Associations among cardiorespiratory fitness (thus referred to as “fitness”), adiposity, and mortality in older adults have not been adequately examined.
To examine these associations, we report on a 12-year follow-up of adults ages 60 years and older, in whom fitness was assessed by a maximal exercise test and adiposity was assessed by body mass index (BMI), waist circumference (WC), and percent body fat.
Design, Setting, and Patients
2603 adults (age 64.4±4.8 yr; 19.8% women) completed a baseline health examination at the Cooper Clinic during 1979-2001. Low fitness was defined as the lowest fifth of the gender-specific distribution of maximal treadmill exercise test duration. The distributions of BMI, WC, and percent body fat were grouped for analysis according to clinical guidelines.
Main Outcome Measures
There were 450 deaths during an average follow-up of 12 years and 31 236 person-years of exposure. Death rates per 1000 person-years, adjusted for age, gender, and examination year were: 13.9, 13.3, 18.3, and 31.8 across BMI groups of 18.5-24.9, 25.0-29.9, 30.0-34.9, and ≥35 kg/m2, respectively (trend P=.01); 13.3 and 18.2 for normal and high WC (≥102 cm in men; ≥88 cm in women), respectively (P=.004); 13.7 and 14.6 for normal and high percent body fat (≥25% in men; ≥30% in women), respectively (P=.51); and 32.6, 16.6, 12.8, 12.3 and 8.1 across incremental fifths of fitness, respectively (P<.001). The association between WC and mortality persisted after further adjustment for smoking, baseline health status, and BMI (P=.02), but not after additional adjustment for fitness (P=.86). Fitness predicted mortality risk after further adjustment for smoking, baseline health, and either WC, BMI or percent body fat (P<.001).
Fitness is a significant mortality predictor in older adults independent of overall or abdominal adiposity. Practitioners should consider the importance of preserving functional capacity, by recommending regular physical activity for older individuals, normal weight and overweight alike.