Table 2—

Multivariate-adjusted relative risks of incident diabetes across quintiles of dietary fat variables among 35,988 Iowa women, 1986–1992

VariableQuintile of Intake
P for trend
12345
Total dietary fat
 Median intake (g/day)55.756.160.166.886.6
 Cases332351380387440
 Relative risk* (95% CI)1.001.04 (0.88–1.21)1.01 (0.86–1.18)1.02 (0.87–1.19)1.04 (0.89–1.21)0.69
 Relative risk (95% CI)1.001.00 (0.85–1.17)0.95 (0.81–1.11)0.93 (0.79–1.10)0.89 (0.75–1.05)0.11
Saturated fatty acids
 Median intake (g/day)19.319.220.423.231.8
 Cases313342386432417
 Relative risk* (95% CI)1.001.07 (0.91–1.26)1.10 (0.94–1.30)1.16 (1.00–1.36)1.11 (0.95–1.29)0.14
 Relative risk (95% CI)1.001.05 (0.89–1.24)1.06 (0.90–1.25)1.10 (0.94–1.29)1.00 (0.85–1.18)0.91
Polyunsaturated fatty acids
 Median intake (g/day)8.99.210.412.216.6
 Cases412372369351386
 Relative risk* (95% CI)1.000.93 (0.80–1.08)0.90 (0.78–1.05)0.84 (0.73–0.98)0.87 (0.75–1.00)0.03
 Relative risk (95% CI)1.000.94 (0.81–1.08)0.91 (0.78–1.06)0.85 (0.73–0.99)0.88 (0.76–1.02)0.05
Monounsaturated fatty acids
 Median intake (g/day)20.420.922.725.733.8
 Cases336354378368454
 Relative risk* (95% CI)1.001.01 (0.86–1.18)1.05 (0.90–1.23)0.95 (0.81–1.11)1.06 (0.91–1.23)0.58
 Relative risk (95% CI)1.000.99 (0.84–1.16)1.01 (0.86–1.19)0.90 (0.76–1.06)0.96 (0.82–1.13)0.48
Long-chain ω-3 fatty acids
 Median intake (g/day)0.030.090.130.200.39
 Cases387360358345440
 Relative risk* (95% CI)1.000.97 (0.83–1.12)0.99 (0.85–1.16)0.97 (0.83–1.13)1.15 (1.00–1.33)0.02
 Relative risk (95% CI)1.000.98 (0.84–1.14)1.01 (0.87–1.18)0.99 (0.85–1.15)1.20 (1.03–1.39)0.006
Trans fatty acids
 Median intake2.22.42.83.55.2
 Cases363388379360400
 Relative risk* (95% CI)1.001.01 (0.87–1.18)0.93 (0.80–1.09)0.86 (0.74–1.01)0.88 (0.76–1.03)0.03
 Relative risk (95% CI)1.000.99 (0.85–1.15)0.90 (0.77–1.05)0.82 (0.70–0.97)0.83 (0.70–0.97)0.004
Cholesterol
 Median intake (mg/day)185201237281382
 Cases325301368402494
 Relative risk* (95% CI)1.000.87 (0.74–1.03)1.07 (0.91–1.25)1.10 (0.94–1.28)1.24 (1.07–1.43)0.0001
 Relative risk (95% CI)1.000.86 (0.73–1.01)1.04 (0.89–1.22)1.06 (0.91–1.24)1.17 (1.01–1.37)0.002
Keys score
 Median31.437.441.646.053.2
 Cases283346400422439
 Relative risk* (95% CI)1.001.14 (0.97–1.34)1.21 (1.03–1.42)1.25 (1.07–1.46)1.27 (1.08–1.49)0.002
 Relative risk (95% CI)1.001.12 (0.95–1.32)1.17 (1.00–1.37)1.19 (1.01–1.39)1.17 (0.99–1.38)0.06
Animal fat
 Median intake (g/day)29.129.833.740.456.8
 Cases317344364416449
 Relative risk* (95% CI)1.001.08 (0.92–1.27)1.08 (0.92–1.27)1.17 (1.01–1.37)1.19 (1.02–1.39)0.01
 Relative risk (95% CI)1.001.06 (0.90–1.25)1.04 (0.89–1.23)1.12 (0.95–1.31)1.09 (0.93–1.28)0.24
Vegetable fat
 Median intake (g/day)18.620.223.729.241.7
 Cases434377358349372
 Relative risk* (95% CI)1.000.88 (0.76–1.02)0.84 (0.73–0.98)0.81 (0.69–0.94)0.78 (0.68–0.91)0.0007
 Relative risk (95% CI)1.000.86 (0.76–1.03)0.85 (0.73–0.99)0.81 (0.70–0.95)0.79 (0.68–0.92)0.001
  • *

    * Proportional hazards regression models were adjusted for age, total energy, WHR (quintiles: <0.762, 0.763–0.805, 0.806–0.848, 0.849–0.901, >0.901), BMI (quintiles: <22.7, 22.7–24.8, 24.9–27.0, 27.1–30.2, >30.2), physical activity (four levels each for frequency of vigorous and moderate activity: never or rarely, a few times a year, from a few times a month to about once a week, or 2 times a week or more), cigarette smoking (none, 1–19 pack-years, 20–39 pack-years or ≥40 pack-years), alcohol consumption (none, <4 g per day, from 4–10 g per day, or ≥10 g per day), education (no high school diploma, high school diploma, college or vocational school but no degree, or college degree), marital status (currently married, never married, separated or divorced, or widowed), residential area (farm, rural or small town with population up to 2,499, town of population from 2,500–10,000 or city or town with population >10,000), and hormone replacement therapy (current, former, or never).

  • Additionally adjusted for energy-adjusted dietary magnesium (quintiles) and cereal fiber (quintiles).