Table 3. Incidence of subsequent essential tremor and multivariate Cox proportional hazards regression analysis measured hazard ratio by various tiers of frequency of annual medical visits related to migraine.
| Average annual medical visits related to migraine | N | Event | PYs | Rate | Adjusted HR (95% CI) |
|---|---|---|---|---|---|
| Migraine-free cohort | 90784 | 319 | 662554 | 4.81 | ref |
| Migraine cohort | |||||
| <6 | 21967 | 126 | 165489 | 7.61 | 1.57 (1.27–1.95) |
| 6–11 | 531 | 11 | 3120 | 35.3 | 5.42 (2.96–9.95) |
| ≥12 | 198 | 15 | 922 | 163 | 30.9 (18.3–52.2) |
| p for trend | <0.0001 |
Model adjusted for age (continuous), sex, hypertension, DM, CAD, stroke, epilepsy, head injury, RLS, depression, dementia, asthma, COPD and migraine prophylaxis
PYs: person-years; rate: incidence rate, per 10000 person-years