Dietary Intake of Calcium and Vitamin D and the Prevalence of Metabolic Syndrome in Tehranian Adults: Tehran Lipid and Glucose Study (TLGS)

Recent studies have shown that dairy consumption is inversely associated with the metabolic syndrome. Calcium and vitamin D, two major components of dairy products, have been postulated as being primarily responsible for the beneficial effect of dairy consumption. The objective was to examine whether and to what extent intakes of calcium and vitamin D are related to the metabolic syndrome in adults. In this population-based cross sectional study, a representative sample of 808 subjects (male and female) aged 18-74 y were randomly selected. Subjects were categorized based on quartile cut-points of dietary intakes of calcium and vitamin D. Multivariate logistic regression was used in 4 models to compare different dietary intake levels of calcium and vitamin D adjusted for lifestyle and nutritional confounders. Each model was additionally adjusted for more variables than the previous one. After adjusting for age, calories, smoking status, exercise, BMI and parental history of myocardial infarction before age 60 years, dietary calcium levels were significantly and inversely associated with the prevalence of metabolic syndrome, and the ORs of having the metabolic syndrome for increasing quartiles of dietary calcium intake were 1.00 (reference), 0.90 (95% CI 0.61–1.04), 0.85 (0.78–0.99) and 0.74 (0.62–0.95) P for trend <0.02, and was not appreciably altered by additional adjustment for dietary vitamin D intake. Dietary vitamin D was inversely associated with the 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 and the multivariable OR comparing highest with lowest intake quartiles was 0.81(0.64-0.98), P for trend <0.03. It is concluded that intakes of calcium and dairy products may be associated with a lower prevalence of the metabolic syndrome in adults.