Coronary artery disease (CAD) has been the leading cause of death in industrialized countries for male over 40 years of age and female over 50 years of age. There has been alarming rise in the incidence of CAD in Pakistan. In comparison to caucacian the incidence of CAD is very high in younger population, for which the actual reason is yet not known. Considering the influence of environmental, nutrition and genetic factors it is very pertinent to identify the risk factors that must be responsible for this early onset.
The main objective of this study was to determine the serum lipids, lipoprotein and apolipoprotein A1, apolipoprotein B and Lp (a) as risk factor associated with CAD, and determine the correlation between older and younger patients with regards to the presence of conventional risk factors. For this purpose a one to one case control study was conducted during a two years period 1996-1998 on angio-graphically diagnosed patients of coronary artery bypass graft (CABG) at National Institute of Cardiovascular disease (NICVD) Karachi.
The risk factors which were assessed in this study were: diabetes mellitus, smoking, hypertension, family history of CAD, obesity, sedentary life style. Biochemical parameters measured were: lipid profile, Apo-A1, Apo-B and Lp(a). Descriptive univariate stratified and multivariate analysis was done using, statistical package for the social sciences (SPSS). A Chi Square test independent samples t tests, one way Nova and logistic regression, correlation was applied to se the association between outcome and independent variable as well as between independent variable where appropriate. A total of the cases 80% were age 40 and above while this is 78% among control.
Univariate analysis showed significant association among sedentary life (SL). They were more among cases as compared to control (OR = 12.57, 95% CI:3.68, 42.98) Serum TAG levels (OR=2.45,95% CI:1.27, 4.72), HDL-C (OR = 4.95,95% CI:2.35, 10.42, apolipoprotein-A1 (OR = 1.86, 95% CI:1.032, 3.360), apolipoprotein-B (OR = 10.49, 95% CI:4.40, 24.76) and lipoprotein (a) (OR = 2.15, 95% CI:1.20, 3.84) when stratified on age (≤ 40, ≥ 40 years).
Triacylglycerol levels, HDL-C, apolipoprotein A, LDL-C and HDL-C ratio, total cholesterol and HDL-C ratio were found to be significant among age ≥ 40 years while LDL-C, apolipoprotein B and LP(a)_was highly significant among age ≤ 40 years.
In multivariate analysis significant association were found among age, SL, TAG, HDL-C apo-B and Lp(a) and they were more among cases than control, age (AOR = 3.57, 95% CI 1.30, 9.83), sedentary life (AOR = 15.63, 95% CI 3.86, 63.58), serum TAG levels (AOR = 2.27, 95% CI 0.94, 5.48), HDL-C (AOR = 3.57, 95% CI 1.30, 9.83), apolipoprotein B (AOR = 13.21, 95% CI 4.8,36.810) and Lp(a) (AOR = 2.30, 95% CI 1.04, 5.0) were identified as risk factors in multivariate analysis.