PUTTING BODY-WEIGHT AND OSTEOPOROSIS INTO PERSPECTIVE

Osteoporosis is characterized by a reduction in bone mineral density ( BMD). Women more than men are at risk for osteoporosis-related fractur es, especially in the wrists, lumbar spine, and hips. Numerous diet an d lifestyle factors, including body weight, influence BMD, and in turn , fracture risk. BMD in the total body, hip, lumbar spine, and radius is weakly to moderately correlated to body weight, fat mass, and lean body mass in adolescent, perimenopausal, and elderly women, possibly a s the result of stress on the skeleton from the mechanical loading of body weight alone. In addition, greater lean body mass may be a cause. Other explanations include increased hormonal circulation in obese wo men and greater conversion of adrenal androgens to estrogens linked to greater mass of adipose tissue. Currently no value is agreed on for w eight-to-height versus osteoporosis and related fracture risk, but som e extra fat mass yielding a body mass index > 26-28 does confer limite d protection, whereas a slender figure yielding a body mass index < 22 -24 increases risk.