Serum nitric oxide metabolite levels in a general healthy population: Relation to sex and age

Abstract

This study aims at determining serum nitrite/nitrate (NO x) levels in healthy subjects within the framework of a population-based study. NO x concentration was measured in 3505 subjects aged ≥ 20 years. Subjects with diabetes, renal dysfunction, those undergoing treatment for dyslipidemia and hypertension, were excluded; also excluded were smokers, pregnant women, and subjects with cardiovascular and infectious diseases or cancer; leaving 1983 (667 men, 1316 women) asymptomatic non-smoking subjects for the analysis. NO x concentrations were determined in serum and compared in different age groups. Mean ± SE of NO x concentration was 24.8 ± 0.02 and 24.4 ± 0.01 µmol/l in men and women respectively. Men aged 20–29 years had significantly higher NO x levels compared to corresponding women (25.1 ± 0.03 vs. 22.7 ± 0.02). Serum NO x concentration peaked at 50–59 years in both genders. Comparison between lower and upper quartiles of NO x levels was performed in both genders. Women with high serum NO x were older and had significantly higher body mass index and fasting plasma glucose. The results of this study determine the normal levels of serum NO x concentrations in asymptomatic non-smoker subjects; also show that serum NO x concentrations indicate sex and age differences in these subjects.