Accumulation of persistent organic pollutants in consumers of eel from polluted rivers compared to marketable eel

Globally, many river sediments are seriously contaminated with persistent organic pollutants (POPs) known to accumulate in aquatic food. In the Netherlands, toxicological risks of human exposure to dioxins and dioxin-like compounds led to a ban on eel fishing in the Rhine-Meuse delta. The aim of this study is to investigate differences in serum POP levels in consumers of eel from high-polluted areas and consumers of eel from low-polluted areas or aquaculture. In total 80 Dutch men were included, aged 40-70 years, with a habitual eel consumption of at least one portion (150 g) per month. Total levels of dioxins and dioxin-like compounds were measured in serum of all participants with the DR CALUX bioassay, validated with GC-MS. For a subgroup of 38 participants extensive POP measurements were performed. We revealed that consumption of eel from polluted rivers resulted in 2.5 and up to 10 times increased levels of dioxins and polychlorinated biphenyls (PCBs) respectively compared to controls. The highest PCB levels were detected for PCB 153, with a median level of 896 ng/g lipid and a maximum level of 5000 ng/g lipid in the high-exposed group. Furthermore, hydroxylated PCB metabolites (OH-PCBs: sum of 4-OH-CB107, 4-OH-CB146, 4'-OH-CB172, and 4-OH-CB187) were 8 times higher in men who consumed eel from polluted areas, and detected at levels (median 4.5 ng/g ww) reported to cause adverse health effects. Also, the majority of the perfluoroalkyl substances (PFASs) were significantly higher in consumers of eel from pullulated areas. In conclusion, this study is the first to reveal that (past) consumption of eel from polluted rivers resulted in high body burdens of dioxins, PCBs, OH-PCBs and PFASs. We confirmed the predictions made in a former risk assessment, and the high levels of dioxins and dioxin-like compounds as well as the OH-PCBs are of health concern.

Anthropometry and the Risk of Lung Cancer in EPIC

The associations of body mass index (BMI) and other anthropometric measurements with lung cancer were examined in 348,108 participants in the European Investigation Into Cancer and Nutrition (EPIC) between 1992 and 2010. The study population included 2,400 case patients with incident lung cancer, and the average length of follow-up was 11 years. Hazard ratios were calculated using Cox proportional hazard models in which we modeled smoking variables with cubic splines. Overall, there was a significant inverse association between BMI (weight (kg)/height (m)(2)) and the risk of lung cancer after adjustment for smoking and other confounders (for BMI of 30.0-34.9 versus 18.5-25.0, hazard ratio = 0.72, 95% confidence interval: 0.62, 0.84). The strength of the association declined with increasing follow-up time. Conversely, after adjustment for BMI, waist circumference and waist-to-height ratio were significantly positively associated with lung cancer risk (for the highest category of waist circumference vs. the lowest, hazard ratio = 1.25, 95% confidence interval: 1.05, 1.50). Given the decline of the inverse association between BMI and lung cancer over time, the association is likely at least partly due to weight loss resulting from preclinical lung cancer that was present at baseline. Residual confounding by smoking could also have influenced our findings.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research lifestyle recommendations in colorectal cancer survivors: results of the PROFILES registry

We examined adherence to the eight The World Cancer Research Foundation/American Institute for Cancer Research (WCRF/AICR) recommendations on diet, physical activity, and body weight among colorectal cancer survivors, and whether adherence was associated with intention to eat healthy and with the need for dietary advice. Adherence to these recommendations may putatively reduce the risk of recurrence and death. Studies on adherence to these recommendations in colorectal cancer (CRC) survivors are lacking. Adherence was assessed in a cross-sectional study among 1196 CRC survivors and could range between 0 (no adherence) and 8 points (complete adherence). Participants completed questionnaires on dietary intake, physical activity, and body weight. Prevalence Ratios were calculated to assess whether adherence to recommendations were associated with dietary intentions and needs. Twelve percentage of the survivors adhered to 6 or more recommendations; 65% had a score between >4 and 6 points; 23% scored no more than 4 points. The recommendation for to be modest with consumption of meat showed lowest adherence: 8% adhered; whereas the recommendation not to use dietary supplements showed highest adherence (75%). 18% reported a need for dietary advice, but this was not associated with adherence to recommendations. Survivors with higher adherence reported less often that they had received dietary advice, were less likely to have the intention to eat healthier, but reported more often that they had changed their diet since diagnosis. There is ample room for improvement of lifestyle recommendations in virtually all CRC survivors. A minor part of CRC survivors expressed a need for dietary advice which was not associated with adherence to the recommendations.

