Keywords
anthropometric index - body mass index - colorectal cancer - waist to hip circumstances
- colonoscopy
Introduction
Colorectal polyps and diverticulosis are two common gastrointestinal conditions that
affect a significant portion of the population worldwide. Colorectal polyps and diverticulosis
are prevalent conditions that impact the gastrointestinal health of individuals across
different age groups and geographical locations.[1] Colorectal polyps are abnormal growths that develop on the inner lining of the colon
or rectum.[2] While diverticulosis refers to the formation of small pouches in the lining of the
large intestine.[3] According to epidemiological studies, the prevalence of colorectal polyps varies
widely in the general population.[4]
[5]
[6] The incidence of diverticulosis increases with age, affecting approximately individuals
younger than 40.[7]
[8] Colonic diverticulosis in any location may lead to an increased incidence of adenoma
and colorectal polyps.[9]
[10]
[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]
[13] Anthropometric 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. Abdominal fat accumulation is more metabolically active and associated
with higher levels of inflammation and insulin resistance than overall body fat.[14]
[15]
[16]
On the other hand, diverticulosis is thought to result from increased colonic pressure
and structural alterations in the intestinal wall.[17] Factors 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]
[19] Excess 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]
[21] Obesity and central adiposity play a prominent role in their development, highlighting
the importance of maintaining a healthy weight and daily physical activity.[22]
[23]
However, 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.
Methods
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/m2), average weight (BMI = 18.5–24.99 kg/m2), overweight (BMI = 25–29.9 kg/m2), and obese (BMI≥30 kg/m2, 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 ± 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 SPSS version 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 ± 13.33
years, 27.59 ± 4.99 kg/m2, and 0.92 ± 0.07, respectively. Most of the studied population were aged upper 60,
female gender, under diploma, urban residents with high BMI (overweight and obese),
high-risk WHR, and low physical activity levels.
Table 1
Frequency of demographical data and clinical characteristics of patients referred
for colonoscopy (n = 536)
|
Variables
|
Frequency (%)
|
|
Age
(year)
|
≤40
|
71 (13.2)
|
|
41-50
|
84 (15.7)
|
|
51-60
|
169 (31.5)
|
|
60<
|
212 (39.6)
|
|
Gender
|
Male
|
246 (45.9)
|
|
Female
|
290 (54.1)
|
|
Educational level
|
Illiterate
|
106 (19.8)
|
|
Under diploma
|
267 (49.8)
|
|
Diploma
|
122 (22.8)
|
|
University degree
|
41 (7.6)
|
|
Habitat
|
Urban
|
359 (67.0)
|
|
Rural
|
177 (33.0)
|
|
BMI
(kg/m2)
|
18.5<
|
12 (2.2)
|
|
18.5≤BMI < 25
|
164 (30.6)
|
|
25≤BMI < 30
|
195 (36.4)
|
|
30≤
|
165 (30.8)
|
|
WHR
|
Low-risk
|
189 (35.3)
|
|
Normal-risk
|
98 (18.3)
|
|
High-risk
|
249 (46.5)
|
|
Physical activity
|
Low
|
364 (67.9)
|
|
Middle
|
153 (28.5)
|
|
High
|
19 (3.5)
|
|
Smoking
|
Yes
|
48 (9.0)
|
|
No
|
488 (91.0)
|
|
Alcohol consumption
|
Yes
|
7 (1.3)
|
|
No
|
529 (98.7)
|
|
Occupational exposure
|
Yes
|
27 (4.9)
|
|
No
|
509 (95.1)
|
|
Family history of colorectal cancer
|
Yes
|
84 (15.7)
|
|
No
|
452 (84.3)
|
|
Number of polyps
|
One
|
137 (25.6)
|
|
Two
|
35 (6.5)
|
|
Three
|
14 (2.6)
|
|
Four
|
4 (0.7)
|
|
Types of polyp
(Among 265 detected polyps)
|
Pedunculated
|
240 (90.6)
|
|
Sessile
|
25 (9.4)
|
|
Size of polyps
(Among 265 detected polyps)
|
< 5mm
|
32 (12.1)
|
|
5-10 mm
|
159 (60.0)
|
|
>10mm
|
74 (27.9)
|
|
Location of polyp
(Among 265 detected polyps)
|
Rectum
|
52 (19.6)
|
|
Sigmoid colon
|
63 (23.8)
|
|
Descending colon
|
36 (13.6)
|
|
Transvers colon
|
54 (20.4)
|
|
Ascending colon
|
49 (18.5)
|
|
Cecum
|
11 (4.2)
|
|
Number of diverticula
|
In one location
|
32 (6.0)
|
|
In two location
|
10 (1.9)
|
|
In three location
|
8 (1.5)
|
|
In four location
|
11 (2.1)
|
|
Location of diverticula
(Among 120 locations of diverticula)
|
Rectum
|
0 (0.0)
|
|
Sigmoid colon
|
38 (31.7)
|
|
Descending colon
|
29 924.2)
|
|
Transvers colon
|
23 (19.2)
|
|
Ascending colon
|
27 (22.5)
|
|
Cecum
|
3 (2.5)
|
Abbreviatoins: BMI, Body mass index; WHR, Waist -hip circumstance.
