Kin-based alloparenting and infant hospital admissions in the UK Millennium cohort

Background and objectivesKin-selected altruism is an evolutionary explanation for why biological kin other than parents are willing childcare providers or alloparents. Kin alloparents may increase lineage fitness by reducing maternal energy depletion and improving child survival through childcare activities. The aim of this research was to apply the hypothesis that kin-based alloparental care has benefits for child health in a western, educated, industrialized, rich, democratic context.MethodologyThe hypothesis was tested using the first sweep of the UK Millennium Cohort Study (n = 18 552 infants). The outcome was number of hospitalizations by age 9 months, and the main predictors were kin-based alloparental care during work hours, socioeconomic position and infant health-related variables and their interactions with kin-based alloparenting. Analysis of hospitalizations was carried out using negative binomial regression.ResultsKin alloparents were primary day carers in 17% of households. Infants whose main care arrangement during work hours was with kin allocarers had statistically significantly fewer hospitalizations than infants in all other care arrangements combined (Incidence rate ratio = 0.86, P