The study – published in Journal of General Internal Medicine – investigated the potential link between daily consumption of soft drinks and the risk of vascular events such as heart attack and stroke. The researchers found that individuals who drink diet soft drinks on a daily basis could be at a 43% increased risk of such vascular events, but found no increase in risk for consumption of ‘regular’ soft drinks.
"Our results suggest a potential association between daily diet soft drink consumption and vascular outcomes. However, the mechanisms by which soft drinks may affect vascular events are unclear,” said lead researcher Hannah Gardener of the Columbia University Medical Center, USA.
However the British Soft Drinks Association (BSDA) responded, warning that “we should be cautious in drawing lessons” from the study because it does not take important risk factors including family histories or weight gain into consideration.
“It [also] conflicts with a very well-established idea that the consumption of diet drinks as part of a calorie-controlled diet can help reduce obesity and thus reduce the incidence of strokes,” said the BSDA.
Gardener said that further research in the area is needed “before any conclusions can be drawn regarding the potential health consequences of diet soft drink consumption."
Rising rates of obesity in recent decades have led to artificially sweetened soft drinks being marketed as healthier alternatives to ‘regular’ sugar-sweetened beverages – due to their lack of calories.
However, the authors noted that the long-term health consequences of drinking diet soft drinks remain unclear. They added that previous research has linked both diet and regular soft drinks with diabetes and metabolic syndrome, whilst regular soft drinks have been associated with an increased risk of coronary heart disease.
In the new study Gardener and team examined the relationship between both diet and regular soft drink consumption and risk of stroke, myocardial infarction (or heart attack), and vascular death.
The researchers analysed data from 2,564 participants who took part in the Northern Manhattan Study, which was designed to determine stroke incidence, risk factors and prognosis.
Gardener and her team looked at how often individuals drank soft drinks – both diet and regular - and correlated the information with the incidence of vascular events over a ten-year period.
They found that those who drank diet soft drinks daily were 43% more likely to have suffered a vascular event than those who drank none, after taking into account pre-existing vascular conditions such as metabolic syndrome, diabetes and high blood pressure.
In contrast, they found that regular soft drink consumption and a more moderate intake of diet soft drinks – between one a month and six a week – did not appear to be linked to a higher risk of vascular events.