Childhood lead exposure and sleep problems in adolescents: a longitudinal cohort study

Childhood lead exposure is linked to poorer neurobehavioral function in adolescence, but the relationship between lead and adolescent sleep health remains inconsistent. This study aimed to investigate concurrent and longitudinal associations between lead exposure and multiple sleep health domains in adolescents.

A total of 972 adolescents from China Jintan Child Cohort were included in analyses. The Blood lead levels (BLLs) were assessed in two Waves, at ages 3-5 years (mean 6.50 ± 2.76 μg/dL) and 11-13 years (mean 3.12 ± 1.17 μg/dL). Sleep problems at age 11-13 were parent-reported via the Child Sleep Health Questionnaire (CSHQ) and self-reported by adolescents using the Pittsburgh Sleep Quality Index (PSQI).

Both early and later BLLs were associated positively with parental reported sleep problems, including sleep onset delay, night waking, short duration, parasomnias, and disordered breathing. Sex-stratified analyzes showed that most adjusted associations between two-Wave BLLs and sleep outcomes (CSHQ and PSQI) remained statistically significant in males, with a minor increase in the magnitude of these associations. The association between Wave II BLLs and shorter self-reported sleep duration was only statistically significant in female adolescents. Compared to children with consistently low BLLs at both ages, those with persistently high BLLs at both ages had significantly shorter parental-reported sleep duration and worse sleep onset delay.

Findings suggest that both early and later childhood lead exposures link to more adolescent sleep problems, with recent BLLs showing stronger associations with poor adolescent sleep health reported by their parents.