The Joint Contributions of Overweight/Obesity and Physical and Mental Working Conditions to Short and Long Sickness Absence among Young and Midlife Finnish Employees: A Register-Linked Follow-Up Study

Introduction: Overweight/obesity and strenuous working conditions are associated with work disability, but their joint contributions to sickness absence (SA) are unknown. We aimed to examine their joint contributions to SA periods of 1–7 and ≥8 days. Methods: Self-reported data on body mass index and working conditions, including perceived physically and mentally strenuous work and hours per day spent in heavy physical work, were linked to the employer’s SA register for the City of Helsinki, Finland, employees (n = 4,323, women 78%) who were 19–39 years old at baseline. We calculated rate ratios (RRs) and 95% confidence intervals (CIs) for SA periods using negative binomial regression models among participants with healthy weight and overweight/obesity, with and without exposure to strenuous working conditions. The mean follow-up time was 2.1 years. Results: Participants with overweight/obesity and exposure to physically strenuous working conditions had the highest age- and gender-adjusted RRs for SA periods of both 1–7 and ≥8 days (physically strenuous work: RR: 1.38, CI: 1.25–1.52, and RR: 1.87, CI: 1.60–2.18, respectively; ≥3 h per day spent in physical work: RR: 1.40, CI: 1.26–1.55 and 2.04, CI: 1.73–2.40, respectively). The interaction between overweight/obesity and physically strenuous working conditions was additive for SA periods of 1–7 days and weakly synergistic for SA periods of ≥8 days. For mentally strenuous work, participants with overweight/obesity and exposure to mentally strenuous work had the highest age-adjusted RRs for SA periods of ≥8 days, and the interaction was additive. Conclusion: The joint contributions of overweight/obesity and exposure to strenuous working conditions to SA should be considered when aiming to reduce employees’ SA. Employers might benefit from providing employees adequate support for weight management and adherence to healthy lifestyles while improving employees’ working conditions.