Figure 4From: Epidemiological studies in incidence, prevalence, mortality, and comorbidity of the rheumatic diseasesAnnual incidence of psoriatic arthritis by age and sex. Shown is the annual incidence (per 100,000) of psoriatic arthritis by age and sex (1 January 1970 to 31 December 1999; Olmsted County, Minnesota). Broken lines represent smoothed incidence curves obtained using smoothing splines. Reproduced from [55] with permission.Back to article page