Adulthood Weight Change and Risk of Colorectal Cancer in the Nurses' Health Study and Health Professionals Follow-up Study

The Complex Connection between Obesity and Cancer: Signaling Pathways and Therapeutic Implications

Obesity has emerged as an important global health challenge, significantly influencing the incidence and progression of various cancers. This comprehensive review elucidates the complex relationship between obesity and oncogenesis, focusing particularly on the role of dysregulated signaling pathways as central mediators of this association. We delve into the contributions of obesity-induced alterations in key signaling cascades, including PI3K/AKT/mTOR, JAK/STAT, NF-κB, and Wnt/β-catenin to carcinogenesis. These alterations facilitate unchecked cellular proliferation, chronic inflammation and apoptosis resistance. Epidemiological evidence links obesity with increased cancer susceptibility and adverse prognostic outcomes, with pronounced risks for specific cancers such as breast, colorectal, endometrial and hepatic malignancies. This review synthesizes data from both animal and clinical studies to underscore the pivotal role of disrupted signaling pathways in shaping innovative therapeutic strategies. We highlight the critical importance of lifestyle modifications in obesity management and cancer risk mitigation, stressing the benefits of dietary changes, physical activity, and behavioral interventions. Moreover, we examine targeted pharmacological strategies addressing aberrant pathways in obesity-related tumors and discuss the integration of cutting-edge treatments, including immunotherapy and precision medicine, into clinical practice.

Aircraft noise exposure and body mass index among female participants in two Nurses' Health Study prospective cohorts living around 90 airports in the United States

OBJECTIVE

Aircraft noise exposure is linked to cardiovascular disease risk. One understudied candidate pathway is obesity. This study investigates the association between aircraft noise and obesity among female participants in two prospective Nurses' Health Study (NHS and NHSII) cohorts.

METHODS

Aircraft day-night average sound levels (DNL) were estimated at participant residential addresses from modeled 1 dB (dB) noise contours above 44 dB for 90 United States (U.S.) airports in 5-year intervals 1995-2010. Biennial surveys (1994-2017) provided information on body mass index (BMI; dichotomized, categorical) and other individual characteristics. Change in BMI from age 18 (BMI18; tertiles) was also calculated. Aircraft noise exposures were dichotomized (45, 55 dB), categorized (<45, 45-54, ≥55 dB) or continuous for exposure ≥45 dB. Multivariable multinomial logistic regression using generalized estimating equations were adjusted for individual characteristics and neighborhood socioeconomic status, greenness, population density, and environmental noise. Effect modification was assessed by U.S. Census region, climate boundary, airline hub type, hearing loss, and smoking status.

RESULTS

At baseline, the 74,848 female participants averaged 50.1 years old, with 83.0%, 14.8%, and 2.2% exposed to <45, 45-54, and ≥55 dB of aircraft noise, respectively. In fully adjusted models, exposure ≥55 dB was associated with 11% higher odds (95% confidence interval [95%CI]: -1%, 24%) of BMIs ≥30.0, and 15% higher odds (95%CI: 3%, 29%) of membership in the highest tertile of BMI18 (ΔBMI 6.7 to 71.6). Less-pronounced associations were observed for the 2nd tertile of BMI18 (ΔBMI 2.9 to 6.6) and BMI 25.0-29.9 as well as exposures ≥45 versus <45 dB. There was evidence of DNL-BMI trends (ptrends ≤ 0.02). Stronger associations were observed among participants living in the West, arid climate areas, and among former smokers.

DISCUSSION

In two nationwide cohorts of female nurses, higher aircraft noise exposure was associated with higher BMI, adding evidence to an aircraft noise-obesity-disease pathway.

Gastrointestinal: Weight gain increases the risk of metachronous advanced colorectal neoplasm observed in post-polypectomy surveillance colonoscopy

BACKGROUND AND AIM

Although obesity is a known risk factor for colorectal neoplasms, the correlation between weight change and colorectal neoplasm is unclear. Thus, we aim to evaluate the association between weight change and advanced colorectal neoplasm (ACRN) recurrence during post-polypectomy surveillance colonoscopy.

METHODS

This retrospective cohort study included 7473 participants diagnosed with colorectal neoplasms between 2003 and 2010 who subsequently underwent surveillance colonoscopies until 2020. We analyzed the association between the risk of metachronous ACRN and weight change, defining stable weight as a weight change of <3% and weight gain as a weight increase of ≥3% from baseline during the follow-up period.

RESULTS

During a median 8.5 years of follow-up, 619 participants (8.3%) developed ACRN. Weight gain was reported as an independent risk factor for metachronous ACRN in a time-dependent Cox analysis. A weight gain of 3-6% and ≥6% had adjusted hazard ratios (AHRs) of 1.48 (95% confidence interval [CI]: 1.19-1.84) and 2.14 (95% CI: 1.71-2.69), respectively. Participants aged 30-49 and 50-75 years with weight gain of ≥6% showed AHRs of 2.88 (95% CI: 1.96-4.21) and 1.90 (95% CI: 1.43-2.51), respectively. In men and women, weight gain of ≥3% was significantly correlated with metachronous ACRN.

CONCLUSIONS

Weight gain is associated with an increased risk of metachronous ACRN. Furthermore, weight gain is associated with the recurrence of ACRN in both men and women regardless of age.

Changes in Lifestyle and Risk of Colorectal Cancer in the European Prospective Investigation Into Cancer and Nutrition

INTRODUCTION

We investigated the impact of changes in lifestyle habits on colorectal cancer (CRC) risk in a multicountry European cohort.

