24-h urinary sodium to potassium ratio and its association with obesity in children and adolescents

Abstract

Purpose: There are epidemiologic studies indicating a positive correlation between high sodium and low potassium intake and body mass index. Therefore, this study was conducted in a cross-sectional sample of Iranian children and adolescents to evaluate the link between 24-h urinary Na:K ratio and risk of obesity.

Methods: In this cross-sectional study, 374 participants aged 11-18 years were included. One 24-h urine sample was collected by each participant to estimate Na:K ratio. Anthropometric measurements were carried out and overweight/obesity was defined as a BMI ≥ 85th percentile and abdominal obesity as a waist:height ratio (WHtR) of more than 0.5.

Results: As expected, 24-h urinary Na:K ratio showed significant associations with risk of overweight/obesity. Risk of adiposity assessed by WC and PBF was significantly associated with Na:K ratio after adjusting for SSBs consumption and calorie intake. Urinary Na:K ratio showed significant association with risk of adiposity assessed by WC only in girls in the highest tertile group with OR of 2.71 (95% CI 1.14-6.43), only after the addition of calorie intake. Adiposity assessed by PBF was only associated with Na:K ratio among boys with OR of 4.47 (95% CI 1.44-9.87) and 3.87 (95% CI 1.20-8.48), after adjusting for SSBs consumption and calorie intake, respectively.

Conclusion: Our findings suggest that reducing Na and increasing K intake could be used as a useful approach to lower the risk of obesity and associated burden of disease in Iran. However, more studies are warranted.

Keywords: 24-h urine; Adolescents; Children; Iran; Obesity; Overweight; Potassium; Sodium.