The Association Between the Introduction of a Universal School Lunch Program and Healthcare Utilization among Children in Public Assistance Households: A Difference-in-Differences Study

Abstract Background Universal school lunch programs support children’s nutrition and development and may serve as a safety net for socioeconomically disadvantaged children. Their effects on healthcare utilization may be bidirectional: improved nutrition may reduce healthcare needs, whereas reduced non-financial barriers and increased contact with schools may facilitate access to healthcare and increase healthcare utilization. However, evidence based on objective medical claims data remains limited. This study examined the association between the introduction of a universal school lunch program and healthcare utilization among junior high school students from households receiving public assistance in Japan. Methods This observational study used a quasi-experimental difference-in-differences design. The intervention group consisted of students in City A, where a school lunch program was introduced in September 2016. The control group consisted of students in neighboring City B, where a school lunch program had already been implemented. The study included 411 junior high school students from households receiving public assistance during fiscal year 2016. Medical assistance claims data were used to assess monthly medical use days, medical expenditures, outpatient visits, and any outpatient visit. Individual and month fixed effects were included in regression models. Event-study analyses were conducted to assess the parallel trends assumption and dynamic effects. Results Relative to the control group, the introduction of the school lunch program was associated with higher medical expenditures and outpatient utilization. The estimate for medical use days was 0.23 days per person-month (p = 0.052), and medical expenditures increased by 728 medical fee points per person-month, equivalent to JPY 7,280 (approximately USD 45) (p = 0.03). Outpatient visits increased by 0.13 visits per person-month (p = 0.02), and the probability of at least one outpatient visit per month increased by 5.6 percentage points (p = 0.04). Event-study analyses showed no systematic pre-intervention trend and were consistent with the parallel trends assumption. Conclusions The introduction of a school lunch program was associated with increases in several measures of healthcare utilization among junior high school students from households receiving public assistance, suggesting that such programs may have implications for healthcare use among socioeconomically disadvantaged children.