Body mass index and screening for colorectal cancer: gender and attitudinal factors

The multifactorial effect of obesity on the effectiveness and outcomes of cancer therapies

Epidemiology studies have demonstrated a clear association between obesity and the development of several distinct malignancies, with excessive visceral adiposity being an increasingly prevalent feature in patients with cancer presenting for therapeutic intervention. Clinical trials and meta-analyses have helped to inform effective and safe dosing of traditional systemically administered anticancer agents in adult patients with cancer and obesity, but there remains much debate not only regarding the effect of obesity on the more novel targeted molecular and immune-based therapies, but also about how obesity is best defined and measured clinically. Low muscle mass is associated with poor outcomes in cancer, and body composition studies using biochemical and imaging modalities are helping to fully delineate the importance of both obesity and sarcopenia in clinical outcomes; such studies might also go some way to explaining how obesity can paradoxically be associated with favourable clinical outcomes in certain cancers. As the cancer survivorship period increases and the duration of anticancer treatment lengthens, this Review highlights the challenges facing appropriate treatment selection and emphasizes how a multidisciplinary approach is warranted to manage weight and skeletal muscle loss during and after cancer treatment.

Impact of body mass index and examination type on utilization of screening programs: A big data study

OBJECTIVE

To investigate the relationship between Body Mass Index (BMI) and adherence to recommended screening tests, addressing gaps in previous literature by utilizing a large cohort, while considering longitudinal changes in weight and the type of screening.

METHODS

Data from Clalit Health Services in Israel were retrospectively analyzed, including participants aged 50 and above from 2002 to 2021. BMI measurements and various screening test records were examined. Generalized Estimating Equations were employed for analysis, adjusting for potential confounding variables, including age, gender, geographic location, and socioeconomic status.

RESULTS

The study included 634,879 participants with 4,630,030 BMI measurements and 56,453,659 test records. Participants were categorized into BMI cohorts at the time of the test, with overweight and obese individuals showing lower odds of undergoing intimate examination-based screening tests (mammography, PAPS, and skin examination), as opposed to higher odds of several non-intimate tests (e.g., diabetes and eye disorder screenings).

DISCUSSION

Our findings suggest that individuals with overweight and obesity are less likely to undergo screenings involving intimate physical examinations, potentially due to weight stigma and discomfort. This avoidance behavior may contribute to increased morbidity rates in these populations. Interventions addressing weight stigma, improving access to care, and enhancing patient engagement are warranted.

Assessment of Body Mass Index, Polygenic Risk Score, and Development of Colorectal Cancer

IMPORTANCE

Excess weight, the prevalence of which is high and increasing in many countries, is linked to multiple adverse health outcomes, including increased colorectal cancer (CRC) risk. Better communication of health risks associated with excess weight might support efforts of prevention.

OBJECTIVE

To evaluate the individual and joint associations of body mass index (BMI) and polygenic risk with CRC, to assess potential interactions among them, and to quantify by how much increased polygenic risk for CRC can be offset by having a BMI within reference range.

DESIGN, SETTING, AND PARTICIPANTS

This population-based case-control study was conducted in the Rhine-Neckar region of southwest Germany, with recruitment from 2003 to 2017. Participants with both risk factor and genetic information were included for analysis. Data analysis was conducted from December 8, 2021, to February 17, 2022.

EXPOSURES

BMI was calculated as self-reported weight in kilograms approximately 10 years before diagnosis or interview and current height in meters squared. A polygenic risk score (PRS) was built based on 140 CRC-related risk loci.

MAIN OUTCOMES AND MEASURES

Individual and joint associations of BMI and PRS with CRC were estimated using multiple logistic regression. Associations of excess weight with CRC were quantified by adjusted odds ratios (aORs) and genetic risk equivalents (GREs), the equivalent outcomes conveyed by defined differences in PRS percentiles.

RESULTS

Among 9169 participants (median [IQR] age, 69 [62-76] years; 5589 [61.0%] male participants) included, 5053 had CRC and 4116 did not. BMI of 30 or greater was associated with higher odds of having CRC compared with BMI less than 25 (aOR, 1.71; 95% CI, 1.49-1.97), independent of PRS levels (P for interaction = .45). Participants with BMI of 30 or greater and a PRS in the highest tertile had higher odds of CRC compared with participants with BMI less than 25 and a PRS in the lowest tertile (aOR, 3.82; 95% CI, 3.03-4.82). The estimated association of BMI greater than 30 with CRC risk was equivalent to that of having a 41 (95% CI, 29-53)-percentile higher PRS. BMI of 30 or greater was particularly associated with stage IV CRC (aOR, 2.21; 95% CI, 1.71-2.84).

