Very low LDL-C levels tied to increased risk of mortality, study finds
Very Low LDL-C levels are significantly associated with a significantly higher risk of all-cause mortality than those with high LDL-C levels (≥ 144 mg/dL).
Japan: A recent study has found that very low levels of LDL-C (< 70 mg/dL) are predictive of higher all-cause mortality, after adjusting for potential confounders such as metabolic factors and body composition indices.
According to the study, published in the journal Lipids in Health and Disease, there is an inverse relationship between the levels of LDL-C and all-cause mortality risk, and the association is statistically significant.
Previous studies have shown low-density lipoprotein cholesterol (LDL-C) to be independently associated with aging-related health outcomes and to have a critical role in cardiovascular diseases (CVDs). However, predictive data on all-cause mortality is limited, especially for the Japanese community population. To address the same, Ryuichi Kawamoto, Seiyo Municipal Nomura Hospital, Seiyo-city, Ehime, Japan, and colleagues examined whether LDL-C is related to survival prognosis based on 7 or 10 years of follow-up.
The study included 1610 men (63 ± 14 years old) and 2074 women (65 ± 12 years old) who were the participants of the Nomura cohort study conducted in 2002 (first cohort) and 2014 (second cohort) and who continued throughout the follow-up periods (follow-up rates: 94.8 and 98.0%). Using a basic resident register, adjusted relative risk estimates were obtained for all-cause mortality
The data were analyzed by a Cox regression with the time variable defined as the length between the age at the time of recruitment and that at the end of the study (the age of death or censoring), and risk factors including gender, age, body mass index (BMI), presence of diabetes, lipid levels, renal function, serum uric acid levels, blood pressure, and history of smoking, drinking, and CVD.
Of the 3684 participants, 326 (8.8%) were confirmed to be deceased. Of these, 180 were men (11.2% of all men) and 146 were women (7.0% of all women).
Key findings of the study include:
- Lower LDL-C levels, gender (male), older age, BMI under 18.5 kg/m2 and the presence of diabetes were significant predictors for all-cause mortality.
- Compared with individuals with LDL-C levels of 144 mg/dL or higher, the multivariable-adjusted hazard ratio for all-cause mortality was 2.54 for those with LDL-C levels below 70 mg/dL, 1.71 for those with LDL-C levels between 70 mg/dL and 92 mg/dL, and 1.21 for those with LDL-C levels between 93 mg/dL and 143 mg/dL. This association was particularly significant among participants who were male and had CKD.
"The current results, based on a follow-up study of people aged 22 years and older, show that having very low LDL-C levels (< 70 mg/dL) is predictive of higher all-cause mortality, after adjustment for potential confounders such as body composition indices and metabolic factors," wrote the authors. "Therefore, further attention to individuals for whom lower LDL-C levels are not induced by lipid-lowering medication may be necessary."
Kawamoto, R., Kikuchi, A., Akase, T. et al. Low density lipoprotein cholesterol and all-cause mortality rate: findings from a study on Japanese community-dwelling persons. Lipids Health Dis 20, 105 (2021). https://doi.org/10.1186/s12944-021-01533-6