Environmental titanium exposure and reproductive health: Risk of low birth weight associated with maternal titanium exposure from a nested case-control study in northern China.

Titanium (Ti) is commonly used in additives in the form of titanium dioxide (TiO). However, our understanding of the effect of Ti on reproductive health remains limited. This nested case-control study, performed in a Ti mining exposure field, investigated the association between maternal blood Ti concentration and the risk of low birth weight (LBW), as well as the potential biological mechanism. A total of 45 women who delivered LBW infants (cases) and 352 women with normal birth weight infants (controls) were included. We collected maternal peripheral blood samples in the first or early second trimester to measure Ti concentration in serum (Ti) and blood cells (Ti), as well as inflammatory, lipid, and oxidative stress biomarkers thereof. The demographic characteristics of the women included in the study were also obtained. The results showed that the median total blood Ti concentration (Ti) in the case group was significantly higher than that in the control group (134 vs. 129 ng/mL, P = 0.039). A higher Ti level was associated with a greater risk of LBW [odds ratio = 2.62; 95% confidence interval (CI): 1.16-5.90], but no such association was observed for Ti or Ti after adjusting for potential confounders. The serum lipid biomarkers TC, TG, and total lipids (TL) were all negatively associated with Ti and Ti. Serum 8-OHdG was positively associated with Ti. We concluded that a high Ti during early pregnancy may increase the risk of LBW. Lipid metabolism and oxidative stress may play an important role in the adverse health effects associated with Ti exposure. Thus, our results merit more attention to the probable adverse effects of titanium exposure during pregnancy.