RHEUMATOID-ARTHRITIS, THE CONTRACEPTIVE PILL, AND ANDROGENS

Evidence is accumulating that low androgen concentrations are a cause of rheumatoid arthritis. This would explain a number of established fe atures of the epidemiology of the disease. These include: (a) the vari ation of disease activity with pregnancy; (b) the variation of age at onset by sex; (c) the variation by sex with HLA-B15; (d) the associati on with bone mineral density; and (e) the differing time trends in inc idence rates by sex. It is argued, moreover, that if one makes a plaus ible assumption-namely, that women who choose oral contraceptives have high androgen concentrations at the time they first make this choice- then an explanation becomes available for the confusion about the rela tion between rheumatoid arthritis and oral contraception. Grounds are adduced for that assumption. If this line of reasoning is substantiall y correct it also has implications for the relations between rheumatoi d arthritis and smoking and consumption of alcohol.