Dietary calcium, vitamin D, and the prevalence of metabolic syndrome in middle-aged and older U.S. women.

Diabetes care

Dec 2005

DOI: 10.2337/DIACARE.28.12.2926

Citations:481

Influential Citations:28

Observational Studies (Human)

Enhanced Details

Methods

Observational, prospective cohort analysis of 10,066 women aged 45 years and older from the Women’s Health Study who were free of cardiovascular disease, cancer, or diabetes at baseline and had never used postmenopausal hormones.

Results

Calcium intake (total, dietary, and from supplements) is associated with a lower prevalence of metabolic syndrome after adjustment for age, energy intake, and lifestyle. Highest vs lowest quintiles showed: total calcium OR 0.64 (0.54-0.77); dietary calcium OR 0.69 (0.58-0.82); supplemental calcium OR 0.84 (0.70-0.99). Adjusting for dietary factors or total vitamin D did not alter these inverse associations. Vitamin D intake was not independently associated with metabolic syndrome after adjusting for calcium. Dietary dairy products also related to lower prevalence (OR 0.66 (0.55-0.80)); results suggest calcium and dairy intake may help lower metabolic syndrome prevalence in this population, while vitamin D alone did not show an independent effect. Findings warrant confirmation in prospective studies and trials.

Limitations

Cross-sectional analysis cannot establish temporality; dietary assessment has measurement error and may bias toward null; study population was predominantly Caucasian, limiting generalizability; potential residual confounding; calcium and vitamin D intakes are highly correlated, complicating disentanglement of independent effects; limited statistical power for five-component metabolic syndrome.

Abstract

OBJECTIVE To examine whether and to what extent intakes of calcium and vitamin D are related to the metabolic syndrome in middle-aged or older women. RESEARCH DESIGN AND METHODS We analyzed data from 10,066 women aged > or =45 years participating in the Women's Health Study who were free of cardiovascular disease, cancer, or diabetes and who never used postmenopausal hormones. We used multiple logistic regression models to estimate multivariable odds ratios (ORs) and 95% CIs comparing different dietary intake levels of calcium and vitamin D. RESULTS In age- and calorie-adjusted analyses, higher intakes of total, dietary, and supplemental calcium were significantly and inversely associated with the prevalence of metabolic syndrome. After further adjusting for smoking status, exercise, alcohol intake, multivitamin use, and parental history of myocardial infarction before age 60 years, the ORs of having the metabolic syndrome for increasing quintiles of total calcium intake were 1.00 (reference), 0.82 (95% CI 0.70-0.97), 0.84 (0.71-0.99), 0.70 (0.59-0.83), and 0.64 (0.54-0.77) (P for trend <0.0001). This association was not appreciably altered by additional adjustment for other dietary factors or total vitamin D intake. In contrast, neither total (P for trend = 0.13) nor supplemental (P for trend = 0.45) vitamin D was significantly associated with metabolic syndrome. Dietary vitamin D was inversely associated with prevalence of metabolic syndrome but was not independent of total calcium intake. Similar strong relations between intakes of dairy products and metabolic syndrome were also observed. After adjustment for lifestyle and dietary factors, the multivariable ORs comparing highest with lowest intake categories were 0.66 (0.55-0.80) (P for trend <0.0001) for total dairy products and 0.85 (0.71-1.02) (P for trend = 0.05) for total milk intake. CONCLUSIONS Our results indicate that intakes of calcium and dairy products may be associated with lower prevalence of the metabolic syndrome in middle-aged and older women. show less