| NHS cases | Person-years | Age-adjusted RR (95% CI) | Multivariable RR (95% CI)† | NHSII cases | Person-years | Age-adjusted RR (95% CI) | Multivariable RR (95% CI)† | NHS and NHSII pooled MV RR‡ | |||
| Total vitamin D intake (IU/day)* | |||||||||||
| Quintile 1 | 20 | 362 228 | 1.0 (Ref.) | 1.0 (Ref.) | 13 | 221 374 | 1.0 (Ref.) | 1.0 (Ref.) | 1.0 (Ref.) | ||
| Quintile 2 | 25 | 364 092 | 1.3 (0.7, 2.3) | 1.4 (0.8, 2.6) | 19 | 221 363 | 1.5 (0.7, 3.0) | 1.6 (0.8, 3.4) | 1.5 (0.9, 2.5) | ||
| Quintile 3 | 23 | 362 938 | 1.2 (0.7, 2.1) | 1.3 (0.7, 2.5) | 12 | 222 826 | 0.9 (0.4, 2.0) | 1.0 (0.4, 2.2) | 1.2 (0.7, 2.1) | ||
| Quintile 4 | 23 | 360 426 | 1.2 (0.7, 2.2) | 1.3 (0.7, 2.4) | 14 | 222 518 | 1.0 (0.5, 2.2) | 1.2 (0.5, 2.6) | 1.3 (0.8, 2.2) | ||
| Quintile 5 | 27 | 353 521 | 1.4 (0.8, 2.6) | 1.7 (0.9, 3.0) | 14 | 220 616 | 1.4 (0.6, 3.2) | 1.2 (0.6, 2.7) | 1.4 (0.8, 2.3) | ||
| p for trend¶ | 0.2 | 0.2 | 0.9 | 0.9 | 0.3 | ||||||
| Vitamin D intake from supplements only (IU/day)§ | |||||||||||
| 0 | 64 | 865 504 | 1.0 (Ref.) | 1.0 (Ref.) | 29 | 491299 | 1.0 (Ref.) | 1.0 (Ref.) | 1.0 (Ref.) | ||
| 1–199 | 21 | 422 110 | 0.8 (0.5, 1.3) | 0.8 (0.5, 1.4) | 18 | 225856 | 1.4 (0.8, 2.6) | 1.5 (0.8, 2.8) | 1.1 (0.6, 2.0) | ||
| 200-399 | 18 | 318 718 | 0.9 (0.5, 1.5) | 0.9 (0.5, 1.6) | 13 | 218875 | 1.0 (0.6, 2.0) | 1.0 (0.5, 2.0) | 1.0 (0.6, 1.5) | ||
| >400 | 15 | 196 287 | 1.1 (0.6, 1.9) | 1.1 (0.6, 1.9) | 12 | 172667 | 1.2 (0.6, 2.3) | 1.4 (0.7, 2.7) | 1.2 (0.8, 1.8) | ||
| p for trend¶ | 0.9 | 1.0 | 0.7 | 0.6 | 0.7 | ||||||
*Cumulative average of vitamin D intake from food and supplements.
NHS quintile cut-offs: 1 = 2–160.3; 2 = >160.25–234.4; 3 = >234.4–333.6; 4 = >333.6–489.1; 5 = >489.1–3964.8.
NHSII quintile cut-offs: 1 = 3–187.9; 2 = >187.9–280.9; 3 = >280.9–392.0; 4 = >392.0–558.7; 5 = >558.7–5203.0.
†Multivariable model adjusted for: age at menarche, oral contraceptive use, menopausal status, postmenopausal hormone use, cigarette smoking, latitude of residence at age 15 (north, middle or south USA), physical activity in metabolic equivalent hours per week, BMI (kg/m2) and race.
‡Risk estimates pooled using Dersimonian and Laird random effects model. p heterogeneity for all models <0.05.
§Also adjusted for vitamin D intake from food in multivariable models.
¶p for trend is from the midpoint of the categories in both age-adjusted and multivariable models.
NHS, Nurses' Health Study; NHSII, Nurses' Health Study II.