Anthropometry-based Obesity Phenotypes and Risk of Colorectal Adenocarcinoma: A Large Prospective Cohort Study in Norway

Abdominal obesity and digestive system cancer: a systematic review and meta-analysis of prospective studies

BACKGROUND

The diagnostic criteria for abdominal obesity are usually waist circumference or waist-to-hip ratio. The magnitude of the risks for cancers of the digestive system and abdominal obesity is unknown. To assess whether abdominal obesity increases the risk of digestive cancer, we conducted a systematic review and meta-analysis of prospective cohort studies in a database.

METHODS

PubMed, Embase, and Web of Science databases were searched from their inception to December 2022. The 9-star Newcastle Ottawa Scale was used to assess  study quality. Pooled relative risks and 95% confidence intervals were calculated using fixed or random effect models respectively. The stability of the results was explored by one-by-one exclusion. Subgroup analysis was conducted to explore sources of heterogeneity. Publication bias was evaluated by Begg's and Egger's tests.

RESULTS

A total of 43 cohort studies were included. There were 42 and 31 studies in the meta-analysis of waist circumference and waist-to-hip ratio on digestive system cancer, respectively. The results of the meta-analysis revealed that the greater waist circumference and waist-to-hip ratio were correlated with increased incidence of digestive system cancers: waist circumference: RR 1.48, 95% CI 1.38-1.59, p < 0.001; waist-to-hip ratio: RR 1.33, 95% CI 1.28-1.38, p = 0.001. Subgroup analysis by cancer type showed that higher WC and WHR would increase the prevalence of LC, PC, GC, EC, and CRC. The sensitivity analysis was conducted by a one-by-one elimination method, and the results of the meta-analysis remained stable. It is proved that the results were robust by the trim-and-fill method.

CONCLUSIONS

There was evidence to suggest that abdominal obesity increased the incidence of digestive cancer, it is necessary to take appropriate measures to reduce abdominal obesity. Waist circumference and waist-to-hip ratio may be better predictors of digestive system cancers. However, the association between waist circumference and digestive system cancer was greater, so more attention should be paid to measuring abdominal obesity with waist circumference.

The Protective Effect of Bariatric Surgery on the Development of Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity is a known risk factor for developing colorectal cancer (CRC) and is associated with the formation of precancerous colonic adenomas. Bariatric surgery (BRS) is considered to reduce the cancer risk in morbidly obese patients. However, the currently available literature yields contradicting results regarding the impact of bariatric surgery on the incidence of CRC.

METHODS

A systematic literature search of the Medline, Embase, CENTRAL, CINAHL, Web of Science, and clinicaltrials.gov databases was undertaken following the PRISMA guidelines. A random effects model was selected.

RESULTS

Twelve retrospective cohort studies, incorporating a total of 6,279,722 patients, were eligible for inclusion in the final quantitative analysis. Eight studies originated from North America, while four reported on European patients. Patients in the Bariatric Surgery group exhibited a significantly reduced risk for developing colorectal cancer (RR 0.56, 95% CI 0.4-0.8, p < 0.001), while sleeve gastrectomy was found to be significantly associated with a smaller incidence of CRC (RR 0.55, 95% CI 0.36-0.83, p < 0.001), and gastric bypass and banding did not.

CONCLUSIONS

A significant protective effect of BRS against the development of CRC is implied. In the present analysis, the incidence rate of colorectal cancer was approximately halved amongst the obese individuals that were operated on.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

Optimization of the surveillance strategy in patients with colorectal adenomas: A combination of clinical parameters and index colonoscopy findings

BACKGROUND AND AIM

In addition to index colonoscopy findings, demographic parameters including age are associated with the risk of metachronous advanced colorectal neoplasia. Here, we aimed to develop a risk scoring model for predicting advanced colorectal neoplasia (ACRN) during surveillance using a combination of clinical factors and index colonoscopy findings.

METHODS

Patients who underwent the removal of one or more adenomas and surveillance colonoscopy were included. A risk scoring model for ACRN was developed using the Cox proportional hazard model. Surveillance interval was determined as a time point exceeding 4% of the cumulative ACRN incidence in each risk group.

RESULTS

Of 9591 participants, 4725 and 4866 were randomly allocated to the derivation and validation cohorts, respectively. Age, abdominal obesity, advanced adenoma, and ≥ 3 adenomas at index colonoscopy were identified as risk factors for metachronous ACRN. Based on the regression coefficients, point scores were assigned as follows: age, 1 point (per 1 year); abdominal obesity, 10 points; advanced adenoma, 10 points; and ≥ 3 adenomas, 15 points. Patients were classified into high-risk (≥ 80 points), moderate-risk (50-79 points), and low-risk (30-49 points) groups. In the validation cohort, the high-risk and moderate-risk groups showed a higher risk of ACRN than the low-risk group (hazard ratio [95% confidence interval]: 7.11 [4.10-12.32] and 1.58 [1.09-2.30], respectively). Two-, 4-, and 5-year surveillance intervals were recommended for the high-risk, moderate-risk, and low-risk groups, respectively.

