Table 1.

Selected characteristics in relation to psoriasis, IWHS/Medicare, 1991–2004

Characteristics	No psoriasis n = 32,191 (97.8%)	Psoriasis n = 719 (2.2%)	Age-adjusted odds ratiosb of psoriasis (95% CI)	Multivariate-adjustedb,c odds ratios of psoriasis (95% CI)
Mean age at the start of follow-up ± SD (years)	68.1 ± 3.2a	67.8 ± 3.0a	1.0 (0.9–1.0)
BMI categories in 1986 (kg/m2) (%)d
<24.9	39.5	41.3	1	1
25–30	37.3	33.4	0.9 (0.7–1.0)	0.9 (0.7–1.1)
≥30	23.2	25.3	1.0 (0.9–1.3)	1.1 (0.9–1.4)
			p = 0.7	p = 0.3
Education in 1986 (%)d
Less than high school	19.6	17.9	1	1
High school	42.2	38.2	1.0 (0.8–1.2)	1.0 (0.8–1.3)
More than high school	38.1	43.9	1.3 (1.0–1.6)	1.3 (1.0–1.6)
			p = 0.03	p = 0.02
Smoking in 1986 (%)d
Never	67.6	53.1	1	1
Former	18.6	25.0	1.4 (1.1–1.8)	1.4 (1.1–1.7)
Current	13.8	22.0	1.5 (1.1–2.0)	1.5 (1.1–2.0)
			p = 0.004	p = 0.006
Alcohol intake in 1986 (%)d
Never	56.9	52.8	1	1
<4 g/day	23.6	22.4	1.0 (0.9–1.2)	1.0 (0.8–1.2)
≥4 g/day	19.5	24.8	1.4 (1.1–1.6)	1.1 (0.9–1.4)
			p = 0.0007	p = 0.3
Regular physical activity in 1986 (%)
No	57.9	63.7	1	1
Yes	42.1	36.3	0.8 (0.7–0.9)	0.8 (0.7–1.0)
History of HT use up to 2004 (%)
Never	56.1	51.7	1	1
Ever	43.9	48.3	1.2 (1.0–1.4)	1.19 (1.0–1.4)
Diabetes up to 2004 (%)
Never	84.2	80.7	1	1
Ever	15.8	19.3	1.4 (1.2–1.7)	1.4 (1.2–1.7)
Heart disease up to 2004 (%)
Never	86.6	85.4	1	1
Ever	13.4	14.6	1.2 (1.0–1.4)	1.1 (1.0–1.3)
Hypertension up to 2004 (%)
Never	57.8	54.1	1	1
Ever	42.2	45.9	1.3 (1.07–1.5)	1.2 (1.1–1.5)

^aMean ± standard deviation

^bPrevalent odds ratio

^cAdjusted for age, education, smoking status, pack-years of smoking, alcohol, and BMI

^dThese variables were adjusted for each other in multivariate-adjusted analyses