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Objective: To explore the association between vitamin B(12) (B(12))-containing supplement use, low B(12) concentrations and biochemically defined B(12) deficiency in US adults.Design: A cross-sectional study with adjustment for survey design. Prevalence ratios for two age groups (18-50 and >50 years) were estimated using unconditional logistic models. Outcome measures included prevalence of low serum B(12) concentration (<148 pmol/l) and biochemical B(12) deficiency (serum B(12)< 148 pmol/l with concomitant homocysteine > 10 mumol/l).Setting: A population survey of health and nutritional measures.Subjects: Subjects were non-institutionalized adults, aged 18 years and older, who participated in Phase 2 of NHANES III (Third National Health and Nutrition Examination Survey).Results: Low B(12) concentrations were less prevalent among persons consuming B(12)-containing supplements (P = 0.001) with an adjusted prevalence ratio of 0.6 (95 % CI 0.3, 1.0). Biochemical B(12) deficiency showed a similar trend (P = 0.0002), with an adjusted prevalence ratio of 0.3 (95 % CI 0.1, 0.8). Prevalence ratios were similar in adults >50 years of age, although the prevalence of low B(12) and biochemical deficiency was proportionally higher.Conclusions: Consumption of B(12)-containing supplements was associated with at least 50 % lower prevalence of both low serum B(12) and biochemical B12 deficiency in a nationally representative sample of US adults, suggesting increased consumption of B(12) from supplements or from fortified foods may reduce the prevalence of B(12) deficiency. Additionally, the current Recommended Daily Allowance for B(12) of 2.4 microg may be insufficient for those aged >50 years. [ABSTRACT FROM AUTHOR]

A few epidemiologic studies have shown an increased risk of death from external causes among men with hypertension. Previous studies were limited by small numbers of events, however, and none assessed the association of blood pressure with specific types of 'accidental' death. The authors examined data obtained from baseline interviews and 25 years of mortality follow-up (1973-1999) for 347,978 men screened for the US Multiple Risk Factor Intervention Trial. Proportional hazards regression analyses were used to quantify associations of blood pressure with all external causes of death and individual causes. There were 3,910 deaths from external causes, including 2,313 unintentional injuries, 1,248 suicides, and 349 homicides. Compared with those for men whose blood pressure status was 'normal' according to the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, the multivariate-adjusted hazard ratios and 95% confidence intervals for death from external causes among men with prehypertension, stage 1 hypertension, and stage 2 hypertension were 0.91 (95% confidence interval (CI): 0.83, 1.00), 1.06 (95% CI: 0.96, 1.16), and 1.44 (95% CI: 1.28, 1.62), respectively. Men with stage 2 hypertension had multivariate-adjusted hazard ratios of 1.90 for falls (95% CI: 1.32, 2.74), 1.45 for motor vehicle injuries (95% CI: 1.14, 1.85), 1.33 for other 'accidents' (95% CI: 1.06, 1.66), 1.40 for suicide (95% CI: 1.13, 1.73), and 1.35 for homicide (95% CI: 0.92, 1.97). For men, hypertension may signal an increased risk of death from external causes. [ABSTRACT FROM AUTHOR]

Epidemiological studies have shown that cigarette smoking is associated with a reduced risk of endometrial cancer, in contrast to the increased risks observed with many other non-respiratory-tract cancers, including those of the bladder, pancreas, and cervix uteri. Some studies of endometrial cancer suggest that the inverse association with smoking is limited to certain groups of women, such as those who are postmenopausal or those taking hormone-replacement therapy. The biological mechanisms that might underlie this association remain unclear, although several have been proposed, including an antioestrogenic effect of cigarette smoking on circulating oestrogen concentrations, a reduction in relative bodyweight, and an earlier age at menopause. We have examined the evidence for an association between cigarette smoking and risk of endometrial cancer, including studies related to the proposed biological mechanisms. [ABSTRACT FROM AUTHOR]

Lycopene has been associated with reduced prostate cancer risk, although the results of epidemiological studies have varied. We hypothesize that an effect of lycopene may be modified by XRCC1 genotype and other antioxidants. We used a food-frequency questionnaire to assess lycopene intake in a case-control study of prostate cancer in North Carolina. Plasma alpha-tocopherol and beta-carotene levels were measured using high-performance liquid chromatography. XRCC1 genotypes were detected using polymerase chain reaction-restriction fragment length polymorphism. The final dataset included 77 cases and 174 controls with complete questionnaires, genotyping, and plasma analyses. Among men with the Arg/Arg genotype at codon 399, odds ratios (ORs) for prostate cancer risk associated with medium (732-1,529 mug/day) and high (>1,529 mug/day) lycopene intake were 0.59 (95% confidence interval = 0.23-1.50) and 0.21 (0.06-0.71), respectively (P(trend) < 0.01). Similar analyses for persons with Arg/Gln or Gln/Gln genotypes produced null results. Above-median (1,048 mug/day) lycopene intake combined with above-median levels of alpha-tocopherol and beta-carotene was associated with an OR of 0.11 (0.02-0.65) among men with the Arg/Arg genotype but not those with at least one Gln allele (P(interaction) = 0.01). Although limited by small sample size, these findings indicate that the association between lycopene and prostate cancer is complex and may be modified by other antioxidants and by XRCC1 genotype. [ABSTRACT FROM AUTHOR]

Objective: High-glycaemic-load diets may increase endometrial cancer risk by increasing circulating insulin levels and, as a consequence, circulating oestrogen levels. Given the paucity of epidemiological data regarding the relationship between dietary glycaemic index and glycaemic load and endometrial cancer risk, we sought to examine these associations using data from a prospective cohort study.Design, Setting and Subjects: We examined the association between dietary glycaemic load and endometrial cancer risk in a cohort of 49,613 Canadian women aged between 40 and 59 years at baseline who completed self-administered food-frequency questionnaires between 1982 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000.Results: During a mean of 16.4 years of follow-up, we observed 426 incident cases of endometrial cancer. Hazard ratios for the highest versus the lowest quartile level of overall glycaemic index and glycaemic load were 1.47 (95% confidence interval (CI) = 0.90-2.41; P for trend = 0.14) and 1.36 (95% CI = 1.01-1.84; P for trend = 0.21), respectively. No association was observed between total carbohydrate or total sugar consumption and endometrial cancer risk. Among obese women (body mass index >30 kg m(-2)) the hazard ratio for the highest versus the lowest quartile level of glycaemic load was 1.88 (95% CI = 1.08-3.29; P for trend = 0.54) and there was a 55% increased risk for the highest versus the lowest quartile level of glycaemic load among premenopausal women. There was also evidence to support a positive association between glycaemic load and endometrial cancer risk among postmenopausal women who had used hormone replacement therapy.Conclusions: Our data suggest that diets with high glycaemic index or high glycaemic load may be associated with endometrial cancer risk overall, and particularly among obese women, premenopausal women and postmenopausal women who use hormone replacement therapy. [ABSTRACT FROM AUTHOR]