| Since 1998, we抳e begun to collect female twins aged 5-60 from two certain cities in Anhui province, so as to study genetics of common traits, including Bone mass density. The study reported today is part of the whole study and the objectives are:1)to make sure the distribution of BMD with age and to depict independent effects of age, year since menopause, height and weight on BMD and then to develop predictive model based on such determinants. 2) to analysis the heritability of bone mass density and to see whether it changes with bone site and subjects?age; 3) to detect the relationship polymorphism of ACP1 gene and the relationship with BMD. Registering data for newborns were used to collect female twins of 5-60 years. All epidemiologic data were obtained by standard questionnaire. Dual-energy X ray absorptionmetry (DPX) was used to measure subjects?BMD of all bones. To identify zygosity of twins, ten highly polymorphic genetic marker were selected and scaned on AB1377 machine ; sequencing was applied to detect polymorphism of gene, and restriction fragment length polyrnorphism(RFLP) were used here to genotype polymorphism of the gene. All the data were entried twice and checked and then analysed by SAS~. S PLUS software and FBAT program. variables studied here included BMDs of second to forth lunar spine , total spine, femoral neck, wards抰riangle, trochanter, arm and total body. The results showed: BMDs of all sites changed with age similarly, but age for peak bone mass and bone mass loss were different with bone sites. Those made of trabecular mainly reached peak bone mass and began to bone loss earlier, and their loss rates were higher; the independent correlation of age, years since menopause, height and weight with BMD was nonlinear over the whole age range studied here; All subjected were divided into three age groups and predictive models for each bone site were developed. These models were tested and 6 found that the predictive values of bone mass density, obtained by these predictive model, were similar to their actual values. BMD of all sites were heritable, but the heritability changed with bone site and age groups.When Bone mass densities were adjusted by age, The heritabilities for Lunar spine, femoral neck and wards triangle were highest in 3 0-40 age group, while those for ann, total body and torchanter reached their peak value in 10-20 age group. The heritability for each site was almost among 0.6-0.8, and the heritability for torchanter was highest, followed by femoral neck. Except for BMD of second to forth lunar spine, which change little with age, all other BMDs decreased in 40 or over age group. Compared with those adjusted by only age, when BMDs were adjusted by age,height,weight and year since menopause, heritabilities for arm and total bone decreased in 10-20 age group,which lead to the highest heritabilities value happened in 3 0-40 age group (for arm) or 20-3 0 age group(for total bone); morever, heritabilities for femoral neck,ward抯 triangle and trochanter increased in 40 or over age group, but they were still less than those of other age groups. TaqI polymorphism in ACP1 gene related with BMI1), which showed that t allele( that is ACP1 *A) correlated with lower lunar spine抯 and total spine抯 BMD; The relationship between Hinc polymorphism and BMD was insignificant; Hinc polymorphism was in linkage disequalibrium with TaqI polymorphism. And the...
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