Design of Physicians' Health Study II--a randomized trial of beta-carotene, vitamins E and C, and multivitamins, in prevention of cancer, cardiovascular disease, and eye disease, and review of results of completed trials

Adherence to healthy lifestyle factors and risk of death in men with diabetes mellitus: The Physicians' Health Study

BACKGROUND & AIMS

The relationship between healthy lifestyle factors and mortality in people with type 2 diabetes is unclear. The purpose of this study was to examine whether healthy lifestyle factors are associated with mortality in people with type 2 diabetes.

METHODS

We prospectively studied 1163 men with type 2 diabetes from the Physicians' Health Study. Lifestyle factors consisted of currently not smoking, moderate drinking (1-2 drinks/day), vigorous exercise (1+/week), BMI < 25 kg/m², and being in the top 2 quintiles of the alternate healthy eating index-2010 (AHEI-2010). Multivariate Cox regression models were used to estimate hazard ratios (95% confidence intervals) of mortality.

RESULTS

At baseline, average age was 69 years and mean follow up was 9 years. About 22% of study participants had ≤1 healthy lifestyle factor, 37% had two, 29% had three, and 12% had four or more healthy lifestyle factors. An inverse relationship was found between the number of lifestyle factors and total mortality. Compared with participants who had ≤1 healthy lifestyle factor, the risk of death was 42% (95% CI; 19%-58%) lower for those with two healthy lifestyle factors, 41% (95% CI; 18%-58%) lower for those with three, and 44% (95% CI; 12%-64%) lower for those with 4 or more healthy lifestyle factors.

CONCLUSION

Adherence to modifiable healthy lifestyle factors is associated with a lower risk of death among adult men with type 2 diabetes. Our study emphasizes the importance of educating individuals with diabetes to adhere to healthy lifestyle factors.

Smoking and the risk of dry eye: a Meta-analysis

AIM

To collect the evidence to estimate the correlation between smoking and the incidence of dry eye.

METHODS

The PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL, last issue), CBM (Chinese BioMedical Literature Database), and CNKI (China National Knowledge Infrastructure/Chinese Academic Journals full-text Database) were searched for eligible studies published from January 1964 to December 2015 to investigate the association of smoking with the risk of dry eye. The odds ratio (OR) and 95% confidence interval (CI) were summarized and calculated. The extracted studies were pooled by the fixed-effects model or a random-effects model.

RESULTS

Two cohort studies and eight cross-sectional surveys were included in our Meta-analysis. There was no statistically significant relationship between current (OR=1.32; 95% CI: 0.99-1.76; P=0.055) or ever smoking (OR=1.12; 95% CI: 0.98-1.28; P=0.107) and the risk of dry eye among the studies, even when age and gender were adjusted (OR=1.16; 95% CI: 0.83-1.64; P=0.383). In the sensitivity analysis in which only general population were included, the association was significant between smoking and dry eye (OR=1.50; 95% CI: 1.08-2.09; P=0.016).

CONCLUSION

This Meta-analysis suggests that smoking may associate with the risk of dry eye in general population.

Cholesterol Metabolism and Prostate Cancer Lethality

Cholesterol metabolism has been implicated in prostate cancer pathogenesis. Here, we assessed the association of intratumoral mRNA expression of cholesterol synthesis enzymes, transporters, and regulators in tumor specimen at diagnosis and lethal prostate cancer, defined as mortality or metastases from prostate cancer in contrast to nonlethal disease without evidence of metastases after at least 8 years of follow-up. We analyzed the prospective prostate cancer cohorts within the Health Professionals Follow-up Study (n = 249) and the Physicians' Health Study (n = 153) as well as expectantly managed patients in the Swedish Watchful Waiting Study (n = 338). The expression of squalene monooxygenase (SQLE) was associated with lethal cancer in all three cohorts. Men with high SQLE expression (>1 standard deviation above the mean) were 8.3 times (95% confidence interval, 3.5 to 19.7) more likely to have lethal cancer despite therapy compared with men with the mean level of SQLE expression. Absolute SQLE expression was associated with lethal cancer independently from Gleason grade and stage, as was a SQLE expression ratio in tumor versus surrounding benign prostate tissue. Higher SQLE expression was tightly associated with increased histologic markers of angiogenesis. Collectively, this study establishes the prognostic value of intratumoral cholesterol synthesis as measured via SQLE, its second rate-limiting enzyme. SQLE expression at cancer diagnosis is prognostic for lethal prostate cancer both after curative-intent prostatectomy and in a watchful waiting setting, possibly by facilitating micrometastatic disease. Cancer Res; 76(16); 4785-90. ©2016 AACR.

ω-3 Polyunsaturated Fatty Acid Biomarkers and Coronary Heart Disease: Pooling Project of 19 Cohort Studies

IMPORTANCE

The role of ω-3 polyunsaturated fatty acids for primary prevention of coronary heart disease (CHD) remains controversial. Most prior longitudinal studies evaluated self-reported consumption rather than biomarkers.

OBJECTIVE

To evaluate biomarkers of seafood-derived eicosapentaenoic acid (EPA; 20:5ω-3), docosapentaenoic acid (DPA; 22:5ω-3), and docosahexaenoic acid (DHA; 22:6ω-3) and plant-derived α-linolenic acid (ALA; 18:3ω-3) for incident CHD.

DATA SOURCES

A global consortium of 19 studies identified by November 2014.

STUDY SELECTION

Available prospective (cohort, nested case-control) or retrospective studies with circulating or tissue ω-3 biomarkers and ascertained CHD.

DATA EXTRACTION AND SYNTHESIS

Each study conducted standardized, individual-level analysis using harmonized models, exposures, outcomes, and covariates. Findings were centrally pooled using random-effects meta-analysis. Heterogeneity was examined by age, sex, race, diabetes, statins, aspirin, ω-6 levels, and FADS desaturase genes.

MAIN OUTCOMES AND MEASURES

Incident total CHD, fatal CHD, and nonfatal myocardial infarction (MI).

RESULTS

The 19 studies comprised 16 countries, 45 637 unique individuals, and 7973 total CHD, 2781 fatal CHD, and 7157 nonfatal MI events, with ω-3 measures in total plasma, phospholipids, cholesterol esters, and adipose tissue. Median age at baseline was 59 years (range, 18-97 years), and 28 660 (62.8%) were male. In continuous (per 1-SD increase) multivariable-adjusted analyses, the ω-3 biomarkers ALA, DPA, and DHA were associated with a lower risk of fatal CHD, with relative risks (RRs) of 0.91 (95% CI, 0.84-0.98) for ALA, 0.90 (95% CI, 0.85-0.96) for DPA, and 0.90 (95% CI, 0.84-0.96) for DHA. Although DPA was associated with a lower risk of total CHD (RR, 0.94; 95% CI, 0.90-0.99), ALA (RR, 1.00; 95% CI, 0.95-1.05), EPA (RR, 0.94; 95% CI, 0.87-1.02), and DHA (RR, 0.95; 95% CI, 0.91-1.00) were not. Significant associations with nonfatal MI were not evident. Associations appeared generally stronger in phospholipids and total plasma. Restricted cubic splines did not identify evidence of nonlinearity in dose responses.

CONCLUSIONS AND RELEVANCE

On the basis of available studies of free-living populations globally, biomarker concentrations of seafood and plant-derived ω-3 fatty acids are associated with a modestly lower incidence of fatal CHD.

Cost-effective recruitment methods for a large randomised trial in people with diabetes: A Study of Cardiovascular Events iN Diabetes (ASCEND)

Background

Clinical trials require cost-effective methods for identifying, randomising, and following large numbers of people in order to generate reliable evidence. ASCEND (A Study of Cardiovascular Events iN Diabetes) is a randomised ‘2 × 2 factorial design’ study of aspirin and omega-3 fatty acid supplements for the primary prevention of cardiovascular events in people with diabetes; this study used central disease registers and a mail-based approach to identify, randomise, and follow 15,000 people. In collaboration with UK consultants and general practitioners (GPs), researchers identified potentially eligible people with diabetes from centrally held registers (e.g. for retinopathy screening) and GP-held disease registers. Permission was obtained under section 251 of the National Health Service Act 2006 (previously section 60 of the NHS act 2001) to allow invitation letters to be generated centrally in the name of the holder of the register. In addition, with the collaboration of the National Institutes for Health Research (NIHR) Diabetes and Primary Care Research Networks (DRN and PCRN), general practices sent pre-assembled invitation packs to people with a diagnosis of diabetes. Invitation packs included a cover letter, screening questionnaire (with consent form), information leaflet, and a Freepost envelope. Eligible patients entered a 2-month, pre-randomisation, run-in phase on placebo tablets and were only randomised if they completed a randomisation form and remained willing and eligible at the end of the run-in. Follow-up is ongoing, using mail-based approaches that are being supplemented by central registry data.

Results

Information on approximately 600,000 people listed on 58 centrally held diabetes registers was obtained, and 300,188 potentially eligible patients were invited to join the study. In addition, 785 GP practices mailed invitations to 120,875 patients. A further 2,340 potential study participants were identified via other routes. In total, 423,403 people with diabetes were invited to take part; 26,462 entered the 2-month, pre-randomisation, run-in phase; and 15,480 were randomised.

Conclusion

If sufficient numbers of potentially eligible patients can be identified centrally and the trial treatments do not require participants to attend clinics, the recruitment and follow-up of patients by mail is feasible and cost-effective. Wider use of these methods could allow more, large, randomised trials to be undertaken successfully and cost-effectively.

