Table 2—

Intake of vitamin D and risk of type 2 diabetes in the Nurses Health Study

Total vitamin D intake (IU/day)
≤200201–400401–600601–800> 800P for trend
No. of new cases of diabetes1,7801,812832313106
Follow-up person-years603,041553,325271,764107,17445,653
RR (95% CI)
    Age adjusted1.000.94 (0.88–1.00)0.87 (0.80–0.94)0.86 (0.76–0.97)0.74 (0.61–0.91)<0.001
    Multivariate without diet*1.000.93 (0.87–0.99)0.93 (0.86–1.01)0.89 (0.79–1.01)0.77 (0.63–0.94)0.002
    Multivariate with diet1.000.97 (0.89–1.05)0.99 (0.88–1.10)0.94 (0.81–1.10)0.80 (0.64–1.00)0.15
    Multivariate with diet + calcium1.001.00 (0.93–1.10)1.05 (0.93–1.18)1.01 (0.86–1.19)0.87 (0.69–1.09)0.67
Dietary vitamin D intake (IU/day)
≤100101–200201–300301–400>400P for trend
No. of new cases of diabetes8292031125735080
Follow-up person-years299,091670,048371,830109,93829,595
RR (95%CI)
    Age adjusted1.000.92 (0.85–1.00)0.98 (0.89–1.07)0.95 (0.84–1.08)0.91 (0.72–1.14)0.80
    Multivariate without diet*1.000.86 (0.80–0.94)0.89 (0.81–0.97)0.82 (0.73–0.94)0.81 (0.64–1.01)0.01
    Multivariate with diet1.000.90 (0.83–0.98)0.98 (0.89–1.08)0.93 (0.81–1.01)0.91 (0.72–1.16)0.86
    Multivariate with diet + calcium1.000.94 (0.85–1.03)1.06 (0.95–1.18)1.02 (0.88–1.19)1.00 (0.78–1.29)0.25
Supplemental vitamin D intake (IU/day)§
≤100101–200201–300301–400>400P for trend
No. of new cases of diabetes2,956678497347365
Follow-up person-years947,379206,980155,352125,792145,455
RR (95% CI)
    Age adjusted1.000.87 (0.80–0.95)0.88 (0.80–0.97)0.81 (0.72–0.90)0.79 (0.71–0.88)<0.001
    Multivariate without diet*1.000.92 (0.84–1.00)0.97 (0.89–1.07)0.90 (0.81–1.01)0.88 (0.79–0.98)0.007
    Multivariate without diet1.000.91 (83–1.00)0.96 (0.85–1.07)0.88 (0.76–1.00)0.84 (0.73–0.97)0.01
    Multivariate with diet + calcium1.000.92 (0.84–1.01)0.97 (0.87–1.09)0.90 (0.78–1.03)0.87 (0.75–1.00)0.04
  • * RR adjusted for age, BMI, hypertension, family history of diabetes, smoking, physical activity, caffeine, alcohol, and state of residence (southern states [California, Florida, and Texas] or northern states [Connecticut, Maryland, Massachusetts, Michigan, New Jersey, New York, Ohio, and Pennsylvania]).

  • RR adjusted for everything in footnote ∗ plus type of fat (saturated, polyunsaturated, or trans), cereal fiber, glycemic load, magnesium, and retinol.

  • Women who were specific vitamin D supplement users were excluded at baseline and during follow-up (2,058 at baseline, 8,745 during follow-up). The entire analysis for supplemental vitamin D was also adjusted for multivitamin use (yes or no).

  • § The entire analysis was adjusted for multivitamin use (yes or no) and dietary vitamin D intake.