No association was observed between dietary inflammatory potential (DIP) and endothelial biomarkers including E-selectin, sVCAM-1 and sICAM-1 in the participants. This dissociation remained significant after adjusting for possible confounders. This is the first study of the association between adhesion molecules and DIP. Other studies assessed the correlation between DIP and cardiovascular disease.
Adhesion of circulating molecules, including E-selectin, sICAM-1 and sVCAM-1, plays an essential role in endothelial dysfunction and atherosclerosis [14, 35–39]. Furthermore, reactive oxygen species (ROS) activate endothelial markers by inducing E-selectin, sICAM-1 and sVCAM-1. It has been reported that sICAM-1 plays an important role as a predictor of CVD [40]. Moreover, the sVCAM-1 expression represents the inflammatory conditions of the vascular walls and predicts fatal coronary artery disease in the future [39, 41]. Plasma levels of endothelial markers such as sE-selectin and sICAM-1 correlate with prognosis [11]. Many studies have assessed the correlation of DIP with CVD.
The results of the present study are consistent with a study by Imran khan et al who carried out a cohort study on 1111 subjects to evaluate the relationship between DIP and cardiovascular disease (CVD). The results showed no a significant correlation between DIP and CVD in females while a significant relationship was found in male subjects [42]. Similarly, Gabriela Pocovi-Gerardino et al conducted a cross-sectional study on 105 women with a mean age of 45.4 years old and found no significant correlation between the DIP score and CVD markers [43]. A study of 585 women aged 50–55 years old by Linda E. T. Vissers et al failed to show any correlation between DIP and CVD, ischemic heart disease, and myocardial infarction (MI) [44]. Furthermore, a prospective case-control study of 100000 participants showed no significant relationship between DII and MI [45].
By contrast, Bondonno et al reported that a high DIP score was associated with atherosclerotic vascular disease in women aged over 70 although they did not find any association between DIP and carotid plaque severity [46]. Moreover, Stefanos Tyrovolas et al carried out a dose-dependent study to assess the correlation between DIP and CVD risk factors. They found a significant correlation between DIP and CVD risk factors such as diabetes mellitus, obesity, hypertension, and hypercholesterolemia. In addition, the participants with a high DIP score in the 3rd and 4th quartile had at least one CVD risk factor in comparison to the participants in the 1st quartile [47].
It was difficult to sort out consistent results with our findings because many studies were carried out on subjects with unhealthy conditions. Moreover, there were differences between the studies in terms of the sample size. The geographic dietary pattern may also affect the results. Furthermore, many studies did not measure the plasma levels of sICAM-1, sVCAM-1 and E-selectin directly. Therefore, more studies are required to assess the correlation between endothelial markers and the DIP score.
This study had some limitations. For example, it had a cross-sectional design and therefore no conclusions can be made regarding causality. Moreover, there were some unknown confounders including shift time, bias in reporting food items, and difference in the dietary pattern between nurses in private and public hospitals, which could affect the results. Studies with larger sample sizes are required to obtain concrete results.