Dehydration and Suboptimal Sleep Aggravate Early Renal Impairment in Children: Longitudinal Findings from the PROC Study

Background: While dehydration is associated with pediatric renal impairment, the regulation of hydration status can be affected by sleep. However, the interaction of hydration and sleep on kidney health remains unclear.

Methods: We conducted a cohort study among 1914 healthy primary school children from October 2018 to November 2019 in Beijing, China. Four-wave urinary β₂-microglobulin and microalbumin excretion were assayed to assess transient renal tubular and glomerular impairment, and specific gravity was measured to determine hydration status with contemporaneous assessment of sleep duration, other anthropometric, and lifestyle covariates. We used generalized linear mixed-effects models to assess longitudinal associations of sleep duration and hydration status with renal impairment.

Results: We observed 1378 children with optimal sleep (9-<11 h/d, 72.0%), 472 with short sleep (<9 h/d), and 64 with long sleep (≥11 h/d, 3.3%). Over half (55.4%) of events determined across 6968 person-visits were transient dehydration, 19.4% were tubular, and 4.9% were glomerular impairment events. Taking optimal sleep + euhydration as the reference, the results of generalized linear mixed-effects models showed that children with long sleep + dehydration (odds ratio [OR]: 3.87 for tubular impairment [tubules] and 3.47 for glomerular impairment [glomerulus]), long sleep + euhydration (OR: 2.43 for tubules), optimal sleep + dehydration (OR: 2.35 for tubules and 3.00 for glomerulus), short sleep + dehydration (OR: 2.07 for tubules and 2.69 for glomerulus), or short sleep + euhydration (OR: 1.29 for tubules) were more likely to present transient renal impairment, adjusting for sex, age, body mass index z-score, systolic blood pressure z-score, screen time, physical activity, and Mediterranean diet adherence.

Conclusions: Dehydration and suboptimal sleep aggravate transient renal impairment in children, suggesting its role in maintaining pediatric kidney health.