Table 3. Predictors of serum 25(OH)D3 (nmol/L) expressed as percentage change per defined unit change in the explanatory variablea.
| Model 1 | Model 2 | Model 3 | Model 4 | |||||
| Adjusted for age, gender, residence, ethnicity, smoking, alcohol, socioeconomic position, BMI and supplementation | Additionally adjusted for traditional food | Additionally adjusted for season | Additionally adjusted for latitude | |||||
| (n = 1817) | (n = 1779) | (n = 1764) | (n = 1764) | |||||
| % (95% CI) | P value | % (95% CI) | P value | % (95% CI) | P value | % (95% CI) | P value | |
| Age (per year) | 2.7 (1.9; 2.3) | <0.001 | 1.9 (1.7; 2.1) | <0.001 | 2.0 (1.7; 2.2) | <0.001 | 2.0 (1.7; 2.2) | <0.001 |
| Gender | 0.100 | 0.004 | 0.010 | 0.006 | ||||
| Male | ref | ref | ref | ref | ||||
| Female | 4.4 (−0.8; 10.0) | 7.8 (2.4; 13.4) | 6.6 (1.5; 12.0) | 7.1 (2.0; 12.5) | ||||
| Residence | <0.001 | <0.001 | 1.110 | 0.161 | ||||
| Town | ref | ref | ref | ref | ||||
| Village | 50.9 (41.7; 60.8) | 35.3 (26.8; 44.3) | 6.1 (−1.3; 14.2) | 5.4 (−2.7; 13.3) | ||||
| Ethnicityb | 0.316 | 0.138 | 0.289 | 0.386 | ||||
| Partly Inuit | ref | ref | ref | ref | ||||
| Fully Inuit | −3.4 (−9.8; 3.4) | −5.0 (−11.2; 1.7) | −3.4 (−9.5; 3.0) | −2.8 (−9.0; 3.7) | ||||
| Smoking | <0.001 | <0.001 | <0.001 | <0.001 | ||||
| No | ref | ref | ref | ref | ||||
| Yes | −11.0 (−15.5; −5.5) | −10.5 (−15.3; −5.4) | −12.0 (−16.2; −6.9) | −11.6 (−16.2; −6.9) | ||||
| Alcohol (per drinks/week) | 0.3 (0.1; 0.5) | 0.001 | 0.3 (0.1; 0.5) | 0.004 | 0.2 (0.0; 0.4) | 0.022 | 0.2 (0.0; 0.4) | 0.038 |
| Socioeconomic position | 0.008 | 0.220 | 0.056 | 0.057 | ||||
| Highc | ref | ref | ref | ref | ||||
| Skilled | −1.0 (−9.0; 7.6) | −0.7 (−8.5; 7.8) | −2.6 (−10.0; 5.4) | −2.2 (−9.6; 5.9) | ||||
| Unskilled | 1.39 (−6.5; 9.9) | 0.5 (−7.2; 7.8) | 0.5 (−7.0; 8.5) | 1.6 (−5.9; 9.8) | ||||
| Hunters/fishermen | 16.9 (3.7; 32.0) | 8.0 (−4.1; 21.7) | 11.2 (−0.9; 24.7) | 12.3 (0.1; 9; 25.9) | ||||
| Unemploidd | 9.3 (−0.3; 19.0) | 6.7 (−1.9; 16.1) | 6.3 (−2.5; 15.3) | 6.7 (−1.6; 15.7) | ||||
| BMI (per kg/m2) | −0.6 (−1.1; −0.1) | 0.019 | −0.7 (−1.2; −0.2) | 0.009 | −0.7 (−1.1; −0.2) | 0.008 | −0.6 (−1.1; −0.2) | 0.009 |
| Supplementatione | 0.033 | 0.017 | 0.002 | 0.002 | ||||
| No | ref | ref | ref | ref | ||||
| yes | 8.7 (0.7; 17.3) | 9.6 (1.6; 18.2) | 12.3 (4.5; 20.7) | 12.0 (4.2; 20.4) | ||||
| Traditional food intake (per 100 g/d)f | - | - | 11.6 (9.5; 13.8) | <0.001 | 9.6 (7.6; 11.6) | <0.001 | 10.0 (7.9; 12.1) | <0.001 |
| Seasong | - | - | <0.001 | <0.001 | ||||
| Winter | - | - | ref | ref | ||||
| Spring | - | - | −3.6 (−10.2; 3.5) | −3.9 (−10.5; 3.1) | ||||
| Summer | - | - | 28.7 (17.0; 41.5) | 31.0 (19.1; 44.2) | ||||
| Autumn | - | - | 45.2 (34.2; 57.1) | 47.1 (35.8; 59.2) | ||||
| Latitude (per degree) | - | - | - | - | - | - | −0.7 (−1.3; −0.2) | 0.008 |
Only Inuit in the IHIT-study reporting a realistic energy intake were included in the analyses (n = 2570).
A participant was perceived as fully Inuit if he/she reported him/her-self to be Inuit and to have four Inuit grandparents, and as partly Inuit if 1–3 of the grandparents were not Inuit.
Work that presupposes a medium-long education (white collar employees).
Students, individuals receiving transfer payment, unemployed and stay-at-home individuals.
Vitamin D or multivitamins.
Traditional food was defined as seal, blubber (boiled or frozen), white whale, other whales, walrus, mattak (whale skin), offal from seal, cod, halibut, capelin, trout, dried fish and other fish.
Winter: January + February; Spring: March-May; Summer: June + August; Autumn: September + October. Blood samples (and thereby vitamin D measurements) were not available from July, November and December due to summer annual leave and rough weather conditions during winter.