Table 3.
Strength training and risk of type 2 diabetes according to potential risk factors for type 2 diabetes
| No. cases | Person-years | No strength training | Engaging in strength training | P for interaction‡ | |
|---|---|---|---|---|---|
| Adjusted HR† (95% CI) | |||||
| Age (years) | |||||
| ≥50 | 807 | 41,043 | 1.00 (reference) | 0.45 (0.25–0.83) | 0.21 |
| <50 | 963 | 98,705 | 1.00 (reference) | 0.79 (0.55–1.15) | |
| Sex | |||||
| Male | 1,654 | 122,730 | 1.00 (reference) | 0.64 (0.46–0.89) | 0.53 |
| Female | 116 | 17,018 | 1.00 (reference) | 0.99 (0.30–3.24) | |
| BMI (kg/m2) | |||||
| ≥25 | 891 | 37,422 | 1.00 (reference) | 0.58 (0.36–0.95) | 0.56 |
| <25 | 879 | 102,326 | 1.00 (reference) | 0.83 (0.54–1.25) | |
| Smoking | |||||
| Smoker | 863 | 59,856 | 1.00 (reference) | 0.67 (0.40–1.12) | 0.70 |
| Non-smoker | 907 | 79,892 | 1.00 (reference) | 0.67 (0.45–1.05) | |
| Aerobic exercise | |||||
| None or low | 1,400 | 108,344 | 1.00 (reference) | 0.64 (0.40, 1.04) | 0.98 |
| Moderate or high | 370 | 31,404 | 1.00 (reference) | 0.68 (0.45, 1.03) | |
| Occupational PA | |||||
| Sedentary | 1,063 | 84,274 | 1.00 (reference) | 0.73 (0.50, 0.94) | 0.34 |
| Non-sedentary | 707 | 55,474 | 1.00 (reference) | 0.51 (0.28, 0.99) | |
| Shift work | |||||
| Shift worker | 317 | 26,943 | 1.00 (reference) | 0.55 (0.24, 1.25) | 0.58 |
| Non-shift worker | 1,453 | 112,805 | 1.00 (reference) | 0.69 (0.49, 0.97) | |
| Family history of DM | |||||
| Presence | 412 | 19,023 | 1.00 (reference) | 0.55 (0.27, 1.12) | 0.56 |
| Absence | 1,358 | 120,726 | 1.00 (reference) | 0.70 (0.49, 0.99) | |
†Adjusted for age, sex, smoking status (non-smoker or current smoker consuming 1–10, 11–20 or ≥21 cigarettes per day), alcohol consumption (non-drinker or drinker consuming <1, 1 to <2, or ≥2 go of Japanese sake equivalent per day, 1 go of Japanese sake contains approximately 23 g of ethanol), sleep duration (<5, 5 to <6, 6 to <7 or ≥7 h per day), aerobic exercise (none, low, moderate or high), hypertension (presence or absence), shift work (yes or no), occupational physical activity (mostly sitting, mostly standing, walking often or fairly active) and family history of diabetes (presence or absence). ‡Calculated using a likelihood ratio test comparing models with and without interaction terms between strength training and the potential risk factors for type 2 diabetes. BMI, body mass index; CI, confidence interval; DM, diabetes mellitus; HR, hazard ratio; PA, physical activity.