Table 1 Distribution of serum vitamin D quartiles in relation to reproductive history, life-style factors and season
Factor | Serum vitamin D quartile [nmol/L] | ||||
|---|---|---|---|---|---|
1 [18–69] | 2 [70–86] | 3 [87–104] | 4 [105–173] | All | |
n = 179 | n = 187 | n = 177 | n = 184 | n = 727 | |
Column percent*; mean (SD) in italics | |||||
Age (years) | 56.2 (7.3) | 56.2 (7.9) | 58.1 (7.2) | 57.2 (7.2) | 56.9 (7.2) |
 ≤50 | 27.9 | 23.5 | 18.1 | 19.6 | 22.3 |
 >50 – ≤55 | 22.3 | 23.0 | 18.6 | 26.1 | 22.6 |
 >55 – ≤60 | 19.0 | 20.3 | 21.5 | 16.8 | 19.4 |
 >60 – ≤65 | 17.9 | 21.9 | 20.9 | 19.6 | 20.1 |
 >65 | 12.8 | 11.2 | 20.9 | 17.9 | 15.7 |
BMI (kg/m2) | 26.7 (4.96) | 25.5 (4.5) | 25.1 (3.4) | 24.6 (3.4) | 25.5 (4.2) |
 <20 | 5.0 | 6.4 | 4.5 | 6.5 | 5.6 |
 ≥20 – <25 | 39.1 | 44.9 | 48.6 | 52.2 | 46.2 |
 ≥25 – <30 | 34.6 | 34.2 | 40.1 | 33.7 | 35.6 |
 ≥30 | 21.2 | 14.4 | 6.8 | 7.6 | 12.5 |
Oral contraception | |||||
 No | 52.5 | 52.9 | 51.4 | 44.6 | 50.3 |
 Yes | 47.5 | 47.1 | 48.6 | 55.4 | 49.7 |
Menopausal status | |||||
 Pre | 30.7 | 26.7 | 21.5 | 23.9 | 25.7 |
 Peri/post | 69.3 | 73.3 | 78.5 | 76.1 | 74.3 |
MHT** (n = 537) | |||||
 No | 77.4 | 86.1 | 72.7 | 76.4 | 78.1 |
 Yes | 21.0 | 13.9 | 26.6 | 23.6 | 21.3 |
Smoking status | |||||
 Never | 40.8 | 43.3 | 42.9 | 41.3 | 42.1 |
 Current | 29.6 | 24.1 | 29.4 | 27.7 | 27.6 |
 Ex | 29.6 | 32.6 | 27.7 | 31.0 | 30.3 |
Alcohol consumption | |||||
 Zero | 11.7 | 6.4 | 7.9 | 5.4 | 7.8 |
 <15 g/day | 58.7 | 68.4 | 61.6 | 62.5 | 62.9 |
 15 – 30 g/day | 12.8 | 11.2 | 16.9 | 14.1 | 13.8 |
 >30 g/day | 3.9 | 1.1 | 2.8 | 3.3 | 2.8 |
 Infrequent | 12.8 | 12.8 | 10.7 | 14.7 | 12.8 |
Baseline season | |||||
 Spring | 43.6 | 25.1 | 27.1 | 14.1 | 27.4 |
 Summer | 14.5 | 22.5 | 31.1 | 43..5 | 27.9 |
 Autumn | 15.6 | 22.5 | 20.3 | 23.4 | 20.5 |
 Winter | 26.3 | 29.9 | 21.5 | 19.0 | 24.2 |
Education | |||||
 O-level college | 67.0 | 66.3 | 67.8 | 71.7 | 68.2 |
 A-level college | 10.1 | 7.0 | 7.9 | 6.5 | 7.8 |
 University | 22.9 | 26.7 | 24.3 | 21.7 | 23.9 |
Socio-economic index | |||||
 Manual | 39.1 | 35.8 | 35.6 | 40.2 | 37.7 |
 Non-manual | 53.1 | 51.3 | 59.9 | 53.8 | 54.5 |
 Employer | 7.3 | 12.8 | 4.5 | 6.0 | 7.7 |
Born in Sweden | |||||
 Yes | 83.2 | 91.4 | 93.8 | 92.9 | 90.4 |
 No | 16.8 | 8.6 | 6.2 | 7.1 | 9.6 |