METHODS

We used baseline and follow-up questionnaire data from the European Prospective Investigation into Cancer cohort to assess changes in lifestyle habits and their associations with CRC development. We calculated a healthy lifestyle index (HLI) score based on smoking status, alcohol consumption, body mass index, and physical activity collected at the 2 time points. HLI ranged from 0 (most unfavorable) to 16 (most favorable). We estimated the association between HLI changes and CRC risk using Cox regression models and reported hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

Among 295,865 participants, 2,799 CRC cases were observed over a median of 7.8 years. The median time between questionnaires was 5.7 years. Each unit increase in HLI from the baseline to the follow-up assessment was associated with a statistically significant 3% lower CRC risk. Among participants in the top tertile at baseline (HLI > 11), those in the bottom tertile at follow-up (HLI ≤ 9) had a higher CRC risk (HR 1.34; 95% CI 1.02-1.75) than those remaining in the top tertile. Among individuals in the bottom tertile at baseline, those in the top tertile at follow-up had a lower risk (HR 0.77; 95% CI 0.59-1.00) than those remaining in the bottom tertile.

DISCUSSION

Improving adherence to a healthy lifestyle was inversely associated with CRC risk, while worsening adherence was positively associated with CRC risk. These results justify and support recommendations for healthy lifestyle changes and healthy lifestyle maintenance for CRC prevention.

Changes in Gut Microbiome upon Orchiectomy and Testosterone Administration in AOM/DSS-Induced Colon Cancer Mouse Model

PURPOSE

Sex hormones are known to affect the gut microbiota. Previously, we reported that endogenous and exogenous testosterone are associated with colorectal cancer (CRC) development and submucosal invasion. In the present study, we investigated whether the gut microbiota is affected by orchiectomy (ORX) and testosterone propionate (TP) administration using an azoxymethane/dextran sulfate sodium (AOM/DSS)-induced CRC mouse model.

MATERIALS AND METHODS

Gut microbiota was evaluated by means of 16S rRNA gene sequencing of stool DNA extracted from feces that were obtained at 13 weeks after AOM injection (from 22-week-old animals) and stored in a gas-generating pouch.

RESULTS

The increase in microbial diversity (Chao1 and Phylogenetic Diversity index) and Firmicutes/Bacteroidetes (F/B) ratio upon AOM/DSS treatment in ORX mice was significantly decreased by TP supplementation. The ratio of commensal bacteria to opportunistic pathogens was lower in the TP-administered females and ORX mice than in the AOM/DSS group. Opportunistic pathogens (Mucispirillum schaedleri or Akkermansia muciniphila) were identified only in the TP group. In addition, microbial diversity and F/B ratio were higher in male controls than in female and ORX controls. Flintibacter butyricus, Ruminococcus bromii, and Romboutsia timonensis showed similar changes in the male control group as those in the female and ORX controls.

CONCLUSION

In conclusion, testosterone determines the dysbiosis of gut microbiota, which suggests that it plays a role in the sex-related differences in colorectal carcinogenesis.

The timing of adiposity and changes in the life course on the risk of cancer

Excess body weight has been established as a risk factor for at least twelve cancer sites, though questions remain as to the timing of associations for adiposity and cancer risk throughout the life course. We conducted a narrative review summarizing existing evidence to provide insights into the complex timing relationship between adiposity and risk of seven common obesity-related cancers. We considered five types of studies, including traditional epidemiologic studies examining adiposity at different time points, studies examining weight gain in specific life phases, studies examining weight loss over a period including from bariatric surgery, life course trajectory analysis, and Mendelian randomization studies. The results showed that lifetime excess body weight is associated with increased risk of cancers of endometrium, colorectum, liver, kidney, and pancreas. Early life obesity is one of the strongest risk factors for pancreatic cancer but less directly important than adult obesity for endometrial and kidney cancer. Interestingly, heavy weight during childhood, adolescence, and early adulthood is protective against pre- and postmenopausal breast cancer and possibly advanced prostate cancer. It is apparent that preventing weight gain later in adulthood would likely reduce risk of many cancers, including postmenopausal breast cancer, endometrial cancer, colorectal cancer (especially in men), liver cancer, kidney cancer, and probably advanced prostate cancer. Furthermore, weight loss even late in life may confer benefits for cancers of breast, endometrium, colorectum, and liver among patients with obesity, as mostly demonstrated by studies of bariatric surgery. Overall, maintaining a healthy weight throughout the life course will help prevent a large number of cancers.

Weight-change trajectory in relation to cancer risk: findings from a nationwide cohort study in South Korea

OBJECTIVE

This study examined relationships between weight-change trajectories and all cancers and obesity-related cancer risks.

METHODS

A total of 1,882,304 men and 899,912 women from the 2002 to 2017 National Health Insurance Service cohort were included. Weight-change trajectories in 2002 to 2009, according to BMI, were determined using group-based trajectory modeling. Cox proportional hazards regression assessed associations between trajectories and cancer incidence.

RESULTS

Overall, >50% of individuals maintained stable weight, as did two-thirds of those in the overweight and obesity groups. A total of 64,725 men and 37,608 women developed incident cancer. Weight stability in overweight or obesity groups was associated with greater cancer risk. In both sexes, higher weight across BMI groups increased risks of all cancers, obesity-related cancers and thyroid, colorectal, stomach, liver, prostate, and postmenopausal breast cancer. Stratified by BMI, weight gain increased risks of all cancers and obesity-related cancers in men with obesity class I and women with overweight. Weight loss decreased risks of obesity-related cancers, thyroid cancer, and kidney cancer among men with overweight, premenopausal breast, endometrial, and ovarian cancer in women with overweight, and obesity-related cancers and thyroid cancer in women with class I obesity.