CONCLUSIONS AND RELEVANCE

These findings suggest that excess weight was associated with CRC regardless of PRS levels. The association of having a BMI within reference range may be similar to that of having a substantially lower polygenic risk for CRC.

A systematic review of obesity as a barrier to accessing cancer screening services

Introduction

Obesity is a known risk factor for the development of cancers, and a significant proportion of the population may be at risk of developing cancer owing to their weight status. There is acknowledged societal stigma towards people living with obesity, which can influence health behaviors and deter help seeking, such as cancer screening. Healthcare professionals' attitudes and views toward people living with obesity may adversely affect the patient-professional interface and treatment.

Methods

A systematic review was carried out which aimed to explore the impact of living with obesity on the uptake of three main cancer-screening services: breast, cervical, and colorectal.

Results

Ten studies were included in the review. Three main areas were identified from both a patient and healthcare professional perspective: barriers and challenges to screening, gender issues, and disparities in the population living with obesity.

Conclusion

Further research is needed to improve uptake of cancer screening services, and for education on weight bias, which is often unconscious, to be considered for healthcare professionals working in cancer screening services. This may help to increase the incidence of early differential diagnosis of potential cancers and improve health outcomes for people living with obesity.

Review article: obesity and colorectal cancer

BACKGROUND

Obesity is a growing global public health problem. More than half the European and North American population is overweight or obese. Colon and rectum cancers are still the second leading cause of cancer death worldwide, and epidemiological data support an association between obesity and colorectal cancers (CRCs).

AIM

To review the literature on CRC epidemiology in obese subjects, assessing the effects of obesity, including childhood or maternal obesity, on CRC, diagnosis, management, and prognosis, and discussing targeted prophylactic measures.

METHOD

We searched PubMed for obesity/overweight/metabolic syndrome and CRC. Other key words included 'staging', 'screening', 'treatment', 'weight loss', 'bariatric surgery' and 'chemotherapy'.

RESULTS

In Europe, about 11% of CRCs are attributed to overweight and obesity. Epidemiological data suggest that obesity is associated with a 30%-70% increased risk of colon cancer in men, the association being less consistent in women. Visceral fat or abdominal obesity seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m² increase in body mass index confers more risk (hazard ratio 1.03). Obesity might increase the likelihood of recurrence or mortality of the primary cancer and may affect initial management, including accurate staging. The risk maybe confounded by different factors, including lower adherence to organised CRC screening programmes. It is unclear whether bariatric surgery helps reduce rectal cancer risk.

CONCLUSIONS

Despite a growing body of evidence linking obesity to CRC, many questions remain unanswered, including whether we should screen patients with obesity earlier or propose prophylactic bariatric surgery for certain patients with obesity.

Public Awareness of Bowel Cancer Risk Factors, Symptoms and Screening in Tasmania, Australia: A Cross-Sectional Study

Tasmania has one of the highest bowel cancer incidence and death rates in the world. Public awareness of risk factors, symptoms, and early detection of bowel cancer is important for minimising the burden of disease. This study measured awareness levels of bowel cancer risk factors, symptoms and screening in Tasmania. An online survey of 3703 participants aged 18 years and older found that alcohol consumption, low physical activity levels, and having diabetes were the least known risk factors for bowel cancer. Over half of all participants were unaware the risk of bowel cancer increased with age, and 53 percent were not confident they would notice a bowel cancer symptom. Over a third of survey respondents did not know that screening commenced at the age of 50. The results indicate that a targeted campaign to increase bowel cancer awareness in Tasmania may help reduce the high rates of morbidity and mortality from the disease.

Clinical stages of colorectal cancer diagnosed in obese and overweight individuals in the Polish Colonoscopy Screening Program

Background

Obesity is a known risk factor of colorectal cancer (CRC). However, precise interconnections between excessive body fat and CRC are still vague. Therefore, the aim of this study was to assess whether stage of CRC detected in overweight and obese individuals differs from individuals with normal body mass index (BMI). A secondary aim of this study was to elucidate whether overweight and obesity influence the overall survival in CRC.

