Table 1 Covariates: demographic background and labour status variables

Demographic background

 (Var.1) Sex: (2 categories: men vs. women)

 (Var.2) Age: (4 categories: 20–29, 30–39, 40–49, 50–60)

 (Var.3) Education: (3 categories: up to secondary school, up to Bachelor’s degree, Master’s degree & above)

 (Var.4) Occupational category: (4 categories: white collars, intermediate professions, employees, blue collars)

 (Var.5) Father’s occupational category: (7 categories: not filled out; farmers; artisans, merchants, company directors; white collars; intermediate professions; employees; blue collars) Assessed at the end of the respondent’s own schooling.

 (Var.6) Born abroad: (2 categories: born in France vs. born abroad) Respondents were asked ‘Where were you born?’. Responses options were 1) in France and 2) not in France.

 (Var.7) Cohabiting: (2 categories: living together with someone vs. living alone) Respondents were asked ‘Are you living together with someone in one household?’. Response options were (1) yes and (2) no. The variable cohabiting was preferred to the marital status i.e., the legal recognition of cohabitation, because it allows us to capture all the workers that beneficiated from a lower mortality rate [38] and not only those having the legal recognition of their situations.

 (Var.8) Children: (2 categories: has a child (ren) vs. does not have child (ren)) Respondents were asked ‘Do you have children in the household or in alternate care?’. Response options were (1) yes and (2) no.

 (Var.9) Departments: (11 categories: departments of residence (see Fig. 1: The French cross-border regions))

 (Var.10) Urban area: (2 categories: place of residence located in an urban area with fewer than 200,000 inhabitants vs. with 200,000 inhabitants or more)

 (Var.11) Permanency of the job: (3 categories: permanent contract, temporary contract, interim contract)

Labour status

 (Var.12) Sector: (10 categories: not filled out; agriculture; industry-construction; trade-transport-accommodation and catering; information and communication; finance and insurance; real estate; scientific activities and administrative services; public administration; other services)

 (Var.13) Number of persons working at the local unit: (5 categories: not filled out, 1 to 9 workers, 10 to 49 workers, 50 to 499 workers, 500 workers and more). Respondents were asked ‘How many employees are approximately on the site which employs you?’.

 (Var.14) Wage: (3 categories: up to 2000 net € per month, premiums included, between 2001 and 4000€, 4001€ and higher) Nominal wage.

 (Var.15) Full-time/part-time employment: (2 categories: full-time employment vs. part-time employment)

 (Var.16) Overtime: (2 categories: overtime vs. no overtime) Respondents were asked ‘How many extra hours do you usually work per week in your professional job?’.

 (Var.17) Night work: (2 categories: night work vs. no night work). Respondents were asked ‘Did you work during the night (between midnight and 5 a.m.) during the four precedent weeks?’.