Table 2.

Topics and items included in the Nightingale Study baseline questionnaire

Topics	Items
Socio-demographics	Date of birth, birth country of participant and her parents, marital status, current employment status
Reproductive history	Ever pregnant, pregnancies of at least 24 weeks (for each birth: date, gender, vital status at birth, duration of pregnancy in weeks and breastfeeding in months), number of pregnancies less than 24 weeks, infertility, age at menarche, age at menopause (no menstruation in the last 12 months and reason it stopped)
Education	Nursing and other degrees, and for each degree year of graduation
Occupational history	For each job conducted for at least six month: job type (caregiver, nurse (sector specified) or other (type and sector specified)), start and stop year, hours per week, physical load (sedentary, standing/walking, heavy)
Shift work	- Total number of years working night shifts during educational period (start and stop year)
	- For each job listed: ever/never conducted early morning shifts, evening shifts, night shifts and sleep shiftsa for at least six months
	- By job and shift type: number of shifts per month, number of shifts in a row, start and stop time of shift, rotation type (forward or backward rotating, variable, permanent), number of years (start and stop year), shifts on voluntary basis. Additional item for sleep shifts: proportion worked and slept. If women indicated that shift characteristics differed within a job, women were asked to complete these items for each period
	- For the most recent night work period the following items were reported: sleeping habits between 2 successive nights worked (hours, difficulty with falling and staying asleep, use of medication or other substances to sleep, light and sound circumstances at in the bedroom), time spent outdoors between 2 successive nights worked, light circumstances at work during the biological night, diet, timing of warm meal, regularity of eating and sleeping, activity after the last night worked, method of switching back to normal day-night rhythm, shift work adaptability compared to peers.
Occupational exposures	For each job listed: ever/never worked with X-ray examinations, fluoroscopic examinations, radiotherapy, MRI, artificial optical radiation, ultrasound equipment, dielectric heating, and/or industrial sewing machines, or near (i.e. within 5 meters) product/person detection gates, transmission installations, subway/train tracks, high-voltage network like power lines, and/or radar installations
Lifestyle	Current height, body weight (birth weight, current weight, weight at age 18, weight at ages 20–29, 30–39, 40–49, 50–59, 60–65), physical activity (walking/cycling and sport activity before age 18, sports activity at ages 20–29, 30–39, 40–49, 50–59, 60–65, and walking, cycling, sporting, gardening, do-it-yourself, housekeeping in the past summer and winter), time spend outdoors in the past summer and winter, smoking (ever, current, age at start, total duration, and number of cigarettes), alcohol consumption (ever, age at start, number of units in the past year and at ages 20–29, 30–39, 40–49, 50–59, 60–65), and dietary pattern and regularity of eating and sleeping
Lifetime mobile phone use	Past and current mobile phone use, hands free use, preferred side of the head during mobile phone use supplemented by information on current and prospective use obtained from the network operators. In addition, past and current cordless phone use [38].
Residential history	Lifetime residential history (i.e. place of residence in the Netherlands), for the assessment of environmental exposures.
Current sleeping habits	MOS sleep scale, light and sound circumstances in the bedroom, chronotype
‘Night shifts’ that is not work-related	Period-specific information on disruptions of sleep because of personal circumstances (e.g. young children, social engagements). Items include start and stopping ages, mean number of nights per week disrupted, and number of hours awake during those nights
Current health and Medical history	General health assessment (1 item of SF12) and items on headaches (Headache impact test, ID-migraine), hearing, tinnitus; cancer, benign lesions, cardiovascular diseases, neurodegenerative diseases, and metabolic disorders (ever diagnosed and age at diagnosis), and surgeries
Prescribed drugs	Period-specific information on use of hormonal contraceptives, hormone replacement therapy, hormones for IVF treatment, and on prescribed drugs like aspirin, medication for heart diseases, sleeping pills, diabetes medications, antidepressants, immunomodulators, and medications for Parkinson’s’ disease and asthma
Use of dietary supplements	Items on multivitamins, vitamin D, and calcium: ever/never, age at first use, age at last use, number of years use in total. For melatonin period-specific information was reported: start- en stopping ages and whether the use was daily or only during periods of circadian disruption
Diagnostic and therapeutic radiation exposures	Number of fluoroscopies, chest X-rays, coronary angiogram/angioplasty, CT-scans, diagnostics involving radioisotopes, and mammograms for age categories <20, 20–30, and after age 30; radiotherapy (age and location)
Family history of diseases	For mother, father, brothers, sisters, and children: diabetes, Parkinson’s’ disease, dementia, stroke, myocardial infarct, asthma, hay fever, and cancer of the lung, breast, prostate, ovary, uterus, colon/rectum. For grandmothers and aunts: breast cancer, ovarian cancer, and uterus cancer

^a Early morning shift: starting between 5.00 am and 6.59 am; evening shift: having worked at least one hour after 7.00 pm and with the shift ending no later than midnight; night shift: having worked at least one hour between midnight and 5.00 am; sleep shift (including weekend and on call shifts): having slept at work and woken up to work whenever necessary.