The association of nitrate exposure with bone mineral density in adolescents aged 12 to 19: A cross-sectional study.

The association between urinary nitrates exposure and bone mineral density (BMD) in adolescents is unclear. This study aimed to examine the association between nitrate levels and BMD in adolescents aged 12 to 19. Cross-sectional data were obtained from the National Health and Nutrition Examination Survey conducted between 2011 and 2018. Weighted multivariate logistic regression analyses, and sensitivity analyses were employed to assess the independent association between BMD and nitrate levels, with subgroup analyses based on sex, age, poverty-to-income ratio and race. Additionally, smooth curve fitting and saturation threshold analysis were employed to explore nonlinear relationships. After adjusting for relevant covariates, nitrate levels were found to be negatively associated with lumbar spine BMD (β = -0.036, 95% confidence interval: -0.054, -0.019) and total BMD (β = -0.027, 95% confidence interval: -0.040, -0.014). Subgroup analyses demonstrated that this negative correlation remained consistent across all subgroups. Smoothed curve fitting also confirmed a negative relationship between nitrate levels and BMD. The nonlinear relationship between nitrate levels and BMD was characterized by a seemingly L-shaped curve in adolescents aged 12 to 15 years. The results of sensitivity analysis were consistent with the above analysis results. These findings indicate the negative association between urinary nitrate and BMD in adolescents. The findings also underscore the significance of nitrates exposure levels in identifying individuals at risk for low BMD.