Weekday daylight exposure buffers against depressive and anxiety symptoms in children: Evidence from a prospective...

Depressive and anxiety symptoms are common and increasing among school-aged children. Daytime light exposure influences circadian and neurobiological pathways involved in emotional regulation, yet prospective evidence using objective light assessment in pediatric populations remains limited. Because children's routines are typically more structured during school days, weekday daytime light exposure may be more regular and biologically salient. We therefore examined whether weekday daytime light exposure duration predicts subsequent depressive and anxiety symptoms in children.

In this longitudinal study, 932 children aged 7-11 years from two elementary schools in Chuzhou, China wore HOBO pendant sensors for five consecutive days to objectively assess personal light exposure. Cumulative durations above ≥250, ≥500, and ≥ 1000 lx were calculated separately for weekdays and weekends. Depressive and anxiety symptoms were parent-reported at baseline and self-reported 19 months later. Multivariable linear and logistic regression models estimated associations with continuous symptom scores and clinically elevated symptoms after adjusting for sociodemographic and behavioral factors and baseline symptoms. Restricted cubic splines examined non-linearity.

Greater weekday daytime light exposure was prospectively associated with lower depressive symptom scores across all thresholds and reduced odds of clinically elevated depressive symptoms. For anxiety, longer weekday exposure was associated with lower symptom scores across all thresholds, but only duration ≥1000 lx exposure was associated with reduced odds of clinically elevated anxiety (OR = 0.55, P = 0.031). Weekend daytime light exposure was not significantly associated with either outcome.

Consistent daytime light exposure during structured school days may represent an important environmental factor supporting emotional health in children.