CONCLUSIONS

Maintaining weight and avoiding weight gain are crucial for reducing cancer risk, but achieving a stable, normal BMI optimizes cancer prevention.

Identification of Smartwatch-Collected Lifelog Variables Affecting Body Mass Index in Middle-Aged People Using Regression Machine Learning Algorithms and SHapley Additive Explanations

Body mass index (BMI) plays a vital role in determining the health of middle-aged people, and a high BMI is associated with various chronic diseases. This study aims to identify important lifelog factors related to BMI. The sleep, gait, and body data of 47 middle-aged women and 71 middle-aged men were collected using smartwatches. Variables were derived to examine the relationships between these factors and BMI. The data were divided into groups according to height based on the definition of BMI as the most influential variable. The data were analyzed using regression and tree-based models: Ridge Regression, eXtreme Gradient Boosting (XGBoost), and Category Boosting (CatBoost). Moreover, the importance of the BMI variables was visualized and examined using the SHapley Additive Explanations Technique (SHAP). The results showed that total sleep time, average morning gait speed, and sleep efficiency significantly affected BMI. However, the variables with the most substantial effects differed among the height groups. This indicates that the factors most profoundly affecting BMI differ according to body characteristics, suggesting the possibility of developing efficient methods for personalized healthcare.

Role of Perirectal Fat in the Carcinogenesis and Development of Early-Onset Rectal Cancer

Purpose

The incidence of early-onset rectal cancer (EORC) has been increasing since the past decade, while its underlying cause remained unknown. This study was aimed at clarifying the relationship between perirectal fat area (PFA) and EORC. Patients and Methods. All patients with rectal cancer who received radical excision between January 2016 and December 2017 at our hospital were included. The fat series images of pelvic magnetic resonance imaging scans were obtained and PFA at the ischial spine level was calculated using the ImageJ software.

Results

A total of 303 patients were finally included and divided into two groups according to the median PFA: Group 1 (<20.2 cm², n = 151) and Group 2 (≥20.2 cm², n = 152). PFA positively correlated with body weight and body mass index. PFA increased with invasion depth, lymph node metastasis, TNM stage, tumor deposits, and vascular invasion. Patients with EORC had higher PFA than those with late-onset rectal cancer (LORC; P = 0.009). Among patients with stage I–III rectal cancers, those in Group 2 had significantly shorter disease-free survival (P = 0.010) and overall survival (P = 0.034) than those in Group 1, and PFA was an independent predictor of disease-free survival (OR: 1.683 [1.126-3.015], P = 0.035) and overall survival (OR: 1.678 [1.022-2.639], P = 0.046).

Conclusions

Patients with EORC had significantly higher PFA than those with LORC. PFA is positively correlated with T stage, N stage, TNM stage, tumor deposit, and vascular invasion and is an independent predictor of disease-free survival and overall survival. Therefore, perirectal fat may be involved in the carcinogenesis and development of EORC.

Changes in general and central fatness are associated with hepatocellular carcinoma: A Korean nationwide longitudinal study

We investigated the impact of short-term changes in general and central fatness on the risk of hepatocellular carcinoma (HCC) in a large, population-based cohort. We screened 7,221,479 subjects who underwent health examinations provided by the National Health Insurance Service of South Korea in 2009 and 2011. In total, 6,789,472 subjects were included in the final analysis. General fatness was defined as a body mass index (BMI) ≥25 kg/m² , and central fatness was defined as a waist circumference (WC) ≥90 cm in men and ≥85 cm in women. Subjects were classified according to the change in body fatness between 2009 and 2011, as follows: 1) persistent no fatness as no fatness in both 2009 and 2011, 2) reversed fatness as fatness in 2009, but no fatness in 2011, 3) incident fatness as no fatness in 2009, but fatness in 2011, or 4) persistent fatness as fatness in both 2009 and 2011. During a median 6.4-year follow-up, we documented 9,952 HCC cases. Compared to subjects with a persistent no general fatness, the risk of HCC significantly increased in those with incident (adjusted hazard ratio [aHR]=1.10, 95% confidence interval [CI]=1.01-1.20) and persistent (aHR=1.28, 95% CI=1.23-1.34) general fatness. Compared to subjects with persistent no central fatness, those with incident and persistent central fatness showed a significantly increased risk of HCC (aHR=1.19, 95% CI=1.11-1.27, and aHR=1.33, 95% CI=1.26-1.40, respectively). Taken together, these findings indicate the importance of strategies for preventing and reversing body fatness to reduce the incidence of HCC. This article is protected by copyright. All rights reserved.

Body mass index and weight gain after middle adulthood are associated with risk of papillary thyroid cancer: A case-control study

BACKGROUND

It is unclear whether weight change after middle adulthood influences the risk of thyroid cancer. The aim of this study was to investigate associations between the risk of papillary thyroid cancer (PTC) and body mass index (BMI) and weight change after middle adulthood (age 35).

METHODS

A matched case-control study based on three hospitals included 516 pairs of cases newly diagnosed with PTC and controls. Current height and weight after defecation in the morning were measured by trained nurses. During measurement, all subjects were requested to wear lightweight clothing and no shoes. Weight at age 35 was self-reported. BMI and weight change were modeled as continuous and categorical variables. Conditional and unconditional logistic regression models were used to estimate the odds ratio (OR) and 95% confidence interval (95%CI) for the association between BMI and weight change after middle adulthood and PTC.