Trial registration

Current Controlled Trials, ISRCTN60635500, registered on 14 July 2005

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1354-9) contains supplementary material, which is available to authorized users.

Multivitamin Use and the Risk of Cardiovascular Disease in Men

BACKGROUND

Although multivitamins are widely used by US adults, few prospective studies have investigated their association with the long- and short-term risks of cardiovascular disease (CVD).

OBJECTIVE

The aim of this study was to investigate how multivitamin use is associated with the risk of CVD in initially healthy men at baseline.

METHODS

We studied 18,530 male physicians aged ≥40 y from the Physicians' Health Study I cohort who were free of CVD and cancer at baseline (1982). All men provided a wide range of self-reported lifestyle and clinical factors plus intake of selected foods and dietary supplements. Cox proportional hazards models were used to calculate multivariable-adjusted HRs (95% CIs).

RESULTS

During a mean follow-up of 12.2 y (total of 225,287 person-years), there were 1697 incident cases of major CVD (defined as nonfatal myocardial infarction, nonfatal stroke, and CVD death). In multivariable-adjusted analyses, no significant associations were observed among baseline multivitamin users compared with nonusers for the risk of major CVD events (HR: 0.94; 95% CI: 0.84, 1.05), whereas a self-reported duration of ≥20 y at baseline was associated with lower risk (HR: 0.56; 95% CI: 0.35, 0.90; P-trend = 0.05). Baseline multivitamin use was also significantly inversely associated with the risk of cardiac revascularization (HR: 0.86; 95% CI: 0.75, 0.98). Baseline use of multivitamins was not significantly associated with other CVD endpoints.

CONCLUSION

In this long-term prospective study in initially healthy men, multivitamin use for ≥20 y was associated with a lower risk of major CVD events.

Efficacy of Multivitamin/mineral Supplementation to Reduce Chronic Disease Risk: A Critical Review of the Evidence from Observational Studies and Randomized Controlled Trials

We reviewed recent scientific evidence regarding the effects of multivitamin/mineral (MVM) supplements on risk of chronic diseases, including cancer, cardiovascular disease, and age-related eye diseases. Data from randomized controlled trials (RCTs) and observational, prospective cohort studies were examined. The majority of scientific studies investigating the use of MVM supplements in chronic disease risk reduction reported no significant effect. However, the largest and longest RCT of MVM supplements conducted to date, the Physicians' Health Study II (PHS II), found a modest and significant reduction in total and epithelial cancer incidence in male physicians, consistent with the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) trial. In addition, PHS II found a modest and significant reduction in the incidence of nuclear cataract, in agreement with several other RCTs and observational, prospective cohort studies. The effects of MVM use on other subtypes of cataract and age-related macular degeneration remain unclear. Neither RCTs nor prospective cohort studies are without their limitations. The placebo-controlled trial design of RCTs may be inadequate for nutrient interventions, and residual confounding, measurement error, and the possibility of reverse causality are inherent to any observational study. National surveys show that micronutrient inadequacies are widespread in the US and that dietary supplements, of which MVMs are the most common type, help fulfill micronutrient requirements in adults and children.

Sleep duration and risk of lung cancer in the physicians' health study

Background and Objectives

Lung cancer is the most common cancer and cancer related cause of death worldwide. However, the association between sleep duration and incident lung cancer has not been investigated in a prospective cohort study.

Methods

We prospectively examined the association between sleep duration and incident lung cancer in a cohort of 21, 026 United States (US) male physicians. Self-reported sleep duration was ascertained during 2002 annual follow-up questionnaire. Incident lung cancer was ascertained through yearly follow-up questionnaires. Cox regression was used to estimate relative risk of incident lung cancer.

Results

The average age at baseline was 68.3±8.8 yr. During a mean follow up of 7.5 (±2.2) yr, 150 cases of lung cancer occurred. Using 7 h of sleep as the reference group, multivariable adjusted hazard ratios (95%CI) for lung cancer were 1.18 (0.77-1.82), 1.0 (ref), and 0.97 (0.67-1.41) from lowest to the highest category of sleep duration (P for quadratic trend 0.697), respectively. In a secondary analysis, smoking status did not modify the sleep duration-lung cancer association (P=0.78). Tere was no evidence for an interaction between sleep duration and sleep apnea on the risk of lung cancer either (P=0.65).

Conclusions

Our data failed to show a higher risk of lung cancer in association with altered sleep duration among US male physicians.

Evaluating a 4-marker signature of aggressive prostate cancer using time-dependent AUC

BACKGROUND

We previously identified a protein tumor signature of PTEN, SMAD4, SPP1, and CCND1 that, together with clinical features, was associated with lethal outcomes among prostate cancer patients. In the current study, we sought to validate the molecular model using time-dependent measures of AUC and predictive values for discriminating lethal from non-lethal prostate cancer.

METHODS

Using data from the initial study, we fit survival models for men with prostate cancer who were participants in the Physicians' Health Study (PHS; n = 276). Based on these models, we generated prognostic risk scores in an independent population, the Health Professionals Follow-up Study (HPFS; n = 347) to evaluate external validity. In each cohort, men were followed prospectively from cancer diagnosis through 2011 for development of distant metastasis or cancer mortality. We measured protein tumor expression of PTEN, SMAD4, SPP1, and CCND1 on tissue microarrays.

RESULTS

During a median of 11.9 and 14.3 years follow-up in the PHS and HPFS cohorts, 24 and 32 men (9%) developed lethal disease. When used as a prognostic factor in a new population, addition of the four markers to clinical variables did not improve discriminatory accuracy through 15 years of follow-up.

CONCLUSIONS

Although the four markers have been identified as key biological mediators in metastatic progression, they do not provide independent, long-term prognostic information beyond clinical factors when measured at diagnosis. This finding may underscore the broad heterogeneity in aggressive prostate tumors and highlight the challenges that may result from overfitting in discovery-based research.

Central adiposity, obesity during early adulthood, and pancreatic cancer mortality in a pooled analysis of cohort studies

BACKGROUND

Body mass index (BMI), a measure of obesity typically assessed in middle age or later, is known to be positively associated with pancreatic cancer. However, little evidence exists regarding the influence of central adiposity, a high BMI during early adulthood, and weight gain after early adulthood on pancreatic cancer risk.

DESIGN

We conducted a pooled analysis of individual-level data from 20 prospective cohort studies in the National Cancer Institute BMI and Mortality Cohort Consortium to examine the association of pancreatic cancer mortality with measures of central adiposity (e.g. waist circumference; n = 647 478; 1947 pancreatic cancer deaths), BMI during early adulthood (ages 18-21 years) and BMI change between early adulthood and cohort enrollment, mostly in middle age or later (n = 1 096 492; 3223 pancreatic cancer deaths). Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models.

RESULTS

Higher waist-to-hip ratio (HR = 1.09, 95% CI 1.02-1.17 per 0.1 increment) and waist circumference (HR = 1.07, 95% CI 1.00-1.14 per 10 cm) were associated with increased risk of pancreatic cancer mortality, even when adjusted for BMI at baseline. BMI during early adulthood was associated with increased pancreatic cancer mortality (HR = 1.18, 95% CI 1.11-1.25 per 5 kg/m(2)), with increased risk observed in both overweight and obese individuals (compared with BMI of 21.0 to <23 kg/m(2), HR = 1.36, 95% CI 1.20-1.55 for BMI 25.0 < 27.5 kg/m(2), HR = 1.48, 95% CI 1.20-1.84 for BMI 27.5 to <30 kg/m(2), HR = 1.43, 95% CI 1.11-1.85 for BMI ≥30 kg/m(2)). BMI gain after early adulthood, adjusted for early adult BMI, was less strongly associated with pancreatic cancer mortality (HR = 1.05, 95% CI 1.01-1.10 per 5 kg/m(2)).

CONCLUSIONS

Our results support an association between pancreatic cancer mortality and central obesity, independent of BMI, and also suggest that being overweight or obese during early adulthood may be important in influencing pancreatic cancer mortality risk later in life.

Association Between High-Sensitivity C-Reactive Protein and Total Stroke by Hypertensive Status Among Men

BACKGROUND

High-sensitivity C-reactive protein (hsCRP), a marker of systemic inflammation, may promote atherosclerosis, particularly among adults with elevated blood pressure; however, data are sparse. We examined the association between hsCRP concentrations and risk of total stroke by hypertension status (normotension, prehypertension, and hypertension) among men in the Physicians' Health Study (PHS).

METHODS AND RESULTS

Blood samples were collected (1996-1997) and assayed for hsCRP among 10 456 initially healthy men from PHS I and PHS II and followed from 1997 to 2012. Self-reported hypertension status, cardiovascular risk factors, lifestyle, and alcohol consumption were obtained from the baseline questionnaire prior to randomization in PHS II. Strokes were updated approximately annually and confirmed by medical records according to the National Survey of Stroke criteria. Multivariable Cox models were used. We observed 395 incident total strokes over 115 791 person-years. In analyses adjusted for potential confounders and stroke risk factors, clinically elevated hsCRP (>3 mg/L) was associated with a 40% significantly greater hazard of total stroke compared with hsCRP <1 mg/L (hazard ratio 1.40, 95% CI 1.06 to 1.87; Ptrend=0.01). Additional adjustment for blood pressure and biomarkers associated with cardiovascular risk marginally attenuated the estimates. Results were similar by hypertension status, although not statistically significant among normotensive and prehypertensive participants due to limited events.

