High blood pressure and bone-mineral loss In elderly white women: a prospective study

Background High blood pressure is associated with abnormalities in calcium metabolism. Sustained calcium loss may lead to increased bone-mineral loss in people with high blood pressure. We investigated the prospective associa tion between blood pressure and bone-mineral loss over time in elderly whit e women. Methods We studied 3676 women who were initially assessed in 1988-90 (mean age 73 years [SD 4, range 66-91 years]; mean bodyweight 65.3 kg [11.5]; blo od pressure 137/75 mm Hg [17/9]) who were not on thiazide diuretics. Mean f ollow-up was 3.5 years. Anthropometry, blood pressure, and bone-mineral den sity at the femoral neck were measured at baseline and bone densitometry wa s repeated after 3.5 years by dual-energy X-ray absorptiometry. Findings After adjustment for age, initial hone-mineral density, weight and weight change, smoking, and regular use of hormone-replacement therapy, th e rate of bone loss at the femoral neck increased with blood pressure at ba seline. In the quartiles of systolic blood pressure, yearly bone losses inc reased from 2.26 mg/cm(2) (95% CI 1.48-3.04) in the first quartile to 3.79 mg/cm(2) in the fourth quartile (3.13-4.45; test for heterogeneity, p=0.03; test for linear trend, p=0.01), equivalent to yearly changes of 0.34% (0.2 0-0.46) and 0.59% (0.49-0.69; test for heterogeneity, p=0.02; test for line ar trend, p=0.005). There was no significant interaction with age. The excl usion of women on antihypertensive drugs did not alter the results, For dia stolic blood pressure, there was an association with bone loss in women you nger than 75 years. Interpretation Higher blood pressure in elderly white women is associated w ith increased bone loss at the femoral neck. This association may reflect g reater calcium losses associated with high blood pressure, which may contri bute to the risk of hip fractures.