Table 2. Study characteristics.

Author & year	Country	Study design	Study period	Sample size (n)	Response rate (%)	Female (%)	Age (yr)
Danielsson 2008	Sweden	Cross-sectional	No data	469	72.5	74	21–64
Pejtersen 2011	Denmark	Cross-sectional	2005	2,403	62	55	42.4 (18–59)
Danielsson 2014 Danielsson 2016	Sweden	Longitudinal	2010–2012	1,852	57	58	23–71
Platts 2020	Sweden	Cross-sectional	2011–2012	a: 988 b: 1,237	69.5	a: 61 b: 63	a: 48.3 b: 47.8
Nielsen 2020	Norway	Cross-sectional	2004–2014	6,328	48	57	19–70

a: employer records; b: self-reported sick leave.