As shown in Table 3, according to whether individuals carry the risk allele (APOE*4 and CETP*V), Student t-test suggested higher TC (P = 0.004), TG (P = 0.044), and LDL-c (P = 0.007) in oldest-old females with APOE*4 compared to APOE*2, which was also observed in controls (data not shown). In addition, TG was significantly increased in subjects with CETP*3.39 18.25 3.48 0.115 0.074 HR (times/min) 81.77 14.23 79.86 10.98 79.78 10.82 80.47 12.67 0.398 0.493 SBP (mmHg) 157.45 23.16 154.47 26.36 153.78 25.84 156.90 26.35 0.549 0.232 DBP (mmHg) 83.59 12.60 79.27 12.64 82.44 15.49 82.46 14.86 0.087 0.987 FPG: fasting plasma glucose; TC: total cholesterol; TG: triglycerides; HDL-c: high-density lipoprotein cholesterol; LDL-c: low-density lipoprotein cholesterol; BMI: body mass index; HR: heart rate; SBP: systolic blood pressure; DBP: diastolic blood pressure.
Subjects were selected to reduce the confounding of gender and ensure preferable statistical power, as dyslipidemia is a significant risk factor for CVD and shortens life expectancy in US life tables (Stamler et al.,2000). Because the effects of APOE polymorphism were stronger in women (Song et al.,2004), we only included oldest-old females in this study.

Table4 shows the OR and95%CI of hTG by CETP and APOE polymorphism for oldest-old females.The interaction between CETP and APOE was found to be significantly associated with hTG for oldest-old female subjects, with more than a fourfold increase in hTG risk observed for subjects with both risk alleles (Fig1). Although APOE*4 was not strongly associated with hTG in this population, when APOE*4 was analyzed together with CETP*V, a more significant risk was observed for subjects with both risk alleles.

The stratification Chi-square test, multivariable-adjusted logistic regression, and nonparametric MDR analysis all suggested a significant interaction between CETP and APOE associated with hTG for oldest-old female subjects. CETP*V was significantly associated with hTG, and the risk increased with increasing CETP*V numbers. Subjects who carry the risk CETP*V had a significantly higher risk for hTG compared to CETP*II homozygotes independent from APOE*4, age, BMI, alcohol drinking, TC, TG, HDL-c, and LDL-c.

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