Methods

This study was a cross-sectional analysis of 163,129 individuals who underwent screening colonoscopy performed on data from a prospectively maintained database of the Polish Colonoscopy Screening Program.

Results

Overweight and obese individuals present with a less advanced CRC in screening setting (p = 0.014). This trend is the most pronounced in males (p = 0.001). Univariable and multivariable analyses revealed that obesity was a negative predictor of detection of advanced CRC with odds ratio 0.72 (95% confidence interval 0.52-1.00; p = 0.047). Furthermore, overweight and obesity were not statistically significant predictors of risk of death (p = 0.614 and p = 0.446, respectively).

Conclusions

Obese screenees present with a less advanced disease in comparison to non-obese. Moreover, survival stratified by clinical stage seems to not be influenced by BMI category. Therefore, a higher proportion of early diagnosed cancers can potentially create a survival benefit in this group.

Perceived risk of colorectal and breast cancers among women who are overweight or with obesity

Many overweight women or women with obesity do not acknowledge their high weight status and may be unaware of their elevated cancer risk. We explored the relationship between weight status and women's perceived risk of colorectal (CRC) and breast cancers, overall and by race/ethnicity, in a nationally representative sample.

Data was combined from NHIS 2005, 2010, and 2015 sample adult questionnaires and cancer control supplements. The analytic sample included females aged 18 years and over without reported history of cancer diagnosis. Multivariable logistic regression was performed and adjusted estimates for perceived risk of CRC and breast cancers were examined, stratified by body mass index and race/ethnicity. Data were reported using predicted marginal risk ratio (PMR).

Colorectal cancer risk perception remained lowest among Non-Hispanic (NH) Black women regardless of weight status (PMR = 0.53 obesity, 0.65 overweight, 0.55 normal) compared to NH White women after adjustment for all covariates. Hispanic women who were overweight or had obesity also saw themselves at lower risk of CRC compared to NH White women, however these findings were statistically insignificant. Breast cancer risk perception also remained low for NH Blacks and Hispanics at any weight compared with NH Whites.

Greater effort is needed to develop, disseminate, and widely adopt or institutionalize multilevel weight management interventions and programs. These programs increase awareness of excess weight as a risk factor for cancer and empower women in diverse communities to achieve and maintain a healthy weight by adopting healthy behaviors related to nutrition and physical activity.

A Comparative Study Evaluating the Incidence of Colorectal Neoplasia(s) in Candidates for Bariatric Surgery by Screening Colonoscopy, 40-49 Versus 50-65 Years Old: a Preliminary Study

INTRODUCTION

Obesity and metabolic syndrome (MetS) are associated with colorectal neoplasia (CRN) and carcinoma (CRC). Whether such subjects must undergo screening colonoscopy (SC) earlier, is unknown. Incidences of CRNs in 40-49- versus 50-65-year-old bariatric patients were compared by SC. No prospective data on SC is available in morbidly obese/MetS.

MATERIAL AND METHODS

Surgical weight loss candidates over 39 years of age, asymptomatic, and average-risk for CRC offered SC. Those giving written informed consent were enrolled. Colonoscopies were done by the same surgeon. Smoking/drinking history, fasting blood glucose (FBG), insulin, C-peptide, triglyceride, high density lipoprotein, vitamin D, HbA1c, and insulin resistance parameters were recorded. CRN rate and the distribution of variables in patients 40-49 years of age were compared with 50-65. Student's t and Chi-square tests were used as appropriate. P < 0.05 was regarded as statistically significant.

RESULTS

Among 168 SCs, 47 had CRNs (27.9%). Including carcinoma, 15 had an advanced CRN (aCRN) (8.9% aCRN and 0.6% CRC). CRN rate was 35.6% in ≥ 50 years old whereas 22.1% in 40-49 (p = 0.053). aCRN rates (8.4% in 40-49 versus 9.6% in 50-65) were similar (p = 0.792). Metabolic parameters and smoking-drinking history were equally distributed between the groups except FBG and HbA1c as their mean levels were slightly higher in the 50-65 age group (p < 0.05).

CONCLUSIONS

Presented results warrant routine SC in the 40-49-year-old morbidly obese and/or MetS patient population with average risk, and in aged > 50, it certainly must be enforced and included in the preoperative check-list if not done before.

