Ethnic and genetic differences in bone mass: a review with a hereditary vs environmental perspective.

Based on a review of the literature, ethnic and genetic factors are significant determinants of bone mass, along with such environmental factors as diet and exercise. Differences in bone density between blacks and whites remain even after adjustment for body mass. Black-white differences in bone mass appear to be related to ethnicity because blacks have not only greater skeletal calcium content, but also greater total body potassium and muscle mass. Genetic studies of twins and parent-offspring pairs reflect strong constitutional associations of both bone mineral content and bone density at commonly measured skeletal sites. At least for females, bone mass accumulation by age 20 y is highly associated with maternal bone mass; up to menopause it is enhanced by child-bearing and lactation; beyond menopause environmental factors seem to dominate. Dietary calcium and physical activity are significant in the control of bone mass. These findings are important for osteoporosis and fractures, especially in elderly people.