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	22.0	(20.6, 23.5)	13.3	(11.8, 14.9)	31.2	(28.8, 33.7)
Male	10.5	(9.5, 11.5)	8.6	(7.4, 9.9)	12.4	(10.9, 14.0)
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/hr
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)	0.462
Sex (Male vs. Female)	0.6	(0.5, 0.8)	< 0.001	0.4	(0.3, 0.5)	< 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 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 timeperiods 1972–1992 and 1993–2012

ESR Erythrocyte sedimentation rate

CI Confidence interval