CONCLUSIONS

Elevated hsCRP levels were associated with a greater risk of total stroke, even after adjustment for potential confounders and cardiovascular risk factors. Risk of total stroke was significantly higher among hypertensive men with elevated hsCRP compared with normotensive men with low hsCRP.

Chocolate Consumption and Risk of Atrial Fibrillation (from the Physicians' Health Study)

Chocolate consumption has been shown to protect against various cardiovascular end points; however, little is known about the association between chocolate consumption and incident atrial fibrillation (AF). Therefore, we prospectively examined the association between chocolate consumption and incident AF in a cohort of 18,819 US male physicians. Chocolate consumption was ascertained from 1999 to 2002 through a self-administered food frequency questionnaire. Incident AF was ascertained through yearly follow-up questionnaires. Cox regression was used to estimate relative risks of AF. The average age at baseline was 66 years (±9.1). During a mean follow-up of 9.0 years (±3.0), 2,092 cases of AF occurred. Using <1 per month of chocolate consumption as the reference group, multivariable adjusted hazard ratios (95% confidence interval) for AF were 1.04 (0.93 to 1.18), 1.10 (0.96 to 1.25), 1.14 (0.99 to 1.31), and 1.05 (0.89 to 1.25) for chocolate intake of 1 to 3 per month and 1, 2 to 4, and ≥5 per week (p for trend 0.25), respectively. In a secondary analysis, there was no evidence of effect modification by adiposity (p interaction = 0.71) or age (p interaction = 0.26). In conclusion, our data did not support an association between chocolate consumption and risk of AF in US male physicians.

GermLine Variation in Superoxide Dismutase-2 (SOD2) and Survival Outcomes After Radiation Therapy for Prostate Cancer: Results of a Test and Validation Set Analysis

BACKGROUND

Genetic variants in antioxidant pathways might decrease the efficacy of radiation therapy (RT) by suppressing the generation of reactive oxygen species. We studied the association between single nucleotide polymorphisms (SNPs) in the antioxidant gene superoxide dismutase-2 (SOD2) and cancer-specific outcomes after RT.

PATIENTS AND METHODS

Among 816 prostate cancer patients who received radiation as primary therapy from the Physicians' Health Study and the Health Professionals Follow-up Study, we evaluated the association of 7 tagging SNPs in SOD2 with lethal prostate cancer (death from prostate cancer or distant metastasis among living patients). We sought to validate findings in a separate cohort of 612 prostate cancer patients treated with RT with a greater proportion of intermediate and high-risk Gleason scores at the Dana-Farber Cancer Institute. Genetic effects were analyzed using a codominant model, using the genotype homozygous for the major allele as baseline.

RESULTS

Among patients who underwent RT in the test cohort, there was a significant association between 3 of the 7 SOD2 SNPs and lethal prostate cancer: rs6917589 (overall P = .006), rs2758331 (P = .04) and the functional valine to alanine polymorphism in rs4880 (P = .04). These SNPs were not associated with outcome among men who had undergone prostatectomy. The associations were not replicated in the validation cohort.

CONCLUSION

Germline genetic variation in the SOD2 gene might be a predictive biomarker of response to RT for prostate cancer but is not consistently associated with outcome after RT across prostate cancer cohorts with different clinical characteristics.

Mendelian Randomization Study of Body Mass Index and Colorectal Cancer Risk

BACKGROUND

High body mass index (BMI) is consistently linked to increased risk of colorectal cancer for men, whereas the association is less clear for women. As risk estimates from observational studies may be biased and/or confounded, we conducted a Mendelian randomization study to estimate the causal association between BMI and colorectal cancer.

METHODS

We used data from 10,226 colorectal cancer cases and 10,286 controls of European ancestry. The Mendelian randomization analysis used a weighted genetic risk score, derived from 77 genome-wide association study-identified variants associated with higher BMI, as an instrumental variable (IV). We compared the IV odds ratio (IV-OR) with the OR obtained using a conventional covariate-adjusted analysis.

RESULTS

Individuals carrying greater numbers of BMI-increasing alleles had higher colorectal cancer risk [per weighted allele OR, 1.31; 95% confidence interval (CI), 1.10-1.57]. Our IV estimation results support the hypothesis that genetically influenced BMI is directly associated with risk for colorectal cancer (IV-OR per 5 kg/m(2), 1.50; 95% CI, 1.13-2.01). In the sex-specific IV analyses higher BMI was associated with higher risk of colorectal cancer among women (IV-OR per 5 kg/m(2), 1.82; 95% CI, 1.26-2.61). For men, genetically influenced BMI was not associated with colorectal cancer (IV-OR per 5 kg/m(2), 1.18; 95% CI, 0.73-1.92).

CONCLUSIONS

High BMI was associated with increased colorectal cancer risk for women. Whether abdominal obesity, rather than overall obesity, is a more important risk factor for men requires further investigation.

IMPACT

Overall, conventional epidemiologic and Mendelian randomization studies suggest a strong association between obesity and the risk of colorectal cancer.

Topical nutraceutical Optixcare EH ameliorates experimental ocular oxidative stress in rats

PURPOSE

Based on the hypothesis that oral nutraceuticals do not adequately reach all ocular tissues in the anterior segment, we evaluated the ability of a 3% concentration of the ingredients in a topical nutraceutical antioxidant formulation called Optixcare Eye Health (Optixcare EH) to ameliorate oxidative stress in rat models of age-related ocular diseases.

METHODS

Diabetes was induced by tail-vein injection of streptozotocin, and the development of cataracts was monitored by slit lamp. Young rats were exposed to ultraviolet (UV) light, and the reduction in lens glutathione (GSH) levels and increase in 4-hydroxynonenol (4-HNE) were measured. Oxidative stress in the neural retina was generated by exposure of dark-adapted rats to 1,000 lx of light, and oxidative stress markers were measured. Dry eye was induced in rats by twice daily (b.i.d.) subcutaneous scopolamine injections. Topical Optixcare EH was administered b.i.d. and compared in select experiments to the multifunctional antioxidant JHX-4, the topical aldose reductase inhibitor (ARI) Kinostat™, oral Ocu-GLO™, and the topical ocular comfort agents Optixcare Eye Lube, Optixcare Eye Lube + Hyaluron, and Idrop Vet Plus hyaluronic acid.

RESULTS

In diabetic rats, topical ARI treatment prevented cataract formation while the nutraceuticals delayed their development with Optixcare EH>Ocu-GLO. In UV-exposed rats, the reduction of GSH and increase in 4-HNE in the lens were normalized in order JHX-4>Optixcare EH>Ocu-GLO. In the retina, oxidative stress markers were reduced better by oral JHX-4 compared with topical Optixcare EH. In the scopolamine-induced dry-eye rats, tear flow was maintained by Optixcare EH treatment, while none of the comfort agents examined altered tear flow.

CONCLUSIONS

Topical administration of a 3% concentration of the ingredients in Optixcare EH reduces experimentally induced reactive oxygen species in rats exposed to several sources of ocular oxidative stress. In addition, Optixcare EH maintains tear volume in scopolamine-induced dry eye. This suggests that in the anterior segment, the ingredients in Optixcare EH may have clinical potential against ocular oxidative stress.

Mendelian randomization study of height and risk of colorectal cancer

BACKGROUND

For men and women, taller height is associated with increased risk of all cancers combined. For colorectal cancer (CRC), it is unclear whether the differential association of height by sex is real or is due to confounding or bias inherent in observational studies. We performed a Mendelian randomization study to examine the association between height and CRC risk.

METHODS

To minimize confounding and bias, we derived a weighted genetic risk score predicting height (using 696 genetic variants associated with height) in 10,226 CRC cases and 10,286 controls. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for associations between height, genetically predicted height and CRC.

RESULTS

Using conventional methods, increased height (per 10-cm increment) was associated with increased CRC risk (OR = 1.08, 95% CI = 1.02-1.15). In sex-specific analyses, height was associated with CRC risk for women (OR = 1.15, 95% CI = 1.05-1.26), but not men (OR = 0.98, 95% CI = 0.92-1.05). Consistent with these results, carrying greater numbers of (weighted) height-increasing alleles (per 1-unit increase) was associated with higher CRC risk for women and men combined (OR = 1.07, 95% CI = 1.01-1.14) and for women (OR = 1.09, 95% CI =  .01-1.19). There was weaker evidence of an association for men (OR = 1.05, 95% CI = 0.96-1.15).

CONCLUSION

We provide evidence for a causal association between height and CRC for women. The CRC-height association for men remains unclear and warrants further investigation in other large studies.

Tumor expression of adiponectin receptor 2 and lethal prostate cancer

To investigate the role of adiponectin receptor 2 (AdipoR2) in aggressive prostate cancer we used immunohistochemistry to characterize AdipoR2 protein expression in tumor tissue for 866 men with prostate cancer from the Physicians' Health Study and the Health Professionals Follow-up Study. AdipoR2 tumor expression was not associated with measures of obesity, pathological tumor stage or prostate-specific antigen (PSA) at diagnosis. However, AdipoR2 expression was positively associated with proliferation as measured by Ki-67 expression quartiles (P-trend < 0.0001), with expression of fatty acid synthase (P-trend = 0.001), and with two measures of angiogenesis (P-trend < 0.1). An inverse association was observed with apoptosis as assessed by the TUNEL assay (P-trend = 0.006). Using Cox proportional hazards regression and controlling for age at diagnosis, Gleason score, year of diagnosis category, cohort and baseline BMI, we identified a statistically significant trend for the association between quartile of AdipoR2 expression and lethal prostate cancer (P-trend = 0.02). The hazard ratio for lethal prostate cancer for the two highest quartiles, as compared to the two lowest quartiles, of AdipoR2 expression was 1.9 (95% confidence interval [CI]: 1.2-3.0). Results were similar when additionally controlling for categories of PSA at diagnosis and Ki-67 expression quartiles. These results strengthen the evidence for the role of AdipoR2 in prostate cancer progression.

