Job type and other socio-demographic factors associated with participation in a national, cross-sectional study of Danish employees

Objectives Participation in population-based surveys and epidemiological studies has been declining over the years in many countries. The aim of this study was to examine the association between job type and participation in the work environment and health in Denmark survey with/without taking into account other socio-demographic factors. Design Cross-sectional survey using questionnaire data on working environment and registry data on job type, industry and socio-economic variables. Setting The work environment and health study. Participants A total of 50806 employees (15767 in a stratified workplace sample; 35039 in a random sample) working at least 35 hours/month and earning at least 3000 Danish Krones. Outcome measures The outcome was participation (yes/no) and logistic regression was used to estimate the OR for participation with 95% CI. Results In the random sample, women were more likely to participate than men, and married/non-married couples were more likely to participate than persons living alone or more families living together. Participation increased with higher age, higher annual personal income, higher education and Danish origin, and there were marked differences in participation between job types and geographical regions. For armed forces, craft and related trade workers, and skilled agricultural, forestry and fishery workers, the association between job type and participation was strongly attenuated after adjustment for sex and age. Additional adjustment for annual income, education, cohabitation, country of origin and geographical region generally attenuated the association between job type and participation. Similar results were found in the stratified workplace sample. Conclusion In this population of Danish employees, participation varied across types of jobs. Some but not all the variation between job types was explained by other socio-demographic factors. Future studies using questionnaires may consider targeting efforts to (sub-)populations, defined by job type and other factors, where response probability is particularly important.