Objective: The purpose of this article was to examine the risk of cancer mortality across levels of fitness and to examine the fitness-mortality relation for site-specific cancers in men with pre-diabetes and diabetes.
Research design and methods: We examined the fitness-mortality relation for all-cause and site-specific cancer mortality among 18,858 men with pre-diabetes and 2,805 men with diabetes (aged 46.3 +/- 9.7 years [mean +/- SD]) from the Aerobics Center Longitudinal Study. We identified 719 cancer deaths during 354,558 person-years of risk. The duration of follow-up was 16.4 +/- 7.8 years (range <1-30.0 years).
Results: In men with pre-diabetes, moderate (hazard ratio 0.71 [95% CI 0.57-0.88]) and high fitness (0.76 [0.60-0.96]) were associated with lower risks of cancer mortality compared with the low-fit group in a model adjusted for age, examination year, smoking, alcohol use, fasting glucose concentration, previous cancer, and BMI. Similarly, for individuals with diabetes, moderate (0.53 [0.35-0.82]) and high fitness (0.44 [0.26-0.73]) were associated with lower risks of cancer mortality compared with the low-fit group. Among all men, being fit was associated with a lower risk of mortality from gastrointestinal (0.55 [0.39-0.77]), colorectal (0.53 [0.30-0.96]), liver (0.22 [0.07-0.71]), and lung cancer (0.43 [0.30-0.60]).
Conclusions: In men with pre-diabetes and diabetes, higher levels of cardiorespiratory fitness were associated with lower risk of cancer mortality, particularly as a result of cancers of the gastrointestinal tract, compared with those who had low levels of fitness.