The Association between Anthropometric Indicators and Colorectal Polyps and Diverticulosis

Abstract Introduction  Colonic polyps and diverticulosis are common colon findings on colonoscopy. One of the risk factors of colorectal polyps and diverticulosis is the anthropometric index. Therefore, we aimed to investigate the association between the anthropometric index and colorectal findings. Methods  In this cross-sectional study, we included 536 patients referred to Razi Hospital, Rasht, Iran, in 2023 for colonoscopy evaluation. Demographical data, clinical characteristics, and colonoscopy findings were recorded for further analysis. All data were analyzed using SPSS.16 by considering a significant level < 0.05 Results  The results showed that 35.4% of the patients had polyps, with the majority having a single polyp. The patient's mean age was 55.94 ± 13.33 years; most were females (54.1%). The most common type of polyp was pedunculated, and most were located in the sigmoid colon. The prevalence of diverticular was 11.4%, most of which were also located in the sigmoid colon. Obesity was significantly associated with an increased risk of polyps, while overweight individuals had a higher risk of diverticula ( P  < 0.05). Age, rural residence, and low physical activity level were identified as factors associated with an increased risk of polyps and diverticula. Conclusion  The findings suggest that obesity and overweight are risk factors for polyps and diverticula, respectively. Further research is warranted to explore additional factors and develop preventive strategies for colorectal diseases. These results support the need for preventive strategies and screening programs to reduce the risk of future colorectal lesions.


Introduction
Colorectal polyps and diverticulosis are two common gastrointestinal conditions that affect a significant portion of the population worldwide.5][6] The incidence of diverticulosis increases with age, affecting approximately individuals younger than 40. 7,8][11] The etiology of colorectal polyps and diverticulosis involves a complex interplay of genetic, environmental, and lifestyle factors.While the exact mechanisms underlying their development are not fully understood, several hypotheses have been proposed.Colorectal polyps may arise from genetic mutations, chronic inflammation, and dietary factors. 12,13nthropometric indicators, waist-to-hip ratio (WHR), and body mass index (BMI) indicators of central adiposity have also been linked to an elevated risk of these colorectal disorders.][16] On the other hand, diverticulosis is thought to result from increased colonic pressure and structural alterations in the intestinal wall. 17Factors such as a low-fiber diet, obesity, a sedentary lifestyle, and aging contribute to the development of diverticulosis.Chronic constipation and prolonged straining during bowel movements may also play a role in the formation of diverticular pouches.Obesity, defined as a high BMI, has been consistently associated with an increased risk of both conditions. 18,19Excess body weight and abdominal adiposity are thought to promote chronic inflammation, insulin resistance, and hormonal imbalances, which can contribute to developing colorectal polyps and diverticulosis. 20,21Obesity and central adiposity play a prominent role in their development, highlighting the importance of maintaining a healthy weight and daily physical activity. 22,23owever, further research is needed to elucidate the underlying mechanisms and establish more robust causal relationships.By better understanding the association between anthropometric indicators and colorectal polyps and diverticulosis, healthcare professionals can enhance preventive strategies, early detection, and management of these gastrointestinal disorders; in this regard, we conducted this study to investigate the association between BMI and WHR, and prevalence of colorectal polyp and diverticulosis.

Study Design
This cross-sectional study was conducted on 536 patients referred for colonoscopy evaluation at the Razi Hospital, Rasht, Iran, in 2023.Patients were selected through a convenience sampling method during 2023.The demographical and clinical data of patients, including age, gender, habitat (urban or rural), educational level (illiterate, under diploma, diploma, and with a university degree), history of smoking, alcohol consumption, occupational exposure, family history of colorectal cancer, level of physical activity according to International Physical Activity Questionnaires (IPAQ) 24 as low, middle, and high, BMI as low weight BMI < 18.5 kg/m 2 ), average weight (BMI ¼ 18.5-24.99kg/m 2 ), overweight (BMI ¼ 25-29.9kg/m 2 ), and obese (BMI!30 kg/m 2 , and WHR as low, normal, and high-risk, were recorded.Moreover, colonoscopy findings included types and numbers of polyps (pedunculated or sessile), size of polyps (<5mm, 5-10 mm, and >10 mm), numbers of diverticula, and location of polyps and diverticula (rectum, sigmoid colon, descending colon, ascending colon, and cecum).Patients with a history of gastrointestinal and other underlying diseases, inflammation, malignancies, and colectomy were excluded from the study.This study was approved by the ethical committee of the Guilan University of Medical Sciences (IR.GUMS.REC.1401.505).All patients gave their consent to participate in the study.

