Plenary Lecture
Environmental Factor，Carotid Atherosclerosis，Cerebrovascular Disease and Cardiovascular Disease
Professor Dafang Chen
Department of Epidemiology & Biostatistics
School of Public Health
Peking University
China
E-mail: dafangchen@bjmu.edu.cn
Abstract: Background and aims: Atherosclerosis is a disease process that occurs throughout the arterial system. On one hand, as a complex subclinical cardiovascular disorder, is the pathology underlying most ischemic strokes and heart attacks. On the other hand, as a consequence, it may result from other risk factors, metabolic diseases, lifestyles, genetic and so on. Dissecting the risk factor of atherosclerosis, therefore, has a great value for our health. We aim to investigate the relationship between environmental factors and carotid atherosclerosis and cerebrovascular disease and cardiovascular disease. Methods:
A community-based cross-sectional study was conducted in Beijing, China. All subjects completed a standardized questionnaire, and anthropometric, laboratory examination was conducted. Ultrasound examination of carotid plaques was performed, the amounts of sites with plaques and area of plaques was measured. Using generalized linear regression models, we examined relations between environmental factors and carotid atherosclerosis and cerebrovascular disease and cardiovascular disease. Results:
1. Interaction of 2h post-load glucose, fasting blood glucose with insufficient exercise After adjustment for covariates, 2h post-load glucose(PG) and fasting blood glucose(FBG) were positively related to rAIP75 with B(95%CI) for continuous 2h-PG of 0.100(0.019,0.181), for binary 2h-PG of 0.937(0.101,1.737), for continuous FBG of 0.215(0.020,0.409) and for binary FBG of 1.102(0.162,2.041). The effect of binary variables further magnified in the presence of physical exercise 5 times per week (Pint= 0.007, 0.088; respectively). The joint effect resulted in subjects of 2h PG 11.1 mmol/l with physical exercise 5 times per week having an increasing rAIP75 risk 2.543 times that of 2h PG 11.1 mmol/l with physical exercise 5 times per week(B = 2.543, 95%CI: 1.178 ~ 3.909, P < 0.001). Likewise, there was a similar interaction between binary FBG and physical exercise on rAIP75 (B = 2.579, 95%CI: 1.113 ~ 4.045, P < 0.001).
2. Different associations between blood pressure indices and carotid artery damages
Each BP index was significantly and independently associated with increased cIMT and plaques except the association of baSBP with plaques. When every two BP indices were put into one model, brachial pressure indices were associated with increased cIMT independently of central pressures, whereas the association between central pressure indices and plaque presence were stronger than those of brachial pressures. In addition, SBP indices were associated with increased cIMT independently of PP indices, whereas PP indices were more strongly related to plaques. 3. Association between sleep duration and carotid atherosclerosis
After adjustment for covariates, short sleep duration(less than 5 hours per day) isrelated to carotid plaque in both in incidence（OR=1.321, 95%CI:1.037~1.681, p=0.024） and number of plaque (OR=1.292, 95%CI:1.061~1.575, p= 0.011). The joint effect resulted in subjects of age over 60 years old with sleep duration less than 5 hours per day having an increasing risk of 3.472 times on incidence of carotid plaque and 4.181 times on number of carotid plaques than that of age under 60 years old with sleep duration more than 5 hours per day (OR=3.472, 95%CI: 2.347~5.137, P < 0.001; OR=4.181, 95%CI: 3.121~5.601, P < 0.001). Furthermore, the interaction of sleep duration and age has appeared a positive connection in more quantity of plaque (OR=1.008, 95%CI:1.005~1.011, P < 0.001) ,while the incidence didn’t appear a significant difference（P =0.0895）.