RESULTS

After adjustment for covariates, measured BMI at the time of current diagnosis was positively associated with PTC (OR 1.16, 95%CI 1.10-1.21). According to WHO BMI guidelines for Asia-Pacific populations, the OR (95%CI) for PTC risk in obesity was 2.99 (1.92-4.67) compared to normal weight (p-trend <0.001). Moreover, PTC was positively associated with BMI at age 35; the OR (95%CI) for PTC risk per unit increase in BMI was 1.06 (1.02-1.11). Compared to stable weight (changed <0.5 kg/year), weight gain ≥1.0 kg/year after middle adulthood was positively associated with PTC (OR 2.57, 95%CI 1.39-4.76, p-trend <0.001). Compared to maintaining non-overweight status, the PTC risk was significantly increased in those individuals who gained weight and became overweight after middle adulthood (OR 3.82, 95%CI 2.50-5.85).

CONCLUSION

This study showed that high BMI and obesity were positively associated with increased risk of PTC, and weight gain after middle adulthood also could elevate the PTC risk.

Metabolic Risk Factors Associated with Early-Onset Colorectal Adenocarcinoma: A Case-Control Study at Kaiser Permanente Southern California

BACKGROUND

The incidence of early-onset colorectal cancer (eoCRC) diagnosed among individuals under age 50 has been rising. However, risk factors for eoCRC are unclear. We investigated whether metabolic abnormalities are risk factors for eoCRC adenocarcinoma.

METHODS

Invasive colorectal adenocarcinoma cases diagnosed between ages 15 and 49 from 2008 to 2018 at Kaiser Permanente Southern California (KPSC) were identified. Those with a history of inflammatory bowel disease were excluded. Noncancer controls were selected 5:1 for each case matched by age, sex, and length of membership prior to index date. Data were collected from KSPC's electronic medical records. The exposures of interest included obesity, type II diabetes, hypertension, and dyslipidemia, assessed from ≥1 year prior to eoCRC diagnosis/index date. Conditional logistic regressions were used to evaluate the associations between these metabolic risk factors and risk of eoCRC adenocarcinoma, adjusting for race/ethnicity, smoking, family history, neighborhood socioeconomic status, and health care utilization.

RESULTS

A total of 1,032 cases and 5,128 controls were included. Risk of colorectal adenocarcinoma was significantly associated with obesity [odds ratio (OR) = 1.41; 95% confidence interval (CI), 1.15-1.74], but not diabetes, hypertension or dyslipidemia. In analysis stratified by tumor location, obesity was significantly associated with risk of colon adenocarcinoma OR = 1.56 (1.17-2.07), but its association with rectal adenocarcinoma was less clear OR = 1.19 (0.85-1.68). No significant interaction was detected between obesity and age (≥40 vs. <40), and obesity and sex.

CONCLUSIONS

Obesity was associated with risk for eoCRC adenocarcinoma.

IMPACT

This finding could help inform early-onset colorectal adenocarcinoma screening and prevention recommendations.See related commentary by Hayes, p. xxx.

Adiposity, Adulthood Weight Change and Risk of Incident Hepatocellular Carcinoma

Prospective data are limited regarding dynamic adulthood weight changes and hepatocellular carcinoma (HCC) risk. We included 77,238 women (1980-2012) and 48,026 men (1986-2012), who recalled young-adult weight (age 18 years [women]; 21 years [men]), and provided biennially-updated information regarding weight, body mass index (BMI) and comorbidities. Overall adulthood weight change was defined as the difference in weight (kilograms) between young-adulthood and present. Using Cox proportional hazards models, we calculated multivariable-adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Over 3,676,549 person-years, we documented 158 incident HCC cases. Elevated HCC risk was observed with higher BMI in both young-adulthood and later-adulthood (continuous aHRs per each 1-unit=1.05, 95%CI=1.02-1.09 [Ptrend=0.019], and 1.08, 95%CI=1.06-1.10 [Ptrend=0.004], respectively). Moreover, overall adulthood weight gain was also significantly associated with increased HCC risk (aHR per each 1-kg increase=1.03, 95%CI=1.01-1.08; Ptrend=0.010), including after further adjusting for young-adult BMI (Ptrend=0.010) and later-adult BMI (Ptrend=0.008). Compared to adults with stable weight (+/-5kg), the multivariable-aHRs with weight gain of 5-<10kg, 10-<20kg and {greater than or equal to}20kg were, 1.40 (95%CI=0.67-2.16), 2.09 (95%CI=1.11-3.95) and 2.61 (95%CI=1.42-5.22), respectively. In two prospective, nationwide cohorts, adulthood weight gain was significantly associated with increased HCC risk.

Gender Differences in Obesity-Related Cancers

PURPOSE OF REVIEW

In this review, we summarize the role of obesity in carcinogenesis, providing details on specific cancer sites. Special emphasis is given to gender differences in obesity-related cancers and on the effect of bariatric surgery on cancer risk.

RECENT FINDINGS

Accumulating evidence has highlighted the detrimental role of overweight/obesity in cancer, with almost 55% of cancers diagnosed in women and 24% diagnosed in men considered overweight- and obesity-related cancers. Sufficient data have shown that higher BMI is associated with risk of gynecologic malignancies (mainly breast and endometrial cancers) as well as cancers in sites such as the esophagus (adenocarcinoma), gastric cardia, colon, rectum, liver, gallbladder, pancreas, kidney, thyroid gland, and multiple myeloma. The main mechanisms underlying this relationship include the insulin/IGF1 system, the effect of sex hormones, and adipocytokines. Marked differences may be seen in specific cancer sites when comparing men to women. There is a higher overall incidence of obesity-related cancers among females (endometrial, ovarian, and postmenopausal female breast cancers), whereas cancers that concern both sexes show a higher incidence in males, particularly esophageal adenocarcinoma (male to female ratio: 9: 1 in the USA). Additionally, bariatric surgery has provided evidence of lowering overall cancer risk in patients with morbid obesity. Interestingly, bariatric surgery may lower overall cancer risk in women within the first 5 years after surgery due to the reduced risk of breast and endometrial cancer, and non-Hodgkin lymphoma. Obesity constitutes the base for marked metabolic, hormonal, and inflammatory alterations, including increased cancer risk in both men and women. Implementation of early obesity prevention strategies could ameliorate the continuously increasing incidence of cancer attributed to obesity.

