Transient and sustained effects of child-care attendance on hospital admission for gastroenteritis.

BACKGROUND There is evidence that children experience a transient increase in mild episodes of gastroenteritis when they start attending out-of-home child care. We assessed the transient and sustained effects of cumulative day-care attendance, age at first enrolment and type of child care facility attended on hospitalization rates for gastroenteritis. METHODS Cox proportional hazard models were used to estimate the risk of being hospitalized for gastroenteritis in two large cohorts of preschool (<6 years old) and elementary school-going (6-10 years old) children in Denmark. Day-by-day child-level registry data were used. Together, the two cohorts comprised 443,872 children, 21,038 hospitalizations and 1742,284 child-years (1994-2011). RESULTS From first day-care attendance until 12 months of cumulated attendance, preschool children attending day-care centres, but not those attending day-care homes, had an increased risk of hospitalization for gastroenteritis compared with children never attending registered day-care. Such increased risk was highest shortly after starting day-care attendance and then gradually declined. After 12 months of attendance, attending either day-care centres or day-care homes was associated with a lower risk for hospitalization. Such decreased risk was confined to children starting day-care attendance before the age of one year and extended throughout, but not beyond, their preschool years. CONCLUSIONS Attending day-care centres is associated with a higher risk for gastroenteritis hospitalization until completing 1 year of attendance. However, if children start attending day-care before the age of 1 year, they experience a lower risk of being hospitalized during their preschool years. This apparent protective effect does not last into the elementary school years.