Table 1 Median 25(OH)D concentrations (nmol/L) of the sample, by potential influential factors
Variable | n | Median (Q1; Q3) | P-value |
|---|---|---|---|
Sex |  |  | < 0.001 |
 Female | 872 | 32.95 (19.45; 52.88) |  |
 Male | 625 | 45.58 (26.10; 61.80) |  |
Age (years) |  |  | < 0.001 |
 65–69 | 412 | 44.35 (29.95; 63.98) |  |
 70–74 | 372 | 38.35 (25.60; 58.68) |  |
 75–79 | 319 | 34.20 (20.20; 58.30) |  |
  ≥ 80 | 394 | 24.85 (14.50; 44.83) |  |
NUTS II |  |  | < 0.001 |
 North | 468 | 35.50 (20.35; 58.40) |  |
 Center | 391 | 31.50 (17.20; 50.80) |  |
 Lisbon Metropolitan Area | 383 | 42.20 (28.80; 62.30) |  |
 Alentejo | 136 | 30.60 (22.15; 51.48) |  |
 Algarve | 65 | 36.30 (20.75; 55.20) |  |
 Madeira | 30 | 54.45 (39.23; 74.85) |  |
 Azores | 24 | 42.75 (21.10; 59.88) |  |
Education (years) |  |  | < 0.001 |
 0 | 212 | 23.80 (13.53; 35.20) |  |
 1–4 | 1029 | 36.90 (21.95; 57.10) |  |
 5–12 | 188 | 44.95 (29.18; 65.63) |  |
  ≥ 13 | 68 | 46.30 (31.18; 74.88) |  |
Professionally active | Â | Â | 0.038 |
 No | 1462 | 35.75 (21.58; 57.15) |  |
 Yes | 30 | 46.55 (29.33; 65.60) |  |
Marital status |  |  | < 0.001 |
 Single, divorced or widowed | 796 | 29.85 (17.30; 48.20) |  |
 Married or common-law marriage | 700 | 43.40 (28.63; 64.10) |  |
Residence |  |  | < 0.001 |
 Home | 1425 | 36.80 (22.35; 58.00) |  |
 Institution | 72 | 17.90 (10.23; 38.28) |  |
Household income (€) |  |  | < 0.001 |
  < 500 | 248 | 29.95 (17.48; 44.93) |  |
 500–999 | 305 | 36.40 (24.15; 58.70) |  |
  ≥ 1000 | 174 | 48.55 (33.65; 69.88) |  |
 Doesn’t declare/Doesn’t know | 770 | 35.30 (19.90; 56.95) |  |
Skin phenotype | Â | Â | 0.064 |
 I + II | 305 | 37.30 (24.85; 51.90) |  |
 III + IV | 1109 | 36.30 (21.30; 59.15) |  |
 V + VI | 80 | 30.00 (18.95; 46.33) |  |
Cognitive performance (MMSE) |  |  | < 0.001 |
 Maintenance | 1398 | 36.50 (22.10; 58.43) |  |
 Impairement | 99 | 28.10 (13.60; 45.90) |  |
Smoking habits | Â | Â | 0.850 |
 No | 1429 | 35.90 (21.75; 57.40) |  |
 Yes | 68 | 36.15 (22.65; 51.83) |  |
Alcoholic beverages consumption |  |  | < 0.001 |
 Does not drink | 952 | 32.95 (20.33; 51.78) |  |
 Moderate | 388 | 43.85 (24.33; 64.63) |  |
 Heavy | 155 | 41.80 (27.80; 61.10) |  |
Physical activity (IPAC) |  |  | < 0.001 |
 Normal | 1234 | 38.30 (23.60; 59.00) |  |
 Low | 261 | 25.60 (14.85; 47.75) |  |
Adherence to Mediterranean diet (PREDIMED) | Â | Â | 0.001 |
 Low | 849 | 34.20 (20.40; 54.70) |  |
 High | 648 | 39.05 (23.63; 60.30) |  |
Fish/shellfish consumption ≥ 3 servings/week |  |  | 0.150 |
 No | 372 | 37.00 (23.70; 60.45) |  |
 Yes | 1125 | 35.50 (21.00; 56.30) |  |
Self-perceived health |  |  | < 0.001 |
 Very good | 69 | 44.30 (32.50; 64.20) |  |
 Good | 409 | 42.20 (24.40; 62.60) |  |
 Moderate | 730 | 35.30 (22.30; 57.10) |  |
 Bad | 232 | 28.30 (15.50; 44.23) |  |
 Very bad | 53 | 25.50 (17.25; 47.55) |  |
Supplement intake | Â | Â | <0.001 |
 No | 1369 | 34.90 (20.95; 54.85) |  |
 Yes | 128 | 54.55 (35.53; 82.78) |  |
Undernutrition status (MNA-SF) | Â | Â | <0.001 |
 Without undernutrition | 1256 | 37.50 (22.50; 58.88) |  |
 Undernourished/at risk of undernutrition | 241 | 29.00 (16.90; 47.65) |  |
Body mass index | Â | Â | <0.001 |
 Underweight | 3 | 38.20 (21.90; a) |  |
 Normal range | 248 | 42.75 (23.25; 65.38) |  |
 Overweight | 660 | 38.55 (23.53; 60.60) |  |
 Obese | 582 | 31.20 (19.10; 50.10) |  |
mUVI categories |  |  | < 0.001 |
 Low | 570 | 30.05 (17.10; 48.50) |  |
 Moderate | 518 | 32.30 (19.88; 50.88) |  |
 High | 222 | 45.55 (29.88; 65.00) |  |
 Very high | 187 | 52.00 (39.00; 69.80) |  |
Period of blood collection |  |  | < 0.001 |
 December – March | 807 | 28.10 (16.70; 46.40) |  |
 April – June | 690 | 45.45 (30.40; 66.30) |  |