This study examined the associations among chronotype, sleep quality, and risky health behaviors in early adolescents and explored the independent contribution of chronotype to these outcomes after controlling for sociodemographic covariates. This cross-sectional study enrolled 295 seventh- and eighth-grade students (48.5% female; mean age 13.29 ± 0.63 y) from two public middle schools in Muş, eastern Türkiye. Data were collected using the Morningness-Eveningness Scale for Children (MESC), the Pittsburgh Sleep Quality Index (PSQI), and the Risky Behavior Scale (RBS). Normality was evaluated with the Shapiro-Wilk test and skewness/kurtosis values. Pearson correlation, independent-samples t-test, one-way ANOVA with Bonferroni post-hoc comparisons, hierarchical multiple regression, and Baron-Kenny mediation analysis with 2,000 bootstrap resamples were employed. Most students displayed an intermediate chronotype (61.0%), and 76.6% had poor sleep quality (PSQI > 5). MESC scores were negatively correlated with PSQI (r = -.297, 95% CI [-.398, -.189], p < 0.001) and RBS (r = -.495, 95% CI [-.577, -.404], p < 0.001). After Benjamini-Hochberg FDR correction, MESC independently explained 7.1% additional variance in sleep quality (ΔR2 = .071, p < 0.001) and 18.0% in risky behaviors (ΔR2 = .180, p < 0.001) beyond demographic predictors. Sleep quality partially mediated the chronotype - risky behavior association (indirect β = -.047, 95% CI [-.086, -.014]). Male sex, single-parent family structure, paternal unemployment, and smoking were additional significant risk factors. Chronotype was independently associated with both sleep quality and risky behaviors in early adolescents, with sleep quality functioning as a partial statistical mediator in this relationship. These findings highlight the potential value of chronotype assessment in school health contexts, though longitudinal and intervention studies are needed to confirm these associations and evaluate targeted strategies.
