This study was designed to compare the bone mineral density (BMD) and the prevalence of osteoporosis in community-dwelling women (aged 50-89) living in Northern (Beijing) and Southern (Hong Kong) China.
The incidences of osteoporosis and hip fractures have been on the rise in some Asian countries. This study aims to gain insight into aetiology behind by comparing bone health indicators between Northern Chinese (Beijing) and Southern Chinese (Hong Kong) women.
Method: A total number of 6,099 and 6,302 Chinese postmenopausal women aged 50 to 89 years old from Hong Kong and Beijing were recruited respectively from 2008 to 2011. Height, weight and BMI were measured and compared between the two groups, as well as bone mineral density (BMD) that was measured by DXA scans at the spine (L1-L4 level), total hip and femoral neck, and expressed as BMD (g/cm2)
- Key Findings:
- The prevalence of osteoporosis increased rapidly with age, where Hong Kong women had a higher overall prevalence (24.9%) than that in Beijing women (20.3%).
- After adjustments for age, height and weight were made, the BMD of Hong Kong Chinese women was found to be significantly higher than that in Beijing Chinese women, with differences of 4.8%, 2.7% and 1.4% at the lumbar spine, total hip and femoral neck respectively.
- Body weight accounted for 13.3%, 14.6%, and 10.6% of the difference in BMD of lumbar spine, total hip, and femoral neck respectively between the 2 populations.
- Independent of age, for each 5 kg increase in body weight in Hong Kong Chinese women, BMD increased by 0.035, 0.026 and 0.022 g/cm2 at lumbar spine, total hip and femoral neck respectively, where the increments observed were significantly higher than those in Beijing Chinese women across all sites. Postulated reasons for the relationship include additional load carried by skeleton, fat-bone interaction and genetic variations.
BMD of Southern Chinese women living in Hong Kong was higher than Northern Chinese women living in Beijing. The overall prevalence of osteoporosis is high in both populations and continues to be a major public health problem.
Lau EM, Chung HL, Ha PC, Tang H, Lam D. Bone mineral density, anthropometric indices, and the prevalence of osteoporosis in Northern (Beijing) Chinese and Southern (Hong Kong) Chinese women – The largest comparative study to date. J Clin Densitom. Epub 2015 Jan 13;S1094-6950. Link to PubMed