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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]

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]