Understanding Cancer Worry Among Patients in a Community Clinic-Based Colorectal Cancer Screening Intervention Study

BACKGROUND

To reduce colorectal cancer (CRC) screening disparities, it is important to understand correlates of different types of cancer worry among ethnically diverse individuals.

OBJECTIVES

The current study examined the prevalence of three types of cancer worry (i.e., general cancer worry, CRC-specific worry, and worry about CRC test results) as well as sociodemographic and health-related predictors for each type of cancer worry.

METHODS

Participants were aged 50-75, at average CRC risk, nonadherent to CRC screening guidelines, and enrolled in a randomized controlled trial to increase CRC screening. Participants completed a baseline questionnaire assessing sociodemographics, health beliefs, healthcare experiences, and three cancer worry measures. Associations between study variables were examined with separate univariate and multivariable logistic regression models.

RESULTS

Responses from a total of 416 participants were used. Of these, 47% reported experiencing moderate-to-high levels of general cancer worry. Predictors of general cancer worry were salience and coherence (aOR = 1.1, 95% CI [1.0, 1.3]), perceived susceptibility (aOR = 1.2, 95% CI [1.1, 1.3), and social influence (aOR = 1.1, 95% CI [1.0, 0.1]). Fewer (23%) reported moderate-to-high levels of CRC-specific worry or CRC test worry (35%). Predictors of CRC worry were perceived susceptibility (aOR = 1.4, 95% CI [1.3, 1.6]) and social influence (aOR = 1.1, 95% CI [1.0, 1.2]); predictors of CRC test result worry were perceived susceptibility (aOR = 1.2, 95% CI [1.1, 1.3) and marital status (aOR = 2.0, 95% CI [1.1, 3.7] for married/partnered vs. single and aOR = 2.3, 95% CI [1.3, 4.1] for divorced/widowed vs. single).

DISCUSSION

Perceived susceptibility consistently predicted the three types of cancer worry, whereas other predictors varied between cancer worry types and in magnitude of association. The three types of cancer worry were generally predicted by health beliefs, suggesting potential malleability. Future research should include multiple measures of cancer worry and clear definitions of how cancer worry is measured.

National Disparities in Colorectal Cancer Screening Among Obese Adults

INTRODUCTION

Obesity is a major risk factor for colorectal cancer (CRC), particularly among men. The purpose of this study was to characterize the prevalence of guideline-adherent CRC screening among obese adults using nationally representative data, assess trends in screening strategies, and identify obesity-specific screening barriers.

METHODS

Data from 8,550 respondents aged 50-75 years in the 2010 National Health Interview Survey, representing >70 million adults, were analyzed in 2015 using multivariable logistic regression. Prevalence of guideline-adherent CRC screening, endoscopic versus fecal occult blood test screening, and reasons for non-adherence were compared across BMI categories.

RESULTS

Obese class III men (BMI ≥40), compared with normal-weight men, were significantly less likely to be adherent to screening guidelines (38.7% vs 55.8%, AOR=0.35, 95% CI=0.17, 0.75); less likely to have used an endoscopic test (36.7% vs 53.0%, AOR=0.37, 95% CI=0.18, 0.79); and had a trend toward lower fecal occult blood test use (4.2% vs 8.9%, AOR=0.42, 95% CI=0.14, 1.27). Among women, odds of guideline adherence and use of different screening modalities were similar across all BMI categories. Reasons for non-adherence differed by gender and BMI; lacking a physician screening recommendation differed significantly among men (29.7% obese class III vs 15.4% non-obese, p=0.04), and pain/embarrassment differed significantly among women (11.6% obese class III vs 2.6% non-obese, p=0.002).

CONCLUSIONS

Despite elevated risk, severely obese men were significantly under-screened for CRC. Addressing the unique screening barriers of obese adults may promote screening uptake and lessen disparities among the vulnerable populations most affected by obesity.

Do recent epidemiologic observations impact who and how we should screen for CRC?

Colorectal cancer (CRC) screening is recommended to begin at age 50 for those patients with no significant family history of CRC. However, even within this group of average-risk patients, there is data to suggest that there may be variation in CRC risk. These observations suggest that perhaps CRC screening should be tailored to target those patients at higher risk for earlier or more invasive screening as compared to those individuals at lower risk. The strategy of how to identify those higher-risk patients may not be straightforward. One method might be to use single risk factors such as smoking or elevated BMI as has been suggested in the recent American College of Gastroenterology CRC screening guidelines. Another paradigm involves the use of models which incorporate several risk factors to stratify patients by risk. This article will highlight recent large studies that examine recognized CRC risk factors as well as review recently developed CRC risk models. There will also be a discussion of the application of these factors and models in an effort to make CRC screening more efficient.

