TABLE 3

Linear Regression for Log (25OHD)

CharacteristicTotal SubjectsaSimple RegressionMultiple Regression
Percent Difference in 25OHD Concentration (95% CI)PPercent Difference in 25OHD Level (95% CI)P
Diagnosis
    CD94ReferenceReference
    UC3619.5 (−3.1 to 47.2).108.9 (−11.9 to 34.6).43
Age−1.6 (−4.4 to 1.2).25
Gender
    Male67Reference
    Female636.2 (−12.1 to 28.2).53
Ethnicity
    White12052.6 (7.8 to 116.0).0252.5 (8.0 to 115.3).02
    Other10ReferenceReference
Season
    Winter38−33.4 (−45.2 to −19.0)<.001−31.4 (−44.0 to −16.1)<.001
    Other92ReferenceReference
Vitamin D supplementationb
    Yes9931.5 (5.2 to 64.4).024.8 (−16.1 to 31.0).67
    No29ReferenceReference
zHt1257.8 (−1.9 to 18.4).12
zWt1299.1 (1.2 to 17.5).02
zBMI1258.6 (0.3 to 17.6).041.8 (−6.2 to 10.3).67
Disease duration, per y1293.1 (−0.3 to 6.7).082.9 (−0.8 to 6.8).13
Lifetime steroids, per 1000 mg129−0.6 (−2.3 to 1.2).50−1.2 (−3.1 to 0.6).19
Resection
    Yes13−6.8 (−32.0 to 27.6).66−0.3 (−27.2 to 36.6).98
    No116ReferenceReference
Albumin46.8 (26.0 to 71.1)<.00132.6 (8.5 to 62.0).01
ESR128−0.7 (−1.2 to −0.1).010.0 (−0.6 to 0.6).97
Hematocrit0.1 (−2.3 to 2.6).93
  • a Where applicable, when N not specified, assume 130.

  • b Refers to intake of any form of vitamin D supplement including multivitamins at any time during the 3 months before the 25OHD measurement and not to dietary vitamin D intake. Subjects who reported taking vitamin D supplements were taking between 400 and 800 IU of vitamin D per day in addition to dietary vitamin D.