Association of formaldehyde concentration with depression risk in US adults: a population-based epidemiology study

The association of formaldehyde exposure with depression remains unknown. We used the data from National Health and Nutrition Examination Survey (NHANES) 2015–2016 to evaluate the association between formaldehyde exposure and depression. Multivariable logistic regressions and restricted cubic spline (RCS) were implemented to examine the association between formaldehyde exposure and depression. A total of 1336 participants were included in the analysis, of which 110 (8.23%) participants were depressed. After adjusting for confounders, a significant association between formaldehyde exposure and depression ( OR = 1.01, 95% CI: 1.00–1.02, P = 0.043) was observed. The RCS plot showed a positive association in a linear manner ( P Nonlinear = 0.109), and the risk began to rise rapidly with concentrations above 129.37 nmol/g HB. The positive association remained in participants with high-intensity physical activity ( OR = 1.08, 95% CI: 1.02–1.13, P = 0.003), but not in participants with other physical activities. Moreover, we constructed a novel nomogram to easily estimate the individual-specific probabilities of depression. In conclusion, formaldehyde exposure was associated with an elevated risk of depression, and the effect exhibited differences in participants with different levels of physical activity.