Association between urinary arsenic species and vitamin D deficiency: a cross-sectional study in Chinese pregnant women.

BACKGROUND: An increasing number of studies suggest that environmental pollution may increase the risk of vitamin D deficiency (VDD). However, less is known about arsenic (As) exposure and VDD, particularly in Chinese pregnant women.

OBJECTIVES: This study examines the correlations of different urinary As species with serum 25 (OH) D and VDD prevalence.

METHODS: We measured urinary arsenite (As3+ ), arsenate (As5+ ), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) levels and serum 25(OH)D2 , 25(OH)D3 , 25(OH) D levels in 391 pregnant women in Tianjin, China. The diagnosis of VDD was based on 25(OH) D serum levels. Linear relationship, Logistic regression, and Bayesian kernel machine regression (BKMR) were used to examine the associations between urinary As species and VDD.

RESULTS: Of the 391 pregnant women, 60 received a diagnosis of VDD. Baseline information showed significant differences in As3+ , DMA, and tAs distribution between pregnant women with and without VDD. Logistic regression showed that As3+ was significantly and positively correlated with VDD (OR: 4.65, 95% CI: 1.79, 13.32). Meanwhile, there was a marginally significant positive correlation between tAs and VDD (OR: 4.27, 95% CI: 1.01, 19.59). BKMR revealed positive correlations between As3+ , MMA and VDD. However, negative correlations were found between As5+ , DMA and VDD.

CONCLUSION: According to our study, there were positive correlations between iAs, especially As3+ , MMA and VDD, but negative correlations between other As species and VDD. Further studies are needed to determine the mechanisms that exist between different As species and VDD.