Abstract P593: Urinary Nitrate Was Not Associated With Prevalence of Dyslipidemia Among Adults in the National Health and Nutrition Examination Survey, 2009-2016

Abstract

Introduction: Exogenous dietary sources of nitrate (green leafy vegetables) and endogenous oxidation of nitric oxide are potential sources of urinary nitrate. While nitrate exposure elicits a profound impact on vascular health and higher levels of urinary nitrate correlate with reduced blood pressure, less is known about its association with blood cholesterol. Hypothesis: Higher urinary nitrate levels are inversely related to dyslipidemia prevalence. Methods: Cross-sectional 2009-2016 National Health and Nutrition Examination Survey (NHANES) was used to identify participants aged ≥20 years. Participants were categorized into four quartiles based on urinary nitrate levels (ng/mL) - Q1: ≤26,300; Q2: 26,300-45,800; Q3: 45,800-72,200; Q4: >72,200. Primary analysis was survey-weighted logistic regression modeling to estimate the association of urinary nitrate with dyslipidemia prevalence (defined as self-report, total cholesterol [TC] ≥200 mg/dL, high-density lipoprotein cholesterol [HDL-C] <40 mg/dL for men or <50 mg/dL for women, low-density lipoprotein cholesterol [LDL-C] ≥100 mg/dL, triglycerides [TG] ≥150 mg/dL, or non-HDL-C ≥130 mg/dL). The model was adjusted for age, sex, race/ethnicity, smoking status, income level, hypertension, and diabetes. Secondary analysis included comparison of TC, HDL-C, LDL-C, TG, and non-HDL-C stratified by urinary nitrate quartiles. Survey-weighted ANCOVA, adjusted for the same co-variates, was performed at a significance level of 0.05; if significance level was met, post-hoc multiple comparison test using the Dunnett-Hsu method was performed, with Q1 as the reference. Results: Across the 8-year NHANES survey, 3,099 participants (74.7% aged <60 years, 50.5% women, and 65.6% non-Hispanic white) were included in the study. Hypertension and diabetes prevalence were 24.5% and 9.3%, respectively. Urinary nitrate was not significantly associated with hypercholesterolemia prevalence (Q2 vs. Q1, OR 0.87 [95% CI, 0.62-1.23]; Q3 vs. Q1, OR 1.09 [95% CI, 0.71-1.68]; Q4 vs. Q1, OR 0.89 [95% CI, 0.59-1.37]). No statistically significant trends in TC, HDL-C, LDL-C, TG, or non-HDL-C were observed with urinary nitrate quartiles. Conclusion: Higher urinary nitrate excretion, a marker of nitrate exposure and elevated nitrate levels, was not associated the prevalence of dyslipidemia. Therefore, while a healthy diet may lead to changes in cholesterol, such changes may be independent of dietary nitrate intake.