Associations Between Serum Lipids and Causes of Mortality in a Cohort of 3499 Urban Thais: The Electricity Generating Authority of Thailand (EGAT) Study

Abstract

The association between serum lipids and mortality has not previously been established in Thailand. Baseline data from the Electricity Generating Authority of Thailand (EGAT) cohort study, plus a resurvey of the cohort 15 years later were analyzed. Participants were employees of EGAT: 2702 men and 797 women. Total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were taken as predictive variables; age, sex, hypertension, diabetes, cigarette smoking, alcohol drinking, and body mass index were taken as confounders. Dependent variables were all-causes and specific causes of mortality over 17 years of follow-up. The major cause of death among men was cardiovascular disease (CVD); among women, it was cancer. Relative risks (RR) for specific causes of death, for a mmol/L increase in each lipid, were estimated after adjustment for confounding factors using Cox proportional hazards regression. TC and LDL-C were negatively associated with liver cirrhosis mortality, although it was likely that the low cholesterol concentration was a consequence of the disease. HDL-C was negatively associated with CVD mortality (RR = 0.59; 95% confidence interval [CI], 0.39-0.93), coronary heart disease (CHD) mortality (RR = 0.36; 95% CI, 0.17-0.75) and all cause-mortality (RR = 0.68; 95% CI, 0.54-0.87). TG was not associated with mortality. HDL-C is an important risk factor for CVD in middle-class urban Thais. Health promotion programs to improve lipid profiles, such as effective exercise campaigns and dietary advice, are required to increase HDL-C and to help prevent CVD and premature death in Thailand.