Quantification of the smoking-associated cancer risk with rate advancement periods: meta-analysis of individual participant data from cohorts of the CHANCES consortium

BACKGROUND

Smoking is the most important individual risk factor for many cancer sites but its association with breast and prostate cancer is not entirely clear. Rate advancement periods (RAPs) may enhance communication of smoking related risk to the general population. Thus, we estimated RAPs for the association of smoking exposure (smoking status, time since smoking cessation, smoking intensity, and duration) with total and site-specific (lung, breast, colorectal, prostate, gastric, head and neck, and pancreatic) cancer incidence and mortality.

METHODS

This is a meta-analysis of 19 population-based prospective cohort studies with individual participant data for 897,021 European and American adults. For each cohort we calculated hazard ratios (HRs) for the association of smoking exposure with cancer outcomes using Cox regression adjusted for a common set of the most important potential confounding variables. RAPs (in years) were calculated as the ratio of the logarithms of the HRs for a given smoking exposure variable and age. Meta-analyses were employed to summarize cohort-specific HRs and RAPs.

RESULTS

Overall, 140,205 subjects had a first incident cancer, and 53,164 died from cancer, during an average follow-up of 12 years. Current smoking advanced the overall risk of developing and dying from cancer by eight and ten years, respectively, compared with never smokers. The greatest advancements in cancer risk and mortality were seen for lung cancer and the least for breast cancer. Smoking cessation was statistically significantly associated with delays in the risk of cancer development and mortality compared with continued smoking.

CONCLUSIONS

This investigation shows that smoking, even among older adults, considerably advances, and cessation delays, the risk of developing and dying from cancer. These findings may be helpful in more effectively communicating the harmful effects of smoking and the beneficial effect of smoking cessation.

Candidate Predictors of Health-Related Quality of Life of Colorectal Cancer Survivors: A Systematic Review

The population of colorectal cancer (CRC) survivors is growing and many survivors experience deteriorated health-related quality of life (HRQoL) in both early and late post-treatment phases. Identification of CRC survivors at risk for HRQoL deterioration can be improved by using prediction models. However, such models are currently not available for oncology practice. As a starting point for developing prediction models of HRQoL for CRC survivors, a comprehensive overview of potential candidate HRQoL predictors is necessary. Therefore, a systematic literature review was conducted to identify candidate predictors of HRQoL of CRC survivors. Original research articles on associations of biopsychosocial factors with HRQoL of CRC survivors were searched in PubMed, Embase, and Google Scholar. Two independent reviewers assessed eligibility and selected articles for inclusion (N = 53). Strength of evidence for candidate HRQoL predictors was graded according to predefined methodological criteria. The World Health Organization's International Classification of Functioning, Disability and Health (ICF) was used to develop a biopsychosocial framework in which identified candidate HRQoL predictors were mapped across the main domains of the ICF: health condition, body structures and functions, activities, participation, and personal and environmental factors. The developed biopsychosocial ICF framework serves as a basis for selecting candidate HRQoL predictors, thereby providing conceptual guidance for developing comprehensive, evidence-based prediction models of HRQoL for CRC survivors. Such models are useful in clinical oncology practice to aid in identifying individual CRC survivors at risk for HRQoL deterioration and could also provide potential targets for a biopsychosocial intervention aimed at safeguarding the HRQoL of at-risk individuals.

IMPLICATIONS FOR PRACTICE

More and more people now survive a diagnosis of colorectal cancer. The quality of life of these cancer survivors is threatened by health problems persisting for years after diagnosis and treatment. Early identification of survivors at risk of experiencing low quality of life in the future is thus important for taking preventive measures. Clinical prediction models are tools that can help oncologists identify at-risk individuals. However, such models are currently not available for clinical oncology practice. This systematic review outlines candidate predictors of low quality of life of colorectal cancer survivors, providing a firm conceptual basis for developing prediction models.

