Longitudinal Associations Between Changes in Physical Activity and Onset of Type 2 Diabetes in Older British Men

OBJECTIVE-To determine how much physical activity (PA) is needed to protect against diabetes onset in older adults, whether protection is greater among overweight individuals, and whether taking up moderate activity in later life is beneficial. RESEARCH DESIGN AND METHODS-Men (4,252) from a U.K. population-based cohort self-reported usual PA (regular walking and cycling, recreational activity, and sport) in 1996 and in 1998-2000, alongside other health behaviors and medical history. Fasting blood lipids were measured. Median follow-up was 7.1 years, during which 135 cases of type 2 diabetes (validated self-report) occurred. RESULTS-Among 3,012 men free from cardiovascular disease and diabetes in 1998-2000, 9% reported no usual leisure-time PA, 23% occasional PA, and 15% vigorous PA. Compared with men reporting no activity, men reporting occasional, light, moderate, moderately vigorous, and vigorous PA had lower diabetes risks: hazard ratio (HR) 0.58 (95% CI 0.33-1.02), 0.39 (0.20-0.74), 0.38 (0.19-0.73), 0.39 (0.20-0.77), and 0.33 (0.16-0.70), respectively; P (trend) = 0.002, adjusted for age, social class, tobacco, alcohol, diet, and blood lipids. Adjustment for BMI, waist circumference, or fasting insulin attenuated HRs. HRs were stronger in men with BMI >= 28 vs. <28 kg/m(2) (interaction P = 0.02). Compared with men reporting light activity or less in 1996 and 2000, men who became at least moderately active by 2000 or remained at least moderately active at both times had adjusted HRs of 0.62 (0.34-1.12) and 0.51 (0.31-0.82), respectively. CONCLUSIONS-Even light PA markedly reduced diabetes risk in older men, especially among the overweight or obese. Taking up or maintaining at least moderate PA in older adulthood strongly protected against diabetes.