Health and hormonal characteristics of premenopausal women with lower bone mass.

A study of clinical renal and endocrinologic status was undertaken to determine whether the lowest maximal bone mass observed in premenopausal women, aged 20-40 years, was a result of undiagnosed disease or represented a continuum of measurement in young adult women. A clinical sample (n = 53) was generated from an epidemiologic cross-sectional study (n = 535) designed to characterized correlates of maximal bone mass. Cases were 28 premenopausal women whose femoral bone mass as in the lowest 5th percentile of the distribution, less than 0.75 g/cm2 at the femoral neck. Controls were 25 randomly selected premenopausal women whose femoral bone mass was within 1 SD of the mean of the femoral bone mass distribution. There was no indication of increased frequency of disease among the cases as compared with the controls. No occult hypogonadism, thyrotoxicosis, hyperparathyroidism, myeloma, or renal insufficiency was observed to explain lower bone mass measurement. However, cases had significantly lower estradiol levels (75 versus 106 pg/ml, P less than 0.05) and higher luteinizing hormone levels (3.8 versus 3.1 mIU/ml, P less than 0.07) than controls. Though preliminary, these findings suggest that lower estradiol levels may contribute to significant differences in bone mass even among healthy women at the time of maximal bone accumulation.