CONCLUSIONS

Our proposed model may facilitate effective risk stratification of ACRN during surveillance and the determination of appropriate surveillance intervals.

The Impact of Body Mass Index on the Clinicopathological and Prognostic Factors of Colorectal Cancer in Saudi Arabia

Background Obesity is a known risk factor of colorectal cancer (CRC); however, the relationship between obesity and clinicopathologic characteristics and prognosis of CRC remains unclear. This study aimed to investigate the relationship between body mass index (BMI) and clinicopathological and prognostic factors of CRC in Saudi Arabia. Method This was a retrospective cross-sectional study of patients with CRC diagnosed between 2014 and 2018 at King Abdulaziz University Hospital in Jeddah, Saudi Arabia. BMI was calculated by dividing the patient's weight in kilograms by height in meter squared and was classified according to the World Health Organization criteria. Statistical tests, including analysis of variance and chi-square tests, were used to investigate the relationship of each BMI category with clinicopathologic (histological type, degree of differentiation, tumor location, and medical comorbidities) and prognostic variables (TNM stage, lymph nodes involvement, and lymph nodes yield). Results Of 233 patients who were included, 60.1% were male and 39.9% were female patients, with a mean age (standard deviation) of 58.8 ± 13.7 (range: 26-99) years. The median BMI was 26.5 kg/m². Overall, 3%, 34.3%, 33.0%, and 29.6% patients were classified as underweight, normal weight, overweight, and obese, respectively. Furthermore, 57.1% (4/7), 39.2% (31/80), 38.7% (29/77), and 25.8% (17/69) of underweight, normal, overweight, and obese patients had Stage IV disease (p = 0.20). Of 16 patients with transverse colon cancer, 8 (50%) were obese (p = 0.38), and 1 (6%), 5 (31%), and 2 (13%) were underweight, normal weight, and overweight, respectively. Conclusion Underweight patients are more likely to present with metastatic CRC, while obese patients are more likely to present at earlier stages, although the difference was not statistically significant. BMI is not related to lymph node yield, histological type, or the degree of differentiation.

Changes in Abdominal Obesity Affect the Risk of Metachronous Advanced Colorectal Neoplasia Development after Polypectomy

PURPOSE

The impact of changes in body mass index and waist circumference on the development of metachronous colorectal neoplasia (CRN) after polypectomy has rarely been examined. We evaluated the association between changes in overall/abdominal obesity and metachronous CRN risk.

MATERIALS AND METHODS

We studied patients who underwent ≥1 adenoma removal and surveillance colonoscopy. Patients were classified into the following four groups based on the changes in overall obesity from index to follow-up colonoscopy: non-obesity persisted (group 1), obesity to non-obesity (group 2), non-obesity to obesity (group 3), and obesity persisted (group 4). Patients were also divided into another four groups based on similar changes in abdominal obesity (groups 5-8).

RESULTS

The number of patients in groups 1, 2, 3, and 4 was 5074, 457, 643, and 3538, respectively, and that in groups 5, 6, 7, and 8 was 4229, 538, 656, and 2189, respectively. Group 4 had a significantly higher risk of metachronous CRN compared to groups 1 and 2. However, metachronous advanced CRN (ACRN) risk was not different among groups 1, 2, 3, and 4. Metachronous CRN risk in group 8 (abdominal obesity persisted) was higher than that in groups 5 (non-abdominal obesity persisted) and 7 (non-abdominal obesity to abdominal obesity), and tended to be higher than that in group 6 (abdominal obesity to non-abdominal obesity). Additionally, group 8 had a significantly higher risk of metachronous ACRN compared to groups 5, 6, and 7.

CONCLUSION

Changes in obesity affected the metachronous CRN risk. In particular, changes in abdominal obesity affected the metachronous ACRN risk.

Association between waist circumference and risk of colorectal neoplasia in normal-weight adults

BACKGROUND AND AIM

Abdominal obesity, measured using waist circumference (WC), is associated with the colorectal neoplasia (CRN) risk. We examined whether WC is associated with the CRN risk even in normal-weight individuals.

