Dietary sodium content, mortality, and risk for cardiovascular events in older adults: the Health, Aging, and Body Composition (Health ABC) Study

Abstract

Importance: Additional information is needed about the role of dietary sodium on health outcomes in older adults.

Objective: To examine the association between dietary sodium intake and mortality, incident cardiovascular disease (CVD), and incident heart failure (HF) in older adults.

Design, setting, and participants: We analyzed 10-year follow-up data from 2642 older adults (age range, 71-80 years) participating in a community-based, prospective cohort study (inception between April 1, 1997, and July 31, 1998).

Exposures: Dietary sodium intake at baseline was assessed by a food frequency questionnaire. We examined sodium intake as a continuous variable and as a categorical variable at the following levels: less than 1500 mg/d (291 participants [11.0%]), 1500 to 2300 mg/d (779 participants [29.5%]), and greater than 2300 mg/d (1572 participants [59.5%]).

Main outcomes and measures: Adjudicated death, incident CVD, and incident HF during 10 follow-up years. Analysis of incident CVD was restricted to 1981 participants without prevalent CVD at baseline.

Results: The mean (SD) age of participants was 73.6 (2.9) years, 51.2% were female, 61.7% were of white race, and 38.3% were black. After 10 years, 881 participants had died, 572 had developed CVD, and 398 had developed HF. In adjusted Cox proportional hazards regression models, sodium intake was not associated with mortality (hazard ratio [HR] per 1 g, 1.03; 95% CI, 0.98-1.09; P = .27). Ten-year mortality was nonsignificantly lower in the group receiving 1500 to 2300 mg/d (30.7%) than in the group receiving less than 1500 mg/d (33.8%) and the group receiving greater than 2300 mg/d (35.2%) (P = .07). Sodium intake of greater than 2300 mg/d was associated with nonsignificantly higher mortality in adjusted models (HR vs 1500-2300 mg/d, 1.15; 95% CI, 0.99-1.35; P = .07). Indexing sodium intake for caloric intake and body mass index did not materially affect the results. Adjusted HRs for mortality were 1.20 (95% CI, 0.93-1.54; P = .16) per milligram per kilocalorie and 1.11 (95% CI, 0.96-1.28; P = .17) per 100 mg/kg/m2 of daily sodium intake. In adjusted models accounting for the competing risk for death, sodium intake was not associated with risk for CVD (subHR per 1 g, 1.03; 95% CI, 0.95-1.11; P = .47) or HF (subHR per 1 g, 1.00; 95% CI, 0.92-1.08; P = .92). No consistent interactions with sex, race, or hypertensive status were observed for any outcome.

Conclusions and relevance: In older adults, food frequency questionnaire-assessed sodium intake was not associated with 10-year mortality, incident CVD, or incident HF, and consuming greater than 2300 mg/d of sodium was associated with nonsignificantly higher mortality in adjusted models.

Figure 1

Ten-year all-cause mortality in the Health ABC Study according to baseline sodium intake. The log-rank chi-square test was 5.22 with d.f. =2; P=0.074.