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Table 2 Characteristics of the selected (nested) case–control studies on breast cancer and night-shift work

From: Night-shift work duration and breast cancer risk: an updated systematic review and meta-analysis

Author Sample size Case/control Exposure data source Adjusted confounders Definition of night shift NSW category Quality score
Hansen and Lassen [20] 218/899 Nationwide pension fund and Danish military’s company registration HRT, number of childbirths, age at menarche, length of education, occasional sun-bathing, tobacco smoking status Working during hours beginning after 17:00 and ending before 9:00 for at least 1 year, not including overtime Short/long High
Hansen and Stevens [58] 310/1240 Danish nurses association Age, family history of BC, MHT, number of mammograms Graveyard shifts which worked after midnight (about 8 h of work between 19 and 9) for at least 1 year Short/long High
Li et al. [21] 1709/4780 Factory records (80%), interviews (20%) Parity, live births, BF, alcohol Working at least once per week for at least 6 months between midnight and 6 a.m Short/long Moderate
Tynes et al. [55] 50/259 Telecom registry Duration of employment, age, and age of first birth Years on ships known to involve night shift work and cross time zones Short/long Moderate
Linnersjo et al. [57] 16/174 Airline archives None ––- Short Moderate
Rafnsson et al. [56] 35/140 Employment records Age, age at first childbirth, live births Employed full-time ≥ 5 years; frequent long distance flights due to remote Iceland location Short Moderate
Hansen [61] 6281/6024 Nationwide Pension Fund Age, age at first and last childbirth, parity, SES  ≥ 6 months employment in a trade where ≥ 60% of randomly surveyed women worked at night Short High
Fritschi et al. [22] 1205/1789 Western Australian (WA) Cancer Registry Age, reproductive history, alcohol intake, smoking, PA and sleep, SES, remoteness of residence, family history of BC Working for any number of hours between midnight and 0500 h Short/long High
Menegaux et al. [59] 1232/1317 French departments of ‘‘Coˆte d’Or’’ or ‘‘Ille-et-Vilaine’’ Age, age at menarche, age at first full-term pregnancy, parity, MHT, family history of BC in first-degree relatives, BMI, alcohol consumption, and tobacco consumption Working for at least 1 h between 11:00 pm and 5:00 am during all or part of each job Short High
Grundy et al. [62] 1034/1179 BC Cancer Registry (Vancouver), Hotel Dieu Breast Assessment Program (Kingston) Age, ethnicity; household income; education; menopausal status; use of fertility drugs, OC, non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants and HRT; reproductive factors including ever having been pregnant, number of pregnancies, age at first birth, BF and age at first mammogram; family history of BC among first-degree relatives; lifestyle factors, including smoking status, pack-years smoking, lifetime alcohol consumption; and BMI  ≥ 50% of time was reported to have been spent on evening and/or night shifts, capturing both rotating and permanent night shift schedules Short/long High
Pesch et al. [65] 857/892 Telephone interview Age, family history, HRT, Mammograms Working the fulltime period between 24:00–05:00 h Short/long High
O'Leary et al. [60] 576/585 In-person occupational history Age, live births, family history, education, benign breast disease Overnight shift which could start as early as 7:00 p.m. and continue until the following morning Short High
Davis et al. [63] 763/741 In-person occupational interview Parity, family history, OC use, recent HRT Graveyard shift which began after 7:00 PM and leaving work before 9:00 AM Short High
Papantoniou et al. [64] 1708/1778 MCC-Spain Study Age, family history, education, marital status, BMI, Tobacco smoking, PA, sleep habits, diet habits, Menopausal status, Parity, age at first birth, BF, ever OC, ever hormonal therapy, past sun exposure Night work was defined as a working schedule that involved partly or entirely working between 00:00 and 6:00 a.m. at least three nights per month. This definition included overnight, late evening (end after 00:00) and early morning (start before 6:00) shifts Short/long High
Santi et al. [67] 743/775 Questionnaire Age, family history, level of education, OC use, alcohol consumption, number of births, and age of first menstruation Nurses were classified as night-shift workers if they worked in hospitals Short/long High
Rabstein et al. [66] 857/892 GENICA (Gene–ENvironment Interaction and breast CAncer) Family history of BC, HRT, number of mammograms, and estrogen receptor status Ever having worked in night shifts for ≥ 1 year and working the fulltime period between 24:00–05:00 h Short/long High
Lie et al. [68] 172/474 Cancer Registry of Norway Age at diagnosis, period of diagnosis, parity, family history of BC in mother or sister, hormonal treatment in the previous 2 years before diagnosis, and frequency of alcohol consumption at the time of diagnosis Work between 12 pm and 6 am Short/long High
Truong et al. [16] 1126/1174 CECILE study Age, study area, age at menarche, age at first full-term pregnancy, parity, MHT, BMI, alcohol consumption, and tobacco consumption Work for at least 1 h between 1100 and 0500 h during all or part of each job period Ever/short High
Pham et al. [69] 1721/1721 Questionnaire and face to face interview Age, educational level, number of pregnancies, age at birth of first child, body mass index, age at menarche, alcohol consumption, smoking, use of female hormone treatment, and family history of breast cancer in first degree relatives Ever having worked in night shifts regularly between 9:00 pm and 8:00 am for at least 2 months in their lifetime Short/long High
  1. NSW night shift work, HRT hormone replacement therapy, BC breast cancer, MHT menopausal hormone therapy, BF breastfeeding, PA physical activity, SES socioeconomic status, BMI body mass index