Swedish Longitudinal Occupational Survey of Health (SLOSH) is drawn from the Swedish Work Environment Survey (SWES) which is in turn drawn from the Labour Force Survey (LFS). The SWES is a cross sectional, biennial survey of work environment conditions. It is based on a random stratified sample of those gainfully employed people aged 16–64 years who responded to the Labour Force Survey in the same year. The first wave of SLOSH in 2006 was based on a random stratified sample of respondents to the 2003 SWES. The response rate was 65% and yielded an initial sample of 9,214 respondents. At wave 2 in 2008 the sample was increased by adding new respondents from the 2005 SWES. Thus wave 2 is composed of a subsample with previous measures from wave 1 (N = 9,095; response rate 61.1%) and a subsample of new entrants (N = 9,639; response rate 61,0%). This gives an overall sample size of 18,739 and overall response rate of 61.1%. This sample was then followed again in 2010 (N = 20,291; response rate 56.8%) and in 2012 (N = 17,409; response rate 56.8%). Thus SLOSH is representative of the working population in Sweden in 2003 and 2005 and, although the response rate has fallen over the study period, it remains broadly so today. However analyses performed by Statistics Sweden show that non-responders are more likely to be male, younger, have less education and be born outside of Scandinavia.
Data collection number five was made in 2014 and number six in 2016, adding even more to the cohorts longitudinal strength. In spring 2018 the seventh data collection is being conducted.
SLOSH is a postal survey. Respondents are invited to complete one of two self-completion questionnaires. One is intended for those who are ‘gainfully employed’, defined as those who are in paid work for at least 30% full time and the other is for those who are ‘not gainfully employed’, i.e. those working less than 30% or who are outside of the labour force, such as retirees. All responses are returned to Statistics Sweden who construct an anonymised dataset before releasing it to researchers. All data collection has been approved by national ethics boards.