COVID-19 impact on overweight and obesity rates in Aotearoa | New Zealand 4-year-old children

Abstract

Abstract Background COVID-19 has had profound societal impacts. This study estimated overweight, obesity, and extreme obesity rates in 4-year-old children over pre- and post-COVID-19 periods, and investigated differential changes between sex, ethnic and deprivation groups. Methods A national screening programme of 4-year-old children undertaking B4 School Checks (B4SCs) between 1 January 2010 and 7 March 2023 was analysed. B4SCs include anthropometric measurements enabling sex-specific body mass index-for-age Z-scores (BMI z-scores) to be derived. Children with ≥85th, ≥95th, and ≥99.7th percentile BMI z-scores were classified as overweight, obese, and extremely obese. Results The eligible sample included 656,038 children (48.8% girls). Overall, 210,492 (32.1%) children were overweight, 95,196 (14.5%) obese, and 19,926 (3.0%) extremely obese. While decreasing in the pre-COVID-19 period, annual prevalence estimates for overweight, obese, and extremely obese significantly (all p < 0.001) increased in the year after COVID-restrictions were implemented. However, after three years, overweight and obese prevalence estimates were no different to pre-COVID levels overall or stratified by sex for ethnicity and deprivation groups. Extreme obesity prevalence estimates also decreased but remained higher than pre-COVID levels. Conclusion The sharp and steep increases in prevalence estimates all dampened relatively quickly. The question remains whether these rates will continue to decrease in time. Impact Compared to pre-COVID-19 estimates, the prevalence of overweight, obesity and extreme obesity significantly and substantially increased for 4-year-old children in the immediate post-COVID-19 period. These post-COVID-19 prevalence estimates dampened relatively quickly, returning to pre-COVID-19 rates for overweight and obesity after 3 years. Inequities between ethnic and social deprivation groups in overweight and obesity prevalence estimates remained similar between pre- and post-COVID-19 periods.