A new study suggests that people with the common skin disease have higher levels of the hormone leptin, which regulates food intake, body weight, and fat stores and is also thought to play a role in immune and inflammatory processes. Those elevated leptin levels may in turn make them more likely to become obese or develop high blood pressure, diabetes, and other heart disease risk factors.
Psoriasis is a disease affecting the immune system that causes red, silvery, scaly skin. Previous studies have linked the skin disease to obesity, heart disease, diabetes, and metabolic syndrome (a clustering of health problems linked to increased risk of heart disease and diabetes), but the mechanism behind these relationships is unclear.
In the study, researchers in Taiwan studied 77 people with psoriasis and 81 individuals of similar age and sex without the skin disease in 2006 and 2007.
The results showed that those with psoriasis were more than twice as likely to be obese or have high blood pressure.
Elevated levels of leptin were also more likely to be found in women, obese participants, and those with hypertension, metabolic syndrome, or psoriasis.
After taking into account obesity, being female, or already having metabolic syndrome, they found that having psoriasis was associated with having high leptin levels.
Researchers say the results suggest that the higher levels of leptin found in people with psoriasis may be at least one contributor to the additional health risks previously linked to psoriasis.
"The high circulating leptin levels in individuals with psoriasis may derive not only from fat tissue but also from inflammation," write researcher Yi-Ju Chen, MD, of Taichung Veterans General Hospital and National Chung Hsing University in Taiwan, and colleagues in the Archives of Dermatology.
"Body weight loss has been reported to significantly decrease leptin levels and improve insulin sensitivity and may reduce the likelihood of developing metabolic syndrome and adverse cardiovascular diseases," they write. "Body weight loss could potentially become part of the general treatment of psoriasis, especially in patients with obesity."
Although the results suggest that psoriasis is associated with elevated leptin levels, researchers say more study is needed to determine if the inflammatory processes associated with psoriasis cause increased leptin production, and what effect leptin has on immune cells and skin cells in psoriasis.