Bone Mineral Density Loss is Not Significantly Different Among Pre and Postmenopausal Women

Bone mineral density (BMD) loss in postmenopausal onset rheumatoid arthritis (post-RA) is not greater than premenopausal onset (pre-RA), according to findings published in the Caspian Journal of Internal Medicine.

Researchers from the Babol University of Medical Sciences in Babol, Iran compared 48 post-RA and 94 pre-RA women to 31 and 57 age matched controls, respectively, in order to determine if post-RA in fact had greater BMD loss than pre-RA due to estrogen deficiency and aging as expected. By comparing the BMD status of the 2 RA groups with non-RA controls, the researchers were able to assess whether or not the hypothesis would hold up. Patients were recruited from an outpatient rheumatology clinic and had confirmed cases of RA from the American College of Rheumatology revised guidelines. All patients were treated similarly with at least 1 disease modifying anti rheumatic drug (DMARD) such as methotrexate (MTX), and hydroxychloroquine, with or without low dose prednisolone (<7.5 mg/daily). Data was collected by researchers about each patient’s age, menopausal status, interview age of onset, duration of disease, duration of treatment, menopausal duration, along with a clinical examination and review of medical records.

The pre- and post-RA women were similar in regards to duration of RA, treatment regimen, rheumatoid factor, and anti-cyclic citrullinated antibody seropositivity. In both groups, the femoral neck BMD (FN BMD) gr/cm² and lumbar spine BMD (LS BMD) gr/cm² were lower than the control groups. For the post-RA group, the mean FN BMD gr/cm² was 16 percent lower than postmenopausal control participants. In the pre-RA group, FN BMD gr/cm² was 21 percent lower than premenopausal controls. LS BMD gr/cm² values were 5 and 12 percent lower than post- and pre-RA groups, respectively. The odds of osteoporosis increased 2.2 percent for each year in post-RA women and 14.5 percent in pre-RA women.

“In spite of estrogen deficiency during postmenopausal period, the magnitude of bone loss in post-RA is not greater than pre-RA as compared with age matched controls,” the authors explained. “It is possible that the age of onset or estrogen related changes on immune response may attenuate disease course and results in milder RA with lower expected bone loss.”

The researchers noted the results are expected to be less confounded because the participants were all recruited from a single population with similar lifestyle and ethnic characteristics. However, because of the similarities, the post- and pre-RA groups’ data can act as reliable comparisons.