The association between pain and diagnosis-specific long-term sickness absence at different levels of body mass index – a register-linked cohort study

Chronic (≥ 3 months) pain and obesity (body mass index [BMI] ≥ 30 kg/m2) are both associated with long-term sickness absence (LTSA). This study aimed to examine the contribution of acute (< 3 months) and chronic pain to total and diagnosis-specific LTSA (> 10 working days) at different levels of BMI among young and early midlife employees. Helsinki Health Study questionnaire data covering 19–39-year-old employees were collected in 2017 (n = 4091). Pain was classified as no pain, acute pain, or chronic pain. BMI was classified as healthy weight (BMI 18.5–24.9 kg/m2), overweight (BMI 25.0–29.9 kg/m2), or obesity. Diagnosis-specific follow-up data on LTSA covering 5 years after the survey collection were obtained from the Social Insurance Institution of Finland’s registers. Negative binomial regression analyses were conducted, adjusting for key covariates. Acute (RR 1.57, 95% CI 1.19 − 2.08) and chronic (RR 2.05, 95% CI 1.52 − 2.75) pain, and overweight (RR 1.42, 95% CI 1.09 − 1.85) and obesity (RR 2.20, 95% CI 1.58 − 3.05) were all associated with LTSA after adjusting for age and gender. The strongest association with LTSA was found for coexistent chronic pain and obesity (RR 3.49, 95% CI 1.89 − 6.43). Adjusting further for other sociodemographic, lifestyle and work-related factors marginally attenuated the associations. Having coexistent acute pain and a healthy weight or having no pain and overweight were not associated with LTSA. Employees with coexistent pain and overweight/obesity have an increased risk of LTSA, particularly employees with coexistent chronic pain and obesity. These employees could benefit from targeted primary and secondary preventive measures at the workplaces and in occupational healthcare to reduce LTSA.