Introduction:
There is still little evidence on the dose-response relation between leisure-time running and incident type 2 diabetes (T2D).
Hypothesis:
We examined the hypothesis that running reduces the risk of developing T2D.
Methods:
Participants were 19,347 adults aged 18 to 100 years (mean age, 44) who received an extensive preventive medical examination during 1974-2006 in the Aerobics Center Longitudinal Study. Participants were free of cardiovascular disease, cancer, and T2D at baseline. Running and other physical activities were assessed on the medical history questionnaire by self-reported leisure-time activities during the past 3 months. We defined T2D as fasting glucose ≥126 mg/dl, insulin use, or physician-diagnosis during follow-up medical examinations. Cox regression was used to quantify the association between running and T2D after adjusting for baseline age, sex, examination year, body mass index, smoking status, heavy alcohol drinking, abnormal electrocardiogram, hypertension, hypercholesterolemia, and levels of other physical activities.
Results:
During an average follow-up of 6.5 years, 1,015 adults developed T2D. Approximately 30% of adults participated in leisure-time running. Runners had a 29% lower risk of developing T2D compared with non-runners. The hazard ratios (95% confidence intervals) of T2D were 0.97 (0.74-1.27), 0.66 (0.49-0.89), 0.62 (0.45-0.85), 0.78 (0.58-1.03), and 0.57 (0.42-0.79) across quintiles (Q) of running time (minutes/week); 0.99 (0.76-1.30), 0.60 (0.44-0.82), 0.72 (0.55-0.94), 0.65 (0.47-0.90), and 0.63 (0.47-0.86) across Q of running distance (miles/week); 1.08 (0.83-1.40), 0.67 (0.50-0.90), 0.70 (0.53-0.93), 0.61 (0.45-0.83), and 0.53 (0.36-0.76) across Q of running frequency (times/week); 0.95 (0.73-1.24), 0.70 (0.52-0.94), 0.62 (0.45-0.84), 0.73 (0.55-0.97), and 0.58 (0.42-0.80) across Q of total amount of running (MET-minutes/week); and 0.95 (0.71-1.28), 0.76 (0.59-0.99), 0.59 (0.42-0.83), 0.66 (0.51-0.85), and 0.62 (0.43-0.90) across Q of running speed (mph), respectively, compared with no running after adjusting for confounders including levels of other physical activities.
Conclusions:
Participating in leisure-time running is associated with markedly lower risk of developing T2D in adults. Except for those in the very lowest Q for running doses, even relatively low running doses (starting with Q 2) were associated with marked reductions in T2D risk over time, supporting the prescription of running to reduce T2D.