METHODS

A cross-sectional study was performed on asymptomatic normal-weight (body mass index 18.5-23 kg/m² ) individuals who underwent colonoscopy as health checkups.

RESULTS

Of 63 057 examinees, 30 498 were men (mean age, 41.1 years) and 32 559 were women (mean age, 41.7 years). The prevalence of overall CRN in WC quartiles 1, 2, 3, and 4 was 14.2%, 15.5%, 15.5%, and 18.7%, respectively, in men and 7.4%, 8.9%, 9.4%, and 11.5%, respectively, in women. The prevalence of advanced CRN (ACRN) in WC quartiles 1, 2, 3, and 4 was 1.5%, 1.3%, 1.6%, and 2.1%, respectively, in men and 1.0%, 1.3%, 1.2%, and 1.3%, respectively, in women. Among men, the overall CRN risk in quartile 4 (> 82 cm) was higher than that in quartiles 1, 2, and 3 (adjusted odds ratio, OR [95% confidence interval, CI], 1.22 [1.11-1.34], 1.12 [1.05-1.23], and 1.18 [1.07-1.29], respectively); the ACRN risk in quartile 4 was also higher than that in quartiles 1, 2, and 3 (adjusted OR [95% CI], 1.41 [1.09-1.81], 1.56 [1.19-2.03], and 1.50 [1.16-1.94], respectively). Among women, the overall CRN risk in quartile 4 (> 77 cm) was higher than that in quartiles 1 and 3; the ACRN risk was not different among all groups.

CONCLUSIONS

Even with a normal weight, a large WC was associated with the CRN risk, especially with the ACRN risk in men.

The prediction of colorectal cancer using anthropometric measures: A Swedish population-based cohort study with 22 years of follow-up

Background

Obesity is a risk factor for colorectal cancer (CRC).

Objective

The objective of this article is to investigate whether anthropometric measures reflecting visceral obesity are better predictors of CRC than body mass index (BMI).

Methods

Data were analysed from the Malmö Diet and Cancer study in Sweden, comprising 16,669 women and 10,805 men (median age 56.6 and 59.1 years) followed for a median 21.5 years. Diagnoses of CRC were identified using Swedish national registers. Cox regression was used to test the associations of BMI, waist circumference (WC), waist-hip ratio, waist-to-height ratio, waist-to-hip-to-height ratio, A Body Shape Index (ABSI) and percentage body fat with the development of CRC adjusted for age, alcohol consumption, smoking, education and physical activity in men and women.

Results

None of the measures were significantly associated with an increased risk for CRC in women. WC was the strongest predictor of colon cancer (CC) in men and the only measure that was independent of BMI. ABSI was the only measure significantly associated with the risk of rectal cancer in men.

Conclusions

Visceral obesity, best expressed as WC, is a risk factor for CC in men but a poor predictive marker for CRC in women.

Abdominal Obesity is More Predictive of Advanced Colorectal Neoplasia Risk Than Overall Obesity in Men: A Cross-sectional Study

GOALS

We aimed to ascertain whether waist circumference (WC) is associated with risk of colorectal neoplasia (CRN), independent of body mass index (BMI).

BACKGROUND

Although several studies have reported the association between abdominal obesity, measured by WC, and CRN, it remains unclear whether their association is biased by BMI.

STUDY

A cross-sectional study was performed on 154,552 asymptomatic examinees who underwent colonoscopy for a health check-up.

RESULTS

The mean age was 42.6 years, and the proportion of males was 65.2%. The prevalence rate of CRN in subjects in WC quartiles 1, 2, 3, and 4 was 15.6%, 18.1%, 20.4%, and 22.0% among men and 7.8%, 9.4%, 12.2%, and 15.8% among women, respectively. WC and BMI were independent risk factors for overall CRN and nonadvanced CRN in both men and women. In men, the association of BMI with advanced CRN was attenuated to null after adjusting for WC [Q2, Q3, and Q4 vs. Q1; odds ratios (95% confidence intervals), 0.93 (0.79-1.10), 0.85 (0.71-1.03), and 0.99 (0.80-1.22), respectively; Ptrend=0.822], whereas the association of WC with advanced CRN significantly persisted even after adjusting for BMI [Q2, Q3, and Q4 vs. Q1; 1.20 (1.02-1.42), 1.45 (1.20-1.75), and 1.64 (1.32-2.04), respectively; Ptrend<0.001]. In women, neither WC nor BMI was associated with the risk of advanced CRN.

CONCLUSIONS

Abdominal obesity is associated with an increased risk of advanced CRN, independent of overall obesity (BMI) in men. Our findings suggest that abdominal obesity is more strongly predictive of advanced CRN than overall obesity in men.