New insight into why more women than men have arthritis
Posted by on February 18, 2013 - 11:55am

Rheumatoid arthritis (RA) strikes three times more women than men and researchers in Europe may have found a clue.   Scientists at the Arthritis Research UK Epidemiology Unit at the U of Manchester have discovered 14 new genes that can lead to RA, adding to the 32 other genes that have already been identified.  The researchers latest study published in Nature Genetics, has reported genes that are specific to the female X-chromosome.  According to Professor Alan Silman, medical director at the Research Unit, "This is the first time that a genetic association has been established between RA and the X chromosome."

 

To "sun" or not to "sun"--is there a logical balance?
Posted by on February 12, 2013 - 2:50pm

More intense sunlight exposure was linked with a decreased incidence of rheumatoid arthritis (RA) among women in the original Nurses' Health Study (NHS), although the more common use of sunscreen likely weakened the association in a later cohort, researchers found.   Rheumatoid arthritis, or RA, is a form of inflammatory arthritis and an autoimmune disease. For reasons no one fully understands, in rheumatoid arthritis, the immune system – which is designed to protect our health by attacking foreign cells such as viruses and bacteria – instead attacks the body’s own tissues, specifically the synovium, a thin membrane that lines the joints. As a result of the attack, fluid builds up in the joints, causing pain in the joints and inflammation that’s systemic – meaning it can occur throughout the body.

In the original Nurses' Health Study, which began in 1976, women (ages 30 to 55) living in states with the highest ultraviolet B (UVB) intensity had a 21% lower risk for RA compared with those living in states with low UVB levels according to Elizabeth Arkema, PhD, and colleagues from Harvard University.

But in NHSII, initiated in 1989 in women ages 25 to 42, no significantly lower risk was seen, the researchers reported online in Annals of the Rheumatic Diseases.

"The later birth cohort of NHSII participants (born between 1946 and 1964) were more likely aware of the dangers of sun exposure and, perhaps, had more sun-protective behavior, making residential UVB not as good a proxy for actual sun exposure in NHSII," they suggested.

Epidemiologic studies have found a correlation between an increased incidence of RA and other autoimmune diseases with higher latitude (more northern) areas  of residence.  In addition, experimental studies have demonstrated that UVB may suppress the immune system (which overacts in RA).  Exposure to UVB also increases vitamin D synthesis in the skin, which, in turn, has altering effects on the immune system properties.

UVB flux is a measure that reflects exposure intensity based on altitude, latitude, and typical cloud cover patterns, and is expressed in Robertson-Berger units. This measure shows considerable variability in the U.S., ranging from 196 R-B units in sunny states such as Arizona and Hawaii to only 93 units in Oregon and Alaska.

Information on residence, health, diet, and lifestyle was acquired every 2 years from participants in both cohorts.

Similar findings of decreased risk for high exposure in NHS though not in NHSII were seen both for exposure levels at birth and at age 15.  It thus remains unclear if the important window for UVB exposure is in childhood or adulthood. Further analyses found no significant heterogeneity according to skin type, vitamin D intake, or physical activity and body mass index.

These findings add to the increasing evidence that more intense sun exposure lowers the risk of RA, the researchers stated.  "The mechanisms are not yet understood, but could be mediated by cutaneous production of vitamin D and attenuated by use of sunscreen or sun avoidant behavior," Arkema and colleagues wrote.  They called for additional research to explore UVB dose intensity and timing of exposure.

EDITOR's NOTE:   While the link to skin cancer and UVB exposure is well known, the increased use of sunscreen raises other health concerns that may require new approaches to find a "balance" so the benefits of  a little sunshine are not totally lost.
Source reference:
Arkema E, et al "Exposure to ultraviolent-B and risk of developing rheumatoid arthritis among women in the Nurses' Health Study" Ann Rheum Dis 2013; DOI: 10.1136/annrheumdis-2012-202302.

 

Arthritis Prevalence Higher in Women than Men
Posted by on August 31, 2010 - 10:24am

In 2006, the Center for Disease Control and Prevention (CDC) reported that 21.6% of the US adult population reported arthritis, with significantly higher prevalence in women than in men (24.4% vs. 18.1%). Arthritis prevalence increased with age and was higher among women than men in every age group.    With the aging of the US population, the prevalence of doctor-diagnosed arthritis is expected to increase in the coming decades.   By 2030, it is estimated that 67 million adults age 18 and older will have arthritis, compared with the current 46 million.  Also, by 2030 an estimated 25 million adults will report arthritis-attributable activity limitations.

