Washington, May 29 (IANS) More and more women are falling prey to rheumatoid arthritis (RA), currently afflicting between one and two million Americans, says a new study.
RA is a chronic inflammatory disease that targets joints and contributes to work-related disability, increased morbidity and shortened survival.
Mayo Clinic study authors are attributing the rise in RA, which follows a four-decade period of decline, to factors such as smoking, vitamin D deficiency and a lower dose of synthetic estrogens in oral contraceptives.
Up to one-half of all RA patients become unable to work within 10-20 years of follow-up and those with the disease have a 60-70 percent higher mortality risk than those in the general population.
The current study, led by Sherine Gabriel of Mayo Clinic, expanded on prior research (1955-1994) from the Mayo Clinic team, by determining RA incidence and prevalence between 1995 and 2007.
Researchers screened medical records of 1,761 of those 18 years and older who had received one or more diagnoses of arthritis (excluding degenerative arthritis or osteoarthritis).
After a thorough review of all medical records, a diagnosis of RA was made in 466 patients whose mean age at RA incidence was 55.6 years, with 321 females (69 percent) in the study cohort.
"We observed a modest increase of RA incidence in women during the study period, which followed a sharp decline in incidence during the previous four decades," said Gabriel.
Prior studies have clearly demonstrated that smoking is associated with a greater risk for RA development in both sexes.
Researchers also note that lower doses of estrogens found in modern oral contraceptives offer less protection against RA development than at the previously higher doses found in older medications, said a Mayo Clinic release.
Furthermore, several studies have shown vitamin D deficiency to be associated with RA development and coupled with evidence that this deficiency, particularly in women, has risen over the past decades the Mayo team considered it a possible contributor to the upward trend in RA.
Details of the study which includes more than 50 years of RA epidemiology data appear in the June issue of Arthritis & Rheumatism.