Association between drug intake and incidence of malignancies in patients with Juvenile Idiopathic Arthritis: a nested case–control study

Table 1 Socio-demographic characteristics and diseases-specific data of the study population

	n _missing	Case n (%)	Control n (%)	OR (95 %-CI)^a
Total		37 (22.8)	125 (77.2)
Sex of the participant
Male	0	7 (18.9)	23 (18.4)	n. a.
Female		30 (81.1)	102 (81.6)
Age (years)
0–17	0	2 (5.4)	8 (6.4)	n. a.
18–24		0 (0.0)	0 (0.0)
25–34		7 (18.9)	28 (22.4)
35–44		12 (32.4)	39 (31.2)
45–54		10 (27.0)	36 (28.8)
55–76		6 (16.2)	14 (11.2)
Education of participant^b
Low	3	8 (21.6)	25 (20.5)	1.00 (Ref.)
Medium		14 (37.8)	51 (41.8)	0.90 (0.33;2.46)
High		15 (40.5)	46 (37.7)	1.03 (0.35;3.06)
Parental education
Low	35	12 (44.4)	39 (39.0)	1.00 (Ref.)
Medium		9 (33.3)	35 (35.0)	0.85 (0.28;2.53)
High		6 (22.2)	26 (26.0)	1.18 (0.33;4.16)
Disease duration since first symptoms (years)	65
Median (1^st–3^rd quartile) (range)		41 (35;44) (3;57)	39 (34.5;45) (4;62)	0.97 (0.83;1.13)
Age at first symptoms (years)	65
Median (1^st–3^rd quartile) (range)		8.5 (5;11) (1;13)	8 (4;11) (0;15)	1.03 (0.90;1.19)

OR odds ratio, CI confidence interval, n. a not available, DMARD disease-modifying anti-rheumatic drugs, CT computed tomography
^aOR of conditional (fixed-effects) logistic regression analysis with cancer (yes/no) as outcome. For each independent variable a separate model was created
^bLevel of education was summarized into high (higher school certificate, university, or college degree), medium (secondary school leaving certificate, or comparable degree) and low (lower secondary education level or no degree). For children, pupils and for those who did not indicate their level of education the highest parental level of education was used as a proxy

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