[Correlation of serum lipids levels of Alzheimer's disease patients with sex, age and apolipoprotein E gene polymorphism]

Objective: To explore the correlation of serum lipids levels of Alzheimer's disease (AD) patients with sex, age and apolipoprotein E (Apo E) gene polymorphism. Methods: The retrospective study method was used, and 407 AD patients (142 males and 265 females, aged 52-91 years) were selected from Beijing Tiantan Hospital from January 2015 to August 2021 as the research target, and 894 healthy persons (339 males and 555 females, aged 52-94 years) who did body examination were selected as the control group. The AD patients were divided into four age groups according to the age interval of 10 years, including 85 aged 50-59 years, 163 aged 60-69 years, 119 aged 70-79 years, and 40 aged more than 80 years. The serum lipids levels were detected by biochemical analyzer, including triglycerides (TG), cholesterol (CHO), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoproteinA1(Apo A1) and apolipoprotein B (Apo B). ApoE gene polymorphism were detected by PCR fluorescent probe method. Mann-Whitney U test and Kruskal-Wallis H test were used to compare the serum lipids levels in each group. Results: The levels of serum CHO and LDL-C were 3.30(1.41,4.82) mmol/L and 1.76(1.39,2.78) mmol/L in AD patients, and 4.84(4.24, 5.56) mmol/L and 2.91(2.36, 3.57) mmol/L in control group, and the levels of serum CHO and LDL-C of AD patients were significantly lower than control group (Z=-15.172,Z=-14.583, P<0.001, P<0.001). The levels of serum HDL-C and Apo B were 1.84(1.30, 3.88) mmol/L and 1.17(0.85, 1.57) g/L in AD patients, and 1.39(1.18, 1.64) mmol/L and 0.93(0.81, 1.09) g/L in control group, and the levels of serum HDL-C and Apo-B of AD patients were significantly higher than control group (Z=-12.249, Z=-9.706, P<0.001, P<0.001). There was no significant difference in TG and Apo A1 between 2 groups (Z=-1.577, Z=-0.408, P=0.115, P=0.683). The levels of TG, CHO, LDL-C in female AD patients were significantly higher than male patients (Z=-2.737, Z=-3.963, Z=-4.417, P=0.006, P<0.001, P<0.001). There were significant differences in TG, CHO, HDL-C, LDL-C, Apo A1 and Apo B among AD patients of all age groups (Z=11.263, Z=10.060, Z=40.246, Z=10.451, Z=24.315, Z=19.922, P=0.010, P=0.018, P<0.001, P=0.015, P<0.001, P<0.001). The serum CHO and LDL-C levels were positively correlated with age (r_s=0.160, r_s=0.174, P=0.001, P<0.001), and HDL-C, Apo A1 and Apo B levels were negatively correlated with age (r_s=-0.312, r_s=-0.272, r_s=-0.146, P<0.001, P<0.001, P=0.003), and there was no correlation between TG level and age in AD patients (r_s=0.086, P=0.082). There were 3 cases (3.33%) of E2, 43 cases of E3 (47.78%) and 44 cases of E4 (48.89%) in AD patients, and 22 cases (12.72%) of E2, 117 cases of E3 (67.63%) and 34 cases of E4 (19.65%) in control group. There was significant difference in Apo E genotype distribution between AD patients and control group (χ²=26.381, P<0.001). Apo E4 was the most common genotype in AD patients, and the proportion was 48.89%. Except for Apo A1(Z=7.821, P=0.020), there was no significant difference in TG, CHO, HDL-C, LDL-C and Apo B levels among all patients with different genotypes (Z=3.732, Z=1.677, Z=1.455, Z=1.619, Z=2.202, P=0.155, P=0.432, P=0.483, P=0.445, P=0.333). Conclusion: The levels of CHO and LDL-C decreased while the levels of HDL-C and Apo B increased in AD patients. The dyslipidemia in AD patients might be correlated with age, but not sex and Apo E genotypes.