Of 536 participants, 290 (54.1%) were females, and 190 (35.4%) patients had polyps;
72.1%, 18.4%, 7.4%, and 2.1% had 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 = 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]).
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
colonoscopy
|
Variables
|
Chance of developing
|
Model 1
|
Model 2
|
Model 3
|
|
(95% CI) OR
|
P value
|
(95% CI) OR
|
P value
|
(95% CI) OR
|
P value
|
|
Polyp
|
BMI
|
<25
|
31.2
|
1 (ref)
|
|
25≤BMI < 30
|
33.8
|
1.13 (0.73-1.74)
|
0.594
|
1.12 (0.72-1.75)
|
0.612
|
1.11 (0.070-1.78)
|
0.651
|
|
30≤
|
41.9
|
1.58(1.01-2.47)
|
0.043
|
1.62 (1.03-2.56)
|
0.037
|
1.44 (0.89-2.33)
|
0.140
|
|
WHR
|
Low-risk
|
31.7
|
1 (ref)
|
|
Moderate-risk
|
36.7
|
1.2 (0.75-2.08)
|
0.396
|
1.47 (0.86-2.52)
|
0.158
|
1.49 (0.85-2.62)
|
0.165
|
|
High-risk
|
37.8
|
1.30 (0.87-1.94)
|
0.193
|
2.06 (1.11-3.81)
|
0.021
|
1.87 (0.98-3.57)
|
0.056̀
|
|
Diverticula
|
BMI
|
<25
|
6.8
|
1 (ref)
|
|
25≤BMI < 30
|
14.9
|
2.39 (1.18-4.84)
|
0.016
|
2.51 (1.22-5.15)
|
0.012
|
2.32 (1.10-4.91)
|
0.028
|
|
30≤
|
12.1
|
1.89 (0.89-3.99)
|
0.097
|
2.02 (0.94-4.35)
|
0.074
|
1.83 (0.83-4.04)
|
0.137
|
|
WHR
|
Low-risk
|
11.1
|
1 (ref)
|
|
Normal-risk
|
16.3
|
1.56 (0.77-3.15)
|
0.214
|
1.68 (0.80-3.50)
|
0.168
|
1.83 (0.85-3.92)
|
0.423
|
|
High-risk
|
9.6
|
0.85 (0.46-1.58)
|
0.615
|
0.84 (0.35-2.02)
|
0.698
|
0.80 (0.32-2.03)
|
0.643
|
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.
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 ± 11.93 and 54.31 ± 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 ± 5.21 and 27.08 ± 4.80 kg/m2, respectively, significantly different among the two studied groups (P = 0.002). Also, the mean of WHR in patients with and without polyp was 0.92 ± 0.07
and 0.91 ± 0.07, respectively, which represented no statistically significant difference
among the two groups (P = 0.086).
Table 3
Comparison of the demographical and clinical characteristics in terms of the prevalence
of polyps and diverticula in patients referred for colonoscopy
|
Variables
|
Patients with polyp
n (%)
|
Patients without polyp
n (%)
|
P value
|
P for trend
|
Patients with diverticula
n (%)
|
Patients without diverticula
n (%)
|
P value
|
P for trend
|
|
Age
(year)
|
≤40
|
13 (6.8)
|
58 (16.8)
|
0.002
|
<0.001
|
3 (4.9)
|
68 (14.3)
|
0.014
|
0.001
|
|
41-50
|
28 (14.7)
|
56 (16.2)
|
5 (8.2)
|
79 (16.6)
|
|
51-60
|
58 (30.5)
|
111 (32.1)
|
19 (31.1)
|
150 (31.6)
|
|
60<
|
91 (47.9)
|
121 (35.0)
|
34 (55.7)
|
178 (37.5)
|
|
Gender
|
Male
|
91 (47.9)
|
155 (44.8)
|
0.491
|
−
