Age-adjusted characteristics of the study population at 2001 baseline by rotating night shift duration
| Variables | |||||
|---|---|---|---|---|---|
| Duration of rotating night shift work (years) | 0 | <2 | 2–5.9 | 6–9.9 | >10 |
| Proportion of sample (%) | 29 | 27 | 24 | 11 | 9 |
| Age, years* | 47.05±4.60 | 46.64±4.73 | 46.22±4.70 | 46.27±4.58 | 47.22±4.28 |
| Body mass index, kg/m2 | 25.66±4.89 | 25.85±4.98 | 26.22±5.09 | 26.76±5.30 | 27.21±5.33 |
| Physical activity, MET-hours/week† | 19.22±21.66 | 19.47±21.55 | 20.33±22.66 | 20.35±22.73 | 20.15±22.96 |
| Alcohol intake, g/day | 3.87±7.04 | 4.07±7.28 | 4.14±7.30 | 3.98±7.34 | 3.52±6.64 |
| Alternate Health Eating Index‡ | 47.82±10.69 | 47.74±10.78 | 47.91±10.63 | 47.68±10.81 | 47.14±10.72 |
| Sleep, ≤6 hours over a 24-hour period, % | 25 | 27 | 31 | 33 | 40 |
| First degree relative history of melanoma, % | 11 | 11 | 12 | 12 | 12 |
| Red or blonde hair, % | 20 | 20 | 20 | 20 | 17 |
| Moles, ≥10 on lower legs, % | 15 | 15 | 14 | 14 | 13 |
| Artificial tanning, ≥6 times/year at ages 25–35, % | 3 | 3 | 3 | 3 | 3 |
| Time spent in sun, ≥5 hours/week at ages 25–35, % | 43 | 43 | 44 | 44 | 45 |
| Severe sunburns, ≥6 at ages 15–20, % | 9 | 10 | 11 | 10 | 11 |
| Skin sensitivity to burning,§ % | 42 | 41 | 41 | 41 | 41 |
| Annual UV-B flux at residence, ≥ 145 R-B units,¶ % | 26 | 23 | 21 | 19 | 16 |
| Sleep not usually adequate, % | 46 | 48 | 51 | 52 | 57 |
| Sleepy ≥4 days/week, % | 11 | 12 | 12 | 13 | 14 |
| Snore most nights, % | 14 | 15 | 17 | 18 | 19 |
| Restless legs syndrome | 2 | 2 | 2 | 2 | 2 |
| Current smoker, % | 7 | 8 | 10 | 10 | 12 |
| Married, % | 82 | 82 | 79 | 76 | 75 |
| In top 20 per cent of economic ladder,** % | 12 | 12 | 11 | 10 | 9 |
| Oral contraceptive use, ≥8 years, % | 22 | 22 | 22 | 22 | 22 |
| Current use of postmenopausal hormones,†† % | 66 | 64 | 64 | 62 | 59 |
Values are means±SD or percentages and are standardised to the age distribution of the study population.
*Value is not age-adjusted.
†Metabolic equivalents from recreational and leisure-time activities.
‡Score of 0–100 measuring adherence to a dietary pattern most predictive of disease risk.
§Skin reaction after two or more hours in the sun without sunscreen on a bright sunny day during childhood and adolescence (none/some redness, burn, painful/blistering burn).
¶Measured in Robertson-Berger units (count×10−4).
**Self-reported economic status compared to others.
††Calculated among postmenopausal women only.
MET, metabolic equivalent.