Age trends for hip geometry in Chinese men and women and the association with femoral neck fracture.

UNLABELLED

Hip dual-energy X-ray absorptiometry (DXA) images were used to calculate hip bone mineral density (BMD) and hip geometry parameters of 18,502 healthy Chinese people (14,435 women and 4,067 men), 254 subjects sustained a femoral neck fracture and 254 age- and sex-matched controls. Our study showed that thinning of the cortical shell and deterioration of the strength index (SI) in femoral neck with aging in both Chinese men and women. SI may be a risk factor for hip fracture in Chinese women.

INTRODUCTION

The purpose of this study was to evaluate age-related trends in the hip geometry of healthy Chinese men and women and to examine whether changes in hip geometric parameters is one of the risk factors of hip fracture.

METHODS

We recruited 14,435 women and 4,067 men as the study population. There were 254 subjects (216 women, 38 men) who had sustained a femoral neck fracture; 254 age- and sex-matched healthy persons served as controls. Hip DXA images were used to calculate hip BMD and hip geometry parameters, including the hip axis length (HAL), cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), neck-shaft angle (NSA) and femoral SI.

RESULTS

Hip BMD, CSMI, CSA and SI showed significantly negative correlations with age. However, after adjustment for height and weight, HAL increased with age, and there was no strong correlation between CSMI and age in either sex. In both genders, hip BMD and CSA were significant lower in fracture cases compared with controls. After adjustment for hip BMD, in women only smaller SI (odds ratio [OR] 1.53; 95% confidence interval [CI], 1.04-2.26) was predictive of hip fracture but in men, none of the geometry parameters was associated with hip fracture risk.

CONCLUSIONS

This study demonstrated thinning of the cortical shell and deterioration of the resistance to bending and SI with aging in femoral neck in Chinese men and women. SI may be a risk factor for hip fracture that is independent of BMD measurement in Chinese women.