Table 1.

The number of cases and controls according to case definition and sample provenance.

	Number of subjects
	Total	Male	Female
Hand OA material	168a	36	132
44 families with ≥ 2 DIP OA casesb	116	22	94
4 families with 1 DIP OA caseb	15	5	10
Additional radiologically verified DIP OA casesb	9	4	5
Physician diagnosed hand OA casesc	28	5	23
Knee OA materialb	113	27	86
Controls	436	277	159
Total	689	335	354

^a = The total number of affected individuals was 134 of which 85 were unrelated

^b = Radiologically verified OA cases

^c = Physician diagnosed hand OA; this group is also a part of radiological knee OA material