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

Table 4 Hazard ratios for psoriasis in the regional breast cancer cohort according to genetic and lifestyle factors

	Total no.	No. of cases	HR (95% CI)
	Total no.	No. of cases	Model 1	Model 2
PRS score
Tertile 1	1440	13	1.00 (Ref.)	1.00 (Ref.)
Tertile 2	1442	36	2.74 (1.45–5.17)	2.83 (1.50–5.34)
Tertile 3	1483	40	2.94 (1.57–5.49)*	2.98 (1.59–5.58)*
BMI
< 25 kg/m²	2331	40	1.00 (Ref.)	1.00 (Ref.)
25–30 kg/m²	1434	28	1.18 (0.73–1.92)	1.15 (0.71–1.87)
> 30 kg/m²	536	19	2.29 (1.32–3.98)	2.10 (1.20–3.68)
Physical activity per week
0 h	762	21	1.00 (Ref.)	1.00 (Ref.)
0–2 h	1645	36	0.77 (0.45–1.33)	0.77 (0.44–1.32)
> 2 h	1910	30	0.56 (0.32–0.98)	0.59 (0.33–1.03)
Regular smoker (cigarette smoking >1 year)
No	1773	26	1.00 (Ref.)	1.00 (Ref.)
Yes	2546	62	1.65 (1.04–2.61)	1.59 (1.00–2.52)
Alcohol consumption
No	104	2	1.00 (Ref.)	1.00 (Ref.)
Yes	2861	58	1.03 (0.25–4.22)	1.12 (0.27–4.70)

Total no. number of breast cancer patients, No. of cases number of psoriasis cases, HR hazard ratio, CI confidence interval, BMI body mass index, PRS polygenic risk score
Analyses were based on a subset of the regional cohort with information on genetic and lifestyle factors. Significant associations are denoted in boldface. Genetic predisposition for psoriasis was defined by a PRS including 35 genetic variants for psoriasis susceptibility. Patients were grouped into tertiles by their genetic risk. Model 1: adjusted for age and calendar period of breast cancer diagnosis. Model 2: all of the risk factors were put into the model, including radiotherapy and mastectomy. Missingness on all variables is <5%, except for alcohol consumption (32.1%, N = 1400). No evidence of non-proportional hazards was found
*P for trend < 0.001, tested by log-linear trend test

ISSN: 1741-7015