Epidemiology and risk factors of osteoporosis.

Recent osteoporosis research has been oriented increasingly toward understanding the determinants of peak bone mass acquisition during childhood and adolescence. Genetic factors may account for approximately half of the variability in peak femoral bone mass density, and racial differences in bone mass have been shown to appear early in life. Physical activity appears to play an important role in increasing bone mass during childhood. Most fractures in the elderly have been found to be associated with reduced bone mass and could therefore be considered osteoporotic. Retrospective reviews of medical records from residents of Rochester, Minnesota, suggest that approximately one third of women with vertebral deformities seek medical attention. Other cross-sectional data suggest that vertebral deformities cause substantial back pain and disability only if vertebral height ratios fall 4 SD below the mean.