The study shows that increasing diet soda intake is directly linked to greater abdominal obesity in adults 65 years of age and older.
Findings raise concerns about the safety of chronic diet soda consumption, which may increase belly fat and contribute to greater risk of metabolic syndrome and cardiovascular diseases, researchers said.
Metabolic syndrome - a combination of risk factors that may lead to high blood pressure, diabetes, heart disease and stroke - is one of the results of the obesity epidemic.
"Our study seeks to fill the age gap by exploring the adverse health effects of diet soda intake in individuals 65 years of age and older," said lead author Sharon Fowler, from the University of Texas Health Science Centre at San Antonio.
"The burden of metabolic syndrome and cardiovascular disease, along with health-care costs, is great in the ever-increasing senior population," said Fowler.
The San Antonio Longitudinal Study of Ageing (SALSA) enrolled 749 Mexican- and European-Americans who were aged 65 and older at the start of the study (1992-96).
Findings indicate that the increase in waist circumference among diet soda drinkers, per follow-up interval, was almost triple that among non-users: 2.11 cm versus 0.77 cm, respectively.
After adjustment for multiple potential confounders, interval waist circumference increases were 0.77 cm for non-users, 1.76 cm for occasional users, and 3.04 cm for daily users.
This translates to waist circumference increases of 0.80 inches for non-users, 1.83 inches for occasional users, and 3.16 inches for daily users over the total 9.4-year SALSA follow-up period.
The study was published in the Journal of the American Geriatrics Society.