|
31 (50.8)
|
215 (45.3)
|
0.412
|
−
|
|
Female
|
99 (52.1)
|
191 (55.2)
|
30 (49.2)
|
260 (54.7)
|
|
Educational status
|
Illiterate
|
41 (21.6)
|
65 (18.8)
|
0.805
|
0.851
|
17 (27.9)
|
89 (18.7)
|
0.346
|
0.099
|
|
Under diploma
|
91 (47.9)
|
176 (50.9)
|
29 (47.5)
|
238 (50.1)
|
|
Diploma
|
42 (22.1)
|
80 (23.1)
|
12 (19.7)
|
110 (23.2)
|
|
University degree
|
16 (8.4)
|
25 (7.2)
|
3 (4.9)
|
38 (8.0)
|
|
Habitat
|
Urban
|
112 (58.9)
|
247 (71.4)
|
0.003
|
−
|
40 (65.5)
|
319 (67.2)
|
0.804
|
−
|
|
Rural
|
78 (41.1)
|
99 (28.9)
|
21 (34.4)
|
156 (32.8)
|
|
BMI
(kg/m2)
|
<25
|
55 (28.9)
|
121 (35.0)
|
0.105
|
0.043
|
12 (19.7)
|
164 (34.5)
|
0.048
|
0.115
|
|
25≤BMI < 30
|
66 (34.7)
|
129 (37.3)
|
29 (47.5)
|
166 (34.9)
|
|
30≤
|
69 (36.3)
|
96 (27.7)
|
20 (32.8)
|
145 (30.5)
|
|
WHR
|
Low-risk
|
60 (31.6)
|
129 (37.3)
|
0.411
|
0.200
|
21 (34.4)
|
168 (35.4)
|
0.208
|
0.562
|
|
Moderate-risk
|
36 (18.9)
|
62 (17.9)
|
16 (26.2)
|
82 (17.3)
|
|
High-risk
|
94 (49.5)
|
155 (44.8)
|
24 (39.3)
|
225 (47.4)
|
|
Physical activity
|
Low
|
133 (70.0)
|
231 (66.8)
|
0.020
|
0.110
|
47 (77.0)
|
317 (66.7)
|
0.245
|
0.095
|
|
Middle
|
56 (29.5)
|
97 (28.0)
|
13 (21.3)
|
140 (29.5)
|
|
High
|
1 (0.5)
|
18 (5.2)
|
1 (1.6)
|
18 (3.8)
|
|
History of smoking
|
Yes
|
11 (5.8)
|
37 (10.7)
|
0.057
|
−
|
3 (4.9)
|
45 (9.5)
|
0.241
|
−
|
|
No
|
179 (94.2)
|
309 (89.3)
|
58 (95.1)
|
430 (90.5)
|
|
Alcohol consumption
|
Yes
|
2 (1.1)
|
5 (1.4)
|
0.702
|
−
|
0 (0.0)
|
7 (1.5)
|
1
|
−
|
|
No
|
188 (98.9)
|
341 (98.6)
|
61 (100.0)
|
468 (98.5)
|
|
Occupational exposure
|
Yes
|
11 (5.8)
|
15 (341)
|
0.453
|
−
|
3 (4.9)
|
23 (4.8)
|
0.979
|
−
|
|
No
|
179 (94.2)
|
331 (95.7)
|
58 (95.1)
|
452 (95.2)
|
|
Family history of colorectal cancer
|
Yes
|
27 (14.2)
|
57 (16.5)
|
0.490
|
−
|
3 (4.9)
|
81 (17.1)
|
0.014
|
−
|
|
No
|
163 (85.8)
|
289 (83.5)
|
58 (95.1)
|
394 (82.9)
|
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.
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 ± 11.87
and 55.17 ± 13.32 years, respectively, significantly different among the two groups
(P < 0.001). The mean BMI in patients with and without diverticula was 28.57 ± 4.45
and 27.46 ± 5.05 kg/m2, respectively, illustrating a statistically non-significant difference among the
two groups (P = 0.104). Also, the mean of WHR in patients with and without diverticula was 0.92 ± 0.07,
which was similar (P = 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 = 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].
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
colonoscopy.
