Also, the women who stayed on the estrogen but were in the placebo group had stable bone density. Probably now there will be a push to measure bone density in women even if they are taking estrogen, with the suggestion that alendronate should be added to those whose bone density is low. Even with the new data, my recommendation is that bisphosphonates should not be added to estrogen unless there is clear-cut evidence of continuing bone loss on the estrogen. Thiazides Several large, prospective epidemiological studies in elderly men and women have shown that thiazide use is associated with a reduced risk of hip fracture. Several possible mechanisms could explain this association.
Thiazides act directly on the distal nephron to enhance calcium reabsorption.
In men with hypercalciuria, thiazides lower urine calcium and lead to positive calcium balance. Thiazides may also reduce osteoclastic activity, possibly by inhibiting carbonic anhydrase. One randomized study of treatment of systolic hypertension included bone mass as a secondary endpoint in a subset of patients. The subjects who took thiazide had increased bone mass, whereas those on other forms of antihypertensive medication showed decreases in bone mass. The effect of thiazides on bone density in patients with normal blood pressure has not been studied, but a randomized trial is underway.