The association between dry eye disease and depression and anxiety in a large population-based study

PURPOSE

To investigate the association between dry eye disease and each of depression and anxiety.

DESIGN

Retrospective, case-control study.

METHODS

setting: University of North Carolina outpatient clinics. study population: All patients over the age of 18 years seen between July 2008 and June 2013 were included in the analysis. observation procedure: Cases were defined according to ICD-9 diagnosis codes for dry eye disease, anxiety, and depression. outcome measure: Separate odds ratios were calculated for dry eye disease and each of anxiety and depression. Similar odds ratios were also calculated between dry eye disease and rheumatoid arthritis, a systemic disease with a known association with dry eye, as a way of validating our approach.

RESULTS

A total of 460 611 patients were screened; 7207 patients with dry eye were included, while 20 004 patients with anxiety and 30 100 patients with depression were included. The adjusted odds ratio for dry eye disease and anxiety was 2.8 (95% confidence interval [CI] 2.6-3.0). For dry eye disease and depression, the odds ratio was 2.9 (95% CI 2.7-3.1).

CONCLUSIONS

We identified a statistically significant association between dry eye disease and each of depression and anxiety. Such an association has implications for ophthalmologists in the management and treatment of dry eye disease.

Chocolate consumption and risk of diabetes mellitus in the Physicians' Health Study

BACKGROUND

Previous studies reported beneficial effects of cocoa or chocolate on insulin resistance, oxidative stress, and inflammation, which are important risk factors of type 2 diabetes mellitus (DM). However, it is unclear whether chocolate consumption is associated with risk of DM.

OBJECTIVE

We tested the hypothesis that chocolate consumption is inversely associated with incident DM in the Physicians' Health Study (PHS).

DESIGN

We prospectively analyzed data on 18,235 PHS participants who were free of DM at baseline (1997-2001). Chocolate consumption was obtained from a baseline food-frequency questionnaire. Incident DM was ascertained via annual follow-up questionnaires and validated in a subsample by a review of medical records. We used Cox proportional hazards models to estimate HRs and 95% CIs of DM.

RESULTS

The mean (±SD) age at baseline was 66.3 ± 9.2 y. During a mean follow up of 9.2 y, 1123 men (6.2%) developed DM. For self-reported chocolate consumption of none, 1-3 servings/mo, 1 serving/wk, and ≥2 servings/wk, multivariable-adjusted HRs (95% CIs) of DM adjusted for lifestyle, clinical, and dietary risk factors including total energy intake were 1.00 (referent), 0.93 (0.79, 1.09), 0.86 (0.72, 1.04), and 0.83 (0.69, 0.99), respectively (P-trend = 0.047). In secondary analyses, the inverse association of chocolate consumption and risk of DM was slightly stronger in subjects without a history of cardiovascular disease or heart failure (P-trend = 0.023). In addition, both age and BMI modified the chocolate-DM relation (P < 0.05 each).

CONCLUSION

Our data support an inverse relation of chocolate intake with incident DM, which appears only to apply in younger and normal-body weight men after controlling for comprehensive life styles including total energy consumption.

Nut consumption and risk of mortality in the Physicians' Health Study

BACKGROUND

Previous studies have suggested that nut consumption is associated with beneficial cardiovascular outcomes. However, limited data are available on the association between nut intake and all-cause mortality.

OBJECTIVE

Our aim was to test the hypothesis that nut consumption is inversely associated with the risk of all-cause mortality.

DESIGN

In this prospective cohort study in 20,742 male physicians, we assessed nut intake between 1999 and 2002 via a food-frequency questionnaire and ascertained deaths through an endpoint committee. We used Cox regression to estimate multivariable-adjusted HRs for death according to nut consumption. In secondary analyses, we evaluated associations of nut consumption with cause-specific mortality.

RESULTS

During a mean follow-up of 9.6 y, there were 2732 deaths. The mean (±SD) age at baseline was 66.6 ± 9.3 y. Median nut consumption was 1 serving/wk. Multivariable-adjusted HRs (95% CIs) were 1.0 (reference), 0.92 (0.83, 1.01), 0.85 (0.76, 0.96), 0.86 (0.75, 0.98), and 0.74 (0.63, 0.87) for nut consumption of never or <1 serving/mo, 1-3 servings/mo, 1 serving/wk, 2-4 servings/wk, and ≥5 servings/wk, respectively (P-linear trend < 0.0001), after adjustment for age, body mass index, alcohol use, smoking, exercise, prevalent diabetes and hypertension, and intakes of energy, saturated fat, fruit and vegetables, and red meat. In a secondary analysis, results were consistent for cardiovascular disease mortality but only suggestive and non-statistically significant for coronary artery disease and cancer mortality.

CONCLUSION

Our data are consistent with an inverse association between nut consumption and the risk of all-cause and cardiovascular disease mortality in US male physicians.

Vitamin E and risk of age-related cataract: a meta-analysis

Objective

We conducted a meta-analysis to evaluate the relationship between vitamin E and age-related cataract (ARC).

Design

The fixed- or random-effect model was selected based on heterogeneity. Meta-regression was used to explore potential sources of between-study heterogeneity. Publication bias was evaluated using Begg’s test. The dose–response relationship was assessed by a restricted cubic spline model.

Setting

Relevant studies were identified by a search of PubMed and the Cochrane Library to May 2014, without language restrictions.

Subjects

Studies involved samples of people of all ages.

Results

Dietary vitamin E intake, dietary and supplemental vitamin E intake, and high serum tocopherol levels were significantly associated with decreased risk of ARC, the pooled relative risk was 0·73 (95 % CI 0·58, 0·92), 0·86 (95 % CI 0·75, 0·99) and 0·77 (95 % CI 0·66, 0·91), respectively. Supplemental vitamin E intake was non-significantly associated with ARC risk (relative risk=0·92; 95 % CI 0·78, 1·07). The findings from dose–response analysis showed evidence of a non-linear association between dietary vitamin E intake and ARC. The risk of ARC decreased with dietary vitamin E intake from 7 mg/d (relative risk=0·94; 95 % CI 0·90, 0·97).

Conclusions

The findings of the meta-analysis indicated that dietary vitamin E intake, dietary and supplemental vitamin E intake, and high level of serum tocopherol might be significantly associated with reduced ARC risk.

Current knowledge and trends in age-related macular degeneration: genetics, epidemiology, and prevention

PURPOSE

To address the most dynamic and current issues concerning human genetics, risk factors, pharmacoeconomics, and prevention regarding age-related macular degeneration.

METHODS

An online review of the database Pubmed and Ovid was performed, searching for the key words: age-related macular degeneration, AMD, pharmacoeconomics, risk factors, VEGF, prevention, genetics and their compound phrases. The search was limited to articles published since 1985 to date. All returned articles were carefully screened and their references were manually reviewed for additional relevant data. The webpage www.clinicaltrials.gov was also accessed in search of relevant research trials.

RESULTS

A total of 366 articles were reviewed, including 64 additional articles extracted from the references and 25 webpages and online databases from different institutions. At the end, only 244 references were included in this review.

CONCLUSION

Age-related macular degeneration is a complex multifactorial disease that has an uneven manifestation around the world but with one common denominator, it is increasing and spreading. The economic burden that this disease poses in developed nations will increase in the coming years. Effective preventive therapies need to be developed in the near future.

Chocolate consumption and risk of heart failure in the Physicians' Health Study

AIMS

To test the hypothesis that chocolate consumption is associated with a lower risk of heart failure (HF).

METHODS AND RESULTS

We prospectively studied 20 278 men from the Physicians' Health Study. Chocolate consumption was assessed between 1999 and 2002 via a self-administered food frequency questionnaire and HF was ascertained through annual follow-up questionnaires with validation in a subsample. We used Cox regression to estimate multivariable adjusted relative risk of HF. During a mean follow-up of 9.3 years there were 876 new cases of HF. The mean age at baseline was 66.4 ± 9.2 years. Hazard ratios [95% confidence intervals (CI)] for HF were 1.0 (ref), 0.86 (0.72-1.03), 0.80 (0.66-0.98), 0.92 (0.74-1.13), and 0.82 (0.63-1.07), for chocolate consumption of less than 1/month, 1-3/week, 2-4/week, and 5+/week, respectively, after adjusting for age, body mass index (BMI), smoking, alcohol, exercise, energy intake, and history of atrial fibrillation (P for quadratic trend = 0.62). In a secondary analysis, chocolate consumption was inversely associated with risk of HF in men whose BMI was <25 kg/m(2) [HR (95% CI) = 0.59 (0.37-0.94) for consumption of 5+ servings/week, P for linear trend = 0.03) but not in those with BMI of 25+ kg/m(2) [HR (95% CI) = 1.01 (0.73-1.39), P for linear trend = 0.42, P for interaction = 0.17).

CONCLUSIONS

Our data suggest that moderate consumption of chocolate might be associated with a lower risk of HF in male physicians.