|
Variables
|
Polyp
|
Diverticula
|
|
Univariable logistic regression
|
Multivariable logistic regression
|
Univariable logistic regression
|
Multivariable logistic regression
|
|
(95% CI) OR
|
P value
|
(95% CI) OR
|
P value
|
(95% CI) OR
|
P value
|
(95% CI) OR
|
P value
|
|
Age (year)
|
1.03 (1.01-1.04)
|
<0.001
|
1.03 (1.01-1.05)
|
<0.01
|
1.04 (1.02-1.07)
|
<0.001
|
1.04 (1.02-1.07)
|
0.001
|
|
Gender
|
Male
|
1 (ref)
|
|
Female
|
0.88 (0.62-1.26)
|
0.491
|
0.59 (0.32-1.08)
|
0.086
|
0.80 (0.47-1.36)
|
0.413
|
1.03 (0.4-2.38)
|
0.937
|
|
Educational status
|
Illustrated
|
1 (ref)
|
|
Under diploma
|
0.82 (0.51-1.31)
|
0.403
|
1.06 (0.64-1.76)
|
0.824
|
0.64 (0.33-1.22)
|
0.173
|
0.75 (0.37-1.54)
|
0.438
|
|
Diploma
|
0.83 (0.48-1.43)
|
0.506
|
1.38 (0.75-2.56)
|
0.305
|
0.57 (0.26-1.26)
|
0.165
|
0.86 (0.35-2.08)
|
0.732
|
|
University degree
|
1.01 (0.48-2.13)
|
0.969
|
2.69 (1.14-6.38)
|
0.025
|
0.41 (0.11-1.49)
|
0.178
|
0.73 (0.18-2.94)
|
0.653
|
|
Habitat
|
Urban
|
1 (ref)
|
|
Rural
|
1.74 (1.20-2.52)
|
0.004
|
2 .00 (1.33-3.02)
|
<0.001
|
1.07 (0.61-1.88)
|
0.804
|
0.94 (0.51-1.72)
|
0.831
|
|
Mean of BMI (kg/m2)
|
1.06 (1.02-1.10)
|
0.002
|
1.05 (1.01-1.09)
|
0.011
|
1.04 (0.99-1.10)
|
0.105
|
1.04 (0.98-1.10)
|
0.159
|
|
WHR
|
Low-risk
|
1 (ref)
|
|
Moderate-risk
|
1.25 (0.75-2.08)
|
0.396
|
1.49 (0.85-2.62)
|
0.165
|
1.56 (0.77-3.15)
|
0.214
|
1.81 (0.84-3.87)
|
0.129
|
|
High-risk
|
1.30 (0.87-1.94)
|
0.193
|
1.87 (0.98-3.57)
|
0.056
|
0.85 (0.46-1.8)
|
0.615
|
0.80 (0.32-2.01)
|
0.631
|
|
Physical activity
|
High
|
1 (ref)
|
|
Middle
|
10.39 (1.35-79.95)
|
0.025
|
10.43 (1.29-84.32)
|
0.028
|
1.67 (0.21-13.54)
|
0.630
|
1.28 (0.14-11.44)
|
0.828
|
|
Low
|
10.36 (1.37-78.51)
|
0.024
|
10.06 (1.27-80.08)
|
0.029
|
2.67 (0.35-20.46)
|
0.345
|
2.23 (0.26-19.13)
|
0.463
|
|
History of smoking
|
Yes
|
0.51 (0.26-1.03)
|
0.061
|
0.48 (0.22-1.07)
|
0.073
|
0.49 (0.15-1.64)
|
0.250
|
0.44 (0.12-1.57)
|
0.205
|
|
Alcohol consumption
|
Yes
|
0.73 (0.14-3.078)
|
0.703
|
1.53 (0.19-12.37)
|
0.692
|
−
|
−
|
−
|
-
|
|
Occupational exposure
|
Yes
|
1.36 (0.61-3.01)
|
0.455
|
1.58 (0.65-3.80)
|
0.310
|
1.02 (0.30-3.49)
|
0.979
|
1.11 (0.30-4.17)
|
0.873
|
|
Family history of colorectal cancer
|
Yes
|
0.84 (0.51-1.38)
|
0.491
|
0.90 (0.53-1.52)
|
0.689
|
0.25 (0.08-0.82)
|
0.022
|
0.27 (0.08-0.90)
|
0.032
|
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.
Discussion
The incidence of diverticulosis and colorectal polyps is increasing rapidly worldwide.[25]
[26]
[27] Previous studies have 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]
[29] We 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.[30] These 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]
[32]
The prevalence of polyps and diverticula is higher in some populations and lower in
others, which may be influenced by factors like different age groups, changes in diet
and lifestyle habits, quality of equipment, or colonoscopy techniques that cause different
detection rates over time.[32]
[33]
[34] The proportion of patients with polyps and diverticula increased with age, which
suggested that age is a significant risk factor for both disorders.[35] Compared to our findings, other studies have shown that these lesions increase with
age.[32]
[36] The 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]
[38]
In 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.[39] Another 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.[40] The 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]
[42]
Peery et al. established that obesity (BMI >30) significantly increased the risk of
colonic diverticulosis in women but not men.[43] Beyond BMI, limited evidence suggests that visceral fat may play a significant role
in the pathogenesis of diverticulitis.[44]
[45]
[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.[47]
Contrary 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. Previous literature reported that Hispanics
living in urban areas are less likely to develop adenomatous polyps, which supports
our findings.[50]
[51]
[52] Medical awareness, access to specialists, and non-adherence 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]
[54] The mechanism of this effect is unknown, but it can lead to decreased insulin levels,
systemic inflammation, and abdominal obesity.[53]
[55]
Finally, 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]
[60] Our 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.
