Economic evaluations of childhood obesity interventions are often used to assist decision making when presented with alternative course of action. Including indirect costs related to productivity losses is recommended; in children this would include school absenteeism. Our aim was to determine the association between school absenteeism and weight status among Australian children and estimate the indirect costs of this.

We used data from a nationally representative sample of 8551 Australian children in the Longitudinal study of Australian Children (LSAC) with follow-up between 2006 and 2018. A mixed-effects negative binomial regression model was used to investigate the relationship between school absenteeism and weight status, controlling for age, sex, socio-economic position, indigenous status, rural/remote status and long-term medical conditions. We used average daily wages for the year 2018 to value the indirect costs of school absenteeism (through caregiver lost productivity).

Australian children with obesity aged 6−13 years missed on average an extra day of school annually compared to children of a healthy weight (p = 0.004), while adolescents with obesity aged 14−17 years missed on average an extra 0.69 days of school annually (p = 0.006). The estimated national cost for children with obesity aged 6−13 years was approximately $64 million AUD ($43 million USD) or $338 AUD ($230 USD) per child through caregiver lost productivity in 2018.

There is a small but significant association between school absenteeism and childhood obesity in Australia which is estimated to generate a considerable national cost through caregiver productivity losses. Our results will assist health economists evaluating childhood obesity interventions capture the full extent of the associated costs with this condition.