Weight gain during early adulthood, trajectory of body shape and the risk of nonalcoholic fatty liver disease: A prospective cohort study among women

BACKGROUND & AIMS

Obesity is established as a major risk factor for the development of nonalcoholic fatty liver disease (NAFLD). However, the influence of dynamic changes in adiposity over the life course on NAFLD risk remains poorly understood.

METHODS

We collected data from 110,054 women enrolled in the Nurses' Health Study II cohort. Early adulthood weight was ascertained at age 18 years, and weight gain since early adulthood was defined prospectively every 2 years. We used a group-based modeling approach to identify five trajectories of body shape from age 5 years up to age 50 years. NAFLD was defined by physician-confirmed diagnoses of fatty liver, after excluding excess alcohol intake and viral hepatitis, using validated approaches.

RESULTS

We documented 3798 NAFLD cases over a total of 20 years of follow-up. Compared to women who maintained stable weight (±2 kg), women with ≥20 kg of adulthood weight gain had the multivariable aHR of 6.96 (95% CI, 5.27-9.18), and this remained significant after further adjusting for early adulthood BMI and updated BMI (both P trend <0.0001). Compared to women with a medium-stable body shape trajectory, the multivariable aHRs for NAFLD were, 2.84 (95% CI, 2.50-3.22) for lean-marked increase, 2.60 (95% CI, 2.27-2.98) for medium-moderate increase, and 3.39 (95% CI, 2.95-3.89) for medium-marked increase.

CONCLUSIONS

Both early adulthood weight gain and lifetime body shape trajectory were significantly and independently associated with excess risk of developing NAFLD in mid-life. Maintaining both lean and stable weight throughout life may offer the greatest benefit for the prevention of NAFLD.

Obesity and younger versus older onset colorectal cancer in the United States, 1998-2017

The etiology behind the increasing incidence of early onset colorectal cancer (EOCRC) are incompletely elucidated, but could be attributed in part to lifestyle factors. We assessed the association between obesity and colorectal cancer (CRC) in younger versus older adults in the National Health Institute Survey. Multivariable logistic regression defined adjusted odds ratios (AORs) and associated 95% confidence intervals (CIs) for CRC including an age (< vs. ≥50 years) *BMI (< vs. ≥30.0 kg/m²) interaction term. Among 583,511 study participants with a total of 3,173 CRC cases, there was a significant age*BMI interaction term (P=0.02) such that for participants aged 18-49 years, BMI ≥30.0 kg/m² was associated with diagnosis of CRC (34.1% vs. 27.4%, AOR 1.39, 95% CI: 1.00-1.92) but not for participants aged ≥50 (29.6% vs. 31.4%, AOR 0.93, 95% CI: 0.85-1.03). Obese BMI appears to be associated with diagnosis of EOCRC, thus weight control by early adulthood, among other healthy lifestyle behaviors, could serve as potential risk reduction strategies for CRC.

Metabolite profile comparisons between ascending and descending colon tissue in healthy adults

BACKGROUND

Obesity is a risk factor for colorectal cancer, yet metabolic distinctions between healthy right and left colon tissue, before cancer is diagnosed, remains largely unknown. This study compared right-ascending and left-descending colon tissue metabolomes to identify differences from the stool metabolome in normal weight, overweight, and obese adults.

AIM

To examine right and left colon tissue metabolites according to body mass index that may serve as mechanistic targets for interventions and biomarkers for colon cancer risk.

METHODS

Global, non-targeted metabolomics was applied to assess right-ascending and left-descending colon tissue collected from healthy adults undergoing screening colonoscopies to test the hypothesis that BMI differentially impacts colon tissue metabolite profiles. The colon tissue and stool metabolome of healthy adults (n = 24) was analyzed for metabolite signatures and metabolic pathway networks implicated in progression of colorectal cancer.

RESULTS

Ascending and descending colon contained 504 host, food, and microbiota-derived metabolites from normal weight, overweight and obese adults grouped according to body mass index. Amino acids, lipids, and nucleotides were among the chemical types that further differentiated from the stool metabolite profiles. Normal weight adults had 46 significantly different metabolites between ascending and descending colon tissue locations, whereas there were 37 metabolite differences in overweight and 28 metabolite differences for obese adults (P < 0.05). Obese adults had trimethylamine N-oxide, endocannabinoids and monoacylglycerols with different relative abundances identified between ascending and descending colon. Primary and secondary bile acids, vitamins, and fatty acids also showed marked relative abundance differences in colon tissue from overweight/obese adults.

CONCLUSION

There were metabolite profile differences between right-ascending and left-descending colon tissue in healthy adults. Colon lipids and other metabolites in obese and overweight adults were distinguished from normal weight participants and associated with gut inflammation, nutrient absorption, and products of microbiota metabolism.

