# Exploring the Association Between Sleep Patterns, Pubertal Health, and Phthalate Exposure—Preliminary Results from Slovakia

## TL;DR

This study explores how sleep patterns in children relate to phthalate exposure and puberty, finding possible nonlinear associations.

## Contribution

The study presents preliminary evidence of nonlinear associations between phthalate metabolites and sleep quality in children.

## Key findings

- Boys slept significantly longer than girls (8 h 44 min on average).
- Nonlinear associations were observed between phthalate metabolites OH-MiNP and MnOP and sleep quality.
- Associations between phthalates and sleep quality became less significant after adjusting for factors like BMI and residence.

## Abstract

Background: This study aims to explore the association between sleep patterns in children and their exposure to phthalates to assess potential health implications. Methods: Participants (n = 60) completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Consumer behavior scores (CBS) were calculated. The Tanner scale was used to monitor the stages of puberty. First-morning urine samples were analyzed by high-performance liquid chromatography–tandem mass spectrometry. Results: The average sleep duration was 8 h and 44 min, with boys sleeping significantly longer (p = 0.01). Notably, 51.7% of participants reported sleeping less than 9 h. The nonlinear effects of phthalate metabolite in association with PSQI were observed for hydroxy-mono-isononyl phthalate (OH-MiNP, p = 0.003) and MnOP (p < 0.001), indicating that the relationship does not follow a simple linear pattern. Simple linear regression revealed a significant positive association between the Mono-n-octyl phthalate (MnOP) and PSQI scores (p = 0.016). After adjustment for place of residence, BMI, CBS, sex, and age, the significance of associations between phthalate metabolites and sleep quality diminished, necessitating cautious interpretation. No statistically significant associations between pubertal changes and the value of PSQI as well as phthalates were observed. Conclusion: Our results provide preliminary evidence of potential nonlinear associations that require validation in a larger cohort. The findings highlight the importance of monitoring phthalate exposure in children, as it may influence sleep patterns and overall health.