Influence of family income on school readiness in children: a population-based study in Korea

Children from households with lower family income may struggle with academics in school. The objective of this study was to investigate the association between family income and school readiness at the age of six years. This population-based cohort study included 268,407 children born in Korea between 2008 and 2012. Their parents responded to the school readiness questionnaires when their children were 54–60 months old. Children with premature birth and low birth weight, and vulnerable children with perinatal complications were excluded. Family income was determined by the amount of insurance copayments in the birth year, which directly reflects family income levels. The sample was divided into three groups based on the family income (low: < 25 percentile, intermediate: > 25 and ≤ 75 percentile, and high: > 75 percentile). The primary outcome was the risk of unreadiness on at least one of the six school readiness questionnaire domains (‘interests in school’, ‘ability to play’, ‘initiative to do’, ‘ability to concentrate’, ‘self-control’, and ‘ability to express’) For the subgroup analysis, the risk of unreadiness for each domain was also investigated. 49.2% subjects were boys. Among all participants, 76,017 (28.3%), 146,496 (54.6%), and 45,894 (17.1%) belonged to the low, intermediate, and high family income groups, respectively. Compared to the high family income group, the aORs for school unreadiness in at least one domain in the low family income group was 1.17 (95% CI 1.12–1.23, p < 0.001). In the interaction analyses, the association between family income and school unreadiness differed according to the presence of atopic dermatitis (P for interaction = 0.043) In five out of the six domains, children from the low family income group showed an increased risk of school unreadiness compared to the high family income group. Children from the lower family income group were more likely to lack school unreadiness at the age of six years. Considerable efforts should be made at the structural level to better prepare preschoolers with lower family income for improved academic achievement, social well-being, and future health.