It’s long been recognized that persons with rheumatoid arthritis (RA) have an increased risk of heart disease. Researchers may have identified one of the possible causes for the disproportionate heart disease risk. In a study conducted by John Hopkins University in Baltimore, researchers found that patients with RA had a 51 percent greater percentage of visceral fat that their RA-free counterparts.
Visceral fat, unlike subcutaneous fat, is the kind of fat that you can’t see. It lies deep under the layers of subcutaneous fat (surface fat that you can “see”) and makes it home around the abdominal organs. Visceral fat is fat that makes your mid-section wide and contributes to the development of some very unpleasant health conditions such as: diabetes, high blood pressure, some types of cancer, metabolic syndrome, and diabetes. It’s also a risk factor in the development of heart disease. A 51 percent greater rate of visceral fat could explain in part why the instance of heart disease is so high in patients with RA.
The study consisted of 131 participants with RA and an additional 121 participants who were RA-free. The average age of the study participants was 62 years and all where white in terms of ethnicity. In addition, all participants were currently part of other studies relating to heart disease. In examining risk factors for heart disease (and adjusting for such things as medications), researchers found as follows:
• Diabetes: With respect to diabetes, there was little difference between the RA and RA-free group. Approximately 8 percent of both groups were found to have diabetes.
• Hypertension: The instance of hypertension was much higher in RA patients (57 percent in RA patients as compared to 42 percent in their RA-free counterparts).
• Metabolic syndrome: Researchers observed that metabolic syndrome was more common in RA patients (36 percent to 27 percent).
• Total fat: There was little difference between total fat in the male RA group and control group. The total fat rate for women with RA was 41 percent greater than RA-free counterparts.
• Subcutaneous fat: As with total fat, the subcutaneous fat between the control and RA group did not exhibit much difference in men. In women, however, the difference was significant with women RA patients having a 68 percent higher rate of subcutaneous fat.
• Visceral fat: Male RA patients had higher rates of visceral fat (51 percent). Overall, RA patients had 33 percent higher rates of visceral fat than those in the control group.
• Men had higher rates of visceral fat in RA patients and higher rates of metabolic syndrome.
Researchers think that one possible reason for the difference between the increased risk factors for heart disease in the RA group and the control group may be the use of prednisone. Prednisone is commonly used to treat symptoms of RA. It’s also known to cause visceral fat to increase the amount of glucose it’s able to take in. The RA participants receiving the highest doses of prednisone were found to have the highest instances of visceral fat and metabolic syndrome. In addition, those with the highest levels of visceral fat were also found to have the highest levels of fasting blood glucose (58 percent), high blood pressure (63 percent) and metabolic syndrome 74 percent).
Visceral fat can be difficult to diagnose because it’s unseen fat. Waist measurement and body mass index isn’t an indicator of whether or not you have visceral fat. For example, in the two groups, both the RA patients and the control group had approximately the same BMI and waist measurements. Researchers indicated that maintaining a healthy weight and limiting the amount of drugs such as prednisone (or similar medications) may help reduce the risk of heart disease in RA patients.
Sources:
Nancy Walsh, Visceral Fat High Among RA Patients, 05 Nov 2010, http://www.medpagetoday.com/Cardiology/MetabolicSyndrome/23182
Belly fat in women: How to keep it off, The Mayo Clinic, 16 Apr 2009, http://www.mayoclinic.com/health/belly-fat/WO00128