Pre-diagnostic vitamin D concentrations and cancer risks in older individuals: an analysis of cohorts participating in the CHANCES consortium

The associations of circulating 25-hydroxyvitamin D [25(OH)D] concentrations with total and site-specific cancer incidence have been examined in several epidemiological studies with overall inconclusive findings. Very little is known about the association of vitamin D with cancer incidence in older populations. We assessed the association of pre-diagnostic serum 25(OH)D levels with incidence of all cancers combined and incidence of lung, colorectal, breast, prostate and lymphoid malignancies among older adults. Pre-diagnostic 25(OH)D concentrations and cancer incidence were available in total for 15,486 older adults (mean age 63, range 50-84 years) participating in two cohort studies: ESTHER (Germany) and TROMSØ (Norway); and a subset of previously published nested-case control data from a another cohort study: EPIC-Elderly (Greece, Denmark, Netherlands, Spain and Sweden) from the CHANCES consortium on health and aging. Cox proportional hazards or logistic regression were used to derive multivariable adjusted hazard and odds ratios, respectively, and their 95% confidence intervals across 25(OH)D categories. Meta-analyses with random effects models were used to pool study-specific risk estimates. Overall, lower 25(OH)D concentrations were not significantly associated with increased incidence of most of the cancers assessed. However, there was some evidence of increased breast cancer and decreased lymphoma risk with higher 25(OH)D concentrations. Our meta-analyses with individual participant data from three large European population-based cohort studies provide at best limited support for the hypothesis that vitamin D may have a major role in cancer development and prevention among European older adults.

Abstract P1-10-28: Cultural and religious differences during breast cancer treatment between Dutch and non-Western immigrant women

Background

Twelve percent of the Dutch population consists of non-Western immigrant women with an incidence of breast cancer that has risen from 2,9% in 2005 to 5% in 2015. For the second generation of these women the incidence of breast cancer is expected to meet the native Dutch population rates soon, partly due to adoption of Western style dietary habits and physical activity. Chemotherapeutic treatment (CT) for breast cancer is associated with increased body fatness and interventions to prevent this increase are currently explored. Whether perceptions on cancer and treatment differ between non-Western immigrant women than for Dutch women needs to be evaluated before these interventions can be set up. This study aimed to explore cultural and religious differences on women's perceptions of the diagnosis of breast cancer and changes in physical activity and eating habits during chemotherapy treatment.

Methods

A longitudinal qualitative multiple case study was conducted. Newly diagnosed women with breast cancer were recruited and purposively selected (n=23, non-immigrant) from six hospitals in the Netherlands. Semi structured interviews were conducted three times (in total 69): before start of CT, halfway and after CT. In addition 38 women (20 non-immigrant and 18 immigrant) were recruited and interviewed after finishing CT. All interviews (n=107, from 61 women) were audiotaped and transcribed verbatim. A thematic content analysis approach was used.

Results

All 43 non-immigrant women, mean age 51,1 yrs. and 18 immigrant women mean age 43,2 yrs., experienced known side effects from CT. Loss of hair and sometimes the breast appeared to be especially for immigrant women a shocking experience and for some even a loss of femininity. Most of the women perceived to have received incomplete and often unclear information from hospitals about weight and CT treatment. Immigrant women participating the Ramadan during treatment encountered resistance from their physicians. Weight gain during period of CT was higher among immigrant women (mean 13,1 kg, 4-28 kg) than among non-immigrant women (mean 2,5 kg, 2-9 kg). Although both groups said to be less physically active and complained about fatigue, non-immigrant women trying to maintain daily structure and were more active with their diet than most immigrants. Immigrant women expressed cancer as a taboo in their culture impeding them to talk openly about their illness, only when side effects of CT such as hair loss were visible they found it inevitable. Cancer was associated with death at time of diagnosis. For most immigrants and a few non-immigrants this was considered a religious ordeal from Allah or God, these women perceived less influence on their behavior during treatment. Most non-religious women perceived breast cancer as bad luck, stress or heredity.

Conclusion

Especially immigrant women experienced little respect for their culture and insufficient information about treatment. Non-immigrants had a need to actively contribute to their treatment while this need was less obvious for immigrants. Probably because they felt not encouraged by their religion and culture.

Citation Format: de Kruif AJ, Derks MJ, de Boer MR, Winkels R, Visser M, Kampman E, Westerman MJ. Cultural and religious differences during breast cancer treatment between Dutch and non-Western immigrant women. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-28.

