Peer-reviewed article

Association between PM2.5 constituents and non-suicidal self-injury among Chinese adolescents: modifying role of biological rhythm.

Xiaodi Ren, Longqing Ouyang, Yang Xie, Shuqin Li, Runyu Wei et al. · 20 Aug 2026

Abstract

BACKGROUND: Non-suicidal self-injury (NSSI) has emerged as a growing public health concern among Chinese adolescents. Although exposure to fine particulate matter (PM2.5) has been associated with adverse mental health outcomes, the specific chemical constituents driving this association and the potential modifying role of biological rhythms remain poorly understood. METHODS: A multicenter, population-based survey was conducted across 15 schools located in four provinces of China. A total of 18,398 adolescents in grades 7 through 12 completed the eligible questionnaires. NSSI behaviors were assessed using the Adolescent Non-suicidal Self-injury Assessment Questionnaire (ANSAQ). The Self-rating Questionnaire of Biological Rhythm Disorders for Adolescents (SBRDA) was used to conduct a comprehensive assessment of participants' multidimensional biological rhythms. Binary logistic regression and weighted quantile sum (WQS) regression were employed to examine the associations between PM2.5 constituents and NSSI, with stratified analyses performed to explore the moderating effects of factors such as biological rhythms. RESULTS: After adjusting for covariates, PM2.5 and its constituents showed significant positive associations with NSSI risk, with black carbon exhibiting the strongest association (OR = 1.76, 95% CI: 1.60-1.94). Mixed exposure analyses consistently identified black carbon as the dominant constituent (WQS weight = 0.810; Qgcomp effect size = 0.671). Stratified analyses revealed heightened vulnerability among adolescents with disrupted biological rhythms, good family economic situations, junior high school enrollment, and heavy learning burdens. Furthermore, disruptions in activity rhythm and eating rhythm can significantly amplify the risk impact of pollutants on NSSI behaviors. DISCUSSION: Exposure to PM2.5 (particularly BC) increases adolescent NSSI risk, with factors like biological rhythm disruption potentially amplifying this effect. Integrating strategies to manage BC emissions with initiatives that encourage adolescents to maintain healthy routines, such as timely meal consumption, could synergistically lower mental health risks.