The Impact of Fatigue on Health, Function, and Survival Between Ages 70 and 100

Although fatigue is common with aging, its association with health outcomes throughout the entire aging life span have been poorly described. This longitudinal study aimed to examine the trajectory of fatigue between ages 70 and 100, and its long-term impact on health, function, and survival.

The Jerusalem Longitudinal Study is a prospective longitudinal cohort study, spanning 1990 to 2022.

A representative sample of community-dwelling Jerusalem residents, born 1920-1921, examined at ages 70, 78, 85, 90, 95, and 100 (n = 604, 1024, 1222, 729, 508, and 205, respectively).

Comprehensive assessment included fatigue and various medical, functional, cognitive and social variables. Risk of fatigue for different outcomes, including health, function, and mortality, was analyzed using multivariate logistic and Cox proportional hazards models adjusting for known risk factors.

At ages 70, 78, 85, 90, 95, and 100, the prevalence of fatigue was 29.4%, 52.3%, 67.9%, 77.2%, 64.9%, and 65.6%. Between age 70 and 100, fatigue was significantly associated with numerous cross-sectional health and functional measures, and subsequent deterioration for loneliness, self-rated health, dependence in activities of daily living, and physical activity. In contrast, no consistent pattern of association with current or subsequent common medical morbidities was observed. Significantly decreased survival rates were observed among fatigued vs nonfatigued subjects at ages 70-78, 78-85, 85-90, and 90-95: 69.6% vs 80.8% (P = .008), 64.9% vs 73.3% (P = .002), 60.6% vs 76.4% (P < .001), and 51.3% vs 65.0% (P = .007), respectively, yet not at ages 95-100: 21.7% vs 18.8% (P = .99). After adjusting for known mortality risk factors, fatigue at ages 70, 85, and 90 was associated with increased mortality.

Our findings highlight the clinical importance of recognizing fatigue throughout the entire aging life span as an independent marker for subsequent negative health outcomes and mortality. Although fatigue might serve as a surrogate for intrinsic capacity, it remains unclear if fatigue is amenable to intervention.