The effects of long-term daily folic acid and vitamin B12 supplementation on genome-wide DNA methylation in elderly subjects

BACKGROUND

Folate and its synthetic form folic acid function as donor of one-carbon units and have been, together with other B-vitamins, implicated in programming of epigenetic processes such as DNA methylation during early development. To what extent regulation of DNA methylation can be altered via B-vitamins later in life, and how this relates to health and disease, is not exactly known. The aim of this study was to identify effects of long-term supplementation with folic acid and vitamin B12 on genome-wide DNA methylation in elderly subjects. This project was part of a randomized, placebo-controlled trial on effects of supplemental intake of folic acid and vitamin B12 on bone fracture incidence (B-vitamins for the PRevention Of Osteoporotic Fractures (B-PROOF) study). Participants with mildly elevated homocysteine levels, aged 65-75 years, were randomly assigned to take 400 μg folic acid and 500 μg vitamin B12 per day or a placebo during an intervention period of 2 years. DNA was isolated from buffy coats, collected before and after intervention, and genome-wide DNA methylation was determined in 87 participants (n = 44 folic acid/vitamin B12, n = 43 placebo) using the Infinium HumanMethylation450 BeadChip.

RESULTS

After intervention with folic acid and vitamin B12, 162 (versus 14 in the placebo group) of the 431,312 positions were differentially methylated as compared to baseline. Comparisons of the DNA methylation changes in the participants receiving folic acid and vitamin B12 versus placebo revealed one single differentially methylated position (cg19380919) with a borderline statistical significance. However, based on the analyses of differentially methylated regions (DMRs) consisting of multiple positions, we identified 6 regions that differed statistically significantly between the intervention and placebo group. Pronounced changes were found for regions in the DIRAS3, ARMC8, and NODAL genes, implicated in carcinogenesis and early embryonic development. Furthermore, serum levels of folate and vitamin B12 or plasma homocysteine were related to DNA methylation of 173, 425, and 11 regions, respectively. Interestingly, for several members of the developmental HOX genes, DNA methylation was related to serum levels of folate.

CONCLUSIONS

Long-term supplementation with folic acid and vitamin B12 in elderly subjects resulted in effects on DNA methylation of several genes, among which genes implicated in developmental processes.

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; I(2) = 0%) and in the US cohort (HR: 0.85; 95% CI: 0.83, 0.87; I(2) = 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.

Vitamin D, Inflammation, and Colorectal Cancer Progression: A Review of Mechanistic Studies and Future Directions for Epidemiological Studies

Survival from colorectal cancer is positively associated with vitamin D status. However, whether this association is causal remains unclear. Inflammatory processes may link vitamin D to colorectal cancer survival, and therefore investigating inflammatory markers as potential mediators may be a valuable next step. This review starts with an overview of inflammatory processes suggested to be involved in colorectal cancer progression and regulated by vitamin D. Next, we provide recommendations on how to study inflammatory markers in future epidemiologic studies on vitamin D and colorectal cancer survival. Mechanistic studies have shown that calcitriol-active form of vitamin D-influences inflammatory processes involved in cancer progression, including the enzyme cyclooxygenase 2, the NF-κB pathway, and the expression of the cytokines TNFα, IL1β, IL6, IL8, IL17, and TGFβ1. Based on this and taking into account methodologic issues, we recommend to include analysis of specific soluble peptides and proteins, such as cytokines, in future epidemiologic studies on this issue. Vitamin D and the markers should preferably be measured at multiple time points during disease progression or recovery and analyzed using mediation analysis. Including these markers in epidemiologic studies may help answer whether inflammation mediates a causal relationship between vitamin D and colorectal cancer survival.

Development of a Website Providing Evidence-Based Information About Nutrition and Cancer: Fighting Fiction and Supporting Facts Online

Background

Although widely available, the general public, cancer patients, and cancer survivors have difficulties accessing evidence-based information on nutrition and cancer. It is challenging to distinguish myths from facts, and sometimes conflicting information can be found in different places. The public and patients would benefit from evidence-based, correct, and clear information from an easily recognizable source.

Objective

The aim of this project is to make scientific information available for the general public, cancer patients, and cancer survivors through a website. The aim of this paper is to describe and evaluate the development of the website as well as related statistics 1st year after its launch.

Methods

To develop the initial content for the website, the website was filled with answers to frequently asked questions provided by cancer organizations and the Dutch Dietetic Oncology Group, and by responding to various fiction and facts published in the media. The website was organized into 3 parts, namely, nutrition before (prevention), during, and after cancer therapy; an opportunity for visitors to submit specific questions regarding nutrition and cancer was included. The website was pretested by patients, health care professionals, and communication experts. After launching the website, visitors’ questions were answered by nutritional scientists and dieticians with evidence- or eminence-based information on nutrition and cancer. Once the website was live, question categories and website statistics were recorded.

Results

Before launch, the key areas for improvement, such as navigation, categorization, and missing information, were identified and adjusted. In the 1st year after the launch, 90,111 individuals visited the website, and 404 questions were submitted on nutrition and cancer. Most of the questions were on cancer prevention and nutrition during the treatment of cancer.

