Studies

Year

Sample size

General demographic factors

Chen [15]

2015

1250

Age, marital status, educational background, length of service, working hours per day, working hours per week, frequencies of night shift

Zhang [16]

2017

143

Age, nursing age, title, frequencies of night shift monthly, annual salary, employment method

Chen [17]

2014

110

Marital status, age, education level, ICU working life and frequencies of night shift

Yin [18]

2017

211

Gender, age, marital status, years of emergency work, department