Epidemiology and Mechanisms of the Increasing Incidence of Colon and Rectal Cancers in Young Adults

In contrast to the decreasing incidence of colorectal cancer (CRC) in older populations, the incidence has nearly doubled in younger adults since the early 1990s. Approximately 1 in 10 new diagnoses of CRC are now made in individuals 50 years or younger. Patients' risk of CRC has been calculated largely by age and family history, yet 3 of 4 patients with early-onset CRC have no family history of the disease. Rapidly increasing incidence rates in younger people could result from generational differences in diet, environmental exposures, and lifestyle factors. We review epidemiologic trends in CRC, data on genetic and nongenetic risk factors, and new approaches for determining CRC risk. These may identify individuals likely to benefit from early screening and specialized surveillance.

Adherence to the World Cancer Research Fund/American Institute for Cancer Research 2018 Recommendations for Cancer Prevention and Risk of Colorectal Cancer

BACKGROUND

The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) 2018 diet, nutrition, and physical activity recommendations aim to reduce cancer risk. We examined adherence to the WCRF/AICR recommendations and colorectal cancer risk in two prospective cohorts.

METHODS

We followed 68,977 women in the Nurses' Health Study and 45,442 men in the Health Professionals Follow-up Study from 1986 until 2012. We created cumulatively averaged WCRF/AICR scores using updated diet, adiposity, and physical activity data from questionnaires, and used Cox regression to estimate sex-specific HRs and 95% confidence intervals (CI) for incident colorectal cancer.

RESULTS

We documented 2,449 colorectal cancer cases. Men in the highest quintile of the WCRF/AICR lifestyle score had a lower risk of colorectal cancer compared with those in the lowest quintile (HRQ5vsQ1 = 0.64; 95% CI, 0.52-0.77). The result was weaker in women (HRQ5vsQ1 = 0.86; 95% CI, 0.72-1.02; P heterogeneity by sex = 0.006). When analyzing the diet recommendations alone, we similarly observed stronger inverse associations in men (HRQ5vsQ1 = 0.74; 95% CI, 0.61-0.90) compared with women (HRQ5vsQ1 = 0.93; 95% CI, 0.77-1.12; P heterogeneity by sex = 0.06). In men, the lifestyle score was more strongly inversely associated with risk of distal colon cancer compared with proximal colon or rectal cancer (P common effects = 0.03); we did not observe significant differences between anatomic locations in women.

CONCLUSIONS

The 2018 WCRF/AICR cancer prevention recommendations are associated with lower colorectal cancer risk in men, with weaker results in women.

IMPACT

Consideration of adiposity and physical activity in conjunction with diet is important for colorectal cancer prevention.

Preventable incidence of carcinoma associated with adiposity, alcohol and physical inactivity according to smoking status in the United States

The changing profile of lifestyles and their intricate relationships with smoking indicate the importance of accounting for smoking status when assessing cancer preventability. We assessed the association of body mass index, weight change, alcohol intake and physical activity with risk of total carcinoma among 53,195 smokers and 62,842 nonsmokers in two prospective cohorts. Then, leveraging the national prevalence estimates, we calculated the population attributable risk (PAR) for healthy lifestyle defined as body mass index ≥18.5 and <27.5 kg/m² , mid-life weight change of ≤20 pounds, no or moderate alcohol drinking (≤1 and 2 drinks/day for women and men, respectively) and weekly moderate or vigorous physical activity of at least 150 min. The PAR (95% CI) for healthy lifestyle was 18% (14-22%) in nonsmokers and 14% (10-19%) in smokers among women, and 20% (12-27%) in nonsmokers and 11% (5-17%) in smokers among men. While adiposity accounted for a substantially higher proportion of carcinoma cases in nonsmokers than smokers (16% vs. 2% in women, 15% vs. 2% in men), alcohol contributed more in smokers than nonsmokers (7% vs. 3% in women, 8% vs. 1% in men). When more strict criteria were used to define healthy lifestyle, the PAR estimates further increased (for women: 37% in smokers and 32% in nonsmokers; for men: 15% and 24%, respectively). In conclusion, lifestyle modification has great potential to reduce cancer risk in both smokers and nonsmokers. Weight control and reducing alcohol consumption should be prioritized for cancer prevention in nonsmokers and smokers, respectively.

Intentional Weight Loss and Obesity-Related Cancer Risk

Background

Epidemiologic studies regarding weight loss and subsequent cancer risk are sparse. The study aim was to evaluate the association between weight change by intentionality and obesity-related cancer incidence in the Women’s Health Initiative Observational Study. Eleven cancers were considered obesity related: breast, ovary, endometrium, colon and rectum, esophagus, kidney, liver, multiple myeloma, pancreas, stomach, and thyroid.

Methods

Postmenopausal women (n = 58 667) aged 50–79 years had body weight and waist circumference (WC) measured at baseline and year 3. Weight or WC change was categorized as stable (change < ±5%), loss (≥5%), and gain (≥5%). Self-report at year 3 characterized weight loss as intentional or unintentional. During the subsequent 12 years (mean) of follow-up, 6033 incident obesity-related cancers were identified. Relationships were evaluated using multivariable Cox proportional hazards regression models.

Results

Compared to women with stable weight, women with intentional weight loss had lower obesity-related cancer risk (hazard ratio [HR] = 0.88, 95% confidence interval [CI] = 0.80 to 0.98). A similar result was observed for intentional WC reduction (HR = 0.88, 95% CI = 0.80 to 0.96). Among all cancers, intentional weight loss was most strongly associated with endometrial cancer (HR = 0.61, 95% CI = 0.42 to 0.88). Intentional WC loss was also associated with lower colorectal cancer risk (HR = 0.79, 95% CI = 0.63 to 0.99). Unintentional weight loss or weight gain was not associated with overall obesity-related cancer risk.

