The joint effect of insomnia symptoms and leisure time physical activity on risk of fibromyalgia at 11-year follow-up
| Physical activity | No insomnia symptoms | Insomnia symptoms* | ||||
| No. of persons | No. of cases | Multi-adjusted† RR (95% CI) | No. of persons | No. of cases | Multi-adjusted† RR (95% CI) | |
| High‡ | 5770 | 156 | 1.00 (reference) | 990 | 49 | 1.55 (1.12 to 2.13) |
| Moderate§ | 4185 | 125 | 1.05 (0.82 to 1.34) | 917 | 49 | 1.63 (1.18 to 2.25) |
| Low¶ | 1820 | 53 | 0.95 (0.69 to 1.29) | 490 | 34 | 1.90 (1.30 to 2.79) |
*Participants were classified to have insomnia symptoms if they answered ‘Often/always’ on one of the questions about ‘Problems falling asleep’ and ‘Waking up too early’ or ‘Yes’ on the question about ‘Impaired work ability due to sleep problems’.
†Adjusted for age (20–29, 30–39, 40–49, 50–59, 60–69 and ≥70 years), body mass index (18.5–24.9, 25.0–29.9 and ≥30 kg/m2), education (primary school, high school, college ≤4 years, college ≥4 years and unknown), The Hospital Anxiety and Depression Scale (no depression and no anxiety, depression and/or anxiety, and unknown) and smoking (never, former, current smoker and unknown).
‡Any hard activity per week.
§≥1-hour light and no hard activity per week.
¶<1-hour light activity per week.
RR, risk ratio.