Statistical Analysis
The variables are number (percentage) and mean AE standard deviation (SD).Chi-square and independent t-tests were performed to assess the association between groups.Moreover, the Cochran-Armitage test was used to compare the studied outcomes in different levels of BMI and WHR in three models (Model 1: Unadjusted, Model 2: Adjusted for age and gender, and Model 3: Adjusted for age, gender, etc.).Logistic regression was applied to evaluate the association between exposure and outcomes.The results were presented as crude odds ratio (OR) and adjusted odds ratio (aOR) with 95% confidence intervals (95% CI).The data was analyzed using SPSSversion 16 software, and a significance level of 0.05 was considered.

Results
The frequency of demographical data and clinical characteristics of the patients referred for colonoscopy have been illustrated in ►Table 1.According to the results, the patient's mean age, BMI, and WHR were 55. 94  one, two, three, and four polyps, respectively.Among 265 detected polyps, most were pedunculated, measured >10 mm, with the location in the sigmoid colon.The frequency of 11.4% (n ¼ 61) in patients.Among them, 52.5%, 16.4%, 13.1%, and 18.0% had diverticula in one, two, three, and four locations, respectively, most located in the sigmoid colon.
The results of the Cochrane-Armitage test in three models illustrated that in models 1 and 2, polyps' OR significantly increased in obese individuals (P < 0.05).In all three models, the OR of diverticula was significantly increased in overweight individuals (P < 0.05).The chance of developing polyps was significantly associated with high-risk WHR in model 2 (P < 0.05).At the same time, no association was observed between the WHR and the chance of developing diverticula in all three models (P > 0.05) (►Table 2).
According to ►Table 3, the prevalence of polyp significantly increased with increasing age and BMI, and it is also higher in rural residents and patients with lower physical activity (P < 0.05).Patients with high-risk WHR represented a higher frequency of polyps, but no statistically significant differences were observed (P > 0.05).The mean age of patients with and without polyps was 58.92 AE 11.93 and 54.31 AE 13.78 years, respectively, significantly different among the two groups (P < 0.001).The mean BMI in patients with and without polyp was 28.51 AE 5.21 and 27.08 AE 4.80 kg/m 2 , respectively, significantly different among the two studied groups (P ¼ 0.002).Also, the mean of WHR in patients with and without polyp was 0.92 AE 0.07 and 0.91 AE 0.07, respectively, which represented no statistically significant difference among the two groups (P ¼ 0.086).
The diverticula's prevalence significantly increased with age and BMI (P < 0.05).Moreover, the frequency of diverticula decreased by increasing physical activity, but no statistically significant differences were reported (P > 0.05).This prevalence in patients with a family history of colorectal cancer was significantly lower than in patients without (P < 0.05).The mean age of patients with and without diverticula was 61.97 AE 11.87 and 55.17 AE 13.32 years, respectively, significantly different among the two groups (P < 0.001).The mean BMI in patients with and without diverticula was 28.57AE 4.45 and 27.46 AE 5.05 kg/m 2 , respectively, illustrating a statistically non-significant difference among the two groups (P ¼ 0.104).Also, the mean of WHR in patients with and without diverticula was 0.92 AE 0.07, which was similar (P ¼ 0.541).
The chance of having diverticulosis in patients with a family history of colorectal cancer was lower than in patients without a family history (P ¼ 0.05).The results showed that upper age had a higher chance of developing diverticulitis (P < 0.05).The chance of getting polyps increased with age, BMI, university degree, rural residents, and low physical activity.The chance of getting polyps in patients with low physical activity was higher compared to patients with moderate and high physical activity levels ►Table 4.

