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.

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. Six thousand ninety-nine ambulatory Chinese women living in Hong Kong and 6302 mainland Chinese women living in Beijing were recruited for the study. The BMD was found to be 2.2% higher at the lumbar spine, 8.4% higher at the total hip, and 7.2% higher at the femoral neck in Beijing women than those in Hong Kong women. However, after adjustment for age, weight, and height, this trend was reversed so that the adjusted BMD at the lumbar spine, total hip, and femoral neck was 4.8%, 2.7%, and 1.4% higher in Hong Kong Chinese women than Beijing Chinese women, 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 between the 2 populations. The prevalence of osteoporosis in Hong Kong women (24.9%) was found to be higher than that in Beijing women (20.3%). We conclude that osteoporosis is a major health problem in Chinese women, and in comparing BMD between subjects of the same ethnicity, body weight must be taken into account.

The prevalence of Apo E4 genotype and its relationship to bone mineral density in Hong Kong Chinese.

Apolipoprotein E (Apo E) polymorphism has been implicated in many chronic diseases, including Alzheimer disease and osteoporosis. Significant association of the Apo E4 allele to low bone mineral density (BMD) has been repeatedly reported. We here examined the Apo E genotype frequencies in the Chinese population (n = 692) and its relationship to BMD. A significantly lower frequency (a prevalence of 7%) of the E4 alleles was found in our Chinese subjects compared to that reported in Caucasians (14.7%) or in Japanese (11.7%). However, no significant association between the Apo E4 allele and BMD Z score was observed in our test subjects; this may be due to the rarity of the Apo E4 allele frequency in Chinese, which requires a larger sample size for detection of significant association. Significant associations detected between Apo E2 allele and BMD at the femoral neck in elderly women (P = 0.02) and at the spine in elderly men (P = 0.03) were in the opposite direction and thus regarded as false-positive results. It is concluded that the Apo E4 allele is rare in Chinese, and a larger population size is needed to see if Apo E4 is associated with BMD in Chinese.

Osteoporosis and transforming growth factor-beta-1 gene polymorphism in Chinese men and women.

Transforming growth factor-beta-1 (TGF-Beta(1)) has been implicated in bone mineral density (BMD) determination. We investigated the relationship between the TGF polymorphism, BMD, and vertebral fractures in 588 Chinese men and women. No association between TGF polymorphism and BMD was observed in postmenopausal women (aged 55-59 years), elderly men (aged 70-79 years), or elderly women (aged 70-79 years) at the hip, spine, or total body ( P >> 0.05 by two-way ANOVA). In all study groups, there was no effect of an interaction between TGF polymorphism and calcium intake on BMD ( P >> 0.05 for the interaction effects by two-way ANOVA). No statistical significant association was observed between TGF polymorphism and vertebral fracture in elderly men or women ( P >> 0.05 by the chi-square test), even though men of the TT and TC genotypes seem to have more vertebral fractures. Contrary to previous studies that found an association between BMD and TGF polymorphism in the Japanese, we found no association between TGF polymorphism and BMD of elderly Chinese men or women. This finding could result from different sampling methods between the previous and current studies and environmental factors and ethnic differences between the two populations.