Relationship between urinary sodium excretion and bone mineral density in pediatrics: population-based study from KNHANES V 2010-2011.

ABSTRACT

OBJECTIVES: Osteoporosis poses a growing public health challenge worldwide. While calcium and vitamin D may influence bone mineral density (BMD), the effect of sodium (Na) intake, particularly in pediatrics, remains unexplored. This study aimed to evaluate the relationship between urinary Na excretion and BMD in a Korean pediatric population. METHODS: A total of 2,018 participants (1,084 males and 934 females) aged 10-18 years were included from the data obtained from Korea National Health and Nutrition Examination Survey V (2010-2011). RESULTS: Daily Na intake was about 4,560 mg and 3,600 mg in boys and girls, respectively. The mean intake of Na per day was positively correlated with the increment of urine Na/Cr ratio quartile (p<0.001). The BMD z-score [lumbar spine (LS), femur neck (FN), and whole body except head (WB)] in the group with high Na/Cr ratio (4th quartile, 4Q) was significantly less than in those with low Na/Cr ratio (1st quartile, 1Q) (p<0.001). Moreover, the LS (p=0.028), FN (p=0.002) and WB (p=0.056) in the 4Q group showed 2.0 times, 2.8 times, and 1.9 times greater risk of low BMD z-scores than in the 1Q group, even after adjusting for other confounding factors, such as age, sex, BMI, vitamin D, moderate activity, and household incomes. CONCLUSIONS: Our findings suggest a strong negative association between urine Na excretion and BMD among Korean children and adolescents. The results underscore the importance of public health interventions targeting Na intake. Further longitudinal studies are recommended to clarify the long-term effects of Na on bone health in younger populations.