Percent body fat, fractures and risk of osteoporosis in women.

OBJECTIVES

Globally, in an aging population, osteoporosis and fractures are emerging as major public health problems; accessible and affordable recognition, prevention and treatment strategies are needed. Percent body fat is known to be associated with bone mineral density and fractures. This paper uses an innovative, virtually cost-free method to estimate percent body fat from age, height and weight, and assesses its validity by examining the association between percent body fat and fractures among women 39 and older.

DESIGN

An epidemiologic study.

PARTICIPANTS

3940 college alumnae, median age 53.6, participated by responding to a mailed questionnaire covering medical history, behavioral factors, birth date, weight and height.

STATISTICAL

METHODS

T-tests, chi-square and multivariable logistic regression.

MEASUREMENTS: Percent body fat estimated from age, weight, height and gender.

RESULTS

Associations of fractures with percent body fat are expressed as odds ratios: for osteoporotic (wrist, hip and/or x-ray confirmed vertebral), the adjusted OR = 2.41, 95% CI (1.65, 3.54), P < 0.0001; for wrist fractures, the adjusted OR = 2.56, 95% CI (1.65, 3.96), P < 0.0001; for x-ray confirmed vertebral fractures the adjusted OR = 4.69, 95% CI (2.05, 10.77), P=0.0003).; and for non-osteoporotic, he adjusted OR= 1.00, 95% CI (0.76 1.32), P=0.999.

CONCLUSION

The findings are consistent with methods using DXA and/or other technologies that show percent body fat is associated with fractures of the wrist and vertebrae. Identification of risk factors is necessary for the prevention and treatment of osteoporosis and osteoporotic fractures. Estimation of percent body fat from age, height and weight may be a valid, cost-saving, and cost-effective alternative tool for screening and assessing risk of osteoporosis in settings where Dual x-ray absorptiometry (DXA) or other radiological techniques are too costly or unavailable.