A possible explanation for the association

A possible explanation for the association between psoriasis and subclinical atherosclerosis is the presence of chronic inflammation that occurs because of persistent secretion of TNF-α and other proinflammatory cytokines such as interleukin-1 and interleukin-6, which precipitate psoriasis. Chronic systemic inflammation induces endothelial dysfunction, altered resperidone metabolism, and insulin resistance that play a significant role in the development of atherosclerosis. It has been proposed that a state of low-grade inflammation, similar to that present in psoriasis, leads to the production of adipokines, particularly from truncal fat. This process results in insulin resistance and diabetogenic tendency, and several studies clearly reported the association between psoriasis and diabetes. In our study, we observed an increased HbA1c and fasting plasma glucose level in psoriatic patients, compared with healthy controls. Furthermore, HbA1c was found to be an independent predictor of severity of psoriasis; this finding of our study is different from those of previous studies. This is probably because HbA1c was significantly associated with the duration of disease, suggesting long-standing inflammation similar to that in psoriatic patients. BMI and waist circumference are complex variables that seem to affect immunity. It has been documented that circulatory levels of TNF-α are significantly increased in obese compared with nonobese individuals. In 2005, Naldi and colleagues even reported BMI to be one of the risk factors associated with psoriasis in their case–control study. Although BMI has most widely been used to measure obesity in populations as an individual\'s level of cardiovascular risk, in recent years, abdominal obesity, principally waist circumference, which more accurately describes the distribution of body fat compared with BMI, has been suggested to be more closely associated with subsequent morbidity and mortality. In the present study, although the mean values of BMI and waist circumference in psoriasis patients were slightly higher than those in controls, there was no statistically significant difference between the two groups. Serum lipids are strong predictors of atherosclerosis and cardiovascular risk. Numerous studies have mentioned that increased clinical cardiovascular morbidity in patients with psoriasis was explained in part by the presence of a pathogenic lipid profile in these patients. In our study, although high-density lipoprotein was higher in the control group, while serum triglycerides, low-density lipoprotein, and total cholesterol were higher in the patient group, these failed to reach a statistically significant difference. In contrast to many previous studies, there was no significant positive correlation between serum lipid parameters and severity of psoriasis. In accordance with many previous studies, we observe that levels of systolic and diastolic blood pressure were significantly elevated in patients with psoriasis compared with controls. Blood pressures are predictors of cardiovascular risk, and our findings are in agreement with the notion of a long-term increase in risk of hypertension and late adverse cardiovascular events in these individuals. Clinically evident atherosclerosis is preceded by preclinical changes in the arterial wall, namely, intima–media complex thickening. Several previous studies revealed that CIMT was increased in psoriatic patients compared with that in healthy individuals. Although common results from previous studies point out an increase in CIMT in psoriatic patients, there are also conflicting results in terms of the factors leading to increased CIMT values. In a study by El-Mongy et al, CIMT was found to be increased in patients with psoriasis without any accompanying risk factors for atherosclerosis. CIMT is biologically and genetically distinct phenotypes of early atherosclerosis. It differs with respect to their natural history, their risk factor patterns, and their predictive value for cardiovascular and cerebrovascular events. CIMT indicates the degree of atherosclerosis caused by systemic inflammation, and it is expected to increase in parallel to the severity of inflammation. Therefore, the relationship between CIMT and PASI can be more apparent than that among other traditional cardiovascular risk factors. We intended to exclude patients with classic cardiovascular risk factors from our study. Interestingly, with multivariate linear regression modeling, CIMT was the most independent predictor of severity of psoriasis indicated by PASI score. To the best of our knowledge, there was no similar correlation in the literature to compare with, as there were only a few studies including psoriatic patients without classic cardiovascular risk factors.