Increases in levels of obesity will cause deaths from diabetes to rise by 25%, a report warns today.

The World Health Organisation said millions of lives and billions of pounds could be saved if action was taken in the UK and worldwide to tackle chronic disease.

The WHO report, Preventing Chronic Diseases: A Vital Investment, concluded that efforts to prevent illnesses such as heart disease, cancer and diabetes could save the lives of 36 million people worldwide who would otherwise be dead by 2015.

In the UK alone, 84% of deaths in 2005 will be from chronic diseases - amounting to 488,000 people.

The report sets a new global goal to reduce the projected trend of chronic disease death rates by 2% each year until 2015.

As well as saving millions of lives, such a reduction would also help world economies by cutting the cost of treatment and lost productivity caused by premature deaths.

The WHO said an extra 2% annual reduction in chronic disease death rates in the UK would result in an economic gain of £1.14bn over the next 10 years.

It said the vast majority of chronic diseases were caused by a small number of known and preventable risk factors, the three most important of which are unhealthy diet, physical inactivity and tobacco use.

The report said 80% of heart disease, stroke and type 2 diabetes and 40% of cancer could be avoided through healthy diet, regular physical activity and avoiding tobacco use.

The report focused on nine countries - Brazil, Canada, China, India, Nigeria, Pakistan, the Russian Federation, the United Republic of Tanzania and the UK.

The WHO estimated that over the next 10 years, almost five million people in the UK will die from a chronic disease.

The report said that deaths from chronic disease in the UK would decrease by around 0.8% in the next decade.

But some chronic diseases will increase - most markedly, it said deaths from diabetes will increase by 25%.

The WHO said the UK had already made good progress in reducing deaths from chronic disease, estimating that from 1970 to 2000, 3m heart deaths were averted in this country.

But the costs to the UK from chronic disease remain high, the report said.