Conclusions

The website provides access to evidence- and eminence-based information on nutrition and cancer. As can be concluded from the number of visitors and the number of questions submitted to the website, the website fills a gap.

Pretreatment body mass index and head and neck cancer outcome: A review of the literature

BACKGROUND

The prevalence of overweight and obesity defined as BMI≥25kg/m(2) is increasing, also among head and neck cancer patients. It is unknown whether the presence of high BMI influences disease-related mortality, overall survival and recurrence in these patients.

METHODS

We reviewed available literature using Pubmed and Web of Science. Human observational studies were included if they reported the impact of high BMI on mortality, recurrence or survival for head and neck cancer.

RESULTS

Eleven full articles and two abstracts met the inclusion criteria: six prospective and seven retrospective cohort studies, which comprised 8.306 patients. Patients with higher BMI had increased overall survival and decreased disease-related mortality and recurrence rate compared with underweight and normal weight patients. Most studies were adjusted for potentially confounding variables, such as stage of disease and smoking habits.

CONCLUSION

High BMI is associated with a better outcome in head and neck cancer.

The proportion of postmenopausal breast cancer cases in the Netherlands attributable to lifestyle-related risk factors

We aimed to estimate the proportion of Dutch postmenopausal breast cancer cases in 2010 that is attributable to lifestyle-related risk factors. We calculated population attributable fractions (PAFs) of potentially modifiable risk factors for postmenopausal breast cancer in Dutch women aged >50 in 2010. First, age-specific PAFs were calculated for each risk factor, based on their relative risks for postmenopausal breast cancer (from meta-analyses) and age-specific prevalence in the population (from national surveys) around the year 2000, assuming a latency period of 10 years. To obtain the overall PAF, age-specific PAFs were summed in a weighted manner, using the age-specific breast cancer incidence rates (2010) as weights. 95 % confidence intervals for PAF estimates were derived by Monte Carlo simulations. Of Dutch women >40 years, in 2000, 51 % were overweight/obese, 55 % physically inactive (<5 days/week 30 min activity), 75 % regularly consumed alcohol, 42 % ever smoked cigarettes and 79 % had a low-fibre intake (<3.4 g/1000 kJ/day). These factors combined had a PAF of 25.7 % (95 % CI 24.2–27.2), corresponding to 2,665 Dutch postmenopausal breast cancer cases in 2010. PAFs were 8.8 % (95 % CI 6.3–11.3) for overweight/obesity, 6.6 % (95 % CI 5.2–8.0) for alcohol consumption, 5.5 % (95 % CI 4.0–7.0) for physical inactivity, 4.6 % (95 % CI 3.3–6.0) for smoking and 3.2 % (95 % CI 1.6–4.8) for low-fibre intake. Our findings imply that modifiable risk factors are jointly responsible for approximately one out of four Dutch postmenopausal breast cancer cases. This suggests that incidence rates can be lowered substantially by living a more healthy lifestyle.

The Consortium on Health and Ageing: Network of Cohorts in Europe and the United States (CHANCES) project--design, population and data harmonization of a large-scale, international study

There is a public health demand to prevent health conditions which lead to increased morbidity and mortality among the rapidly-increasing elderly population. Data for the incidence of such conditions exist in cohort studies worldwide, which, however, differ in various aspects. The Consortium on Health and Ageing: Network of Cohorts in Europe and the United States (CHANCES) project aims at harmonizing data from existing major longitudinal studies for the elderly whilst focussing on cardiovascular diseases, diabetes mellitus, cancer, fractures and cognitive impairment in order to estimate their prevalence, incidence and cause-specific mortality, and identify lifestyle, socioeconomic, and genetic determinants and biomarkers for the incidence of and mortality from these conditions. A survey instrument assessing ageing-related conditions of the elderly will be also developed. Fourteen cohort studies participate in CHANCES with 683,228 elderly (and 150,210 deaths), from 23 European and three non-European countries. So far, 287 variables on health conditions and a variety of exposures, including biomarkers and genetic data have been harmonized. Different research hypotheses are investigated with meta-analyses. The results which will be produced can help international organizations, governments and policy-makers to better understand the broader implications and consequences of ageing and thus make informed decisions.

