The Study of Osteoporotic Fractures, which began over 20 years ago, found that bone mineral density (BMD) of the hip is one of the best predictors of fracture for women, and that weight loss in the elderly and family history of hip fractures are two of the most important risk factors for this condition. Similar studies have now begun to learn about osteoporosis risk factors in men.
National Institutes of Health. . 'NIH Fact Sheet: Osteoporosis'.