BONE-MINERAL DENSITY IN MOTHER-DAUGHTER PAIRS - RELATIONS TO LIFETIMEEXERCISE, LIFETIME MILK CONSUMPTION, AND CALCIUM SUPPLEMENTS

This study investigated associations between lifetime milk consumption , calcium intake from supplements, lifetime weight-bearing exercise, a nd bone mineral density (BMD) among 25 elderly women (mean age 72 y) a nd their premenopausal daughters (mean age 41 y). The BMD of the total , axial, and peripheral skeleton was measured by dual-energy X-ray abs orptiometry. Lifetime milk consumption, supplemental calcium intake, a nd weight-bearing exercise were estimated retrospectively by questionn aire and interview. In multiple-linear-regression analyses, mothers' t otal and peripheral BMD were positively associated with supplemental c alcium intake after age 60 y, body weight, current estrogen replacemen t therapy (ERT), and past oral contraceptive (OC) use, and negatively associated with age and height (all P < 0.05). Mothers' axial BMD was positively correlated with body weight and past OC use. Among daughter s, lifetime weightbearing exercise was a predictor of total and periph eral BMD, whereas total lean mass was a predictor of axial BMD. Mother s' lifetime milk consumption was positively associated with that of th eir daughters. Mothers' and daughters' peripheral BMD values were posi tively correlated after adjustment for daughters' exercise? and mother s' age, body weight, and ERT. These results suggest that calcium suppl ementation and exogenous estrogen positively influence bone mass in po stmenopausal years. Our findings lend support to recommendations for p hysical activity as a means of osteoporosis prevention. In the age gro ups studied, the effects of behavioral and hormonal factors on BMD app eared to dominate over familial similarity, which suggests that women may successfully enhance their genetically determined bone mass throug h weight-bearing exercise, postmenopausal ERT, and adequate calcium in take.