The detection of high-risk people and performing appropriate screening tests on them has important health-related and economic advantages as regards the prevention of colorectal cancer [16]. In the present study, the prevalence of colon polyp among the first-degree relatives of the patients with adenomatous polyp was 34.6%. More than 60% of the detected polyps were neoplastic. The prevalence of neoplastic colon polyp among the siblings of the patients with advanced adenoma was reported to be 11.5% in the study conducted by NG SC et al. [17] and 4.4% in the study conducted by Cottet et al. [18] The higher prevalence of neoplastic polyp in the current study might be the result of different regional factors, dietary regimens, genetic features of the subjects, or higher accuracy in detecting such polyps. In addition, the most prevalent pathology issue in this study was found to be tubular adenoma, which is consistent with the findings reported in previous studies [18–20].
Based on the findings of the current study, polyps were most frequently observed in the rectum; however, large polyps had the highest frequency in the right side of the colon, which was consistent with the findings of the previous studies [21–23]. The reason for this might be the easier diagnosis of small polyps in the left side of the colon, where most of the polyps are hyperplastic [24].
The results revealed that as the age increased, the probability of getting colon polyp also increased. More specifically, with the increase of 1 year in the age of the participants, the probability of getting colon polyp increased by 10%. This finding is consistent with the findings reported in the majority of previous studies [18–20, 25, 26]. Age is an important risk factor for colorectal cancer. This disease rarely occurs before 40 years of age. From 40 to 50 years of age, its incidence rate gradually increases. Beyond that, the incidence of the disease increases considerably [25, 27]. About 85% of the total colorectal cancers are adenocarcinomas, which themselves arise from adenomatous polyps [28]. The incidence rate of colorectal carcinomas in populations with a higher prevalence of mucosal polyps has been found to be higher, and the risk of cancer is also directly associated with the frequency of these polyps [29]. Therefore, it seems that the increased probability of polyps with the increase of age is consistent with the elevated incidence rate of colorectal cancer at higher ages.
In the present study, the probability of getting colon polyp was higher in smokers as compared to non-smokers. In line with our finding, previous studies [30–32] have also indicated that smoking is strongly associated with the higher risk of colorectal polyps. The carcinogens present in tobacco increase the incidence of colorectal cancer [33]. Therefore, it can be argued that smoking causes an increase in the incidence of polyps and, in turn, colorectal cancer either independently or in combination with other factors such as family history of adenomatous polyp.
The results of the current study also indicated that the chances of getting colon polyp was higher among people suffering from hypertension as compared to the normal population. This finding was inconsistent with the finding reported by Ng SC et al. [17] This observation might be due to the higher prevalence of hypertension at higher ages that leads to the elevated probability of polyp development in the affected patients.
The results of this study also revealed that the increase in the consumption of vegetables and fruits significantly reduced the probability of getting colon polyp. The relationship between dietary fiber and colon cancer has been under investigation for three decades; however, no definite relationship has been recognized to date [34, 35]. Higher proportion of dietary fiber in everyday dietary regimen can reduce the recurrence rate of colorectal adenomas [36]. Similar to the process of carcinogenesis, the possible mechanism is that the fiber undergoes anaerobic glycolysis and, therefore, can be oxidized and converted into short-chain fatty acid. The resulting fatty acid can then play a key role in inhibiting cell proliferation and facilitating apoptosis or cell differentiation [37].Therefore, it is expected that the dietary regimens containing vegetables and fruits (due to having plenty of fiber) and the foods containing calcium, selenium, vitamins, folic acid, carotenoids, and plant phenolics play a protective role against CRC [38]. In some studies [39, 40], a relationship has been observed between the consumption of red meat and the recurrence of various colorectal adenomas. In the present study, however, no such relationship was observed, the reason for which might be the eating habits of the subjects under investigation and the lower consumption of red meat by the people living in this region. Yet, further analyses with larger sample sizes can shed more light on the role of the consumption of red meat in the development and progression of colon polyps as the precursors to colorectal cancer.
This study was conducted by one researcher in one place and the preparations were all provided uniformly for all of the participants. The present study has several limitations that should be considered when interpreting the findings. First, the sample size was relatively small, which may have reduced the statistical power to detect factors associated with the presence of polyp colon. Second, the particular conditions of the province in terms of the COVID-19 pandemic, which limited our access to more participants, and the lack of a control group were limitations of the study.