Diet Soda Intake Is Associated with Long-Term Increases in Waist Circumference in a Biethnic Cohort of Older Adults: The San Antonio Longitudinal Study of Aging

ObjectivesTo examine the relationship between diet soda (DS) intake (DSI) and long-term waist circumference (WC) change (WC) in the biethnic San Antonio Longitudinal Study of Aging (SALSA). DesignProspective cohort study. SettingSan Antonio, Texas, neighborhoods. ParticipantsSALSA examined 749 Mexican-American and European-American individuals aged 65 and older at baseline (baseline, 1992-96); 474 (79.1%) survivors completed follow-up 1 (FU1, 2000-01), 413 (73.4%) completed FU2 (2001-03), and 375 (71.0%) completed FU3 (2003-04). Participants completed a mean of 2.64 follow-up intervals, for 9.4 total follow-up years. MeasurementsDSI, WC, height, and weight were measured at outset and at the conclusion of each interval: baseline, FU1, FU2, and FU3. ResultsAdjusted for initial WC, demographic characteristics, physical activity, diabetes mellitus, and smoking, mean interval WC of DS users (2.11cm, 95% confidence interval (CI)=1.45-2.76cm) was almost triple that of nonusers (0.77cm, 95% CI=0.29-1.23cm) (P<.001). Adjusted interval WCs were 0.77cm (95% CI=0.29-1.23cm) for nonusers, 1.76cm (95% CI=0.96-2.57cm) for occasional users, and 3.04cm (95% CI=1.82-4.26cm) for daily users (P=.002 for trend). This translates to WCs of 0.80 inches for nonusers, 1.83 inches for occasional users, and 3.16 for daily users over the total SALSA follow-up. In subanalyses stratified for selected covariates, WC point estimates were consistently higher in DS users. ConclusionIn a striking dose-response relationship, increasing DSI was associated with escalating abdominal obesity, a potential pathway for cardiometabolic risk in this aging population.