risk of type 2 diabetes (T2D), but limited evidence exists. Therefore, we investigated the association between DED and risk of T2D in a large prospective study with heterogeneity of dietary intake. Methodology/Principal Findings A case-cohort study was nested within the European Prospective Investigation into Cancer (EPIC) study of 340,234 participants contributing 3.99 million person years of follow-up, identifying 12,403 incident diabetes cases and a random subcohort of 16,835 individuals from 8 European countries. DED was calculated as energy (kcal) from foods (except beverages) divided by the weight (gram) of foods estimated from dietary questionnaires. Prentice-weighted Cox proportional hazard regression models were fitted by country. Risk estimates were pooled by random effects meta-analysis and heterogeneity was evaluated. Estimated mean (sd) DED was 1.5 (0.3) kcal/g among cases and subcohort members, varying across countries (range 1.4–1.7 kcal/g). After adjustment for age, sex, smoking, physical activity, alcohol intake, energy intake from beverages and misreporting of dietary intake, no association was observed between DED and T2D (HR 1.02 (95% CI: 0.93–1.13), which was consistent across countries (I 2 = 2.9%). Conclusions/Significance In this large European case-cohort study no association between DED of solid and semi-solid foods and risk of T2D was observed. However, despite the fact that there currently is no conclusive evidence for an association between DED and T2DM risk, choosing low energy dense foods should be promoted as they support current WHO recommendations to prevent chronic diseases.