The association between osteoporosis and hypertension: the role of a low dairy intake.

Hypertension and related cardiovascular diseases are reported to be associated with osteoporosis. A nutritional pathway related to dairy intake has been postulated for both diseases. The aim of this study was to assess calcium intake from dairy sources as a possible pathogenic link between osteoporosis and hypertension. This was a cross-sectional observational study performed on 3,301 postmenopausal women referred for a densitometry screening. Osteoporosis was diagnosed by lumbar dual-energy X-ray absorptiometry and hypertension was defined by blood pressure data and/or the use of antihypertensive medication. Dairy food consumption was evaluated using a weekly food-frequency questionnaire. The odds of being affected by osteoporosis, hypertension, or both diseases were calculated for quartiles of dairy intake by logistic regression analyses. Women with hypertension were affected more frequently by osteoporosis (33.2 vs. 23.3 %; p = 0.000), and there was a higher prevalence of hypertension among women with osteoporosis (32.2 vs. 22.5 %; p = 0.000). The proportion of women with hypertension, osteoporosis, and both diseases significantly increased across decreasing quartiles of dairy intake. A dairy intake in the lowest quartile was a significant predictor of osteoporosis [OR (95 % CI): 1.43 (1.12, 1.82)] and hypertension [OR (95 % CI): 1.46 (1.15, 1.85)] when compared to the highest quartile. Similarly, a low dairy intake was associated with increased odds to have both the diseases [OR (95 % CI): 1.60 (1.10, 2.34)]. From these results we conclude that osteoporosis and hypertension are associated in postmenopausal women, and a low dairy intake may increase the risk of both diseases, acting as a possible pathogenic link.