Age and Sex: Important Determinants In Affecting The Levels Of Serum Apolipoprotein B And A1 In Indian Population

摘要

For the past many years, serum lipids and lipoprotein cholesterol levels have been used to assess the risk of coronary artery disease. Recently apolipoprotein A1 and apoB have been proposed as relatively better parameters to assess the risk of this disease. Age and sex are two non modifiable risk factors of CAD which may affect the levels of apoA1 and apoB and for investigating their role in CAD, age and sex related variations in these apolipoproteins must have to be considered. The main objective was to study the effect of age and sex on the levels of serum apoA1 and apoB in normal individuals (males and females) and secondly to investigate the role of these apolipoproteins as CAD risk indicators in Indian (Punjabi) population. Normal individuals (n=270) and coronary artery disease patients (n=290) were divided into three age groups: group1 (35-44yrs), Group11 (45-54yrs) and group111 (55-64yrs). Serum apolipoprotein A1 and B levels were estimated with immunoturbidemetric method in blood samples taken after12-hour overnight fast. Lipid and lipoprotein cholesterol levels were estimated with standard procedures. Serum apoB levels showed continuous increase with age in both normal males and females with males having significantly raised (p<0.01) apoB levels in each age group compared to females. Serum apoA1 levels did not show continuous increase, rather levels declined in the older age group (Group111) in normal males and females and this decline was relatively earlier in males. Within each age group, females were having relatively raised apoA1 levels than males. A significant (p<0.01) positive coefficient of correlation was observed between serum apoA1 and HDL cholesterol levels and between serum apoB and LDL cholesterol levels. Patients suffering from coronary artery disease were having significantly raised (p<0.01) serum apoB, LDL cholesterol and apoB/A1 ratio and significantly low (p<0.01) serum apoA1 and HDL cholesterol levels than age and sex matched normal individuals. Serum apoA1 and apoB levels were significantly affected by sex and age of a person. Males are at higher risk owing to relatively raised serum apoB levels and low serum apoA1 levels compared to females. ApoA1 and apoB could act as good candidates to act as CAD risk factors in our sample population. Introduction Cardiovascular disease is the most common cause of death worldwide. For the past many years total lipid profile i.e. total cholesterol, triglycerides, VLDL cholesterol and LDL cholesterol have been positively associated with coronary artery disease (CAD) while HDL cholesterol has inverse relation 1,2 But lipid and lipoprotein cholesterol levels have failed to explain the increased prevalence of CAD in normolipidemic patients3. Recently serum apoA1 and apo B have been proposed as relatively better markers for assessing the risk of CAD and its treatment regimen. ApoA1 is the constituent component of HDL and apoB is of LDL. It was shown in the AMORIS study that apoA1 and apoB might be of greatest value in predicting the risk of myocardial infarction especially in patients having low or normal LDL cholesterol level 4. A few countries like Canada have incorporated apoB in their clinical management guidelines 5. Age and sex are the two important factors seemed to affect lipid levels. Studies regarding age and sex related variations in serum apoA1 and apoB levels are few and are only confined to European, North American and few Australian and African populations 6,7,8. Such data is very limited in Indian population, which has a very high incidence of coronary artery disease. Global burden of CAD is mainly concentrated in developing countries 9. These apolipoproteins may act as important CAD risk indicators in our population. Hence the present study was aimed to assess age and sex related variations in serum apoA1 and B levels in normal individuals and to investigate the role of these apolipoproteins as CAD risk indicators in Indian (Punjabi) population. Mate