Dietary calcium intake and rates of bone loss in women.

We measured bone mineral density (BMD) at the midradius and lumbar spine in 106 normal women, ages 23-84 yr (61 were postmenopausal). Three to nine measurements (median, four) were made over 2.6 to 6.6 yr (mean, 4.1 yr). The correlation between calcium intake (range, 260-2,035 mg/d) and rate of change in BMD was not significant at the midradius (r = 0.06) or lumbar spine (r = 0.08), even after adjusting for age, menopausal status, and serum estrogen levels by multiple regression analysis. Women in the lower (mean, 501 mg/d) and in the upper (mean, 1,397 mg/d) quartiles of dietary intake had similar rates of change in BMD (%/yr [mean +/- SE], at midradius, -0.78 +/- 0.24 and -0.91 +/- 0.17 for lower and upper quartiles, respectively; at lumbar spine, -1.06 +/- 0.24 and 0.98 +/- 0.24). These data do not support the hypothesis that insufficient dietary calcium is a major cause of bone loss in women.