Table I.

Characteristics of 1633 incident psoriasis subjects between 1/1/1970 and 1/1/2000 in Olmsted County, Minnesota.

	Time period
	1970–1979	1980–1989	1990–1999	Total
Total no. of subjects	311	554	768	1,633
Male	155 (50%)	278 (50%)	395 (51%)	828 (51%)
Female	156 (50%)	275 (50%)	373 (49%)	805 (49%)
Age at incidence, mean (± SD)	39.8 (± 16.8)	41.9 (± 17.0)	45.5 (± 16.9)	43.2 (± 17.0)
Male	41.3 (± 16.3)	41.1 (± 15.8)	45.0 (± 16.7)	43.0 (± 16.4)
Female	38.3 (± 17.2)	42.7 (± 18.0)	46.0 (± 17.2)	43.4 (± 17.7)
Dermatologist confirmation, no.(%)	234 (75%)	475 (86%)	596 (78%)	1,305 (80%)
Skin biopsy, no. (%)	83 (27%)	118 (21%)	103 (13%)	304 (19%)
Psoriasis type, no. (%)
Chronic plaque psoriasis	241 (77%)	450 (81%)	601 (78%)	1292 (79%)
Guttate psoriasis	40 (13%)	49 (9%)	44 (6%)	133 (8%)
Sebo-psoriasis	8 (2.6%)	21 (3.8%)	58 (7.6%)	87 (5.3%)
Pustular psoriasis	14 (4.5%)	15 (2.7%)	24 (3.1%)	53 (3.3%)
No documentation	20 (6.4%)	31 (5.6%)	50 (6.5%)	101 (6.2%)
Location of lesions, no. (%)
Scalp	111 (36.0%)	228 (41.0%)	346 (45.0%)	685 (42.0%)
Elbows and/or knees	99 (32.0%)	201 (36.0%)	264 (34.0%)	564 (35.0%)
Limbs arms and/or legs	128 (41.0%)	190 (34.0%)	246 (32.0%)	564 (35.0%)
Palms and/or soles	19 (6.1%)	401 (7.2%)	59 (7.7%)	118 (7.2%)
Trunk	73 (23.0%)	123 (22.0%)	122 (16.0%)	318 (19.0%)
Face	27 (8.9%)	73 (13.2%)	76 (9.9%)	176 (10.8%)
Axilla	1 (0.3%)	8 (1.4%)	12 (1.6%)	21 (1.3%)
Inframammary	3 (1.0%)	2 (0.4%)	5 (0.6%)	10 (0.6%)
Intragluteal/perianal	34 (11.0%)	62 (11.0%)	74 (10.0%)	170 (10.0%)
Genital	22 (7.1%)	39 (7.0%)	49 (6.4%)	110 (6.7%)
Groin	9 (2.9%)	17 (3.1%)	24 (3.1%)	50 (3.1%)
Multiple locations involved	145 (46.6%)	271 (48.9%)	345 (45.1%)	762 (46.7%)
Nail involvement	36 (12.0%)	97 (18.0%)	103 (13.0%)	236 (14.0%)