High total cholesterol and LDL-C levels during midlife reduce risk of atrial fibrillation

A new study published in PLOS Medicine suggests that midlife high total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were linked to a reduced incidence of atrial fibrillation (AF), although this link persisted only for the first five years following lipid testing.

It is still debatable whether cholesterol levels play a part in the onset of atrial fibrillation. Additionally, the existence and magnitude of an association between apolipoproteins and the risk of AF are seldom investigated. In this investigation, Mozhu Ding and colleagues sought to better understand the relationship between midlife blood lipid levels and the likelihood of developing new-onset AF.

65,136 people from the Swedish Apolipoprotein-Related Mortality Risk (AMORIS) cohort, aged 45 to 60, who had no overt cardiovascular illnesses (CVDs), were included in this population-based investigation. Individuals were monitored for incident AF until December 31, 2019, and lipid measurements were done from 1985 to 1996. (i.e., study outcome). 

The key findings of this study were:

1. 13,871 (21.3%) incident AF cases occurred over a mean follow-up of 24.2 years.

2. During the first five years of follow-up but not later, higher levels of total cholesterol and low-density lipoprotein cholesterol were statistically significantly related with a decreased risk of AF.

3. Over the course of the full follow-up, lower levels of high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (ApoA-I), and greater triglycerides (TG)/HDL-C ratio were statistically substantially linked to a higher risk of AF.

4. The ratio of apolipoprotein B (ApoB) to apolipoprotein A-I did not predict the incidence of AF.

5. Both those who experienced incident heart failure (HF) or coronary heart disease (CHD) and individuals who did not experience the same relationships.

In conclusion, up to 5 years following blood measurement, a lower risk of AF was shown in conjunction with high TC and LDL-C levels in this sizable population-based investigation. On the other hand, during a period of three decades of follow-up, low HDL-C, low ApoA-I, and a high TG/HDL-C ratio were persistently linked to a greater risk of AF. A high ApoB/ApoA-I ratio, which indicates a poor atherogenic and anti-atherogenic balance, is not linked to an increased risk of AF.

Reference: 

Ding, M., Wennberg, A., Gigante, B., Walldius, G., Hammar, N., & Modig, K. (2022). Lipid levels in midlife and risk of atrial fibrillation over 3 decades-Experience from the Swedish AMORIS cohort: A cohort study. PLoS Medicine, 19(8), e1004044. https://doi.org/10.1371/journal.pmed.1004044