Table 1.

Chronic inflammatory diseases with ICD-9 codes included in the sensitivity analysis

Chronic inflammatory disease	ICD9 code
Systemic lupus erythematosus	(710.0)
Juvenile ankylosing spondylitis	(720.0)
Scleroderma	(710.1)
Inflammatory bowel disease	(555.x)
Vasculitis	(447.6)
Multiple sclerosis	(340)
Psoriasis	(696.x)
Juvenile rheumatoid arthritis	(714.3, 714.30, 714.31, 714.32, 714.33)
Juvenile dermatomyositis	(710.3)
Idiopathic thrombocytopenic purpura	(287.31)
Necrotizing enterocolitis	(777.5)
Kawasaki disease	(446.)
Celiac disease	(579.0)
Sickle cell anaemia	(282.6x)