Number of diverticula
In one location 32 (6.0) In two location 10 (1.9) In three location    shown that using colonoscopy to screen for colorectal lesions may help the prevention of malignancy and can reduce colorectal cancer-related deaths by approximately 60 percent. 28,29We performed this study to assess the prevalence and risk factors for the presence and development of colorectal polyps and diverticula.In the cross-sectional study, polyps and diverticula were 35.4% and 11.4%, respectively, indicating a higher prevalence of these lesions than previous studies in the same regional population from 2006 to 2009. 30hese increases are likely the result of an aging population and lifestyle changes and follow trends reported in other developing countries.The frequency of diverticulosis and colorectal polyps in our cohort is consistent with previous studies, showing an increase in frequency with the aging of the patient population. 4,31,323][34] The proportion of patients with polyps and diverticula increased with age, which suggested that age is a significant risk factor for both disorders. 35Compared to our findings, other studies have shown that these lesions increase with age. 32,36The chance for colorectal polyps was higher in obese people, so the chance of developing polyps increased with increasing BMI.Previous studies have shown an association between BMI and colorectal polyps, 4,19,37 but not exclusively. 4,38n this study, polyp prevalence was not statistically significantly associated with WHR, but the chance of polyp development increased with high-risk WHR.Bai et al. demonstrated an association between WHR and conventional adenomas or serrated polyps. 39Another study has indicated that men with a higher BMI and WHR are associated with an increased risk of hyperplastic polyps, adenomas, and the occurrence of both types of polyps. 40The prevalence of colorectal diverticula was higher in overweight people, so the chance of the development of polyps increased with increasing BMI.Prior studies found that Obesity has been associated with an increased risk of colonic diverticulosis. 41,42eery et al. established that obesity (BMI >30) significantly increased the risk of colonic diverticulosis in women but not men. 435][46] However, it is unclear whether WHR concerns diverticulitis in women.Unlike other studies, 47,48 we found that the prevalence and risk of diverticula were unrelated to WHR.In contrast to a study, that showed that the associations between WHR and diverticulitis remained essentially unchanged upon further adjustment of BMI in males, 44 Ma et al. showed that when BMI and WHR were determined together, WHR appeared to play a role in determining diverticulitis in overweight or obese women. 47ontrary to the Fu et al. study, 49 in which people with a lower level of education had a higher risk of polyps, in this study, people with a level of university education had a higher risk of developing colorectal polyps.Perhaps one of the reasons for this result is that people with higher education have more knowledge about diseases and their prevention, and therefore they do medical screenings more often.The current study also demonstrated that rural people have a higher risk of getting polyps.1][52] Medical awareness, access to specialists, and nonadherence to cancer screening recommendations are more likely in rural residents.We observed the expected inverse trend between the chance risk of the polyp and the high level of physical activity.This association is consistent with other studies investigating the protective properties of physical activity and colonic polyps. 53,54The mechanism of this effect is unknown, but it can lead to decreased insulin levels, systemic inflammation, and abdominal obesity. 53,55inally, similar to other studies, [56][57][58] we indicated that patients with a positive family history of diverticulitis are at higher risk for diverticulitis.This phenomenon might be explained by the fact that some genes, such as LAMB4, TNFSF15, ARHGAP15, ANO1, ELN, and SPINT2, play known roles in processes logically related to diverticulitis, including inflammation, intestinal transport, intestinal motility, and extracellular matrix formation. 59,60Our study failed to show the effect of other risk factors of colorectal lesions that need further investigation.

Limitation
One of the limitations of this study is its cross-sectional nature.The limited geographic indications for colonoscopy do not allow any clear conclusions to be drawn, especially considering the lack of comparative studies in this region and Iran.

Conclusion
Our study indicated that colorectal polyps and diverticula are prevalent north of IRAN.Age and BMI were significantly associated with the presence and development of polyps and diverticula.The incidence of colorectal polyps was also influenced by high-risk WHR, university degree, living in rural and low physical activity.In addition, a family history of colorectal cancer affects the risk of diverticulosis development.Due to the possible precursor lesions of colorectal cancer, more attention should be paid to risk factors for colorectal polyps and diverticula to prevent and treat this spectrum of diseases.

Declarations
Authors' Contributions FJ, SNM, and FMGH participated in the research design.MA and SM participated in writing the first draft.SM and MB participated in the performance of the research and analytic tools.SNM, SM, and FJ participated in data analysis.All authors reviewed and confirmed the final manuscript.

Table 2
Cochran-Armitage trend evaluation for the association between BMI and WHR with the chance of developing colorectal polyps and diverticulosis in patients referred for P value < 0.05 as a significant level; OR: crude odds ratio; CI: confidence interval; BMI: Body mass index; WHR: Waist -hip circumstance; Model 1: Unadjusted model; Model 2: Model adjusted for age and gender; Model 3: Model adjusted for demographical data and clinical characteristics.

Table 3
Comparison of the demographical and clinical characteristics in terms of the prevalence of polyps and diverticula in patients referred for colonoscopy Chi-square and independent t-test were used to calculate the association; P-value < 0.05 was considered a significant level; P for trend was calculated using Cochran-Armitage test; BMI: Body mass index; WHR: Waist-hip circumstance.J Coloproctol Vol.44 No. 2/2024 © 2024.The Author(s).

Table 4
Multiple and univariable logistic regression analysis (adjusted) to identify independent factors related to the incidence of polyp and diverticula in patients referred for P value < 0.05 as a significant level; OR: crude odds ratio; CI: confidence interval; BMI: Body mass index; WHR: Waist-hip circumstance; Model 1: Unadjusted model; Model 2: Model adjusted for age and gender; Model 3: Model adjusted for demographical data and clinical characteristics.