Psoriasis and Type 2 Diabetes, What's the Connection?
Psoriasis is an inflammatory disease that affects the skin while type 2 diabetes is a condition characterized by high levels of sugar in the bloodstream. On the surface, there doesn't appear to be a connection between these two conditions, yet a new study suggests that psoriasis is a risk factor for type 2 diabetes.
Why is psoriasis a risk factor for diabetes?
Psoriasis is a chronic condition that typically causes red, raised patches of silver-white patches of dead skin cells to appear anywhere on the body, although it can also manifest as smooth, bright-red lesions or blisters. As many as 7.5 million Americans have psoriasis, which is the most common autoimmune disease in the United States.
Type 2 diabetes is a condition in which the body either does not produce enough insulin or the cells cannot properly utilize the insulin. The task of insulin is to transport sugar (glucose) from the bloodstream into the cells. So far, nothing suggests psoriasis and type 2 diabetes have a connection.
However, results of a study from the United Kingdom indicate that having psoriasis may be a risk factor for type 2 diabetes, and that having severe psoriasis is associated with a greater risk than is a mild form of the disease. To come to that conclusion, the study's authors used data from The Health Improvement Network.
The Network data involved 108,132 individuals with psoriasis and 430,716 patients without it. Participants ranged in age from 18 to 90 years.
An evaluation of the data indicated having psoriasis is a risk factor for type 2 diabetes. Why? According to the study's authors, "Mechanistically, this relationship may be driven by chronic inflammation because both psoriasis and T2DM [type 2 diabetes] are associated with elevated levels of Th1-driven inflammatory markers, and because several studies have pointed to endogenous insulin resistance in patients with psoriasis."
The authors also observed that patients who had severe psoriasis were more likely to have a prescription for oral antidiabetes drugs. There was also a trend among those with severe psoriasis being prescribed insulin than were patients who had mild psoriasis.
Other research of psoriasis and diabetes
Another recent study looked at a relationship between psoriasis and an increased risk of developing diabetes. The meta-analysis evaluated 22 studies that included more than 3 million patients. The reviewers found that compared with individuals who did not have psoriasis, those who had the skin condition had a 1.42-fold increased risk of diabetes.
An earlier study examined an increased prevalence of both diabetes and hypertension among people with psoriasis. A total of 304 people with psoriasis and 300 without were enrolled in the study.
The authors found that among patients with psoriasis, the prevalence of diabetes in women was significantly greater than in men, but this difference did not carry over into women without psoriasis. Diabetes was significantly more prevalent among people with psoriasis compared with those without psoriasis, and hypertension also was more common in psoriasis patients than in those without the autoimmune disease.
Compared with earlier research, the current study was unique because it is believed to be the largest to date to examine the relationship between psoriasis and type 2 diabetes. The authors explained that because they studied a large population, they were able to achieve "a high degree of precision."
The authors suggest further research be planned to better define "the extent to which psoriasis and its treatment play a role in the development of T2DM and its complications." They also pointed out it is necessary to understand why individuals with severe psoriasis who develop type 2 diabetes are more likely to be given a prescription for antidiabetes medications.
Cheng J et al. Psoriasis increased the risk of diabetes: a meta-analysis. Archives of Dermatologic Research 2012 Mar; 304(2): 119-25
Ghiasi M et al. Psoriasis and increased prevalence of hypertension and diabetes mellitus. Indian Journal of Dermatology 2011 Sep-Oct; 56(5): 533-36
National Psoriasis Foundation
Rahat SA et al. Increased rate of diabetes mellitus and likelihood of receiving diabetes mellitus treatment in patients with psoriasis. Archives of Dermatology 2012; 1-6. doi: 10.1001/archdermatol.2012.1401
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