Daily Diet Soft Drinks Linked to Higher Heart Attack & Stroke Risk, New Study Finds

By Editor, on February 29th, 2012

A new study published in the Journal of General Internal Medicine has found that older adults who drank daily diet soft drinks were 43 percent more likely to suffer a heart attack or stroke over a ten-year period than those who did not consume diet soft drinks.

The study did not prove that diet soft drinks directly caused the higher risk, but the association between daily diet soft drink consumption and higher heart attack and stroke risk held even after controlling for other known coronary risk factors.

According to the authors, the new study was one of the first to examine the association between diet soft drink consumption and risk of all vascular events, including heart attack and stroke.

The new study, by lead researcher Hannah Gardener of the University of Miami Miller School of Medicine and colleagues, was published online in the January 27, 2012 issue of the Journal of General Internal Medicine.

The Study; Methodology

“[T]he primary objective of this study is to examine the relationship between diet and regular soft drink consumption and risk for stroke, myocardial infarction (MI) [heart attack], and vascular death in a multi-ethnic population-based cohort,” the authors wrote in an introduction to the new study.

The study included 2,564 adults in New York City who were, on average, 69 years old (plus or minus 10 years) at the beginning of the study. The study participants were of diverse race and ethnicity, with 20% being white, 23% black and 53% Hispanic. Sixty-four percent of the participants were women, and 36% were men.

The researchers measured the participants’ consumption of diet and regular soft drinks based on a food frequency questionnaire which the participants answered at the beginning of the study. Based on their responses, the participants were categorized into three groups for each of diet soft drink consumption and regular soft drink consumption: No Soft Drinks (those who drank less than 1 per month); Light Consumption (those who drank between one per month and 6 per week), and Daily Consumption (those who drank one or more per day).

Over an average follow-up period of 10 years, 591 of the study participants had a heart attack, stroke or died of cardiovascular causes. This included 31 percent of the 163 people who drank a diet soft drink daily at the start of the study.

The researchers analyzed the data to determine the extent of any association between diet or regular soft drink consumption and suffering a heart attack, stroke or death from cardiovascular causes during the follow-up period.

Findings

After controlling for other possible risk factors, including age, sex, race/ethnicity, education, smoking, physical activity, alcohol consumption, BMI, daily calories, consumption of protein, carbohydrates, total fat, saturated fat, and sodium, the researchers found that those who drank diet soft drinks daily had a 43% higher risk of suffering a stroke, heart attack or vascular death during the 10 year follow-up period than those who drank no diet soft drinks.

This association held even after controlling for further known cardiac risk conditions, including “metabolic syndrome, peripheral vascular disease, diabetes, cardiac disease, hypertension, and hypercholesterolemia,” the researchers reported.

However, “there was no increased risk of vascular events associated with regular soft drinks or light diet soft drink consumption,” the study authors reported.

Conclusions and Implications

“Daily diet soft drink consumption was associated with several vascular risk factors and with an increased risk for vascular events,” the researchers concluded. However, “Further research is needed before any conclusions can be made regarding the potential health consequences of diet soft drink consumption,” they cautioned.

Lead author Hannah Gardener, an epidemiologist at the University of Miami Miller School of Medicine, explained to Reuters that while the study did find this association, it did not establish actual causation of increased cardiovascular risk by diet soft drinks, nor did it explain how diet soft drinks may contribute to increased cardiovascular risk, if they do.

There may be other characteristics of those who drink diet soft drinks daily that explain the connection, she suggested. “What we saw was an association. These people may tend to have more unhealthy habits,” Ms. Gardner said.

She noted that she and her colleagues did in fact find that the daily diet-soda drinkers tended to be heavier and more often have heart risk factors such as high blood pressure, diabetes and unhealthy cholesterol levels, factors which the researchers accounted for in deriving their findings.

The lead author emphasized that further research is needed to confirm an association between diet soft drinks and cardiovascular risk and to explain how and why diet sodas may impact heart health.

Meanwhile, “The message for diet soft drink drinkers is not to be alarmed,” Ms. Gardener told The New York Times. “What we’ve found is an association, and it might be due to chance or other unmeasured variables.”

However, she added that if people stop drinking diet soft drinks, they “are not going to be missing out on any important vitamins or minerals.”

More Information

The new study, “Diet Soft Drink Consumption is Associated with an Increased Risk of Vascular Events in the Northern Manhattan Study,” can be found in its entirety in the January 27, 2012 issue of the Journal of General Internal Medicine

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