Hypertriglyceridemia and low HDL-cholesterol are the major lipid abnormalities in normal Pakistani adults: Are these contributing to the high rates of coronary artery disease in this population?

Objective: Lipid abnormalities are related to enhanced risk of developing cardiovascular disease. The objective of the study was to investigate variability in lipid profile in Pakistani normal adults (from the personnel of 4 tertiary care hospitals) by age, gender, body mass index (BMI) and smoking, and to determine the prevalence of hypertriglyceridemia, hypercholesterolemia, "low HDL-cholesterol" and "isolated low HDL-cholesterol" in this population. Method: Serum samples from 323 normal healthy subjects (236 males and 87 females, age 30-70 years) from the personnel of the Aga Khan University, Civil Hospital, Karachi, Armed Forces Institute of Cardiology and Military Hospital, Rawalpindi were analyzed for total cholesterol, HDL-cholesterol and triglycerides using kit methods. LDL-cholesterol was determined using the Friedewald formula. Results: Mean ± SD concentrations of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were found to be 165±37 mg/dl, 37±11.5 mg/dl, 98±34 mg/dl and 155 ± 88 mg/dl, respectively. Mean levels of total cholesterol were found to be significantly higher in hypertriglyceridemia (>200mg/dl) than normotriglyceridemia (181 ±30 mg/dl vs 160±38 mg/dl; p=0.001). Mean concentration of HDL-cholesterol in the younger age group (<50 years) was found to be significantly higher than the value in the older (>50 years) group (39.6±11.7 mg/dl vs 33.4±9.7 mg/dl; p=0.001). Similarly, mean concentration of HDL-cholesterol in females was significantly higher compared to males (44.3±14 mg/dl vs 34.9±9.1 mg/dl; p=0.001). In hypertriglyceridemia (>200 mg/dl), mean HDL-concentration was significantly lower compared to normotriglyceridemia (33.4±8.3 mg/dl vs 38.9±12 mg/dl; p=0.001). The combined effect of age, gender and triglyceridemia was found to be significantly associated with HDL-cholesterol concentration (p<0.001; R²=0.202). Mean triglyceride levels among males were significantly higher than among females (166±88 mg/dl vs 127±83 mg/dl; p=0.001). Similarly, among overweight/obese individuals (BMI>25), triglyceride levels were significantly higher compared to those with BMI<25 (180±107 mg/dl vs 144±71 mg/dl; p=0.001). Levels of triglycerides were, therefore, significantly associated with gender and BMI (p<0.001; R²=0.076). LDL-cholesterol levels were not found to be significant by age, gender, smoking, BMI and triglyceridemia. Smoking had no significant effect on lipid levels of male healthy subjects. Frequencies of hypercholesterolemia, hypertriglyceridemia, "low HDL-cholesterol" and "isolated low HDL-cholesterol" were found to be 17.6%, 26.9%, 45.8% and 29.4%, respectively. High prevalence values of "low HDL-cholesterol" and "isolated low HDL-cholesterol" are reported for the first time In Pakistani normal adults and require further studies at the community level. Conclusion: High levels of triglycerides and low levels of HDL-cholesterol are the most prominent abnormalities in Pakistani adults working in tertiary health care centers.