Health impacts of takeaway management zones around schools in six different local authorities across England: a public health modelling study using PRIMEtime.

Background: In England, the number of takeaway food outlets ('takeaways') has been increasing for over two decades. Takeaway management zones around schools are an effective way to restrict the growth of new takeaways but their impacts on population health have not been estimated.

Methods: To model the impact of takeaway management zones on health, we used estimates of change in and exposure to takeaways (across home, work, and commuting buffers) based on a previous evaluation suggesting that 50% of new outlets were prevented from opening because of management zones. Based on previous cross-sectional findings, we estimated changes in body mass index (BMI) from changes in takeaway exposure, from 2018 to 2040. We used PRIMEtime, a proportional multistate lifetable model, and BMI change to estimate the impact of the intervention, in a closed-cohort of adults (25-64 years), on incidence of 12 non-communicable diseases, obesity prevalence, quality-adjusted life years (QALYs), and healthcare costs saved by 2040 in six local authorities (LAs) across the rural-urban spectrum in England (Wandsworth, Manchester, Blackburn with Darwen, Sheffield, North Somerset, and Fenland).

Results: By 2031, compared to no intervention, reductions in outlet exposure ranged from 3 outlets/person in Fenland to 28 outlets/person in Manchester. This corresponded to mean per person reductions in BMI of 0.08 and 0.68 kg/m², respectively. Relative to no intervention, obesity prevalence was estimated to be reduced in both sexes in all LAs, including by 2.3 percentage points (PP) (95% uncertainty interval:2.9PP, 1.7PP) to 1.5PP (95%UI:1.9PP, 1.1PP) in males living in Manchester and Wandsworth by 2040, respectively. Model estimates showed reductions in incidence of disease, including type II diabetes (e.g. 964 (95% UI: 1565, 870) fewer cases/100,000 population for males in Manchester)), cardiovascular diseases, asthma, certain cancers, and low back pain. Savings in healthcare costs (millions) ranged from £1.65 (95% UI: £1.17, £2.25)/100,000 population in North Somerset to £2.02 (95% UI: £1.39, £2.83)/100,000 population in Wandsworth. Gains in QALYs/100,000 person were broadly similar across LAs.

Conclusions: Takeaway management zones in England have the potential to meaningfully contribute towards reducing obesity prevalence and associated healthcare burden in the adult population, at the local level and across the rural-urban spectrum.