Associations between serum pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) levels and hypertension: a cross-sectional analysis of NHANES data.

Background: Pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) are considered to have protective effects on cardiovascular health. However, research on the relationship between C15:0 and C17:0 levels and hypertension remains limited. This cross-sectional study aims to investigate the association between serum levels of odd-chain fatty acids (C15:0 and C17:0) and prevalent hypertension.

Methods: Data from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) were used for this study. Multiple logistic regression models, restricted cubic spline (RCS) analysis, saturation threshold effect analysis, and interaction effect tests were employed to analyze the relationship between serum C15:0 and C17:0 levels and prevalent hypertension.

Results: A total of 4,775 participants (C15:0 analysis group) and 4,718 participants (C17:0 analysis group) were included in this study. The prevalence of hypertension in the two groups is 46.99% and 46.82%, respectively. To improve the distribution and comparability of the data, the primary analysis used the per mille of total fatty acids (C15:0‰ and C17:0‰). After adjusting for multiple confounders, both C15:0‰ and C17:0‰ levels were significantly inversely associated with the odds of prevalent hypertension. In the fully adjusted model, an increase in C15:0‰ and C17:0‰ levels was associated with a lower odds of prevalent hypertension (C15:0‰: OR = 0.78, 95% CI: 0.66-0.93, P = 0.0063; C17:0‰: OR = 0.77, 95% CI: 0.64-0.93, P = 0.0074). Further restricted cubic splines analysis showed a significant nonlinear relationship between C15:0‰ level and prevalent hypertension. Saturation threshold effect analysis revealed that when C15:0‰ level was below 1.5‰, the inverse association with the odds of prevalent hypertension was stronger (OR = 0.42, 95% CI: 0.23-0.77, P = 0.0052), while the relationship weakened when C15:0‰ level was above 1.5‰ (OR = 0.89, 95% CI: 0.74-1.07, P = 0.2158). Interaction effect tests indicated that, in the subgroup with C15:0‰ level ≥ 1.5‰, age modified the relationship between C15:0‰ level and prevalent hypertension. In the population aged ≥ 65 years, C15:0‰ level was inversely associated with the odds of prevalent hypertension (OR = 0.54, 95% CI: 0.36-0.79, P = 0.0384), while no significant association was observed in the population aged < 65 years (OR = 0.83, 95% CI: 0.68-1.02, P = 0.1032).

Conclusions: Serum C15:0 and C17:0 levels are significantly inversely associated with the odds of prevalent hypertension, suggesting that serum C15:0 and C17:0 levels may serve as potential biomarkers for hypertension monitoring.