Alcohol consumption and risk of death in male physicians with heart failure

The 5-year risk of death after onset of heart failure (HF) is about 50%. Although previous studies have shown beneficial effects of light-to-moderate alcohol consumption and risk of cardiovascular diseases and mortality, it is unclear whether moderate alcohol consumption is associated with a lower risk of death in subjects with HF. We investigated whether alcohol consumption and type of alcohol preference are associated with the risk of total mortality in 449 US male physicians with prevalent HF. Alcohol consumption was assessed through food frequency questionnaire, and mortality was ascertained through annual follow-up questionnaires and adjudicated by an Endpoint Committee. The mean age of subjects was 75.7±8.2 years with an average follow-up of 7 years. We found evidence of a J-shaped relation between alcohol consumption and mortality (hazard ratio [95% confidence interval] 1.00 [reference], 0.85 [0.61 to 1.20], 0.60 [0.40 to 0.88], and 0.71 [0.42 to 1.21] for alcohol intake of none, <1 drink/day, 1 to 2 drinks/day, and 3+ drinks/day, respectively [p for quadratic trend=0.058]). There was no relation between beverage preference (beer, wine, or liquor) and mortality. In conclusion, our data showed a J-shaped association between alcohol intake and mortality in patients with HF.

Vitamin E and C supplementation and risk of cancer in men: posttrial follow-up in the Physicians' Health Study II randomized trial

BACKGROUND

Recent posttrial analysis of a completed randomized trial found an increased risk of prostate cancer among healthy men taking high-dose vitamin E supplements. Trials that examined the effect of vitamin C supplements on cancer risk are few.

OBJECTIVE

We examined whether vitamin E or vitamin C supplementation affects the risk of cancer events during posttrial follow-up of the Physicians' Health Study II.

DESIGN

Beginning in 1997, a total of 14,641 US male physicians aged ≥50 y were randomly assigned to receive 400 IU of vitamin E every other day, 500 mg of vitamin C daily, or their respective placebos. The vitamin E and vitamin C treatment ended in 2007, and observational follow-up continued through June 2011.

RESULTS

This study included an additional 356 cases of incident prostate cancer and 771 total cancers that developed during a mean (maximum) of 2.8 (3.8) y of posttrial observation. During an overall mean of 10.3 (13.8) y, there were a total of 1373 incident prostate cancers and 2669 total cancers documented. In comparison with placebo, vitamin E supplementation had no effect on the incidence of prostate cancer (HR: 0.99; 95% CI: 0.89, 1.10) or total cancers (HR: 1.02; 95% CI: 0.95, 1.10). There was also no effect of vitamin C supplementation on total cancers (HR: 1.02; 95% CI: 0.94, 1.10) or incident prostate cancer (HR: 1.03; 95% CI: 0.93, 1.15). Neither vitamin E nor vitamin C supplementation had effects on other site-specific cancers overall. Stratification by known cancer risk factors, history of cancer, other randomized treatment, and follow-up time showed no significant interactions.

CONCLUSION

In this large-scale randomized trial in men, vitamin E and C supplementation had no immediate or long-term effects on the risk of total cancers, prostate cancer, or other site-specific cancers.

Association between class III obesity (BMI of 40-59 kg/m2) and mortality: a pooled analysis of 20 prospective studies

BACKGROUND

The prevalence of class III obesity (body mass index [BMI]≥40 kg/m2) has increased dramatically in several countries and currently affects 6% of adults in the US, with uncertain impact on the risks of illness and death. Using data from a large pooled study, we evaluated the risk of death, overall and due to a wide range of causes, and years of life expectancy lost associated with class III obesity.

METHODS AND FINDINGS

In a pooled analysis of 20 prospective studies from the United States, Sweden, and Australia, we estimated sex- and age-adjusted total and cause-specific mortality rates (deaths per 100,000 persons per year) and multivariable-adjusted hazard ratios for adults, aged 19-83 y at baseline, classified as obese class III (BMI 40.0-59.9 kg/m2) compared with those classified as normal weight (BMI 18.5-24.9 kg/m2). Participants reporting ever smoking cigarettes or a history of chronic disease (heart disease, cancer, stroke, or emphysema) on baseline questionnaires were excluded. Among 9,564 class III obesity participants, mortality rates were 856.0 in men and 663.0 in women during the study period (1976-2009). Among 304,011 normal-weight participants, rates were 346.7 and 280.5 in men and women, respectively. Deaths from heart disease contributed largely to the excess rates in the class III obesity group (rate differences = 238.9 and 132.8 in men and women, respectively), followed by deaths from cancer (rate differences = 36.7 and 62.3 in men and women, respectively) and diabetes (rate differences = 51.2 and 29.2 in men and women, respectively). Within the class III obesity range, multivariable-adjusted hazard ratios for total deaths and deaths due to heart disease, cancer, diabetes, nephritis/nephrotic syndrome/nephrosis, chronic lower respiratory disease, and influenza/pneumonia increased with increasing BMI. Compared with normal-weight BMI, a BMI of 40-44.9, 45-49.9, 50-54.9, and 55-59.9 kg/m2 was associated with an estimated 6.5 (95% CI: 5.7-7.3), 8.9 (95% CI: 7.4-10.4), 9.8 (95% CI: 7.4-12.2), and 13.7 (95% CI: 10.5-16.9) y of life lost. A limitation was that BMI was mainly ascertained by self-report.

CONCLUSIONS

Class III obesity is associated with substantially elevated rates of total mortality, with most of the excess deaths due to heart disease, cancer, and diabetes, and major reductions in life expectancy compared with normal weight. Please see later in the article for the Editors' Summary.

Genome-wide diet-gene interaction analyses for risk of colorectal cancer

Dietary factors, including meat, fruits, vegetables and fiber, are associated with colorectal cancer; however, there is limited information as to whether these dietary factors interact with genetic variants to modify risk of colorectal cancer. We tested interactions between these dietary factors and approximately 2.7 million genetic variants for colorectal cancer risk among 9,287 cases and 9,117 controls from ten studies. We used logistic regression to investigate multiplicative gene-diet interactions, as well as our recently developed Cocktail method that involves a screening step based on marginal associations and gene-diet correlations and a testing step for multiplicative interactions, while correcting for multiple testing using weighted hypothesis testing. Per quartile increment in the intake of red and processed meat were associated with statistically significant increased risks of colorectal cancer and vegetable, fruit and fiber intake with lower risks. From the case-control analysis, we detected a significant interaction between rs4143094 (10p14/near GATA3) and processed meat consumption (OR = 1.17; p = 8.7E-09), which was consistently observed across studies (p heterogeneity = 0.78). The risk of colorectal cancer associated with processed meat was increased among individuals with the rs4143094-TG and -TT genotypes (OR = 1.20 and OR = 1.39, respectively) and null among those with the GG genotype (OR = 1.03). Our results identify a novel gene-diet interaction with processed meat for colorectal cancer, highlighting that diet may modify the effect of genetic variants on disease risk, which may have important implications for prevention.

The thresholds for statistical and clinical significance - a five-step procedure for evaluation of intervention effects in randomised clinical trials

BACKGROUND

Thresholds for statistical significance are insufficiently demonstrated by 95% confidence intervals or P-values when assessing results from randomised clinical trials. First, a P-value only shows the probability of getting a result assuming that the null hypothesis is true and does not reflect the probability of getting a result assuming an alternative hypothesis to the null hypothesis is true. Second, a confidence interval or a P-value showing significance may be caused by multiplicity. Third, statistical significance does not necessarily result in clinical significance. Therefore, assessment of intervention effects in randomised clinical trials deserves more rigour in order to become more valid.

METHODS

Several methodologies for assessing the statistical and clinical significance of intervention effects in randomised clinical trials were considered. Balancing simplicity and comprehensiveness, a simple five-step procedure was developed.

RESULTS

For a more valid assessment of results from a randomised clinical trial we propose the following five-steps: (1) report the confidence intervals and the exact P-values; (2) report Bayes factor for the primary outcome, being the ratio of the probability that a given trial result is compatible with a 'null' effect (corresponding to the P-value) divided by the probability that the trial result is compatible with the intervention effect hypothesised in the sample size calculation; (3) adjust the confidence intervals and the statistical significance threshold if the trial is stopped early or if interim analyses have been conducted; (4) adjust the confidence intervals and the P-values for multiplicity due to number of outcome comparisons; and (5) assess clinical significance of the trial results.

CONCLUSIONS

If the proposed five-step procedure is followed, this may increase the validity of assessments of intervention effects in randomised clinical trials.

Estimating the heritability of colorectal cancer

A sizable fraction of colorectal cancer (CRC) is expected to be explained by heritable factors, with heritability estimates ranging from 12 to 35% twin and family studies. Genome-wide association studies (GWAS) have successfully identified a number of common single-nucleotide polymorphisms (SNPs) associated with CRC risk. Although it has been shown that these CRC susceptibility SNPs only explain a small proportion of the genetic risk, it is not clear how much of the heritability these SNPs explain and how much is left to be detected by other, yet to be identified, common SNPs. Therefore, we estimated the heritability of CRC under different scenarios using Genome-Wide Complex Trait Analysis in the Genetics and Epidemiology of Colorectal Cancer Consortium including 8025 cases and 10 814 controls. We estimated that the heritability explained by known common CRC SNPs identified in GWAS was 0.65% (95% CI:0.3-1%; P = 1.11 × 10-16), whereas the heritability explained by all common SNPs was at least 7.42% (95% CI: 4.71-10.12%; P = 8.13 × 10(-8)), suggesting that many common variants associated with CRC risk remain to be detected. Comparing the heritability explained by the common variants with that from twin and family studies, a fraction of the heritability may be explained by other genetic variants, such as rare variants. In addition, our analysis showed that the gene × smoking interaction explained a significant proportion of the CRC variance (P = 1.26 × 10(-2)). In summary, our results suggest that known CRC SNPs only explain a small proportion of the heritability and more common SNPs have yet to be identified.

