What is Rheumatoid Arthritis? A Brief Review
Rheumatoid arthritis (RA) is a chronic, multi-systemic, autoimmune disorder of unknown cause.
It affects most of races with Arthritis and Disease Management prevalence of around 1 percent, although prevalence is lower among rural Sub-Saharan Africans and Caribbean Blacks and is higher among Pima Indians in the USA.
Onset typically occurs between the ages of 20 and 50, and is more prevalent among women, with a gender ratio of 2.
5:1.
The precise etiology of RA remains largely unknown, although several interactive, risk factors are believed to be involved.
Family studies suggest there is a genetic tendency to RA.
For example, severe RA appears at four times the expected rate among first-degree relatives of people with RA who test positive for rheumatoid factor.
Further, around 10 percent of people with RA have an effected first-degree relative.
The hereditary tendency has been linked to the human leukocyte antigen, HLA-DR4, although the precise mechanism is poorly understood.
The predominance of RA among women has led to investigation of sex hormones, menstrual and reproductive factors as possible risk factors.
For example, it is widely known that pregnancy can be associated with disease remission, followed by exacerbations during the postpartum period.
Although evidence is inconclusive, there are indications that oral contraceptives protect or postpone development of severe RA.
Several studies report an increased prevalence of RA among smokers.
Further, smoking has been associated with greater disease severity independent of age, disease duration or treatment.
Other factors thought to predispose individuals to the development of RA include low socioeconomic status, low levels of education, stress and trauma.
Regarding the last of these, a case-control study compared 262 RA outpatients with age- and sex-matched controls (262) attending non-rheumatology outpatient clinics fifty five (21 percent) of the RA patients reported significant physical trauma (for example injury) during the previous six months before disease onset, compared to 17 (6.
5 percent) of the controls.
Interestingly, history of trauma was more common among patients who were seronegative for rheumatoid factor.
The authors suggest that those with seronegative RA might have a different form of inflammatory arthritis that is precipitated by physical trauma.
It affects most of races with Arthritis and Disease Management prevalence of around 1 percent, although prevalence is lower among rural Sub-Saharan Africans and Caribbean Blacks and is higher among Pima Indians in the USA.
Onset typically occurs between the ages of 20 and 50, and is more prevalent among women, with a gender ratio of 2.
5:1.
The precise etiology of RA remains largely unknown, although several interactive, risk factors are believed to be involved.
Family studies suggest there is a genetic tendency to RA.
For example, severe RA appears at four times the expected rate among first-degree relatives of people with RA who test positive for rheumatoid factor.
Further, around 10 percent of people with RA have an effected first-degree relative.
The hereditary tendency has been linked to the human leukocyte antigen, HLA-DR4, although the precise mechanism is poorly understood.
The predominance of RA among women has led to investigation of sex hormones, menstrual and reproductive factors as possible risk factors.
For example, it is widely known that pregnancy can be associated with disease remission, followed by exacerbations during the postpartum period.
Although evidence is inconclusive, there are indications that oral contraceptives protect or postpone development of severe RA.
Several studies report an increased prevalence of RA among smokers.
Further, smoking has been associated with greater disease severity independent of age, disease duration or treatment.
Other factors thought to predispose individuals to the development of RA include low socioeconomic status, low levels of education, stress and trauma.
Regarding the last of these, a case-control study compared 262 RA outpatients with age- and sex-matched controls (262) attending non-rheumatology outpatient clinics fifty five (21 percent) of the RA patients reported significant physical trauma (for example injury) during the previous six months before disease onset, compared to 17 (6.
5 percent) of the controls.
Interestingly, history of trauma was more common among patients who were seronegative for rheumatoid factor.
The authors suggest that those with seronegative RA might have a different form of inflammatory arthritis that is precipitated by physical trauma.
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