Conclusion

Intentional weight or WC loss in postmenopausal women was associated with lower risk of obesity-related cancer. These findings suggest that postmenopausal women who intentionally lose weight can reduce their obesity-related cancer risk.

Weight change since age 20 and incident risk of obesity-related cancer in Japan: a pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study

It is unclear whether weight change during adulthood affects the risk of obesity-related cancers such as those of the esophagus, colorectum, pancreas, breast, endometrium, and kidney among Japanese, where obesity is less frequent and less severe. We examined the association between weight change during adulthood and the risk of obesity-related cancer among Japanese by conducting a pooled analysis of two prospective studies of residents in Miyagi Prefecture, Japan. A total of 78,743 persons (40,422 women and 38,321 men) aged 40-79 years participated in the Miyagi Cohort Study in 1990 and in the Ohsaki Cohort Study in 1994. Weight change since age 20 was divided into four categories (weight loss; stable weight; moderate weight gain; high weight gain). Cox proportional hazards regression analysis was used to estimate the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for obesity-related cancer incidence. During 1,057,899 person-years of follow up, 4,467 cases of obesity-related cancer (women; 1,916 cases, men; 2,551cases) were identified. In women, compared to the stable weight, weight gain was associated with an increased risk of obesity-related cancer (moderate weight gain; HRs = 1.10, 95%CIs: 0.97-1.26, high weight gain; HRs = 1.29, 95%CIs: 1.14-1.47). The results indicate that weight gain since age 20 was associated with a significantly increased risk of obesity-related cancer among Japanese women. By contrast, in men, our study found that weight change is not associated with the incidence of obesity-related cancer.

Association Between Obesity and Weight Change and Risk of Diverticulitis in Women

BACKGROUND & AIMS

There is little evidence that adiposity associates with diverticulitis, especially among women. We conducted a comprehensive evaluation of obesity, weight change, and incidence of diverticulitis in a large cohort of women.

METHODS

We conducted a prospective cohort study of 46,079 women enrolled in the Nurses' Health Study who were 61-89 years old and free of diverticulitis, diverticular bleeding, cancers, or inflammatory bowel disease at baseline (in 2008). We used Cox proportional hazards models to examine the associations among risk of incident diverticulitis and body mass index (BMI), waist circumference, waist to hip ratio, and weight change from age 18 years to the present. The primary end point was first incident diverticulitis requiring antibiotic therapy or hospitalization.

RESULTS

We documented 1084 incident cases of diverticulitis over 6 years of follow-up, encompassing 248,001 person-years. After adjustment for other risk factors, women with a BMI ≥35.0 kg/m2 had a hazard ratio for diverticulitis of 1.42 (95% confidence interval [CI], 1.08-1.85) compared to women with a BMI <22.5 kg/m2. Compared to women in the lowest quintile, the multivariable hazard ratios among women in the highest quintile were 1.35 (95% CI, 1.02-1.78) for waist circumference and 1.40 (95% CI, 1.07-1.84) for waist to hip ratio; these associations were attenuated with further adjustment for BMI. Compared to women maintaining weight from age 18 years to the present, those who gained ≥20 kg had a 73% increased risk of diverticulitis (95% CI, 27%-136%).

CONCLUSIONS

During a 6-year follow-up period, we observed an association between obesity and risk of diverticulitis among women. Weight gain during adulthood was also associated with increased risk.

Changes in Adult BMI and Waist Circumference Are Associated with Increased Risk of Advanced Colorectal Neoplasia

BACKGROUND

Waist circumference (WC) is a stronger predictor of colon cancer (CRC) risk than body mass index (BMI). However, how well change in either WC or BMI predicts risk of advanced colorectal neoplasia (AN) is unclear.

AIMS

To determine the relationship between change in BMI and WC from early adulthood to later age and the risk of AN and which change measure is a stronger predictor.

METHODS

In 4500 adults, ages 50-80, with no previous neoplasia and undergoing screening colonoscopy, BMI and WC at age 21 and at time of screening were reported. Changes in BMI and WC were defined using universal risk cutoffs. Known CRC risk factors were controlled in the logistic models.

RESULTS

Overall, model statistics showed WC change (omnibus test χ ² = 10.15, 2 DF, p value = 0.006) was a statistically stronger predictor of AN than BMI change (omnibus test χ ² = 5.66, 5 DF, p value = 0.34). Independent of BMI change, participants who increased WC (OR 1.44; 95% CI 1.05-1.96) or maintained a high-risk WC (OR 2.50; 95% CI 1.38-4.53) at age 21 and at screening had an increased risk of AN compared to those with a low-risk WC. Study participants who were obese at age 21 and at screening had an increased risk of AN (OR 1.87; 95% CI 1.08-3.23) compared to those who maintained a healthy BMI. Maintaining an overweight BMI or increasing BMI was not associated with AN.

CONCLUSIONS

Maintaining an unhealthy BMI and WC throughout adult life may increase risk of AN. WC change may be a better predictor of AN than BMI change.

Associations of Weight Gain From Early to Middle Adulthood With Major Health Outcomes Later in Life

IMPORTANCE

Data describing the effects of weight gain across adulthood on overall health are important for weight control.

OBJECTIVE

To examine the association of weight gain from early to middle adulthood with health outcomes later in life.

DESIGN, SETTING, AND PARTICIPANTS

Cohort analysis of US women from the Nurses' Health Study (1976-June 30, 2012) and US men from the Health Professionals Follow-Up Study (1986-January 31, 2012) who recalled weight during early adulthood (at age of 18 years in women; 21 years in men), and reported current weight during middle adulthood (at age of 55 years).