Effects of multivitamin supplement on cataract and age-related macular degeneration in a randomized trial of male physicians

PURPOSE

To test whether long-term multivitamin supplementation affects the incidence of cataract or age-related macular degeneration (AMD) in a large cohort of men.

DESIGN

Randomized, double-blind, placebo-controlled trial.

PARTICIPANTS

A total of 14,641 US male physicians aged ≥ 50 years.

INTERVENTION

Daily multivitamin or placebo.

MAIN OUTCOME MEASURES

Incident cataract and visually significant AMD responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-reports confirmed by medical record review.

RESULTS

During an average of 11.2 years of treatment and follow-up, a total of 1817 cases of cataract and 281 cases of visually significant AMD were confirmed. There were 872 cataracts in the multivitamin group and 945 cataracts in the placebo group (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.83-0.99; P = 0.04). For visually significant AMD, there were 152 cases in the multivitamin group and 129 cases in the placebo group (HR, 1.19; 95% CI, 0.94-1.50; P = 0.15).

CONCLUSIONS

These randomized trial data from a large cohort of middle-aged and older US male physicians indicate that long-term daily multivitamin use modestly and significantly decreased the risk of cataract but had no significant effect on visually significant AMD.

Long-term multivitamin supplementation and cognitive function in men: a randomized trial

BACKGROUND

Despite widespread use of multivitamin supplements, their effect on cognitive health-a critical issue with aging-remains inconclusive. To date, no long-term clinical trials have studied multivitamin use and cognitive decline in older persons.

OBJECTIVE

To evaluate whether long-term multivitamin supplementation affects cognitive health in later life.

DESIGN

Randomized, double-blind, placebo-controlled trial of a multivitamin from 1997 to 1 June 2011. The cognitive function substudy began in 1998. Up to 4 repeated cognitive assessments by telephone interview were completed over 12 years. (ClinicalTrials.gov: NCT00270647) SETTING: The Physicians' Health Study II.

PATIENTS

5947 male physicians aged 65 years or older.

INTERVENTION

Daily multivitamin or placebo.

MEASUREMENTS

A global composite score averaging 5 tests of global cognition, verbal memory, and category fluency. The secondary end point was a verbal memory score combining 4 tests of verbal memory, which is a strong predictor of Alzheimer disease.

RESULTS

No difference was found in mean cognitive change over time between the multivitamin and placebo groups or in the mean level of cognition at any of the 4 assessments. Specifically, for the global composite score, the mean difference in cognitive change over follow-up was -0.01 SU (95% CI, -0.04 to 0.02 SU) when treatment was compared with placebo. Similarly, cognitive performance did not differ between the multivitamin and placebo groups on the secondary outcome, verbal memory (mean difference in cognitive change over follow-up, -0.005 SU [CI, -0.04 to 0.03 SU]).

LIMITATION

Doses of vitamins may be too low or the population may be too well-nourished to benefit from a multivitamin.

CONCLUSION

In male physicians aged 65 years or older, long-term use of a daily multivitamin did not provide cognitive benefits.

PRIMARY FUNDING SOURCE

National Institutes of Health, BASF, Pfizer, and DSM Nutritional Products.

Physical activity and risk of endometrial adenocarcinoma in the Nurses' Health Study

Studies suggest that greater physical activity may reduce endometrial cancer risk. However, the role of the timing, duration and intensity of activity is unclear. We therefore examined recent and past recreational activities in relation to incident endometrial adenocarcinoma, and compared the importance of total and moderate- or vigorous-intensity activities as well as walking. We analyzed data from 71,570 women in the Nurses' Health Study, a prospective cohort that assessed activity in 1986, with updates every 2-4 years. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). During follow-up from 1986 to 2008 (1.2 million person-years), 777 invasive endometrial adenocarcinoma cases were documented. In multivariable models, compared with <3 MET-hr/week (<1 hr/week walking), women engaged in moderate (9 to <18 MET-hr/week: RR = 0.61, 95% CI: 0.48-0.78) or high (≥27 MET-hr/week: RR = 0.73, 95% CI: 0.58-0.92) amounts of recent total recreational activity were at reduced risk (p-trend = 0.001). Past total activity was not associated with risk. Greater recent moderate- or vigorous-intensity activity was associated with reduced risk (≥4 vs. 0 hr/week: RR = 0.65, 95% CI: 0.47-0.88, p-trend = 0.002). Among women who did not perform any vigorous activity, recent walking was associated with reduced risk (≥3 vs. <0.5 hr/week: RR = 0.65, 95% CI: 0.45-0.93, p-trend = 0.01), and faster walking pace was independently associated with risk reduction. After additional adjustment for body mass index, all associations were statistically non-significant. Greater recent physical activity, including activity of moderate duration and intensity such as walking, may reduce endometrial adenocarcinoma risk. This relation is largely mediated or confounded by body mass index.

Who uses multivitamins? A cross-sectional study in the Physicians' Health Study

PURPOSE

The aim of this study was to examine the prevalence of self-reported multivitamin use in the Physicians' Health Study (PHS) cohort and its association with various lifestyle, clinical, and dietary factors to improve our understanding of who tends to use multivitamins.

METHODS

Among 18,040 middle-aged and older men, information on lifestyle and clinical factors was collected from a baseline enrollment questionnaire, and supplement use and dietary factors were assessed through a food-frequency questionnaire. Four categories of multivitamin use were considered: (1) no supplement use, (2) use of multivitamins only, (3) use of multivitamins with other individual vitamin/mineral supplements, and (4) use of other supplements only. We used logistic regression to calculate multivariate odds ratios and 95% confidence intervals of taking multivitamin supplements for various lifestyle, clinical and dietary factors.

RESULTS

Overall, 36% of men reported current multivitamin use. Men who were older, current smokers, and currently using aspirin were 143, 43, and 74% more likely to use multivitamins only. Men having a history of hypercholesterolemia were 16% more likely to use multivitamins only. A 14, 24, and 26% greater likelihood of using multivitamins was also observed among men consuming more fruits and vegetables, whole grains, and tea, respectively. Similar associations were observed for the likelihood of using multivitamins with other supplements; however, men with higher physical activity, history of cancer, hypertension, higher consumption of nuts, and lower consumption of red meat and coffee were also more likely to use multivitamins with other supplements (all P < 0.05).

CONCLUSION

Self-reported multivitamin use associated with lifestyle, clinical and dietary factors may be an indicator of healthy behaviors. These results provide important information for the interpretation of the recent findings from the PHS II trial and consideration of results from observational studies of multivitamin use and chronic disease.

Plasma phospholipid saturated fatty acids and heart failure risk in the Physicians' Health Study

BACKGROUND & AIMS

Previous studies have suggested that some plasma phospholipid saturated fatty acids (SFA) are associated with an increased risk of coronary heart disease and hypertension, major risk factors for heart failure (HF). However, little is known about the association between SFA and HF. This study examines associations of individual plasma phospholipid SFA with HF risk in US male physicians.

METHODS

The current ancillary study used a prospective nested matched case-control design to select 788 cases of incident HF and 788 controls. Plasma phospholipid SFAs were measured using gas chromatography. HF was self-reported on follow-up questionnaires and validated by review of medical records in a subsample. We used conditional logistic regression to estimate relative risks.

RESULTS

Mean age was 58.7 ± 8.0 years. One standard deviation higher plasma phospholipid 16:0 was associated with an odds ratio (95% CI) of 1.20 (1.04, 1.38) controlling for established HF risk factors and other SFAs (p = 0.042). However, this association was not significant after Bonferroni correction (p > 0.008). We did not observe associations between other SFAs (14:0, 15:0, 18:0, 20:0, or 22:0) and HF risk (all p for trend > 0.05).

CONCLUSIONS

Our data suggested no association between plasma phospholipid SFAs and HF in US male physicians.

Patient reported differences in dry eye disease between men and women: impact, management, and patient satisfaction

Purpose

Dry eye disease affects women twice as often as men, but there is little information on whether dry eye treatments, treatment satisfaction, or the impact of dry eye disease on patients’ lives and vision might differ by sex.

Design

Questionnaire survey of 4000 participants in the Women’s Health Study and the Physicians’ Health Studies I and II with a prior report of a diagnosis of DED.

Methods

Among participants who re-confirmed a diagnosis of dry eye disease, we assessed symptoms, treatments, patient satisfaction and impact of dry eye disease, and analyzed differences between men and women using regression models.

Results

The final study population consisted of 1,518 women (mean age 70.7 years) and 581 men (mean age 76.7 years), with a mean reported duration of dry eye disease of 10.5 years and 10.1 years, respectively. The frequency and severity of dry eye disease symptoms were higher among women (each P<0.0001), and women reported a greater impact on everyday activities (P<0.0001). Women were more likely to use artificial tears (P<0.0001) use them more often (P<0.0001), and to use Restasis® (P<0.0001), omega-3 fatty acids (P=0.0006), and have punctal occlusion (P=0.005). Women spent more money per month on dry eye treatments (P<0.0001), but reported greater dissatisfaction with treatment side effects (P=0.001), and the amount of time before treatments started working (P=0.03).

