Cancer Research UK said this amounts to 41 per cent of all cancers diagnosed north of the Border, which equates to around 13,000 cases each year – the highest proportion of preventable cases compared to other UK nations.
Across the UK, the landmark study found that more than 135,000 cases of cancer a year could be prevented.
The latest figures, calculated from 2015 data, found that smoking remains the biggest preventable cause of cancer in Scotland, despite the continued decline in smoking rates.
Tobacco smoke caused around 3,200 cases of cancer in men (21 per cent of all male cancer cases) and around 2,500 (16 per cent) in women in 2015, according to the research published in the British Journal of Cancer.
Excess weight is Scotland’s biggest preventable cause of cancer after smoking. Around 2,200 (7 per cent) cases of cancer a year in Scotland – around six a day – are down to being overweight or obese. This amounts to around 1,200 (8 per cent) cases of cancer in women and around 910 (6 per cent) in men.
Obesity causes 13 types of cancer, including bowel, breast, womb and kidney. The results suggested that more than one in 20 cancer cases could be prevented by maintaining a healthy weight.
In recent weeks, Cancer Research UK has been running a campaign across the UK featuring posters and radio adverts to increase awareness that obesity can cause cancer.
The charity has renewed its call to the Scottish Government to introduce legislation to restrict bargain buy special offers on junk food.
Professor Linda Bauld, Cancer Research UK’s prevention expert, based at the University of Stirling, said: “These research findings are startling in that, for the first time, we can see how many cases of cancer in Scotland could be prevented by things like not smoking and keeping to a healthy weight.
“With smoking rates continuing to decline, carrying excess weight is the biggest public health threat on the horizon. This alarming number of weight-related cancer cases poses a huge challenge.
“With a higher proportion of weight-related cancers in Scotland than anywhere else in the UK, it’s clear that strong action is needed. As part of its expected diet and obesity strategy, the Scottish Government must tackle what is the biggest preventable health crisis of our generation and make a real difference to the future of everyone in Scotland.”
The third biggest preventable cause of cancer in Scotland is infections, which cause around 1,400 cases of cancer a year (5 per cent of all cancer cases). Most of these cases are linked to strains of human papilloma virus, or HPV (including cervical cancer), and Helicobacter pylori, which attacks the stomach.
Scottish Labour’s health spokesman Anas Sarwar MSP said: “This … highlights the challenge of defeating cancer, which remains Scotland’s biggest killer.
“We know the link between smoking and obesity with cancer rates and health outcomes. This is why we need to see a bold and ambitious obesity strategy in Scotland.
“Labour has already made clear its support for tougher action on advertising, labelling, multi-buys and portion sizes. There is also a clear link with poverty, which is increasing … Labour would use the powers of the Scottish Parliament to end SNP and Tory austerity, to invest in our communities and to create high-wage, high-skill jobs that would tackle poverty.”