Interaction of common sequence variants and selected risk factors in determination of HDL cholesterol levels

Association between the ABCA1 (R219K) polymorphism and lipid profiles: a meta-analysis

Conflicting evidence was found about the relationship between lipid profiles and R219K polymorphism in adenosine triphosphate-binding cassette exporter A1 (ABCA1) gene. In this study, four meta-analyses were conducted to assess the effect of R219K on lipid levels, including high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol, total cholesterol, and triglycerides (TG). A total of 125 samples of 87 studies (about 60,262 subjects) were included. The effect of each study was expressed using the standard mean difference (SMD) and 95% confidence interval (95% CI) and pooled by meta-analysis in the random-effects model. Subgroup and meta-regression analyses were conducted to explore potential heterogeneity sources. The overall pooled effect showed the following results. (1) The R219K was significantly associated with HDLC level (SMD = - 0.25 mmol/L, 95%CI - 0.32 to - 0.18, z = - 6.96, P < 0.01, recessive genetic model). People with different genotypes had significantly different HDLC levels under the recessive, codominant and dominant genetic models (all Ps < 0.01). (2) A weak and indeterminate relationship between R219K and TG level was observed (SMD = 0.18 mmol/L, 95%CI 0.06-0.30, z = 3.01, P < 0.01, recessive genetic model). These findings suggested that R219K was associated with HDLC and TG levels, which might implicate a promising clinical application for lipid-related disorders, though the influences of race, health status, BMI, and other heterogeneity sources should be considered when interpreting current findings. The protocol was registered at PROSPERO (registration number: CRD42021231178).

Associations of the ABCA1 gene polymorphisms with plasma lipid levels: A meta-analysis

BACKGROUND

Studies on the associations of the adenosine triphosphate-binding cassette transporter A1 gene (ABCA1) rs2230806, rs2230808, and rs2066714 polymorphisms with plasma lipid levels have reported apparently conflicting findings. This meta-analysis aimed to clarify the relationships between the 3 polymorphisms and fasting lipid levels.

METHODS

A comprehensive search of the literature was carried out by using the databases including Medline, Google Scholar, Web of Science, Embase, Cochrane Library, CNKI, Wanfang, and VIP. The studies that presented mean lipids and standard deviations or standard errors according to the rs2230806, rs2230808, and/or rs2066714 genotypes were examined and included. The random effects model was used. Standardized mean difference and 95% confidence interval were used to assess the differences in lipid levels between the genotypes. Heterogeneity among studies was tested by Cochran's χ-based Q-statistic, and Galbraith plots were used to detect the potential sources of heterogeneity. Publication bias was assessed by Begg's rank correlation test as well as funnel plots.

RESULTS

Sixty-two studies (48,452 subjects), 12 studies (9853 subjects) and 14 studies (10,727 subjects) were identified for the rs2230806, rs2230808, and rs2066714 polymorphisms, respectively. A dominant model was used for all the polymorphisms in this meta-analysis. The A allele carriers of the rs2230806 polymorphism had higher levels of high-density lipoprotein cholesterol (HDL-C) (P <.001), and lower levels of low-density lipoprotein cholesterol (LDL-C) (P =.03) and triglycerides (TG) (P <.01) than the non-carriers. The A allele carriers of the rs2230808 polymorphism had higher levels of total cholesterol (TC) (P <.001) than the non-carriers. The G allele carriers of the rs2066714 polymorphism had higher levels of TC (P <.01) and HDL-C (P = .02) than the non-carriers.

CONCLUSION

The ABCA1 rs2230806, rs2230808, and rs2066714 polymorphisms are significantly associated with plasma lipid levels in the present meta-analysis.

ApoE rs429358 and rs7412 Polymorphism and Gender Differences of Serum Lipid Profile and Cognition in Aging Chinese Population

ApoE gene polymorphism has been reportedly associated with serum lipids and cognition. However, very few studies have explored the combined effects of ApoE gene polymorphism and gender on serum lipid profile with subsequent impacts on cognition in Chinese population. A total of 1,000 Chinese community dwellers aged 55 years and above were recruited in this cross-sectional study. Demographic information of the participants was collected using well designed self-administered questionnaires. The Montreal Cognitive Assessment (MoCA) test was employed to evaluate the cognitive status of the participants. Semi-quantitative food frequency questionnaire (FFQ) was used to obtain the dietary intake information. Fasting venous blood samples were taken for ApoE genotyping and serum lipid measurements. Significant gender differences in cognition, serum lipid profile and dietary fat-rich foods consumption were observed (p < 0.05). Cognition of the subjects was found to be associated with ApoE genotypes (p < 0.05). ApoE rs429358 and rs7412 variants demonstrated a significant effect on cognitive performance in the male subjects; especially within the attention and language cognitive domains as well as the total MoCA score (p < 0.05), respectively. Serum lipid profile and cognition of Chinese adults are significantly linked with gender and ApoE genetic polymorphism. The ApoE variant rs429358 is found to be notably associated with cognition in aging male Chinese population.