Conclusions

These data show that dry eye disease is generally experienced as being more severe among women, having a greater impact on their self-assessed well-being.

Polyphenols: benefits to the cardiovascular system in health and in aging

Numerous studies have demonstrated the importance of naturally occurring dietary polyphenols in promoting cardiovascular health and emphasized the significant role these compounds play in limiting the effects of cellular aging. Polyphenols such as resveratrol, epigallocatechin gallate (EGCG), and curcumin have been acknowledged for having beneficial effects on cardiovascular health, while some have also been shown to be protective in aging. This review highlights the literature surrounding this topic on the prominently studied and documented polyphenols as pertaining to cardiovascular health and aging.

Biological importance of reactive oxygen species in relation to difficulties of treating pathologies involving oxidative stress by exogenous antioxidants

Findings about involvement of reactive oxygen species (ROS) not only in defense processes, but also in a number of pathologies, stimulated discussion about their role in etiopathogenesis of various diseases. Yet questions regarding the role of ROS in tissue injury, whether ROS may serve as a common cause of different disorders or whether their uncontrolled production is just a manifestation of the processes involved, remain unexplained. Dogmatically, increased ROS formation is considered to be responsible for development of the so-called free-radical diseases. The present review discusses importance of ROS in various biological processes, including origin of life, evolution, genome plasticity, maintaining homeostasis and organism protection. This may be a reason why no significant benefit was found when exogenous antioxidants were used to treat free-radical diseases, even though their causality was primarily attributed to ROS. Here, we postulate that ROS unlikely play a causal role in tissue damage, but may readily be involved in signaling processes and as such in mediating tissue healing rather than injuring. This concept is thus in a contradiction to traditional understanding of ROS as deleterious agents. Nonetheless, under conditions of failing autoregulation, ROS may attack integral cellular components, cause cell death and deteriorate the evolving injury.

Red blood cell MUFAs and risk of coronary artery disease in the Physicians' Health Study

BACKGROUND

Previous studies have reported beneficial effects of a Mediterranean diet rich in monounsaturated fatty acids (MUFAs) on coronary artery disease (CAD) risk. However, these findings remain inconsistent because some experimental studies have suggested atherogenic and lipotoxicity effects of long-chain and very-long-chain MUFAs on cardiomyocytes.

OBJECTIVE

We examined whether red blood cell (RBC) long-chain and very-long-chain MUFAs are associated with risk of CAD in the Physicians' Health Study.

DESIGN

The ancillary study used a prospective nested case-control design to select 1000 cases of incident CAD and 1000 control subjects matched for age, year of birth, and time of blood collection. RBC MUFAs were measured by using gas chromatography, and CAD was validated by an endpoint committee. Conditional logistic regression was used to estimate RRs.

RESULTS

The mean (±SD) age was 68.7 ± 8.7 y. In a multivariable model that was controlled for matching factors and established CAD risk factors and RBC saturated and omega-3 (n-3) fatty acids, ORs for CAD associated with each SD increase of 20:1n-9 and log 22:1n-9 were 0.89 (95% CI: 0.80, 1.00; P = 0.0441) and 0.83 (95% CI: 0.72, 0.95; P = 0.0086). However, only the 22:1n-9-CAD relation remained statistically significant after Bonferroni correction (P < 0.0125). RBC cis 18:1n-9 and 24:1n-9 were not associated with CAD risk.

CONCLUSION

Our data suggest an inverse association of RBC 22:1n-9 but not 20:1n-9, 18:1n-9, or 24:1n-9 with CAD risk after Bonferroni correction in the Physicians' Health Study.

Identification of Genetic Susceptibility Loci for Colorectal Tumors in a Genome-Wide Meta-analysis

BACKGROUND & AIMS

Heritable factors contribute to the development of colorectal cancer. Identifying the genetic loci associated with colorectal tumor formation could elucidate the mechanisms of pathogenesis.

METHODS

We conducted a genome-wide association study that included 14 studies, 12,696 cases of colorectal tumors (11,870 cancer, 826 adenoma), and 15,113 controls of European descent. The 10 most statistically significant, previously unreported findings were followed up in 6 studies; these included 3056 colorectal tumor cases (2098 cancer, 958 adenoma) and 6658 controls of European and Asian descent.

RESULTS

Based on the combined analysis, we identified a locus that reached the conventional genome-wide significance level at less than 5.0 × 10(-8): an intergenic region on chromosome 2q32.3, close to nucleic acid binding protein 1 (most significant single nucleotide polymorphism: rs11903757; odds ratio [OR], 1.15 per risk allele; P = 3.7 × 10(-8)). We also found evidence for 3 additional loci with P values less than 5.0 × 10(-7): a locus within the laminin gamma 1 gene on chromosome 1q25.3 (rs10911251; OR, 1.10 per risk allele; P = 9.5 × 10(-8)), a locus within the cyclin D2 gene on chromosome 12p13.32 (rs3217810 per risk allele; OR, 0.84; P = 5.9 × 10(-8)), and a locus in the T-box 3 gene on chromosome 12q24.21 (rs59336; OR, 0.91 per risk allele; P = 3.7 × 10(-7)).

CONCLUSIONS

In a large genome-wide association study, we associated polymorphisms close to nucleic acid binding protein 1 (which encodes a DNA-binding protein involved in DNA repair) with colorectal tumor risk. We also provided evidence for an association between colorectal tumor risk and polymorphisms in laminin gamma 1 (this is the second gene in the laminin family to be associated with colorectal cancers), cyclin D2 (which encodes for cyclin D2), and T-box 3 (which encodes a T-box transcription factor and is a target of Wnt signaling to β-catenin). The roles of these genes and their products in cancer pathogenesis warrant further investigation.

Vascular risk factors, cardiovascular disease, and restless legs syndrome in men

BACKGROUND

The prevalence of vascular risk factors, cardiovascular disease, and restless legs syndrome increases with age. Prior studies analyzing the associations between vascular risk factors, cardiovascular disease, and restless legs syndrome found controversial results. We therefore aim to evaluate the associations between prevalent vascular risk factors, prevalent cardiovascular disease, and restless legs syndrome.

METHODS

We conducted a cross-sectional study among 22,786 participants of the US Physicians' Health Studies I and II. Restless legs syndrome was classified according to the 4 minimal diagnostic criteria. Vascular risk factors and restless legs syndrome symptoms were self-reported. Prevalent cardiovascular disease events, including major cardiovascular disease, stroke, and myocardial infarction, were confirmed by medical record review. Age- and multivariable-adjusted logistic regression models were used to evaluate the association among vascular risk factors, prevalent cardiovascular disease events, and restless legs syndrome.

RESULTS

The mean age of the cohort was 67.8 years. The prevalence of restless legs syndrome was 7.5% and increased significantly with age. Diabetes significantly increased the odds of restless legs syndrome (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.21-1.65), whereas frequent exercise (OR, 0.78; 95% CI, 0.67-0.91) and alcohol consumption of 1 or more drinks per day (OR, 0.80; 95% CI, 0.69-0.92) significantly reduced the odds of restless legs syndrome in multivariable-adjusted models. Prevalent stroke showed an increased multivariable-adjusted OR of 1.40 (1.05-1.86), whereas men with prevalent myocardial infarction had a decreased OR of 0.73 (0.55-0.97) for restless legs syndrome.

CONCLUSIONS

The restless legs syndrome prevalence among US male physicians is similar to that of men of the same age group in other western countries. A history of diabetes is the most consistent risk factor associated with restless legs syndrome. Prevalent stroke and myocardial infarction are related to restless legs syndrome prevalence.

Sleep duration and risk of atrial fibrillation (from the Physicians' Health Study)

Although sleep quality and duration have been related to cardiovascular end points, little is known about the association between sleep duration and incident atrial fibrillation (AF). Hence, we prospectively examined the association between sleep duration and incident AF in a cohort of 18,755 United States male physicians. Self-reported sleep duration was ascertained during a 2002 annual follow-up questionnaire. Incident AF was ascertained through annual follow-up questionnaires. Cox regression analysis was used to estimate the relative risks of AF. The average age at baseline was 67.7 ± 8.6 years. During a mean follow-up of 6.9 ± 2.1 years, 1,468 cases of AF occurred. Using 7 hours of sleep as the reference group, the multivariate adjusted hazard ratio for AF was 1.06 (95% confidence interval 0.92 to 1.22), 1.0 (reference), and 1.13 (95% confidence interval 1.00 to 1.27) from the lowest to greatest category of sleep duration (p for trend = 0.26), respectively. In a secondary analysis, no evidence was seen of effect modification by adiposity (p for interaction = 0.69); however, prevalent sleep apnea modified the relation of sleep duration with AF (p for interaction = 0.01). From the greatest to the lowest category of sleep duration, the multivariate-adjusted hazard ratio for AF was 2.26 (95% confidence interval 1.26 to 4.05), 1.0 (reference), and 1.34 (95% confidence interval 0.73 to 2.46) for those with prevalent sleep apnea and 1.01 (95% confidence interval 0.87 to 1.16), 1.0 (reference), and 1.12 (95% confidence interval 0.99 to 1.27) for those without sleep apnea, respectively. Our data showed a modestly elevated risk of AF with long sleep duration among United States male physicians. Furthermore, a shorter sleep duration was associated with a greater risk of AF in those with prevalent sleep apnea.

Migraine and restless legs syndrome in men

BACKGROUND

Previous studies suggest an association between migraine and restless legs syndrome (RLS). Population-based data, however, have been limited to women. The aim of this study is to evaluate the association between migraine and RLS in a male cohort.

