It is widely believed that the vasculature plays an important role in bone remodeling. We investigated the relationship between forearm endothelial function and bone mass in the lumbar spine in early postmenopausal women without a history of smoking or
diabetes mellitus. We studied the forearm resistance artery endothelial function in 110 Japanese women-52 postmenopausal women with normal spinal bone mineral density (BMD), 36 postmenopausal women with
osteopenia, and 22 osteoporotic postmenopausal women. Forearm blood flow (FBF) during
reactive hyperemia and after sublingual
nitroglycerin (NTG) administration was measured by strain-gauge plethysmography. BMD of the lumbar spine (L2-L4) was measured by dual-energy X-ray absorptiometry. After adjustment for age, body mass index, years since the start of menopause, and basal FBF, women with
osteoporosis had a lower maximal FBF response to
reactive hyperemia (28.4 +/- 3.8 mL/min per 100 mL tissue) than those with normal BMD (39.8 +/- 2.8 mL/min per 100mL tissue) or
osteopenia (35.6 +/- 2.5 mL/min per 100mL tissue) (P = 0.029). A significant increase in serum
angiotensin-converting enzyme (ACE) activity (P = 0.042) and a significant decrease in the serum concentrations of
nitrite/
nitrate (P = 0.041) were noted in osteoporotic women compared to women with normal BMD or
osteopenia. The present findings suggest that postmenopausal women with low BMD, especially those with
osteoporosis, have impaired endothelial function in the forearm resistance arteries.