The cholesterol paradox in atrial fibrillation: results from the LIPIDOGRAM 2015 study

Background High blood lipid levels are known risk factors for atherosclerotic cardiovascular events, but associations between lipid levels and atrial fibrillation (AF) are unclear. Some previous studies have suggested an inverse association between lipid levels and AF referred to as the “cholesterol paradox”. Purpose To examine the prevalence of AF by differing lipid levels in a large population-based study of almost 14,000 adults in Poland. Methods The LIPIDOGRAM 2015 study is a cross-sectional study of adults aged 18 years and older recruited in Poland in 2015/2016 by 438 family physicians. Poisson regression models with robust variance were used to estimate prevalence ratios (PRs) for AF with 95% confidence intervals (CIs) for participants with differing lipid profiles. Lipid measures including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), total cholesterol (TC) and LDL/HDL ratios were grouped into quartiles with the lowest quartile as the reference group. Models were adjusted for potential confounding factors including age, sex, waist-to-hip ratio, smoking, alcohol intake, regular physical activity, hypertension, antihypertensive medication use and treatment of dyslipidaemia. Results 13,724 participants were recruited to the study, the median (interquartile range: IQR) age was 58.0 (47.7–65.8) years and 5.2% (n=708) had a diagnosis of AF, with a median (IQR) 3 (1–8) years since diagnosis. After adjusting for potential confounding factors, a statistically significant lower prevalence of AF was estimated for participants in the highest quartile for LDL-C (PR (95% CI): 0.60 (0.48, 0.75) p<0.001), HDL-C (0.58 (0.46, 0.74), p<0.001), TC (0.61 (0.49, 0.75), p<0.001) and LDL/HDL ratio (0.75 (0.61, 0.94), p=0.010). No statistically significant difference in prevalence of AF was observed for participants in the highest quartile for TG levels compared to the lowest quartile for TG levels. Conclusions The prevalence of AF was lower for people with higher levels of LDL-C, HDL-C, TC and higher LDL/HDL ratios; some of the difference in prevalence was explained by controlling for confounding factors, but in multivariable models the association remained statistically significant. This research adds to the body of evidence which suggests an inverse relationship between cholesterol levels and AF-the “cholesterol paradox” for AF. Funding Acknowledgement Type of funding source: None