Although associated with bone loss, a recent study did not demonstrate that low bioavailable estradiol translates into worse kyphosis in older men. High sex hormone-binding globulin (SHBG) is associated with bone loss and vertebral fractures, however, and results suggest that high SHBG may also be a risk factor for hyperkyphosis. Researchers examined the cross-sectional associations between individual bioavailable sex hormones and SHBG with radiographically assessed kyphosis. Participants included 1,500 men aged ≥65 years from the Osteoporotic Fractures in Men (MrOS) Study. They found:

• After adjustment for age and other confounding variables, no association was found between bioavailable estradiol or testosterone and Cobb angle, either when kyphosis was analyzed as a continuous variable or dichotomized into highest vs lower 3 quartiles.
• In linear regression models adjusted for age and clinic site, there was a significant association between SHBG and kyphosis (parameter estimate=0.76 per standard deviation [SD] increase).
• In the fully adjusted model, this association was weakened and of only borderline statistical significance (parameter estimate=0.61 per SD).