The relationship between remnant cholesterol and low testosterone in adult males.

Background: Remnant cholesterol (RC) is the cholesterol of triglyceride-rich lipoproteins, which has a high degree of atherogenic effect.

Aim: This study investigates the association between RC and low testosterone in male adults in the United States.

Methods: Data were drawn from the National Health and Nutrition Examination Survey (NHANES) 2013-2014 and 2015-2016 cycles, focusing on males aged over 20. RC was measured as the difference between total cholesterol (TC) and the sum of high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c). Analyses between RC and low testosterone included logistic regression, subgroup assessment, smooth curve fitting, and mediation analysis.

Outcomes: Low testosterone was defined by a serum testosterone level below 300 ng/dL in male adults.

Results: Out of the 2248 participants, 442 exhibited low testosterone levels. Those deficient in testosterone demonstrated notably higher RC levels (P < 0.001). A direct relationship between RC and low testosterone was evident (OR = 1.02, 95% CI: 1.01-1.03, P < 0.001), and smooth curve fitting revealed a linear trend. Subgroup analysis did not identify any special populations. Moreover, body mass index (BMI) and HOMA-IR was found to partially mediate this relationship.

Clinical implications: Evaluating low testosterone in individuals with high RC levels can be beneficial. Similarly, monitoring lipid profiles, particularly RC levels, in patients with low testosterone might be important for preventing cardiovascular diseases.

Strengths & limitations: This study uses data from NHANES, which is nationally representative and has a large sample size. However, the causal relationship needs further investigation due to the cross-sectional design of this study.

Conclusion: This nationwide study provides initial evidence of a close correlation between RC and the risk of low testosterone.