Table 2.
Resident Characteristics and Dietary Patterns According to Serum 25(OH)D Level *.
| Characteristic | <50 nmol/L n = 25 (25%) | 50–74 nmol/L n = 45 (44%) | ≥75 nmol/L n = 32 (31%) | p value |
|---|---|---|---|---|
| Demographics & Level of Training | ||||
| Age, years (mean ± SD) | 30.0 ± 1.6 | 29.3 ± 2.9 | 29.7 ± 2.5 | 0.52 |
| Sex (%) | 0.06 | |||
| Female | 18 | 45 | 37 | |
| Male | 37 | 43 | 20 | |
| Ethnicity (%) | 0.31 | |||
| Hispanic or Latino | 50 | 0 | 50 | |
| Not Hispanic or Latino | 24 | 45 | 31 | |
| Race (%) (n = 1 missing) | 0.01 | |||
| White | 16 | 47 | 37 | |
| Black or African American | 33 | 67 | 0 | |
| Asian | 48 | 35 | 17 | |
| Clinical Factors | ||||
| Body mass index, kg/m2 (mean ± SD) | 23.8 ± 3.9 | 22.3 ± 2.4 | 22.4 ± 2.4 | 0.09 |
| Skin Sensitivity Score (%) † | 0.13 | |||
| 1–2 | 16 | 48 | 36 | |
| 3–4 | 20 | 46 | 34 | |
| 5–6 | 50 | 33 | 17 | |
| Travel History | ||||
| Traveled outside of Massachusetts in past 3 months (%) | 25 | 41 | 34 | 0.48 |
| If yes, lowest latitude traveled to in past 3 months (mean ± SD) | 35 ± 9 | 33 ± 11 | 29 ± 11 | 0.08 |
| Nutritional Supplement Use During the 30 Days | ||||
| Taken any vitamin or supplement in the past 30 days (%) | 14 | 49 | 37 | 0.07 |
| Taken multivitamin in past 30 days (%) | 9 | 52 | 39 | 0.005 |
| In past 30 days, number of days vitamin taken (%) (n = 1 missing) | 0.90 | |||
| 0–14 days | 11 | 54 | 36 | |
| 15+ days | 6 | 50 | 44 | |
| Taken vitamin D or dual calcium/vitamin D supplement in past 30 days (%) | 20 | 32 | 48 | 0.13 |
| Taken vitamin D supplement in past 30 days (%) | 0 | 36 | 64 | 0.03 |
| In past 30 days, number of days vitamin taken (%) (n = 1 missing) | 1.00 | |||
| 0–14 days | -- | 33 | 67 | |
| 15+ days | -- | 25 | 75 | |
| Nutritional Supplement Use During the 30 Days | ||||
| Taken dual calcium/vitamin D supplement in past 30 days (%) | 31 | 31 | 38 | 0.57 |
| In past 30 days, number of days vitamin taken (%) | 0.06 | |||
| 0–14 days | 45 | 36 | 18 | |
| 15+ days | 0 | 20 | 80 | |
| Vitamin D supplement dosage in past 30 days | 0.33 | |||
| None | 26 | 48 | 26 | |
| 200–600 IU | 25 | 33 | 42 | |
| ≥800 IU | 15 | 31 | 54 | |
| Taken cod liver oil in past 30 days (%) | 0 | 100 | 0 | 1.00 |
| Laboratory Values | ||||
| Serum 25 (OH) D, nmol/L | 37.1 ± 8.9 | 62.2 ± 6.6 | 96.6 ± 19.9 | -- |
| PTH, pg/mL (median [IQR]) | 47.3 (33.3–55.8) | 32.0 (26.4–37.7) | 25.9 (21.3–33.5) | <0.001 |
| Calcium, mg/dL (mean ± SD) | 9.4 ± 0.3 | 9.4 ± 0.3 | 9.4 ± 0.3 | 0.90 |
Abbreviations: 25(OH)D: 25-hydroxyvitamin D; SD: Standard deviation; BMI: Body mass index; PTH: Parathyroid hormone; IQR: Interquartile range. * Percentages are for each row. † See Methods section for details. ‡ Doctor-diagnosed illnesses include malabsorptive diseases including inflammatory bowel disease, celiac disease, gastric bypass surgery, liver failure, nephritic syndrome or chronic kidney disease, granulomatous disorders such as sarcoid or TB, heritable rickets or untreated hyperthyroidism.