BMD and Risk of Hip and Nonvertebral Fractures in Older Men:A Prospective Study and Comparison With Older Women

Abstract

In a prospective study of 5384 older men, hip BMD was a very strong predictor of hip fracture, much stronger than spine BMD. The relationship between hip BMD and hip fracture risk seemed to be stronger than observed in a large prospective study of women. Hip BMD is an excellent test for predicting fracture risk in men. There have been few studies of the relationship between BMD and risk of fractures in men and none for the association between lumbar spine BMD and risk of hip and nonvertebral fractures. There is also controversy about whether the associations between BMD and risk of fracture are the same in men and women. We measured proximal femur and lumbar spine BMD in 5384 men, 5384 men, >or= 65 years of age. We compared the results to the very similar cohort of 7871 women >or=65 of age. During 4.4 years of 99% complete follow-up, we validated 317 nonvertebral (59 hip) fractures in men and 1169 nonvertebral (208 hip) fractures in women. Total hip BMD was very strongly associated with risk hip fracture in men (3.2-fold increased risk per sex-specific SD decrease in BMD; 95% CI, 2.4-4.1). The association was stronger than observed in SOF (2.1; 95% CI, 1.8, 2.4; p < 0.001 for interaction). Among the men, lumbar spine BMD was weakly associated with risk of hip fracture (relative risk [RR] per sex-specific SD decrease in BMD: 1.5; 95% CI, 1.2, 2.0). The association between total hip BMD and risk of nonvertebral fractures was somewhat stronger for men (RR = 1.6; 95% CI, 1.5, 1.8) than found for women (p = 0.01 for interaction). The risk of nonvertebral fracture was substantially higher in women than in men for all T scores of hip BMD, regardless of whether sex-specific or female reference values were used. Hip BMD is strongly associated with risk of nonvertebral, and especially hip fracture, in older men. These associations are at least as strong as in women. As in women, lumbar spine BMD in men is only weakly associated with risk of hip fracture. Regardless of whether sex-specific or female reference values were used, T scores indicated different risks of fractures in men than in women.