Table 1. Characteristics among cases with basal cell carcinoma, squamous cell carcinoma, malignant melanoma, and non-Hodgkin's lymphoma and controls (restricted to those cases with no history of organ transplants or cancer before the actual cancer under study).

	Basal cell carcinoma		Squamous cell carcinoma		Malignant melanoma		Non-Hodgkin's lymphoma
	Cases (N=5422)	Controls (N=22457)	Cases (N=935)	Controls (N=4166)	Cases (N=983)	Controls (N=4406)	Cases (N=481)	Controls (N=2004)
Demographic characteristics
Age (median)	68	68	77	77	58	58	64	64
Gender: male	50%	50%	67%	68%	41%	42%	53%	54%
Anatomic site of skin cancer
Head and neck	54%	—	64%	—	16%	—	—
Other sites	46%	—	36%	—	84%	—	—
Comorbidities/history of hospitalisation
Chronic pulmonary disease	299 (6%)	1234 (6%)	65 (7%)	306 (7%)	25 (3%)	187 (4%)	32 (7%)	100 (5%)
Connective tissue disease	123 (2%)	409 (2%)	33 (4%)	74 (2%)	16 (2%)	76 (2%)	13 (3%)	30 (2%)
Inflammatory bowel disease	33 (0.6%)	136 (0.6%)	5 (0.5%)	20 (0.5%)	5 (0.5%)	33 (0.8%)	5 (1%)	9 (0.5%)
Allergy	135 (2%)	432 (2%)	24 (3%)	91 (2%)	13 (1%)	90 (2%)	9 (2%)	27 (1%)
Other drug use/prior drug prescriptions:
Methotrexate	30 (0.6%)	69 (0.3%)	2 (0.2%)	11 (0.2%)	4 (0.4%)	16 (0.4%)	2 (0.4%)	5 (0.3%)
Azathioprine	17 (0.3%)	57 (0.3%)	10 (1%)	8 (0.2%)	1 (0.1%)	9 (0.2%)	1 (0.2%)	3 (0.2%)