A total number of 225 participants were enrolled from which 179 (79.6%) were male and 46 (20.4%) were female. All participants were under 45 years old.
Considering results of coronary angiogram, 97 participants (43.1%) had premature coronary artery disease of which 86 patients (88.7%) were male and 11 (11.3%) were female ;128 participants (56.9%) were free of significant CAD of which 93 (72.7%) were male and 35 (27.3%) were female that stratified in control group. In patients with significant CAD; 32 (33%) had single vessel disease, 37 (38.2%) two vessel disease and 28 (28.8%) had three vessel disease.
The mean age of the study group was (40.1 ± 4.2) years in males and (39.4 ± 4.8) in females. No significant difference was noted between the patient and control group in this regard. Major CAD risk factors are compared between controls and patients in Table . Significant differences were noted for male gender, diabetes mellitus and hyperlipidemia.
Characteristics of study population
The mean serum level of homocysteine was (16.6 ± 1.01 μmol/lit) in the study group and was significantly higher in males (17.9 ± 1.2 μmol/lit) compared to females (11.5 ± 0.9 μmol/lit) (P < 0.01). The mean plasma level of homocysteine in patients (19.3 ± 1.7 μmol/lit) was significantly higher than the control group (13.9 ± 0.9 μmol/lit) (P < 0.005). Considering the sex factor, a similar relationship was present in male participants (P < 0.01) but not in females (P = 0.87) (Table ).
Plasma homocysteine level in study population
In order to evaluate the risk of hyperhomocysteinemia for premature CAD in the context of other known CAD risk factors such as diabetes mellitus, hypertension, hyperlipidemia, lipoprotein disorders, positive family history and cigarette smoking, logistic regression test was performed. Results showed that the risk of premature CAD in those participants with a homocysteine plasma level of more than 15 μmol/lit was 2.4 times more than others (OR = 2.42, 95% CI: 1.28–4.56: P = 0.007) (Table ).
Multivariate logistic regression analysis for development of coronary artery disease
Logistic regression test in males with and without hyperhomocysteinemia compared to total subjects showed similar results in effect of hyperhomocysteinemia on development of CAD (OR = 2.54, 95% CI: 1.23–5.22: P = 0.01) while in females there was no increased chance for premature CAD in individuals with hyperhomocysteinemia. However, prevalence of premature CAD was higher in females with hyperhomocysteinemia (above 15 μmol/lit) than who did not have hyperhomocysteinemia (42.9% versus 20.5%). The role of other known risk factors of CAD in increasing the risk of premature CAD is also demonstrated in Table .
We studied the relation between hyperhomocysteinemia and plasma level of folic acid, vitamin B12, male gender, increasing age, cigarette smoking, diabetes mellitus and hypertension. Mean plasma level of folic acid in the study group was 6.33 ± 0.29 ng/ml (5.6 ± 0.2 ng/ml in males and 8.8 ± 0.7 ng/ml in females). Mean plasma level of vitamin B12 was 282.5 ± 9.1 pg/ml (283.8 ± 10.5 pg/ml in males and 277.5 ± 18.6 pg/ml in females). Therefore, 10.7% of the study group (24 participants) had folic acid deficiency (13.1% of male participants and 2% of females). Also 24.3% (55 participants) had vitamin B12 deficiency (26.6% of males and 16.3% of females).
Although generally speaking there is a reverse relationship between plasma level of homocysteine and folic acid level (Pearson correlation coefficient = -0.148, P = 0.02) or vitamin B12 (Pearson correlation coefficient = -0.22, P = 0.001), the logistic regression test for the study group showed that male sex (OR = 3.87, 95% CI : 1.57–9.50, P = 0.003) and vitamin B12 deficiency (OR = 2.06, 95% CI : 1.06–3.98 : P < 0.0001) were two factors that caused significant increase in homocysteine levels.
Other factors such as cigarette smoking, increasing age, diabetes mellitus and hypertension did not have any statistically significant role in hyperhomocysteinemia (tHcy>15 μmol/lit). Although the mean plasma level of homocysteine in cigarette smokers (17.5 ± 1.4 μmol/lit) was higher than non-smokers (14.9 ± 1.2 μmol/lit), this was not statistically significant (P = 0.16). Mean plasma level of homocysteine in hypertensive individuals was not significantly different from normotensives (16.2 ± 2.6 μmol/lit versus 16.3 ± 0.9 μmol/lit, P = 0.97). The differences in diabetic and non diabetic individuals were also non significant (13.6 ± 1.4 μmol/lit versus 16.4 ± 1.02 μmol/lit, P = 0.44). No significant difference in plasma homocysteine level was observed in either of age groups (above and bellow 35 years) (P = 0.1).