Table 1.

Studies included in the systematic review and meta-analysis (N = 6)

First author (year), country	Study design	N	Recruitment	Participants	Sex	Exposure variable	Outcome measures	Number of outcome events/ cases	Comparison
1. Walia (2012), USA	Retrospective chart review	1275	Clinic	Employed patients	Men and women combined	Fixed shift work and rotating shift work	PSG	day shift work: 474; fixed and rotating shift work: 216	AHI ≥ 15
2. Yazdi (2014), Iran	Cross-sectional study	470	Workplace	Workers in textile factory	Men only	Shift work	Berlin questionnaire	Non-shift workers: 204; shift workers:210	Berlin questionnaire ≥ 2 categories positive
3. Soylu (2014), Turkey	Cross-sectional study	257	Workplace	Nurses and resident doctors	Men and women combined	Shift working	PSG	Non-shift working: 1; shift working: 11	AHI ≥ 5
4. Seyedmehdi (2016), Iran	Cross-sectional study	715	Workplace	Hospital staff	Men and women combined	Night shift	Berlin questionnaire	Day shift: 25; night shift: 24	Berlin questionnaire ≥ 2 categories positive
5. Motlagh (2017), Iran	Cross-sectional study	934	Workplace	Professional drivers	Men only	Evening and night shift work	Stop BANG questionnaire	NR	Stop BANG ≥ 3 items positive
6. Guclu (2019), Turkey	Cross-sectional study	604	Workplace	Healthcare workers	Men and women combined	On-call shift	Berlin questionnaire	Day shift: 30; on-call shift: 62	Berlin questionnaire ≥ 2 categories positive

AHI Apnea–Hypopnea Index, PSG Polysomnography, NR not reported