Association of CRP gene polymorphisms with CRP levels, frailty and co-morbidity in an elderly Chinese population: results from RuLAS

Objectives: to examine the associations of two common CRP gene polymorphisms with CRP levels, frailty and co-morbidity in an elderly Chinese population. Design: a population-based cohort study. Setting and participants: we obtained data on 1,723 elderly participants aged 70-84 from the ageing arm of the Rugao Longevity and Ageing study (RuLAS), a population-based observational cohort study conducted in Rugao, Jiangsu province, China. Measurements: the genotyping of two common CRP gene polymorphisms (rs1205 and rs3093059) was performed. Items concerning the frailty index and co-morbidity were collected. Results: the mean age of the study population was 75.3 +/- 3.9 years, and 53.5% (n = 922) were women. The minor allele frequencies of rs1205 and rs3093059 were 42.4% (C allele) and 16.9% (C allele), respectively. The polymorphisms rs1205 and rs3093059 were significantly associated with CRP levels (beta = 0.113 and 0.222, all P < 0.001). Non-significant association between rs1205 and rs3093059 and frailty, as well as between rs3093059 and co-morbidity was observed. However, SNP rs1205 CC genotype had an increased odds of co-morbidity compared with the TT genotype (odds ratio (OR):1.53; 95% confidence interval (CI): 1.16-2.02). Each additional copy of the C allele of SNP rs1205 was associated with 1.23 times (95% CI: 1.07-1.41) odds of co-morbidity. The significance remained after controlling for covariates such as education level, etc. Conclusions: among elderly Chinese individuals, two CRP gene polymorphisms were significantly associated with CRP levels. However, none of them was associated with frailty. The preliminary findings warrant further validations.