Short-term exposure to ambient nitrogen dioxide and increased hospitalization burden for depression in China: a multicity analysis

Evidence for the increased hospitalization burden, including admissions, expenditures and length of hospital stay (LOS) for depression attributable to ambient nitrogen dioxide (NO₂) is lacking. We investigated the associations between short-term exposure to ambient NO₂ and attributable admissions, hospitalization expenditures and LOS for depression in 57 Chinese cities during 2013–2017 using a well-established two-stage time-series study approach. Short-term exposure to ambient NO₂ was associated with significantly increased admissions, hospitalization expenditures and LOS for depression, and the attributable fractions were 6.87% (95% CI: 2.90%, 10.65%), 7.12% (3.01%, 11.04%) and 6.12% (2.59%, 9.50%) at lag02, respectively. The projected total attributable admissions, hospitalization expenditures and LOS for depression related to ambient NO₂ at the national level were 23,335 (9,863, 36,181) admissions, 318.70 (134.43, 492.21) million CNY and 539.55 (227.99, 836.99) thousand days during the study period, respectively. Short-term exposure to ambient NO₂ is associated with increased hospitalization burden for depression.