Prevalence of rheumatoid arthritis in families.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000453:epidemiology / Q000235:genetics*; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D012216:Rheumatic Diseases / Q000453:epidemiology / Q000235:genetics