New research carried out for the Guardian offers alarming proof of the growing risks from preventable cancers. Economists estimate that around 184,000 people in the UK will be diagnosed this year with diseases that could have been avoided – mostly lung, bowel, melanoma and breast cancers. Globally, too, the rates of these illnesses are rising in younger people. While nine out of 10 cancers affect people over 50, the authors of another new study believe tobacco, diet and alcohol are among the causes of the increase in cancer diagnoses in people under 50 worldwide. Cancer‑linked deaths of adults in their 40s or younger grew by 27% between 1990 and 2019. Frontier Economics, which did the research for the Guardian, estimates that the cost to the UK of all this unnecessary illness will be £78bn between now and 2031 – or 3.5% of annual GDP. For health policymakers such figures can be a useful guide, and a means of building a case for change. But for most people, the more worrying cost is the human one. Nobody wants to be diagnosed with a serious disease and these findings are in line with other recent analysis of the changing nature of illness – and evidence linking poor health to factors including diet and tobacco. Public health experts have long argued for a stronger focus on prevention, and an increase in spending on education and other programmes aimed at keeping people healthy – as opposed to treating them once they become ill. A related debate concerns the role of government in restricting harmful substances and activities, including alcohol and smoking. Henry Dimbleby resigned as the government’s food tsar in March after ministers shelved plans to toughen up food industry rules. The increased reliance of millions of people on cheap processed products that are high in sugar and salt is one of the causes of the current epidemic of obesity. One recent study suggested that people carrying excess weight cost the NHS £14bn a year. Another example of lifestyle-related illness is gambling. So severe are the psychological problems associated with gambling and gaming disorders that NHS England has committed to open 15 clinics by next year. Ten years ago the Conservatives gave councils in England a new responsibility to promote public health (which is devolved to the governments of Northern Ireland, Scotland and Wales). But they took so much away from local government, by cutting budgets, that the policy turned out to be hollow. Then in 2020 they abolished the body that provided national oversight – Public Health England. Currently, the responsibility is shared between local government, the NHS’s 42 new integrated care systems (ICSs), and the Office for Health Improvement and Disparities. Given the reorganisation that is currently in progress, with ICSs tasked with commissioning services in line with locally agreed strategy, the question of whether a greater share of resources can be diverted away from treatments and towards the prevention of illness is moot. Clear messaging – for example, about the risk from exposure to the sun, is useful. But information on its own is not enough. Poor health, poverty and inequality are interrelated, and bad-quality housing and food will have to be tackled if improvements are to be made. A new cross-government approach to health is needed which recognises that while it is the NHS’s job to treat illnesses, including cancers, responsibility for preventing them goes much wider than this.