Adherence to a healthy diet according to the World Health Organization guidelines and all-cause mortality in elderly adults from Europe and the United States

The World Health Organization (WHO) has formulated guidelines for a healthy diet to prevent chronic diseases and postpone death worldwide. Our objective was to investigate the association between the WHO guidelines, measured using the Healthy Diet Indicator (HDI), and all-cause mortality in elderly men and women from Europe and the United States. We analyzed data from 396,391 participants (42% women) in 11 prospective cohort studies who were 60 years of age or older at enrollment (in 1988-2005). HDI scores were based on 6 nutrients and 1 food group and ranged from 0 (least healthy diet) to 70 (healthiest diet). Adjusted cohort-specific hazard ratios were derived by using Cox proportional hazards regression and subsequently pooled using random-effects meta-analysis. During 4,497,957 person-years of follow-up, 84,978 deaths occurred. Median HDI scores ranged from 40 to 54 points across cohorts. For a 10-point increase in HDI score (representing adherence to an additional WHO guideline), the pooled adjusted hazard ratios were 0.90 (95% confidence interval (CI): 0.87, 0.93) for men and women combined, 0.89 (95% CI: 0.85, 0.92) for men, and 0.90 (95% CI: 0.85, 0.95) for women. These estimates translate to an increased life expectancy of 2 years at the age of 60 years. Greater adherence to the WHO guidelines is associated with greater longevity in elderly men and women in Europe and the United States.

Dietary supplement use and colorectal cancer risk: a systematic review and meta-analyses of prospective cohort studies

Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective cohort studies on dietary supplement use and colorectal cancer risk. We identified relevant studies in Medline, Embase and Cochrane up to January 2013. Original and peer-reviewed papers on dietary supplement use and colorectal cancer, colon cancer, or rectal cancer incidence were included. "Use-no use"(U-NU), "highest-lowest"(H-L) and "dose-response"(DR) meta-analyses were performed. Random-effects models were used to estimate summary estimates. In total, 24 papers were included in the meta-analyses. We observed inverse associations for colorectal cancer risk and multivitamin (U-NU: RR = 0.92; 95% CI: 0.87,0.97) and calcium supplements (U-NU: RR = 0.86; 95% CI: 0.79,0.95; H-L: RR = 0.80; 95% CI: 0.70,0.92; DR: for an increase of 100 mg/day, RR = 0.96; 95% CI: 0.94,0.99). Inconsistent associations were found for colon cancer risk and supplemental vitamin A and vitamin C, and for colorectal cancer risk and supplemental vitamin D, vitamin E, garlic and folic acid. Meta-analyses of observational studies suggest a beneficial role for multivitamins and calcium supplements on colorectal cancer risk, while the association with other supplements and colorectal cancer risk is inconsistent. Residual confounding of lifestyle factors might be present. Before recommendations can be made, an extensive assessment of dietary supplement use and a better understanding of underlying mechanisms is needed.

Vitamin D and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from Europe and the United States

OBJECTIVE

To investigate the association between serum 25-hydroxyvitamin D concentrations (25(OH)D) and mortality in a large consortium of cohort studies paying particular attention to potential age, sex, season, and country differences.

DESIGN

Meta-analysis of individual participant data of eight prospective cohort studies from Europe and the US.

SETTING

General population.

PARTICIPANTS

26,018 men and women aged 50-79 years.

MAIN OUTCOME MEASURES

All-cause, cardiovascular, and cancer mortality.

RESULTS

25(OH)D concentrations varied strongly by season (higher in summer), country (higher in US and northern Europe) and sex (higher in men), but no consistent trend with age was observed. During follow-up, 6695 study participants died, among whom 2624 died of cardiovascular diseases and 2227 died of cancer. For each cohort and analysis, 25(OH)D quintiles were defined with cohort and subgroup specific cut-off values. Comparing bottom versus top quintiles resulted in a pooled risk ratio of 1.57 (95% CI 1.36 to 1.81) for all-cause mortality. Risk ratios for cardiovascular mortality were similar in magnitude to that for all-cause mortality in subjects both with and without a history of cardiovascular disease at baseline. With respect to cancer mortality, an association was only observed among subjects with a history of cancer (risk ratio, 1.70 (1.00 to 2.88)). Analyses using all quintiles suggest curvilinear, inverse, dose-response curves for the aforementioned relationships. No strong age, sex, season, or country specific differences were detected. Heterogeneity was low in most meta-analyses.

CONCLUSIONS

Despite levels of 25(OH)D strongly varying with country, sex, and season, the association between 25(OH)D level and all-cause and cause-specific mortality was remarkably consistent. Results from a long term randomised controlled trial addressing longevity are being awaited before vitamin D supplementation can be recommended in most individuals with low 25(OH)D levels.