Vitamin D and juvenile idiopathic arthritis

Table 1 Comparison of classification systems of chronic childhood arthritis^a

	American College of Rheumatology 1977 [2]	European League Against Rheumatism 1978 [3]	International League Against Rheumatism 1994 and 2001 [17]
Classification Title	Juvenile Rheumatoid Arthritis	Juvenile Chronic Arthritis	Juvenile Idiopathic Arthritis
Symptom duration	Minimum 6 weeks	Minimum 3 month	Minimum 6 weeks
Subtypes	Systemic	Systemic	Systemic
	Polyarticular	Polyarticular	Polyarthritis RF negative
		JRA (RF positive Polyarticular)	Polyarthritis RF positive
	Pauciarticular	Pauciarticular	Oligoarthritis
			Persistent
			Extended
		Juvenile psoriatic	Psoriatic arthritis
		Juvenile ankylosing spondylitis	Enthesitis-related arthritis
		Arthritis associated with inflammatory bowel disease
			Undifferentiated arthritis

^aPrior to 1997, two chronic childhood arthritis classification systems were used. The American College of Rheumatology (ACR) [2] classification criteria referred to chronic childhood arthritis as Juvenile Rheumatoid Arthritis (JRA) and the European League Against Rheumatism (EULAR) applied the term Juvenile Chronic Arthritis (JCA) [3]. Differences between the two classification systems hindered exchange and comparison of data between the two systems [61]. To reconcile differences between ACR and EULAR criteria, the International League Against Rheumatism (ILAR) JIA criteria were introduced. This table provides a comparison of diagnostic criteria [17]. The ILAR classification system defines JIA as all forms of inflammation of one or more joints beginning in children younger than age16 years [17]. JIA is further classified into seven categories based on inclusion and exclusion criteria according to features present within the first six months of disease. The seventh category includes those who do not fit into one category, meet criteria for more than one category, or have exclusion criteria that preclude assigning a category