Table 1. Basic information on the included literature with gastroesophageal reflux disease as an outcome.

Author	Year	Country	Study type	Exposure size	Normal size	Age (years)	Sleep problem type	Confounders adjusted
Jansson et al.	2009	Norway	Case-control	3,153	40,210	19–81+	Insomnia, Sleep disturbance	Age, sex, smoking, BMI, SES, anxiety, depression, myocardial infarction, angina pectoris, stroke, nausea, diarrhea, constipation
Emilsson et al.	2022	Sweden	Cohort study	839	4,872	Exposure: 29–57; Normal: 39–67	Short Sleep Duration	Age, BMI, smoking status, caffeine consumption, alcohol dependence, physical activity level, depression, anxiety, snoring
Lindam et al.	2012	Sweden	Case-control	1,327	6,687	65–75+	Insomnia, Sleep disturbance	Age, sex, educational level, BMI, smoking
Zhang et al.	2012a	Hong Kong	Cohort study	185	2,106	Mean (SD): 41.1 (5.4)	Sleep disturbance	Age, gender, education level, marital status, family income, regular use of medication(s), subtypes of insomnia, snoring, sleep duration
Ahmed et al.	2020	Pakistan	Case-control	1,000	1,000	Exposure: mean (SD): 30 (10.47); Normal: mean (SD): 44.73 (13.92)	Short Sleep Duration	Age, gender, BMI
Lindam et al.	2016	Norway	Cohort study	Total: 16,754		Mean (SD): 43 (12)	Insomnia, Sleep disturbance	Sex, age, BMI, smoking, education, anxiety, depression
Yadegarfar et al.	2018	Iran	Case-control	717	308	Exposure: mean (SD): 39.1 (9.6) Normal: mean (SD): 39.93 (10.7)	Short Sleep Duration
Zhang et al.	2012b	Hong Kong	Cohort study	115	2,036	Mean (SD): 46.3 (5.1)	Insomnia	Age, gender, education level, family income, regular use of medication
Fass et al.	2005	USA	Cohort study	6,369	15,699	Exposure: mean (SD): 62.9 (10.9) Normal: mean (SD): 63.6 (10.4)	Insomnia
Ju et al.	2013	Korean	Case-control	21	513	Exposure: mean (SD): 50.8 (13.69) Normal: mean (SD): 50.95 (13.51)	Insomnia	Age, sex, alcohol consumption, BMI, depressed mood
Chang et al.	2021	Taiwan	Case-control	401	2,249	≤30 3.4% 31–60 71.6% >60 25.0%	Sleep disturbance