Serum NO₃⁻ and NO₂⁻ levels among pregnant women from agricultural communities: associations with self-reported dietary and environmental exposures.

Nitrate (NO₃⁻) and nitrite (NO₂⁻) exposure can lead to adverse health impacts, yet data on direct biomarkers are limited. To assess serum NO₃⁻ and NO₂⁻ levels among pregnant women in two agricultural regions of the Jordan Valley in relation to dietary and environmental factors. This cross-sectional study recruited 346 pregnant women aged 18 years or older from four hospitals in the Ghor region between 2023 and 2024. Serum NO₃⁻ and NO₂⁻ levels were measured using a Griess assay. Socio-demographic data, dietary habits, and water source information were gathered through questionnaires. The median serum NO₂⁻ level was 0.63 µM and the median serum NO₃⁻ level was 19.13 µM in the overall sample. Serum NO₂⁻ was significantly higher among women from North Ghor compared to South Ghor (0.83 µM vs. 0.45 µM, p < 0.001), while serum NO₃⁻ levels did not significantly differ between regions. In multivariable models adjusting for maternal age, BMI, hypertension, anemia, and smoking, we found that variables of region of residency and eating green beans once a week or more were significantly associated with higher NO₂⁻ levels in the whole sample (p < 0.001 and p = 0.031, respectively) and in North Ghor (p = 0.032), while hypertension was associated with lower NO₂⁻ levels (p = 0.032 whole sample; p = 0.013 North Ghor). For NO₃⁻, smoking during pregnancy was associated with lower levels in the whole sample (p = 0.003) and in South Ghor (p = 0.004), while employment in crop harvesting/collection was associated with higher NO₃⁻ levels in South Ghor (p = 0.024). Regional differences in serum NO₂⁻ levels exist among pregnant women in rural Jordan, influenced primarily by dietary habits, while occupational exposure to crop harvesting and smoking were associated with serum NO₃⁻ levels. Targeted recommendations and public health strategies are needed to mitigate NO₃⁻ and NO₂⁻ exposure.