Risk and predictors of psoriasis in patients with breast cancer: a Swedish population-based cohort study

Table 1 Descriptive characteristics of the nationwide and regional breast cancer cohorts

	Nationwide cohort n = 56,235	Regional cohort n =8987
Cohort period	2001–2012	2001–2013
Age at diagnosis (years)
Mean (SD)	60.1 (11.0)	58.6 (11.2)
Minimum–maximum	20–80	23–80
Duration of follow-up (years)
Median (IQR)	5.1 (5.4)	7.7 (4.3)
Total no. of person-years at risk	307,684	68,243
Cases of psoriasis	599	150
Age at psoriasis diagnosis (SD)	62.5 (10.0)	63.6 (10.2)

SD standard deviation, IQR interquartile range
The nationwide cohort includes women diagnosed with primary invasive breast cancer at age 20–80 years between 2001 and 2011. In this cohort, follow-up is complete until 31 December 2012. The regional cohort includes women diagnosed with primary invasive breast cancer at age 20–80 years between 2001 and 2008; all patients in this cohort have complete follow-up until 31 December 2013

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