Potential covariate measures for BMD were obtained from the baseline questionnaire, interview, and examination. These included demographic characteristics such as age, race/ethnicity, and clinic site; anthropometric measurements, including height, weight, body mass index, lean and fat mass, and self-reported height and weight change since age 25 years; medical conditions, including hypertension, Parkinson disease, hypothyroidism, diabetes, and stroke; lifestyle factors such as physical activity, history of heavy alcohol use, current smoking, and marital status; family history of fracture; and any history of falls. Race and/or ethnicity was ascertained by self-declaration as white, black or African American, Asian, Hispanic or Latino, and other. Any participant who indicated Hispanic background, regardless of the race category, was classified as Hispanic; those not meeting any of the descriptions listed were classified as other. Physical activity was assessed using the Physical Activity Scale for the Elderly.17 Perceived health status was obtained from the Medical Outcomes Study 12-Item Short-Form Health Survey (SF-12)18 scored for physical and mental well-being. The mental component summary (MCS) scale of the SF-12 is a reliable measure that has been shown to distinguish between major depressive disorder, depressive symptoms, and no depression.19- 20 In addition, the individual questions, as surrogates for depressed mood, were tested for correlation with BMD and use of SSRIs. Accomplishment of independent activities of daily living was self-reported. Dietary calcium and vitamin D intake was calculated using a modified food frequency questionnaire developed specifically for the MrOS Study by Block Dietary Data Systems, Berkeley, Calif (http://www.nutritionquest.com). As part of the clinic visit, participants completed tests of neuromuscular function, including walking speed, grip strength, and completion of 5 chair stands (rising from a seated position without using the chair's arms).