Greater body mass index (BMI) relating to obesity are often linked with higher levels of CRP and ESR, this initiated the researchers to determine the underlying bias behind blood testing for rheumatoid arthritis (RA). The research was pioneered by Michael George, MD MSCE, of the University of Pennsylvania Health System.

Blood tests for C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) assess levels of inflammation in the body thus, may also direct RA. According to Eurekalert, greater BMI was associated with greater CRP in women with severe obesity and RA. ESR has also a slight association in women's body weight and index. These associations were also observed in men, however; the connection between ESR, CRP, and BMI was different. In men with rheumatoid arthritis, lower BMI was associated with greater ESR and CRP.

The findings regarding the difference in the association of obesity, rheumatoid arthritis, ESR, and CRP is very important between weight and inflammation in men and women. The results of the study show that obesity leads to increased levels of CRP and ESR in women with RA, as stated by Dr. George. He also added that the increase in the levels of inflammation was not because of RA rather because of obesity.

As reported by Medicine Net, rheumatoid arthritis is an autoimmune disease that leads to chronic inflammation of the joints and other areas of the body. There is no existing cure for RA the treatment only involves a combination of patient education, rest, diet, exercise, joint protection, medications and in some cases surgery.

Obesity in women leads to very similar increases in CRP and ESR even in women without rheumatoid arthritis. The researchers then warned physicians to take note of these laboratory tests as some might assume that an increase in levels of inflammation is caused by RA alone. Obesity and RA should be taken into account regarding inflammation in order to create the best treatment option.