C-reactive Protein And Lipids In The Prediction Of Cardio-cerebrovascular Disease In Mongolian Population

To explore the relationship between C-reactive protein(CRP) and blood lipids among Mongolian population; to analyze the associations between CRP, blood lipids and cardio-cerebrovascular disease in the Mongolian population; to study the interaction between CRP and lipids on cardio-cerebrovascular disease among Mongolian population.Subjects and MethodsBaseline investigationA cross-sectional survey was carried out during 2002 and 2003,in which 2589 participants aged 20 years and older were recruited from 32 villages in two adjacent townships located in Kezuohou Banner and Naiman Banner in Inner Mongolia. Written informed consent was obtained for all study participants.Information on demographic characteristics, personal medical history, family history of cardiovascular disease and lifestyle risk factors was obtained using a standard questionnaire. Blood pressure, height, weight, and waist circumference were measured for all participants according to standard methods. All blood samples were obtained from the antecubital vein in the morning after a requested overnight fast(at least 8 hours), all plasma and serum samples were frozen at-80℃ until testing. CRP,Triglyceride(TG), total cholesterol(TC), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C), apolipoprotein A1(Apo A1) and apolipoprotein B(Apo B) were detected for all participants.Follow-up surveyFrom year 2002 to 2012, all participants were continually followed up to find cardio-cerebrovascular events including new stroke and coronary heart disease. We interviewed the monitoring data and hospital medical records for the subjects who experienced cardio-cerebrovascular events to confirm and collect the information about the outcome events.The associations between CRP and blood lipids were analyzed by using Spearman’s rank correlation test and non-conditional logistic regression model. Cox proportional hazards models were used to evaluate the associations between CRP, lipids and cardio-cerebrovascular disease. Cox proportional hazards model was also used to estimate multiplicative interaction by bringing the product terms into the model. The additive interaction was evaluated by the interaction calculation sheet made by Andersson, et al.Epidata 3.0 software was used to establish a database, and all data was checked after data entry for two times. All statistical analyses were conducted using SAS 9.1 and SPSS 16.0 statistical softwares. All P-values were based on a 2-sided test and a significance level of 0.05.ResultsA total of 2589 participants aged 20-84 years old were included in the baseline investigation. Fifty-seven participants were excluded for missing key variables and a total of 2532 persons including 1035(40.88%) males and 1497(59.12%) females were included in the final analysis.In the study, all blood lipid parameters significantly correlated with CRP(all P values <0.001). CRP positively correlated to TC(r=0.227), TG(r=0.503), LDL-C(r=0.221), Apo A1(r=0.192), Apo B(r=0.356) and non-HDL-C(r=0.288), and negatively correlated to HDL-C(r=-0.172). CRP also correlated to TC/HDL-C(r=0.328), TG/HDL-C(r=0.486), Apo A1/Apo B(r=0.271), and LDL-C/HDL-C(r=0.282). Multivariate logistic regression analysis showed that higher TC, TG, HDL-C, LDL-C, Apo A1, Apo B, non-HDL-C, TC/HDL-C, TG/HDL-C, Apo A1/Apo B, and LDL-C/HDL-C were significantly associated with risk of high CRP(all P<0.05).During the 9.2 years follow-up, five were lost to follow up among 2532 participants, and the follow-up rate was 99.80%. A total of 196 patients with cardio-cerebrovascular disease(121 stroke and 75 coronary heart disease) occurred during the period of follow-up. The cumulative incidence rate of cardio-cerebrovascular disease was 7.74% and the incidence density was 850.20 per 100 000 person-years.After adjustment for age, gender, smoking, drinking and so on, the risk of cardio-cerebrovascular disease(HR: 1.40, 95% CI: 1.03-1.91) in participants with high CRP(>5.94 mg/L) increased significantly, compared with those with low CRP(≤5.94 mg/L) level.After adjustment for age, gender, smoking, drinking and so on, the risk of Statistical analysis cardio-cerebrovascular disease(HR: 1.73, 95% CI: 1.28-2.32) in participants with low Apo A1(<1.43 mmol/L) increased significantly, compared with those with high Apo A1(≥1.43 mmol/L). HR of cardio-cerebrovascular disease for participants with high Apo B/Apo A1(>0.41 mmol/L) were significant compared to those with low Apo B/Apo A1(≤0.41 mmol/L) in multivariate models(HR: 1.47, 95% CI: 1.08-2.01).After adjustment for multivariate, compared with participants with low CRP and high Apo A1, the risk(HR, 95%CI) of cardio-cerebrovascular disease in those with high CRP and low Apo A1 was 2.45(1.55-3.87). HR of cardio-cerebrovascular disease for the participants with high CRP and high Apo B/Apo A1 were significant compared to those with low CRP and low Apo B/Apo A1 in multivariate models(HR: 1.66, 95% CI: 1.10-2.49).In the analysis of additive interaction, after adjustment for multivariate, no significant interaction was detected between CRP and lipids on cardio-cerebrovascular disease.In the analysis of multiplicative interaction, after adjustment for multivariate, all the HRs of cardio-cerebrovascular disease associated with interactions of CRP and lipids did not reach statistical significance(all P>0.05).ConclusionsIn the Mongolian population, the level of CRP was correlated to TC, TG, HDL-C, LDL-C, Apo A1, Apo B, non-HDL-C, TC/HDL-C, TG/HDL-C, Apo B/Apo A1, and LDL-C/HDL-C.In the Mongolian population, high CRP level might increase the risk of cardio-cerebrovascular disease.Among the lipid parameters, low Apo A1 or high Apo B/Apo A1 level might increase the risk of cardio-cerebrovascular disease in the Mongolian population.In the Mongolian population, co-existence of high CRP with low Apo B further increased the risk of cardio-cerebrovascular disease. Co-existence of high CRP with high Apo B/Apo A1 further increased the risk of cardio-cerebrovascular disease.There was no additive or multiplicative interaction between CRP and lipids on cardio-cerebrovascular disease in the Mongolian population.