Dose-response relationships between dairy intake and chronic metabolic diseases in a Chinese population.

Background: This study investigated associations between dairy intake and chronic metabolic diseases (CMDs), and evaluated possible dose-response relationships in Chinese.

Methods: This cross-sectional study included 6073 adults aged ≥18 years from China. General characteristics were gathered using a validated dietary questionnaire. Multivariable logistic regression analyses investigated associations between dairy intake and chronic metabolic diseases (CMDs) (overweight/obesity, obesity, central obesity, and hyperlipidemia). Restricted cubic spline models explored dose-response relationships between dairy intake and CMDs, and possible dairy intake in the prevention of CMDs. Structural equation modeling explored the potential mechanisms of the effects of dairy intake on CMDs.

Results: Significant inverse associations were found between dairy intake and overweight/obesity, obesity, central obesity, and hyperlipidemia, with odds ratios (ORs) of 0.66 (95% confidence interval [CI] 0.56-0.79), 0.63 (95% CI 0.47-0.85), 0.71 (95% CI 0.60-0.85), and 0.81 (95% CI 0.56-1.17), respectively (P < 0.05 for all). The intake of yogurt, milk, and total dairy to prevent CMDs differed according to age group (16-74, 29-187, and 159-269 mL/d, respectively, in the entire group; 69-110, 59-152, and 138-167 mL/d, respectively, in the young group, ≤ 44 years; 9-58, 57-149, and 117-145 mL/d, respectively, in the middle-aged group, 45-59 years; and 23-59 mL/d yogurt only in the old group, ≥ 60 years). Structural equation modeling showed that dairy intake could reduce body mass index and waist circumference by regulating carbohydrate, fat, protein, and total energy.

Conclusions: Dairy intake was inversely associated with the prevalence of overweight, obesity, central obesity, and hyperlipidemia, and the optimal range of dairy intake differed with age. The beneficial effects of dairy intake in preventing CMDs could involve regulation of carbohydrate, fat, protein, and total energy.