A Mortality Collapse but a Disability Stall: Secondhand-Smoke-Attributable Asthma, Lower Respiratory Infections, and Otitis Media in Children Aged 0–14 Years, 1990–2023

Background: Secondhand smoke (SHS) is an established, preventable cause of childhood respiratory and ear disease. The Global Burden of Disease (GBD) 2023 round made asthma SHS-attributable and apparently revised the otitis media evidence base. This integrated child burden through the COVID-19 pandemic remains unquantified. Methods: GBD 2023 risk-attributable estimates (SHS → asthma, lower respiratory infections (LRI), otitis media) were analysed for ages 0–14 years, five Socio-demographic Index (SDI) quintiles and 21 regions, 1990–2023. Population attributable fractions (PAFs; asthma and LRI only), count-based estimated annual percentage changes (EAPCs), and child SHS summary exposure value (SEV) were computed; the 2019–2021 pandemic window was tested against a 2015–2019 counterfactual. Results: Attributable disability-adjusted life-years (DALYs) fell 77.3% to 5,551,243 (95% uncertainty interval 3,699,752–7,871,761) in 2023, deaths fell 78.2% to 59,008 (39,733–82,577), and years lived with disability fell only 15.2%. Asthma DALYs fell only 21.6%, otitis media 19.1%; LRI drove the decline (−78.4%). PAFs fell for asthma (9.07%→6.84%) and LRI (13.38%→8.48%). Child SEV fell 25.7–28.0% yet remained at 36.7–38.6% in 2023—above 50% at middle SDI (under-5 band). Asthma (EAPC +0.61%) and otitis media (+0.59%) counts rise at low SDI, now carrying 49.2% of the total. Only LRI showed a detectable pandemic interruption (−23.5% vs counterfactual in 2021; +21.3% rebound by 2023). Conclusions: Secondhand smoke has collapsed as a killer of children but stalled as a cause of disability; asthma and otitis media now define the residual burden. Smoke-free homes, tobacco control, and child asthma and otitis services remain unfinished where the burden concentrates.