Modifiable, non-modifiable and health-related risk factors in 2009 across ever versus never night shift workers in Nurses’ Health Study II (N=54 724)†
| Characteristic | Shift work categories | |||
|---|---|---|---|---|
| Never night shift work (n=15 391)‡ | Ever night shift work (n=39 333) | |||
| Per cent | Mean (SD) | Per cent | Mean (SD) | |
| Modifiable factors | ||||
| Age, years | 56.0 (4.3) | 54.9 (4.4) | ||
| Body mass index, kg/m2 | 27.0 (6.0) | 28.1 (6.7)* | ||
| Physical activity, MET-hours/week§ | 22.7 (28.4) | 23.7 (29.8) | ||
| Current average sleep over a 24-hour period, ≤7 h | 63 | 67* | ||
| Ever used oral contraceptives | 89 | 89 | ||
| Ever used postmenopausal hormones | 55 | 54 | ||
| Current smoker | 5 | 7* | ||
| Alcohol consumption, g/day¶ | 6.3 (10.3) | 6.3 (10.2) | ||
| Caffeine consumption, mg/day¶ | 167 (136) | 184 (142)* | ||
| Alternative healthy eating index score¶,†† | 55.3 (11.7) | 55.7 (11.5) | ||
| Total Calories, in kcal/day¶ | 1772 (547) | 1822 (562)* | ||
| Non-modifiable factors | ||||
| Age at menarche, years | 12.4 (1.4) | 12.4 (1.4) | ||
| Age at menopause, years‡‡ | 47.4 (6.2) | 47.2 (6.5) | ||
| Postmenopausal | 76 | 76 | ||
| Nulliparous | 17 | 19* | ||
| Morning chronotype | 38 | 33* | ||
| Living alone | 11 | 13* | ||
| Any allergy | 29 | 30 | ||
| Health-related factors | ||||
| Family history of disease | – | – | ||
| Myocardial infarction | 44 | 46 | ||
| Cancer | 55 | 57 | ||
| Health/illness | – | – | ||
| History of diabetes (type II) | 6 | 8* | ||
| History of angina | 2 | 3* | ||
| History of high blood pressure | 33 | 36* | ||
| Blood cholesterol, ≥200 mg/dL | 35 | 34 | ||
| Medication or supplements | – | |||
| Antihypertension medication | 32 | 34* | ||
| Regular use of aspirin, ≥325 mg/tablet§§ | 9 | 11* | ||
| Regular use of low dose aspirin, ≤100 mg /tablet§§ | 25 | 26 | ||
| Multivitamin use¶¶ | 59 | 60 | ||
| Medical visits in the past 2 years | – | |||
| Mammography | 92 | 90* | ||
| Physical examination | 93 | 93 | ||
| Colonoscopy/sigmoidoscopy | 35 | 35 | ||
†Values are means and SDs or percentages standardised to the age and socioeconomic status (SES) distribution of the study population.
‡Reference group.
§Metabolic equivalents from recreational and leisure time activities.
¶Nutrient intake was assessed in the 2007 cohort questionnaire with an embedded food frequency questionnaire (FFQ).
††Alternative Healthy Eating Index (AHEI) score measures adherence to a diet pattern based on foods and nutrients most predictive of disease risk. The total score ranges from 0 (non-adherence) to 110 (perfect adherence).
‡‡Among postmenopausal women.
§§Reported as current use within the past 2 years and defined as ≥2 tablets per week.
¶¶Assessed in 2007.
*p<0.0011 (significant after Bonferroni correction).