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

Abstract

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.

Keywords: BKMR; arsenic species; cross-sectional study; pregnancy; vitamin D deficiency.