The Case-Control Study On Risk Factor And Association Genes Of Type 2 Diabetes Mellitus Patients

Objective To investigate the risk factors of type 2 DM in community population inYinchuan, and to explore the association between the variation of lipoprotein lipase gene , Cytotoxic T lymphocyte antigen-4 gene and type 2 DM inYinchuan population in order to provide the scientific basis for the etiology and intervention of type 2 DM.Methods (1) A community-based frequency matching case-control study was conducted. 202 subjects with type 2 DM(cases) and 205 non-diabetes mellitus (controls) were recruited at random in Ningxia Yinchuan community from May to July in 2005. Frequence of age, sex and ethnic were matched between the two groups. All information was collected by questionnaire in face-to-face interview. Univariate Logistic regression, multivariate Logistic regression were used to analyse the risk factors. (2) 158 blood samples of patients with type 2 DM and 169 blood samples of non-diabetes from the first and second affiliated hospitals of Ningxia Medical College were collected .The variation of LPL gene S447X,Hindâ…¢and CTLA-4 exon 1 were detected by PCR- RFLP and their relations to type 2 DM were analyzed.Results (1) Results from univariate analysis showed that the following factors were statistically associated with the incidence of T2DM: family history of DM, history of hypertension, history of coronary heart disease, history of cerebrovascular disease, hypertriglyceride, usually sweat food intake, usually grease food intake, usually harslet food intake, usually cooking with tallow, exercise ,exercise time, WHR, cigarette smoking, smoking index, individual businessman, scientist/teacher/doctor, SBP, TG, TC, LDL-C. The positive results were found with multivariate logistic regression analysis, which were associated with increased risk of type 2 diabetes mellitus, including history of hypertension (OR=3.974, CI%: 2.193~7.271), history of coronary heart disease (OR=3.459, CI%: 1.677~7.469), hypertriglyceride (OR=3.599, CI%: 1.854~6.921), usually sweat food intake (OR=1.869, CI%: 1.091~3.052), usually grease food intake (OR=2.758,CI%:1.487 ~6.921), usually harslet food intake (OR=2.129, CI%:0.996~4.761), WHR (OR=1.755, CI%: 1.019~3.491), smoking index (OR=1.630, CI%: 243~4.874), scientist/teacher/doctor (OR=2.960, CI%: 1.094~3.125), TG (OR=2.863,CI%: 1.618~7.695); while exercise (OR= 0.669, CI%: 0.454~1.959) and exercise time (OR=0.416, CI%: 0.248~0.986) were the reverse association. (2) the frequency of the X allele and SX genotype in cases was lower than that of controls (4.1% vs 8.6% & 8.3% vs 17.2%,).The diffrences were significant (P=0.065 & P=0.057). the frequency of the allele and genotype for Hindâ…¢and CTLA-4 exon 1 49A/G polymorsphism were similar between cases and controls (P=0.790 & 0.70, P=0.083 & 0.136). In cases group, the level of plasma TG ,TC, LDL-C of carriers of the SX genotype were signifiantly lower than that of the carriers of SS genotype and HDL-C of the carriers of SX were higher than that of the carriers of SS genotype (P<0.05); The level of plasma TG of the carriers of H+H-/H-H- genotype were signifiantly lower than in H+H+carriers (P<0.05); In cases group, The incidence of CHD in carriers of the SX genotype and the H+H-/H-H- genotype were lower than that of the carriers of SS genotype and H+H+ genotype respectively. The diffrences were significant (P<0.05).Conclusions (1) Family history of DM, history of hypertension, history of coronary heart disease, hypertriglyceride, usually sweat food intake, usually grease food intake, usually harslet food intake, usually cooking with tallow, WHR, cigarette smoking and scientist/teacher/doctor occupation were the main risk factors of the population with type 2 DM in Ningxia Yinchuan, exercise is the protective factor. (2) LPL gene S447X polymorsphism is associated with the incidence of type 2 DM in Ningxia Yinchuan. But LPL gene Hindâ…¢and CTLA-4 gene exon 1 polymorsphisms were not significantly associated with the incidence of type 2 DM in Ningxia Yinchuan. (3) The Ser447Ter and Hindâ…¢mutation had beneficial effects on plasma lipids, and decreased the incidence of CHD of the population with type 2 DM.