High serum nitric oxide metabolites and incident metabolic syndrome

Abstract

Background. Endothelial dysfunction, synonymous with reduced biological activity of nitric oxide, is related to all cardiovascular risk factors. Association between metabolic syndrome and nitric oxide metabolites (nitrite + nitrate = NO_x) has been previously shown in cross-sectional studies. The aim of this study was to determine the ability of serum NO_x levels in predicting the incidence of metabolic syndrome in a population-based study. Methods. Serum NO_x levels measured in 2098 adult subjects, participants of Tehran Lipid and Glucose Study, without metabolic syndrome at baseline. After 3.3 years follow-up, logistic regression analysis was used to calculate the odds ratio (OR) and 95% confidence interval for developing metabolic syndrome, with serum NO_x quartiles as independent variables. Results. Incident metabolic syndrome was diagnosed in 23.0% of men and 16.3% of women after 3.3 years. Age-adjusted risk for developing metabolic syndrome in women who had higher NO_x values (above 75th percentile vs. lower 75th percentile) at baseline, was significantly higher [OR: 1.59 (1.11–2.27), p = 0.011]; OR remained significant after multivariable-adjustment including adjustment for components of metabolic syndrome [OR: 1.75 (1.19–2.59), p = 0.005]. Serum NO_x could not predict the incidence of metabolic syndrome in men. Conclusions. High serum NO_x level is an independent predictor of incident metabolic syndrome in women, but not in men, a finding which presents serum NO_x level as a potential biomarker for assessing cardiometabolic disturbances.

Key Words::

• Endothelium
• nitrate
• nitrite
• population

Acknowledgements

The authors wish to thank Ms V. Khorasani for technical help and Ms N. Shiva for critical editing for English grammar and syntax of the manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of paper.

This work was supported by grant No. 177 from the Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences.