Trends in obesity among 4-year-old children in New Zealand-pre- and post-COVID comparison.

Aims: We described long-term trends in obesity using preschool data from New Zealand and compared rates pre- and post-COVID by key demographic variables.

Methods: Growth data from the B4 School Check (B4SC) information system for the period 1 July 2012 to 30 June 2022 were used to calculate obesity rates. The date 25 March 2020 was the threshold used to compare the rates between pre- and post-COVID periods. Obesity rate ratios for these two periods were calculated for each demographic sub-group.

Results: The overall obesity rate increased by 1.8% after COVID-19. Males had higher obesity rates and a greater absolute increase (2%) in the post-COVID period. The greatest absolute increase in obesity was among Pacific peoples (4.3%), followed by Māori (2.2%). Children in most deprived areas and those in the Auckland Region had greater absolute increases of 3% and 2.5% respectively, post-COVID.

Conclusion: The COVID-19 lockdown has had an immediate impact on obesity rates among 4-year-old children, especially for the Pacific population, those living in high deprivation areas and regions with longer periods of lockdown (Auckland). There are implications for public health policy and practice to support children in adopting a healthy lifestyle, especially during pandemics.