While the study cannot prove soft drinks are a driver of an increased risk of death, the researchers say the work – which is the largest study of its kind – supports recent public health efforts to reduce consumption of soft drinks, such as the UK’s sugar tax.
“Our results for sugar-sweetened soft drinks provide further support to limit consumption and to replace them with other healthier beverages, preferably water,” said Dr Neil Murphy, a co-author of the research from the International Agency for Research on Cancer, part of the World Health Organisation.
Published in the journal Jama Internal Medicine, it also said that more research was needed to unpick possible mechanisms by which artificial sweeteners might affect health.
The British Soft Drinks Association said that the study does not provide evidence that soft drinks are the cause.
Gavin Partington, British Soft Drinks Association director general, said: "This study does not provide evidence of cause, as the authors readily admit.
“Soft drinks are safe to consume as part of a balanced diet. The soft drinks industry recognises it has a role to play in helping to tackle obesity which is why we have led the way in calorie and sugar reduction.
“Soft drinks is the only category to have already hit Public Health England’s calorie-reduction target of 20% by 2020, and Kantar Worldpanel data shows overall sugar intake from soft drinks was down by 30.4% between May 2015 and May 2019.
“According to all leading health authorities in the world, as well as Cancer Research UK and Diabetes UK, low- and no-calorie sweeteners are safe.”
The study analysed data from more than 450,000 people, 70% of whom were women, across 10 European countries including the UK.
Participants had an average age of just over 50, and those with health conditions such as cancer, heart disease or diabetes at the outset were not included in the analysis.
Individuals joined the study between 1992 and 2000 and were then followed up for an average of 16 years, during which time more than 41,600 deaths were recorded.
The results showed that 9.3% of those who drank less than one glass of soft drink a month died during the study, compared with 11.5% of those who drank two or more 250ml glasses a day.
The team say that once factors such as body mass index, diet, physical activity, smoking and education were taken into account, which translateed to a 17% higher risk of death among those consuming two glasses a day compared with those drinking less than one glass a month.
The trend was seen for both sugar-sweetened and artificially sweetened beverages. Similar results were seen for both men and women.