4. Relationship between eGFR，CKD and Carotid Atherosclerosis
Carotid plaque was significantly associated with eGFR (OR 0.985, 95% CI 0.979–0.992, P < 0.001) and chronic kidney disease (CKD) (OR 1.253, 95% CI 1.022–1.537, P < 0.001) by Logistic regression analysis. Significant associations between the number of plaque and eGFR (OR 0.986, 95% CI 0.981–0.992, P < 0.001) or CKD (OR 1.294, 95% CI 1.099–1.524, P = 0.002) were also suggested by Multinomial Logistic regression analysis. Multinomial liner regression showed a negative relation between plaque area and eGFR (standardized estimate -0.223, P < 0.001) and a positive relation between plaque area and CKD (standardized estimate -0.518, P =0.001). All the analyses have been adjusted for potential confounders. A secondary analysis was did in the groups of people with or without diabetes separately, the associations above remained to be significant in people without diabetes, while in diabetics no significant associations were detected. The interaction between diabetes and CKD was approved by further analyses.
5. The relationship between carotid plaques in different sites and coronary heart disease
After adjustment for age, sex, BMI, education, smoking, drinking, hypertension, diabetes, hyperlipidemia, TG, TC, HDL-C, antihypertensive drugs, hypoglycemic agents, the results showed the multivariate-adjusted risk ratio of CHD associated with plaque in common carotid arteries was 1.403 (95% CI 1.054-1.868, P = 0.020),that with plaque in carotid bulb was 1.402 (95% CI 1.109-1.773,P = 0.004) and that with plaque in internal carotid arteries was 1.570(95%CI1.213-2.932,P <0.001). 6. The relationship between carotid plaques and ischemic stroke
A total of 1840 subjects were enrolled. The subjects were 59.2 +/- 9.0 years old, 50.0% were male. Multivariate linear regression analyses revealed an independent and positive relationship between ischemic stroke and plaques located at carotid bulb (OR=3.58, 95%CI=1.46-8.77), as well as internal carotid artery (OR=2.41, 95%CI=1.31-4.04). There is also an independent and positive relationship between ischemic stroke and plaque burden (the total area of plaques) of common carotid artery (OR=1.21, 95%CI=1.01-1.46), carotid bulb (OR=3.58, 95%CI=1.46-8.77), internal carotid artery (OR=2.41, 95%CI=1.31-4.04). A positive relationship can be found between ischemic stroke and the number of sites with plaques. When the number is 2(OR=4.49，95%CI=1.64-12.29) or 3（OR=5.37，95%CI=1.74-16.56）,the patient is more likely to have ischemic stroke. Conclusions:
-High 2h PG and FBG, and its interaction with insufficient exercise increase the risk of rAI in individuals without atherosclerosis cardiovascular disease.
-Central and PP indices might be associated with plaques; however, brachial and SBP indices might be associated with increased cIMT. Nevertheless, whether these BP indices predict increased cIMT and plaque progression warrants further longitudinal and laboratory studies.
-Short sleep duration and its interaction with age (elder than 60 years old) increase the risk of carotid atherosclerosis both in terms of incidence possibility and quantity of carotid plaque.
-Carotid atherosclerosis is associated with eGFR and CKD on the number of carotid plaque and plaque area. The relationship was confirmed in participants without diabetes. And an interaction of CKD and diabetes on risk of carotid plaque has been found.
-The carotid plaques in different sites are associated with the risk of CHD. The more the number of plaque lesions is, the higher the risk is.
-Ischemic stroke was significantly associated with the number of sites with plaques, and total area of carotid plaques. It indicated that carotid plaques are related to the risk of ischemic stroke. The risk of ischemic stroke can be evaluated by B-mode ultrasound examination.
Brief Biography of the Speaker: Dafang Chen, Doctor Advisor, professor of Epidemiology and Biostatistics in Peking University; majors in molecular epidemiology and data mining in medical research. Dr. Chen has served as the deputy director of the Epidemiology Center in Peking University, the deputy director for the Department of Medical Genetics and the director of Epidemiological Key Laboratory of in Ministry of Education. From 1998 to 2000, Dr. Chen visited Harvard University as a senior scholar to study population genetics and biostatistics. Dr. Chen has undertaken many issues includes 9 founded from National Institutes of Health, 15 founded from the National Natural Science Foundation’s Surface project and other over 10 cooperative projects. Dr. Chen has published 193 scientific papers so far.