Mr. Os (Hong Kong) is the first study to address the risk factors for osteoporosis in Asian men. A standardized, structured interview and dual X-ray densitometry (DEXA) were performed on 2,000 Chinese men aged 65-92. By multiple regression, the following factors were found to be positively associated with BMD at both the total hip and the spine: body weight, grip strength and a history of diabetes mellitus. The following factors were found to be negatively associated with BMD at both the total hip and spine: cigarette smoking, a history of gastrectomy or bowel resection, current use of inhaled steroid and a history of fracture after 50 years. Moreover, a history of chronic obstructive pulmonary disease (COPD) was negatively associated with BMD at the total hip, and age, the use of an alpha-blocker, thiazide diuretic and nitrate were associated with a higher BMD at the spine. A total of 21.8% of the variance in total hip and 31.5% of the variance in total spine BMD was accounted for in the multivariate analysis.