Republished: obesity and colorectal cancer

Excess body weight, as defined by the body mass index (BMI), has been associated with several diseases and includes subjects who are overweight (BMI≥25-29.9 kg/m(2)) or obese (BMI≥30 kg/m(2)). Overweight and obesity constitute the fifth leading risk for overall mortality, accounting for at least 2.8 million adult deaths each year. In addition around 11% of colorectal cancer (CRC) cases have been attributed to overweight and obesity in Europe. Epidemiological data suggest that obesity is associated with a 30-70% increased risk of colon cancer in men, whereas the association is less consistent in women. Similar trends exist for colorectal adenoma, although the risk appears lower. Visceral fat, or abdominal obesity, seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m(2) increase in BMI confers additional risk (HR 1.03). Obesity might be associated with worse cancer outcomes, such as recurrence of the primary cancer or mortality. Several factors, including reduced sensitivity to antiangiogenic-therapeutic regimens, might explain these differences. Except for wound infection, obesity has no significant impact on surgical procedures. The underlying mechanisms linking obesity to CRC are still a matter of debate, but metabolic syndrome, insulin resistance and modifications in levels of adipocytokines seem to be of great importance. Other biological factors such as the gut microbita or bile acids are emerging. Many questions still remain unanswered: should preventive strategies specifically target obese patients? Is the risk of cancer great enough to propose prophylactic bariatric surgery in certain patients with obesity?

Patterns of colorectal cancer screening uptake in newly eligible men and women

BACKGROUND

We describe patterns of colorectal cancer screening uptake in a U.S. insured population as individuals become newly eligible for screening at age 50 and assess temporal trends and patient characteristics with screening uptake.

METHODS

We identified a cohort of 81,223 men and women who were members of Group Health and turned 50 years old from 1996 to 2010. We ascertained receipt of colorectal cancer screening within five years. Time to screening was estimated by year of cohort entry using cumulative incidence curves and Cox proportional hazards models-estimated patient characteristics associated with screening uptake.

RESULTS

Stool-based screening tests were the most common, 72% of first screening tests. The proportion of individuals initiating colorectal cancer screening via colonoscopy increased from 8% in 1996 to 1998 to 33% in 2008 to 2010. Patient factors associated with increased colorectal cancer screening were: turning 50 more recently (2008-2010; Ptrend < 0.0001) or Asian race [HR, 1.14; 95% confidence interval (CI), 1.10-1.19]. Patient factors associated with decreased screening were: being a woman (HR, 0.70; 95% CI, 0.68-0.72), Native American (HR, 0.68; 95% CI, 0.60-0.78), or Pacific Islander race (HR, 0.82; 95% CI, 0.72-0.95), and having prevalent diabetes (HR, 0.78; 95% CI, 0.75-0.82) and higher body mass index (Ptrend < 0.0001).

CONCLUSIONS

Patient characteristics associated with initiation of colorectal cancer screening in a newly eligible population are similar to characteristics associated with overall screening participation in all age-eligible adults. Our results identify patient populations to target in outreach programs.

IMPACT

Disparities in receipt of colorectal cancer screening are evident from onset of an age-eligible cohort, identifying key groups for future interventions for screening.

Body mass index and cancer screening: Findings from the English Longitudinal Study of Ageing

Objectives

Obesity is associated with an increased cancer incidence and mortality and therefore cancer screening is particularly important for obese individuals. However, some US studies find lower screening uptake in this group. This study explored whether rates of breast and colorectal screening in England are lower for obese than healthy weight individuals.

Setting

Data were from the English Longitudinal Study of Ageing (ELSA).

Methods

We analysed data from adults who were eligible to have been invited to the UK national screening programmes for breast or colorectal cancer (CRC) in the last five years, and had been given the screening module in Wave 5 of ELSA (N = 1804 for CRC screening, N = 2401 for breast cancer screening). Weight and height were measured by a nurse at Wave 4 (two years earlier). Logistic regression was used to calculate the odds of breast and CRC screening (ever) for participants in higher weight categories (Body Mass Index [BMI] ≥ 25) compared with healthy weight individuals (BMI <25), controlling for socio-demographic variables.

