The characteristics of the NTG and HTG groups are shown in Table . There was no significant difference in the mean age between the two groups (p = 0.748). TC (p = 0.0001) and TG levels (p < 0.0001) were significantly higher in the HTG group as compared to the NTG group. There was no significant difference in LDL, HDL and LDL/HDL ratio.
Characteristics of the NTG and HTG group
The genotypic and allelic distribution of APOC3 polymorphism in the study population is shown in Table . No significant deviation from Hardy-Weinberg equilibrium was observed in the study population. The frequency of the S2 allele in the study population was 0.313 (Table ). The 95% CI of the allele frequency is also presented in Table .
Frequency distribution of various genotypes and alleles of APOC3 SstI polymorphism in the study population *
To determine the association of APOC3 SstI polymorphism with TG levels, the study population was divided into NTG and HTG groups. Out of 139 individuals, 34 subjects (24.46%) were in HTG group i.e. TG levels beyond 1.921 mmol/L. Table summarize the distribution of various genotypes and alleles of APOC3 polymorphism between the NTG and HTG groups. The 95% CI of the allele frequencies is also presented in Table . No significant difference was observed between the expected and observed genotype frequencies of the two groups (NTG: Chi square = 0.9852, df = 1, p = 0.3209 and HTG: Chi square = 0.000, df = 1 and p = 0.9960; in Hardy-Weinberg equilibrium). There was a significant difference in the genotypic distribution between the NTG and HTG groups as shown in Table (Chi square = 14.019, df = 2, p = 0.001). S1S1 genotype was more frequent in the NTG group as compared to the HTG group (53.3% vs. 26.5%). Conversely, S2S2 genotype was almost five times more prevalent in the HTG group as compared to the NTG group (23.5% vs. 4.8%). However, not much difference was observed in the S1S2 frequency between the two groups (HTG: 50% vs. NTG: 41.9%). In totality, 73.5% of HTG group (25/34) were S2 carriers out of which 32% individuals (i.e. 8/25) were S2 homozygotes. Comparatively, NTG group had 46.7%(49/105) S2 carriers, of which only 10.2%(5/49) were S2 homozygotes. Consequently, S2 allele was almost two times more frequent in the HTG group compared to the NTG group (p = 0.001) as shown in Table .
APOC3 SstI polymorphism and triglyceride levels
Logistic analysis revealed a significant association of APOC3 S2 allele with hypertriglyceridemia (Table ). The crude Odds ratio (OR) for S1S2 genotype (in comparison to S1S1 genotype) was found to be 2.4 (95%CI: 0.98–5.90), which was towards significance (p= 0.056) and did not change much after adjusting for age (OR= 2.43, 95% CI = 0.99–6.01, p= 0.054). The crude OR for S2S2 to develop HTG (in comparison to S1S1) was found to be 9.95 (95% CI: 2.66–37.29, p = 0.0006), which was highly significant and remained significant even after adjusting for age (OR = 9.90, 95%CI = 2.64–37.12, p = 0.0007). In totality, S2 carriers had a crude OR of 3.17 to develop HTG (95%CI = 1.35–7.45, p = 0.008) and 3.22 (95% CI = 1.37–7.60, p= 0.007) after age adjustment.
The intergenotypic variations in lipid profile in the HTG, NTG and total subjects are shown in Table . TG was significantly different among various genotypes in the HTG (p = 0.015, log TG: p = 0.015), the total subjects (p < 0.0001) and insignificant in the NTG group (p = 0.114, logTG: p = 0.137). In particular, the S2S2 individuals were associated with highest concentration of TG followed by S1S2 and then by S1S1 in HTG group & total study population. No significant differences were observed in TC, LDL, HDL and LDL/HDL ratio in any of the study group (Table ).
Intergenotypic variation in the lipid profile in NTG group, HTG group and total study population