METHODS

We conducted a cross-sectional study among 22,926 participants in the Physicians' Health Study. Migraine and RLS information was self-reported. RLS was classified according to four minimal diagnostic criteria. Age- and multivariable-adjusted logistic regression models were calculated.

RESULTS

Of the 22,926 participants (mean age 67.8), 2816 (12.3%) reported migraine and 1717 (7.5%) RLS. Migraine was associated with an increased multivariable-adjusted odds ratio (OR) (95% confidence interval (CI)) of 1.20 (1.04-1.38) for having RLS. The association remained stable after excluding men with potential mimics of RLS and was not modified by age.

CONCLUSIONS

Results of our study indicate an association between migraine and RLS in men. The magnitude of effect is similar to what has been reported in women.

Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trial

CONTEXT

Multivitamin preparations are the most common dietary supplement, taken by at least one-third of all US adults. Observational studies have not provided evidence regarding associations of multivitamin use with total and site-specific cancer incidence or mortality.

OBJECTIVE

To determine whether long-term multivitamin supplementation decreases the risk of total and site-specific cancer events among men.

DESIGN, SETTING, AND PARTICIPANTS

A large-scale, randomized, double-blind, placebo controlled trial (Physicians" Health Study II) of 14 641 male US physicians initially aged 50 years or older (mean [SD] age, 64.3 [9.2] years), including 1312 men with a history of cancer at randomization, enrolled in a common multivitamin study that began in 1997 with treatment and follow-up through June 1, 2011.

INTERVENTION

Daily multivitamin or placebo.

MAIN OUTCOME MEASURES

Total cancer (excluding nonmelanoma skin cancer), with prostate, colorectal, and other site-specific cancers among the secondary end points.

RESULTS

During a median (interquartile range) follow-up of 11.2 (10.7-13.3) years, there were 2669 men with confirmed cancer, including 1373 cases of prostate cancer and 210 cases of colorectal cancer. Compared with placebo, men taking a daily multivitamin had a statistically significant reduction in the incidence of total cancer (multivitamin and placebo groups, 17.0 and 18.3 events, respectively, per 1000 person-years; hazard ratio [HR], 0.92; 95% CI, 0.86-0.998; P=.04). There was no significant effect of a daily multivitamin on prostate cancer (multivitamin and placebo groups, 9.1 and 9.2 events, respectively, per 1000 person-years; HR, 0.98; 95% CI, 0.88-1.09; P=.76), colorectal cancer (multivitamin and placebo groups, 1.2 and 1.4 events, respectively, per 1000 person-years; HR, 0.89; 95% CI, 0.68-1.17; P=.39), or other site-specific cancers. There was no significant difference in the risk of cancer mortality (multivitamin and placebo groups, 4.9 and 5.6 events, respectively, per 1000 person-years; HR, 0.88; 95% CI, 0.77-1.01; P=.07). Daily multivitamin use was associated with a reduction in total cancer among 1312 men with a baseline history of cancer (HR, 0.73; 95% CI, 0.56-0.96; P=.02), but this did not differ significantly from that among 13 329 men initially without cancer (HR, 0.94; 95% CI, 0.87-1.02; P=.15; P for interaction=.07). Conclusion In this large prevention trial of male physicians, daily multivitamin supplementation modestly but significantly reduced the risk of total cancer.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00270647.

Multivitamins in the prevention of cardiovascular disease in men: the Physicians' Health Study II randomized controlled trial

CONTEXT

Although multivitamins are used to prevent vitamin and mineral deficiency, there is a perception that multivitamins may prevent cardiovascular disease (CVD). Observational studies have shown inconsistent associations between regular multivitamin use and CVD, with no long-term clinical trials of multivitamin use.

OBJECTIVE

To determine whether long-term multivitamin supplementation decreases the risk of major cardiovascular events among men.

DESIGN, SETTING, AND PARTICIPANTS

The Physicians' Health Study II, a randomized, double-blind, placebo-controlled trial of a common daily multivitamin, began in 1997 with continued treatment and follow-up through June 1, 2011. A total of 14,641 male US physicians initially aged 50 years or older (mean, 64.3 [SD, 9.2] years), including 754 men with a history of CVD at randomization, were enrolled.

INTERVENTION

Daily multivitamin or placebo.

MAIN OUTCOME MEASURES

Composite end point of major cardiovascular events, including nonfatal myocardial infarction (MI), nonfatal stroke, and CVD mortality. Secondary outcomes included MI and stroke individually.

RESULTS

During a median follow-up of 11.2 (interquartile range, 10.7-13.3) years, there were 1732 confirmed major cardiovascular events. Compared with placebo, there was no significant effect of a daily multivitamin on major cardiovascular events (11.0 and 10.8 events per 1000 person-years for multivitamin vs placebo, respectively; hazard ratio [HR], 1.01; 95% CI, 0.91-1.10; P = .91). Further, a daily multivitamin had no effect on total MI (3.9 and 4.2 events per 1000 person-years; HR, 0.93; 95% CI, 0.80-1.09; P = .39), total stroke (4.1 and 3.9 events per 1000 person-years; HR, 1.06; 95% CI, 0.91-1.23; P = .48), or CVD mortality (5.0 and 5.1 events per 1000 person-years; HR, 0.95; 95% CI, 0.83-1.09; P = .47). A daily multivitamin was also not significantly associated with total mortality (HR, 0.94; 95% CI, 0.88-1.02; P = .13). The effect of a daily multivitamin on major cardiovascular events did not differ between men with or without a baseline history of CVD (P = .62 for interaction).

CONCLUSION

Among this population of US male physicians, taking a daily multivitamin did not reduce major cardiovascular events, MI, stroke, and CVD mortality after more than a decade of treatment and follow-up.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00270647.

Erythrocyte stearidonic acid and other n-3 fatty acids and CHD in the Physicians' Health Study

Intake of marine-based n-3 fatty acids (EPA, docosapentaenoic acid and DHA) is recommended to prevent CHD. Stearidonic acid (SDA), a plant-based n-3 fatty acid, is a precursor of EPA and may be more readily converted to EPA than a-linolenic acid (ALA). While transgenic soyabeans might supply SDA at low cost, it is unclear whether SDA is associated with CHD risk. Furthermore, associations of other n-3 fatty acids with CHD risk remain inconsistent. The present ancillary study examined the association of erythrocyte SDA as well as other n-3 fatty acids with the risk of CHD. In a prospective nested case-control study of the Physicians' Health Study, we randomly selected 1000 pairs of incident CHD with matching controls. Erythrocyte fatty acids were measured using GC. We used conditional logistic regression to estimate relative risks. Mean age was 68·7 (SD 8·7) years. In a multivariable model controlling for matching factors and established CHD risk factors, OR for CHD for each standard deviation increase of log-SDA was 1·03 (95% CI 0·90, 1·18). Corresponding values for log-ALA and log-marine n-3 fatty acids were 1·04 (95% CI 0·94, 1·16) and 0·97 (95% CI 0·88, 1·07), respectively. In conclusion, the present data did not show an association among erythrocyte SDA, ALA or marine n-3 fatty acids and the risk of CHD in male physicians.

Drugs for preventing lung cancer in healthy people

BACKGROUND

This is an updated version of the original review published in Issue 2, 2003. Some studies have suggested a protective effect of antioxidant nutrients on lung cancer. Observational epidemiological studies suggest an association between higher dietary levels of fruits and vegetables containing beta-carotene and a lower risk of lung cancer.

OBJECTIVES

To determine whether vitamins, minerals and other potential agents, alone or in combination, reduce incidence and mortality from lung cancer in healthy people.

SEARCH METHODS

For this update we have used a search strategy adapted from the design in the original review. The following electronic databases have been searched up to December 2011: MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). References included in published studies and reviews were also screened.

SELECTION CRITERIA

Included studies were randomised controlled clinical trials comparing different vitamins, mineral supplements or supplements with placebo, administered to healthy people with the aim of preventing lung cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials to be included in the review, assessed the methodological quality of each trial and extracted data using a standardised form. For each study, relative risk and 95% confidence limits were calculated for dichotomous outcomes and pooled results were calculated using the random-effect model.

MAIN RESULTS

In the first version of this review four studies were included; in this review update, an additional five studies have been included. Four studies included only males and two only females; two studies included only participants considered at high risk, namely smokers or exposed to asbestos, and one study included people deficient in many micronutrients. Six studies analysed vitamin A, three vitamin C, four vitamin E, one selenium supplements, and six studied combinations of two or more products. All the RCTs included in this review were classified as being of low risk of bias.For people not at high risk of lung cancer and compared to placebo, none of the supplements of vitamins or minerals or their combinations resulted in a statistically significant difference in lung cancer incidence or mortality, except for a single study that included 7627 women and found a higher risk of lung cancer incidence for those taking vitamin C but not for total cancer incidence, but that effect was not seen in males or when the results for males and females were pooled.For people at high risk of lung cancer, such as smokers and those exposed to asbestos and compared to placebo, beta-carotene intake showed a small but statistically significant higher risk of lung cancer incidence, lung cancer mortality and for all-causes mortality.

AUTHORS' CONCLUSIONS

There is no evidence for recommending supplements of vitamins A, C, E, selenium, either alone or in different combinations, for the prevention of lung cancer and lung cancer mortality in healthy people. There is some evidence that the use of beta-carotene supplements could be associated with a small increase in lung cancer incidence and mortality in smokers or persons exposed to asbestos.