Association between neonatal phototherapy and sleep: The Japan Environment and Children's Study.

This observational cohort study aimed to evaluate the association between the duration of neonatal phototherapy and sleep-and-wakefulness states at 1 month, 1.5 years, and 3 years of age. We analysed data from 77,876 infants using the Japan Environment and Children's Study, a nationwide birth cohort study. The participants were divided into three groups: no phototherapy, short phototherapy (1-24 h), and long phototherapy (>24 h). Multiple regression analysis was performed to assess the effect of phototherapy duration on infant sleep at each age after adjusting for potential risk factors. A longer duration of phototherapy was associated with a shorter sleep time over 24 h at 1 month of age (β, -0.62; SE, -0.77 to -0.47) when compared with a shorter duration of, or no, phototherapy, following the adjustment of confounding factors. Contrastingly, the short duration group, when compared with the no phototherapy group, was associated with later sleep onset (β, 0.04; SE, 0.00-0.08) and later sleep offset (β, 0.05; SE, 0.01-0.09) at 1.5 years of age. We concluded that the duration of phototherapy may be transiently associated with sleep duration in infants, as emphasised by the shortening of the total sleep time per 24 h at 1 month of age.