Functional limitations in routine activities are common among adults with arthrtis:   40% report it is "very difficult" or they "cannot do" at least 1 of 9 important daily functions which include their ability to stoop, bend, grasp, kneel or walk 1/4 mile.  Obesity is a known risk factor for the progression of knee osteoarthritis and possibly of other joints.   Reducing body weight may result in significant improvement in the health-related quality of life of people with arthritis.

Although physical activity and exercise have been shown to benefit people with arthritis by improving pain control, function, and mental health, many people with arthritis report no leisure time physical activity. Low levels of physical activity place individuals with arthritis at further risk of inactivity-associated conditions such as cardiovascular disease, diabetes, obesity, and functional limitations.

Some interesting research is currently taking place at Northwestern U. that is looking at knee alignment and its role in progression of knee osteoarthritis that could lead to earlier and novel interventions that could decrease or prevent arthritic disability in the future.  Many Illinois women who are part of the Illinois Women's Health Registry are participating in those studies.

In the meantime, women (and men) who have arthritis could benefit from keeping their weight down and keeping physically active!!!   As we age, it is even more important that we develop a lifestyle that includes healthy eating and exercise.


Overlooked or misdiagnosed conditions in women
Posted by on October 19, 2009 - 9:18am
Image: WOLDCnews.com

Image: WOLDCnews.com

CNN Health has just published a nice article outlining many conditions that can be overlooked in women, including polycystic ovary syndrome (PCOS), fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome (IBS), and several autoimmune disorders such as lupus, rheumatoid arthritis, and multiple sclerosis. Included in the article is a quote from Virginia Ladd, founder and executive director of the American Autoimmune Related Diseases Association:

"More than 40 percent of women eventually diagnosed with a serious autoimmune disease have basically been told by a doctor that they're just too concerned with their health or they're a hypochondriac."

The resounding message of the article is to trust your (possibly irritable) gut; if you feel off somehow, keep pursuing the topic with your doctor or get a second opinion.

PS- Look for our blog entry on Wednesday about autoimmune disorders and X chromosome inactivation. It will be a more in-depth entry about the genetic reasons women are more at risk for these conditions.

Autoimmunity Disorders and Gender
Posted by on September 22, 2009 - 12:48pm

The NIH has a pretty cool monthly podcast called “Pinn Point on Women’s Health,” which is hosted by Dr. Vivian Pinn, director of the NIH’s Office of Research on Women’s Health. For September, the topic was Autoimmune Disease in women (NIH summary and directions for downloading the podcast can be found here.)

The topic is fascinating! Autoimmune diseases are those where the body , for whatever reason, starts fighting its own cells with an immune response in the same way it would if the cells were a foreign invader (bacteria, virus etc). Women are more likely to get a whole host of autoimmune diseases than men are, including multiple sclerosis, rheumatoid arthritis, and lupus. Apparently, out of all the people suffering from auto-immune diseases in the US, 80% are female. That’s a phenomenal bias for a condition that, on the surface at least, has no clear tie to gender. According to the research (great review here), our increased risk of getting these diseases is simply our great immune systems working against us. Apparently, our immune systems are so great that we’re less prone to infection and have a much greater antibody response to those little invaders that do get in. Unfortunately, our systems are so strong that they also tend to go into overdrive, leading to this attack of our own bodies. The culprits (or overachieving heroes, depending on how you look at it), are likely exactly what you’d expect: hormones or chromosomal influences. The hormone research actually shows that during pregnancy, women's immune systems switch to a far less aggressive regimen, likely to avoid attacking the fetus as an invader. This decreased immunity is the reason for the increased risk of pregnant women getting the flu that Alison mentioned, but it’s also the reason that many pregnant women notice a decrease in their symptoms of autoimmune disorders. I actually have/had a condition called tranverse myelitis, which is thought to be an autoimmune disorder; I also very rarely catch the normal seasonal bugs that float around the office, and I don’t think I’ve ever had the flu (knock on wood!). It’s kind of amazing to think that both the bad and the good stem from the same source: an incredibly strong immune system! Anyone else notice that same thing in his/her self, or anyone they know with autoimmune disorders?