The joint association of insomnia disorder and lifestyle on the risk of activity-limiting spinal pain: the HUNT Study

Objectives: To investigate whether the combination of multiple healthy lifestyle factors modify the well-established association between insomnia disorder and risk of activity-limiting spinal pain. Methods: We conducted a prospective study of 10,228 individuals who participated in two surveys over similar to 11 years and were free of chronic pain in the neck, upper back, and lower back at baseline. Adjusted risk ratios (RRs) were calculated for the risk of activity-limiting chronic spinal pain (i.e., pain that impairs daily activities at work or leisure time) at follow-up associated with the joint association of insomnia disorder and the combination of five lifestyle factors (body mass index, leisure time physical activity, alcohol consumption, diet, and smoking) at baseline. Results: Our data indicate an additive interaction between insomnia disorder and lifestyle on risk of activity-limiting spinal pain, i.e., compared with participants without insomnia disorder and the best lifestyle score, participants with insomnia disorder and the worst lifestyle score had a RR of activity-limiting spinal pain of 3.57 (95 % CI: 2.65-4.80); participants with insomnia disorder and the best lifestyle score had a RR of 1.56 (95 % CI: 0.97-2.50); and those without insomnia disorder and the worst lifestyle score had a RR of 1.32 (95 % CI: 1.12-1.55). Conclusions: Poor lifestyle behaviour amplifies the adverse effect of insomnia disorder on the risk of activity-limiting chronic spinal pain.