Bone density, biochemistry and life-style.

We have assessed the relationship between bone density, biochemistry and life-style factors in a cross-sectional study of 434 pre- and 357 postmenopausal women. Bone-mineral content (BMC) was measured in the non-dominant forearm using single-photon densitometry. Bone mass was corrected for bone size (BMC2) in a sub-set of 263 subjects. Correlation statistics and multiple regression analyses were used to identify physical and biochemical measurements that could be used to best predict BMC or BMC2. These were combined with lifestyle factors, using multiple logistic regression analysis, to identify women at risk of low bone density. Cut-off values were taken as the 5th percentile of the bone density distributions in pre-menopausal women. In postmenopausal women, using BMC2 values to define "risk", and using age, creatinine, alkaline phosphatase, thyroxine treatment, and calcium supplementation as predictors, a sensitivity of 73% and a specificity of 95% were achieved. Such a model may be of use as a "first pass" screening test for osteoporosis.