Results

Of ELSA participants, 63% reported CRC screening, and 92% of the women reported breast cancer screening. Obesity was associated with lower CRC screening, but effects were strongest for class III obesity (BMI ≥40) (45% screened; OR = 0.48, 95% CI = 0.32–0.93, P = .029). There was no association between weight status and breast cancer screening.

Conclusion

Severe obesity appears to be a deterrent to CRC screening but not breast cancer screening. Targeted interventions may be required to promote CRC screening uptake in this group, which already has a heightened risk as a consequence of weight.

Exploring opportunities for colorectal cancer screening and prevention in the context of diabetes self-management: an analysis of the 2010 National Health Interview Survey

Because diabetes is associated with increased colorectal cancer (CRC) risk, it is important that people with diabetes receive CRC screenings according to guidelines. In addition, many diabetes self-care recommendations are associated with a reduced risk of CRC. This study aims to identify potential opportunities for enhancing CRC prevention within the context of diabetes management. Using data from 1,730 adults with diabetes aged 50-75 years who responded to the 2010 National Health Interview Survey, we calculated population estimates of behaviors consistent with US Preventive Services Task Force guidelines for CRC screening and American Diabetes Association recommendations for diabetes care. We examined bivariate associations between CRC screening and selected diabetes self-care behaviors associated with CRC risk. Results were stratified by demographic characteristics. Thirty-nine percent of adults with diagnosed diabetes were not up-to-date with CRC screenings. Sixteen percent smoked and 2 % exceeded alcohol intake recommendations. Among those capable of exercise, 69 and 90 % did not meet aerobic exercise and resistance training recommendations, respectively. CRC screening was generally not associated with diabetes self-care behaviors. Among some demographic groups, CRC screening was associated with adequate aerobic activity, not smoking, and being overweight or obese. Many adults with diabetes do not follow guidelines for CRC screening or recommendations for diabetes care that may also reduce CRC risk. Thus, opportunities may exist to jointly promote CRC screening and prevention and diabetes self-management among adults with diabetes.

Patients whose physicians recommend colonoscopy and those who follow through

BACKGROUND

More than half of eligible individuals are not up-to-date with colon cancer screening.

PURPOSE

To assess the characteristics of those who received a colonoscopy screening recommendation and those who followed the physician recommendation.

METHODS

Patient self-administered questionnaire and medical record review in 16 private family physician practices.

RESULTS

From 8372 patients invited to participate, 685 were enrolled and had a medical record review; 219 (32%) had a colonoscopy recommendation and 86 (39%) received a colonoscopy. Independent factors associated with having a recommendation for colonoscopy were significantly younger in age (odds ratios [OR] = 1.6), higher incomes (annual income ≥$40 000 vs <$40 000; OR = 1.8), physician or nurse discussion about colon cancer tests (OR = 1.6), physical visit in the preceding 26 months (OR = 1.7), distant relative with colon cancer (OR = 2.4), and a medical diagnosis of hyperlipidemia (OR = 2.1). Independent factors associated with following through on colonoscopy after a recommendation were age ≥65 years (OR = 0.3), male patient (OR = 0.4), and feeling that colon cancer screening is very important (OR = 3.2).

CONCLUSIONS

Socioeconomic factors are associated with receipt of a colonoscopy recommendation. Fewer than one third of patients had documentation of a physician colonoscopy recommendation and of those, less than half followed through.

Association between body mass index and colorectal cancer: Recent research progress

Colorectal cancer (CRC) is a common digestive system disease posing a serious threat to people's health. There are about 1. 2 million new cases of CRC diagnosed worldwide each year, and the figure in China is 130 thousand. The socio-economic development and changes in diet and habits in China have led to a significant increase in both the incidence and mortality of CRC. The average age of onset of CRC in China is about 20 years old lower than that in Western countries, ranking second among all malignant tumors. The incidence and mortality of CRC in some developed regions of China, however, is close to those in Western developed countries. The development of CRC results from multiple factors, and nearly a quarter of patients with CRC could have avoided suffering from this disease by making favorable lifestyle habits. Nowadays, two-thirds of adults are fighting against overweight and obesity. Numerous recent studies indicate that high body mass index (BMI) is related with colorectal cancer. This article will review recent advances in understanding the relationship between BMI and CRC.