Table 2.
The incidence of giant cell arteritis (GCA) in Bergen health area 1972–2012
| a Mean annual cumulative incidence | ||||||
| All time | 1972–1992 | 1993–2012 | ||||
| Cumulative incidence | 95% CI | Cumulative incidence | 95% CI | Cumulative incidence | 95% CI | |
| All patients | 16.7 | (15.5, 18.0) | 11.2 | (9.8, 12.7) | 22.5 | (20.5, 24.7) |
| Sex | ||||||
| Female | 37.7 | (35.8, 39.6) | 20.7 | (18.8, 22.7) | 55.4 | (52.2, 58.8) |
| Male | 14.3 | (13.2, 15.5) | 10.5 | (9.2, 12.0) | 18.3 | (16.5, 20.3) |
| Age, years | ||||||
| <60 | 2.8 | (2.3, 3.3) | 1.5 | (1.0, 2.1) | 4.1 | (3.3, 5.0) |
| 60–69 | 15.5 | (14.4, 16.8) | 10.9 | (9.6, 12.4) | 20.3 | (18.4, 22.4) |
| 70–79 | 34.5 | (32.8, 36.4) | 23.4 | (21.4, 25.6) | 46.2 | (43.3, 49.2) |
| 80+ | 26.8 | (25.3, 28.4) | 14.3 | (12.8, 16.0) | 39.9 | (37.2, 42.7) |
| ESR, mm/h | ||||||
| ESR <85 | 8.2 | (7.3, 9.1) | 4.5 | (3.7, 5.5) | 12.0 | (10.6, 13.6) |
| ESR >85 | 8.4 | (7.6, 9.3) | 6.6 | (5.5, 7.7) | 10.4 | (9.0, 11.8) |
| b Relative risk (RR) according to time, sex, age and ESR | ||||||
| 1972–1992 | 1993–2012 | |||||
| RR | 95% CI | p value | RR | 95% CI | p value | |
| Unadjusted | ||||||
| Time, years | 1.1 | (1.1, 1.1) | <0.001 | 1.0 | (1.0, 1.0) | 0.543 |
| Sex | ||||||
| Time, years) | 1.1 | (1.1, 1.1) | <0.001 | 1.0 | (1.0, 1.0) | 0.014a |
| Sex (male vs. female) | 0.5 | (0.4, 0.6) | <0.001 | 0.3 | (0.3, 0.4) | <0.001 |
| Age | ||||||
| Time, years | 1.1 | (1.1, 1.1) | <0.001 | 1.0 | (1.0, 1.0) | 0.135 |
| 60–69 vs. <60 | 7.2 | (5.1, 10.6) | <0.001 | 5.0 | (3.9, 6.4) | <0.001 |
| 70–79 vs. <60 | 15.4 | (11.0, 22.5) | <0.001 | 11.3 | (9.1, 14.3) | <0.001 |
| 80+ vs. <60 | 9.5 | (6.7, 13.9) | <0.001 | 9.8 | (7.8, 12.4) | <0.001 |
| ESR | ||||||
| Time, years | 1.1 | (1.1, 1.1) | <0.001 | 1.0 | (1.0, 1.0) | 0.632 |
| ESR, >median vs. <median | 1.4 | (1.1, 1.9) | 0.006 | 0.9 | (0.7, 1.0) | 0.116 |
Overall and erythrocyte sedimentation rate (ESR)-specific cumulative incidence reported as cases per 100,000 background population over the age of 50 years. Incidence for sex reported per 100,000 women or men, respectively, and incidence for the different age categories reported per 100,000 population of the same age categories (<60 years, 60–69 years, 70–79 years and 80+ years). Relative risk calculated according to Poisson regression models for the two time periods 1972–1992 and 1993–2012. CI confidence interval
aThe RR changed significantly, but the magnitude of the change was too small to visualize with rounding to one decimal place: 1972–1992, RR 1.091 (95% CI 1.076–1.106); 1993–2012, RR 1.011 (95% CI 1.002–1.020)