Table 2

Univariable and adjusted HRs (95% CI) for the association between intake of protein, in quartiles and per 10 g, and incident type 2 diabetes

Quartile 1 (low)Quartile 2Quartile 3Quartile 4 (high)PtrendPer 10 g
Total protein
    Cases/at risk (n)153/9,523185/9,524249/9,524331/9,523
    Quartile median total protein (g/day)64727988
    Univariable11.20 (0.97–1.49)1.63 (1.33–1.99)*2.15 (1.77–2.60)*<0.0011.36 (1.28–1.44)*
    Model 1†: age and sex11.17 (0.94–1.45)1.50 (1.23–1.84)*1.85 (1.53–1.25)*<0.0011.28 (1.22–1.36)*
    Model 2‡: model 1 + dietary intake11.24 (0.99–1.54)1.65 (1.32–2.07)*2.16 (1.69–2.76)*<0.0011.45 (1.34–1.56)*
    Model 3§: model 2 + diabetes risk factors11.16 (0.92–1.45)1.45 (1.15–1.83)*1.67 (1.29–2.16)*<0.0011.33 (1.22–1.45)*
    Model 4‖: model 3 + waist and BMI11.03 (0.82–1.29)1.20 (0.95–1.51)1.18 (0.91–1.53)0.151.16 (1.06–1.26)¶
Animal protein
    Cases/at risk (n)155/9,523182/9,524243/9,524338/9,523
    Quartile median animal protein (g/day)35445262
    Univariable11.16 (0.94–1.44)1.56 (1.28–1.91)*2.18 (1.80–2.63)*<0.0011.32 (1.25–1.39)*
    Model 1†: age and sex11.08 (0.87–1.33)1.35 (1.10–1.65)¶1.73 (1.43–2.10)*<0.0011.24 (1.17–1.30)*
    Model 2‡: model 1 + dietary intake11.17 (0.94–1.46)1.54 (1.23–1.92)*2.09 (1.64–2.67)*<0.0011.40 (1.30–1.51)*
    Model 3§: model 2 + diabetes risk factors11.09 (0.87–1.36)1.31 (1.05–1.65)¶1.58 (1.23–2.04)*<0.0011.28 (1.18–1.39)*
    Model 4‖: model 3 + waist and BMI10.99 (0.79–1.23)1.11 (0.89–1.40)1.14 (0.88–1.47)0.221.13 (1.04–1.22)¶
Vegetable protein
    Cases/at risk (n)245/9,524228/9,524235/9,523210/9,523
    Quartile median vegetable protein (g/day)22262933
    Univariable10.92 (0.76–1.10)0.95 (0.79–1.13)0.84 (0.70–1.01)0.100.87 (0.76–0.99)¶
    Model 1†: age and sex10.94 (0.79–1.13)1.02 (0.85–1.22)1.02 (0.85–1.23)0.641.01 (0.88–1.15)
    Model 2‡: model 1 + dietary intake10.89 (0.73–1.08)0.96 (0.77–1.19)0.91 (0.70–1.19)0.630.85 (0.69–1.06)
    Model 3§: model 2 + diabetes risk factors10.95 (0.78–1.16)1.03 (0.83–1.27)1.05 (0.80–1.37)0.630.97 (0.78–1.20)
    Model 4‖: model 3 + waist and BMI10.99 (0.82–1.21)1.11 (0.89–1.38)1.15 (0.88–1.50)0.231.04 (0.83–1.29)
  • Data are HRs (95% CI).

  • *Significant at P < 0.001 level.

  • †Model 1: Corrected for sex (male or female) and age at recruitment (continuous).

  • ‡Model 2: model 1 + energy-adjusted intake of saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, vitamin E, magnesium, fiber, and glycemic load (continuous).

  • §Model 3: model 2 + energy-adjusted alcohol consumption (<11, 11–25, 26–50, or >50 g/day), physical activity (not active, moderately inactive, moderately active, or active), mean systolic and diastolic blood pressure (continuous), education level (high, middle, or low), and parental history of diabetes (no, one parent, or both parents).

  • ‖Model 4: model 3 + BMI (<20, 20–25 [reference group], 25–30, or >30 kg/m2), and waist circumference (continuous).

  • ¶Significant at P < 0.05 level.