The effects of
triazine herbicides on
glucose metabolism remain unclear. In this study, we aimed to assess the associations between serum
triazine herbicides and glycemia-related risk indicators in general adults, and to evaluate the mediating role of natural
immunoglobulin M antibodies (
IgM) in the above associations among uninfected participants. We measured the concentrations of
atrazine,
cyanazine, and
IgM in serum, as well as fasting plasma
glucose (FPG), and fasting plasma
insulin in 4423 adult participants from the Wuhan-Zhuhai cohort baseline population, enrolled in 2011-2012. Generalized linear models were used to evaluate the associations of serum
triazine herbicides with glycemia-related risk indicators, and mediation analyses were performed to evaluate the mediating role of serum
IgM in the above associations. The median levels of serum
atrazine and
cyanazine were 0.0237 μg/L and 0.0786 μg/L, respectively. Our study found significant positive associations of serum
atrazine,
cyanazine, and Σtriazine with FPG levels, risk of impaired fasting
glucose (IFG), abnormal
glucose regulation (AGR), and
type 2 diabetes (T2D). Additionally, serum
cyanazine and Σtriazine were found to be significant positive associated with the homeostatic model assessment of
insulin resistance (HOMA-IR) levels. Significant negative linear relationships were observed in associations of serum
IgM with serum
triazine herbicides, FPG, HOMA-IR levels, the prevalence of T2D, and AGR (P < 0.05). Furthermore, we observed a significant mediating role by
IgM in the associations of serum
triazine herbicides with FPG, HOMA-IR, and AGR, with the proportions ranging from 2.96% to 7.71%. To ensure the stability of our findings, we conducted sensitivity analyses in normoglycemic participants and found that the association of serum
IgM with FPG and the mediating role by
IgM remained stable. Our results suggest that
triazine herbicides exposure is positively associated with abnormal
glucose metabolism, and decreasing serum
IgM may partly mediate these associations.