Characteristics of the cases and controls, and association of these characteristics with plasma levels of 25(OH)D among controls
| Characteristic | Cases | Controls | Association with 25(OH)D in controls | |
|---|---|---|---|---|
| n (%) | n (%) | Mean*± SEM | P | |
| Sex† | ||||
| Male | 146 (63.8) | 278 (64.1) | 26.6 ± 0.6 | |
| Female | 83 (36.2) | 156 (35.9) | 23.4 ± 0.8 | <0.01 |
| Ethnicity† | ||||
| Japanese American | 89 (38.9) | 171 (39.4) | 27.0 ± 0.7 | |
| Latino | 46 (20.1) | 88 (20.3) | 20.7 ± 0.9 | |
| African-American | 45 (19.7) | 81 (18.7) | 16.8 ± 1.0 | |
| White | 39 (17.0) | 74 (17.1) | 30.8 ± 1.0 | |
| Native Hawaiian | 10 (4.4) | 20 (4.6) | 29.6 ± 1.9 | <0.01 |
| Study area† | ||||
| Hawaii | 127 (55.5) | 245 (56.5) | 28.6 ± 0.6 | |
| Los Angeles | 102 (44.5) | 189 (43.5) | 19.5 ± 0.7 | <0.01 |
| First-degree family history of colorectal cancer | ||||
| No | 200 (87.3) | 394 (90.8) | 25.2 ± 0.5 | |
| Yes | 29 (12.7) | 40 (9.2) | 22.1 ± 1.4 | 0.03 |
| Season of blood draw | ||||
| December to June | 127 (55.5) | 243 (56.0) | 23.4 ± 0.6 | |
| July to November | 102 (44.5) | 191 (44.0) | 27.1 ± 0.7 | <0.01 |
| Mean ± SD | Mean ± SD | Correlation‡ | P | |
| Age at blood draw, y | 69.3 ± 8.0 | 69.2 ± 7.9 | 0.02 | 0.74 |
| Time between blood draw and case diagnosis, y† | 1.7 ± 1.4 | 1.7 ± 1.4 | −0.02 | 0.62 |
| BMI, kg/m2 | 26.7 ± 5.0 | 25.8 ± 4.2 | −0.08 | 0.09 |
| Physical activity, MET-h/d§ | 6.3 ± 7.7 | 6.2 ± 7.1 | 0.07 | 0.13 |
| Energy intake, kcal/d | 2,242 ± 975 | 2,185 ± 1,031 | −0.10 | 0.03 |
| Processed red meat intake, g/1,000 kcal/d | 8.0 ± 6.1 | 7.8 ± 6.6 | −0.01 | 0.82 |
| Calcium intake, mg/1,000 kcal/d | 430.0 ± 229.2 | 479.8 ± 283.3 | 0.11 | 0.02 |
| Vitamin D intake, IU/1,000 kcal/d | 151.6 ± 167.9 | 165.5 ± 204.7 | 0.09 | 0.06 |
| Plasma 25(OH)D, ng/mL | 23.2 ± 10.1 | 25.0 ± 9.9 | — | — |
Abbreviation: MET-h, metabolic equivalent hours.
↵*Among controls, mean 25(OH)D (ng/mL) by level of the characteristic, adjusted for sex and ethnicity as appropriate (except for area). P value from analysis of covariance. To convert to nmol/L, multiply these values by 2.5.
↵†Matching variables.
↵‡Among controls, partial correlation between 25(OH)D and the characteristic, adjusted for sex and ethnicity.
↵§Summary statistics based on slightly fewer than 229 cases and 434 controls due to missing values.