en Internal Internal Original Article Original Article <p> <strong><i> Abstract </i></strong></p><p> <strong><i> Background: </i></strong>Postmenopausal onset rheumatoid arthritis (post-RA) is expected to have greater bone mineral density (BMD) loss than premenopauasal onset (pre-RA) due to estrogen deficiency and aging. This study aimed to compare the BMD status of the two RA groups with age-matched non-RA controls.<strong><i> </i></strong></p><p> <strong><i> Methods: </i></strong>The patients with RA on follow-up examination were stratified according to age of onset. Femoral neck and lumbar spine BMD (FN-BMD and LS-BMD)were assessed by DXA method. The patients of the two groups were compared with non-RA controls in regard to BMD gr/cm²and the risk of osteoporosis (OP). </p><p> <strong><i> Results: </i></strong>Forty-eight post-RA and 94 pre-RA were compared with 31 and 57 age-matched controls. FN-BMD gr/cm²and LS-BMD gr/cm² in both groups of RA was significantly lower than the controls (P=0.001 for all). In post-RA, FN-BMDgr/cm²was 16% lower than controls versus 21% in pre-RA, whereas, LS-BMD reductions were 5% and 12%, respectively (P=NS). FN-OP was observed in 32(68%) and 9 (29%) post-RA and controls (P=0.001) versus 29 (30.8%) and 4 (7%) pre-RA and controls, respectively (P=0.001). Corresponding percentages for LS-OP in post-RA and controls were (37.5% vs 35.5%, P=0.52) and in pre-RA and controls were (21.3% vs 3.5%, P=0.002), respectively. Risk of osteoporosis at either measurement sites of FN or LS in post-RA increased by the adjusted odds of 1.54(95% CI, 0.60-3.9, P=0.36) and in pre-RA by the adjusted odds of 5 (95% CI, 1.78-14.5, P=0.002), respectively. </p><p> <strong><i> Conclusion: </i></strong>These findings indicate that BMD loss in post-RA is not greater than pre-RA as expected. It is possible that estrogen deficiency by modulating immunologic reactions compensates the negative effects of estrogen deprivation on bone mass in post-RA patients. </p> Keywords: Rheumatoid arthritis, Age of onset, Postmenopausal, Premenopausal, Osteoporosis, Bone mineral density. 213 218 http://caspjim.com/browse.php?a_code=A-10-62-200&slc_lang=en&sid=1 Behzad Heidari bheidari6@gmail.com 10031947532846002189 10031947532846002189 Yes Parham Heidari 10031947532846002190 10031947532846002190 No