EXPOSURES

Weight change from early to middle adulthood (age of 18 or 21 years to age of 55 years).

MAIN OUTCOMES AND MEASURES

Beginning at the age of 55 years, participants were followed up to the incident disease outcomes. Cardiovascular disease, cancer, and death were confirmed by medical records or the National Death Index. A composite healthy aging outcome was defined as being free of 11 chronic diseases and major cognitive or physical impairment.

RESULTS

A total of 92 837 women (97% white; mean [SD] weight gain: 12.6 kg [12.3 kg] over 37 years) and 25 303 men (97% white; mean [SD] weight gain: 9.7 kg [9.7 kg] over 34 years) were included in the analysis. For type 2 diabetes, the adjusted incidence per 100 000 person-years was 207 among women who gained a moderate amount of weight (≥2.5 kg to <10 kg) vs 110 among women who maintained a stable weight (weight loss ≤2.5 kg or gain <2.5 kg) (absolute rate difference [ARD] per 100 000 person-years, 98; 95% CI, 72 to 127) and 258 vs 147, respectively, among men (ARD, 111; 95% CI, 58 to 179); hypertension: 3415 vs 2754 among women (ARD, 662; 95% CI, 545 to 782) and 2861 vs 2366 among men (ARD, 495; 95% CI, 281 to 726); cardiovascular disease: 309 vs 248 among women (ARD, 61; 95% CI, 38 to 87) and 383 vs 340 among men (ARD, 43; 95% CI, -14 to 109); obesity-related cancer: 452 vs 415 among women (ARD, 37; 95% CI, 4 to 73) and 208 vs 165 among men (ARD, 42; 95% CI, 0.5 to 94). Among those who gained a moderate amount of weight, 3651 women (24%) and 2405 men (37%) achieved the composite healthy aging outcome. Among those who maintained a stable weight, 1528 women (27%) and 989 men (39%) achieved the composite healthy aging outcome. The multivariable-adjusted odds ratio for the composite healthy aging outcome associated with moderate weight gain was 0.78 (95% CI, 0.72 to 0.84) in women and 0.88 (95% CI, 0.79 to 0.97) in men. Higher amounts of weight gain were associated with greater risks of major chronic diseases and lower likelihood of healthy aging.

CONCLUSIONS AND RELEVANCE

In these cohorts of health professionals, weight gain during adulthood was associated with significantly increased risk of major chronic diseases and decreased odds of healthy aging. These findings may help counsel patients regarding the risks of weight gain.

Global Cancer in Women: Burden and Trends

This review is an abbreviated version of a report prepared for the American Cancer Society Global Health department and EMD Serono, Inc., a subsidiary of Merck KGaA, Darmstadt, Germany, which was released at the Union for International Cancer Control World Cancer Congress in Paris in November 2016. The original report can be found at https://www.cancer.org/health-care-professionals/our-global-health-work/global-cancer-burden/global-burden-of-cancer-in-women.html. Staff in the Intramural Research Department of the American Cancer Society designed and conducted the study, including analysis, interpretation, and presentation of the review. The funding sources had no involvement in the study design, data analysis and interpretation, or preparation of the reviewThere are striking disparities in the global cancer burden in women, yet few publications highlight cancer occurrence in this population, particularly for cancers that are not sex specific. This article, the first in a series of two, summarizes the current burden, trends, risk factors, prevention, early detection, and survivorship of all cancers combined and seven sites (breast, cervix, uterine corpus, ovary, colorectum, lung, and liver) that account for about 60% of the cancer burden among women worldwide, using data from the International Agency for Research on Cancer. Estimated 2012 overall cancer death rates in general are higher among women in low- and middle-income countries (LMICs) than high-income countries (HICs), despite their lower overall incidence rates, largely due to inadequate access to early detection and treatment. For example, the top mortality rates are in Zimbabwe (147 deaths per 100,000) and Malawi (138). Furthermore, incidence rates of cancers associated with economic development (e.g., lung, breast, colorectum) are rising in several LMICs. The burden of cancer among women could be substantially reduced in both HICs and LMICs through broad and equitable implementation of effective interventions, including tobacco control, HPV and HBV vaccination, and screening (breast, cervix, and colorectum). Cancer Epidemiol Biomarkers Prev; 26(4); 444-57. ©2017 AACRSee related article by Islami et al. in this CEBP Focus section, "Global Cancer in Women."

Delineation of body mass index trajectory predicting lowest risk of mortality in U.S. men using generalized additive mixed model

PURPOSE

Few studies have delineated body mass index (BMI) trajectories that associate with premature mortality, which is defined as death occurring before age 75 years.

METHODS

We used generalized additive mixed model to identify BMI trajectories of individuals dying before or after age 75 years among 14,172 U.S. men. We used logistic regression to validate whether the BMI trajectory developed predicted mortality in an independent cohort of 7000 participants.

RESULTS

Comparing to participants with age at death less than 75 years, the BMI among participants with age at death 75 years or more was lower throughout adulthood, and the mean BMI was 23.98, 24.63, 25.33, and 25.29 kg/m2 at age 40, 50, 60, and 70 years. In the validation cohort, participants following the BMI trajectory with age at death less than 75 years had higher risks of total mortality (odds ratio: 1.35; 95% confidence interval: 1.01-1.78) and cardiovascular disease mortality (1.92; 1.10-3.35) compared to participants following the trajectory with age at death 75 years or more. Participants whose BMI trajectories diverged the most from the trajectory with age at death 75 years or more had highest risks of total mortality (1.72; 1.23-2.40) and cardiovascular disease mortality (3.06; 1.49-6.30).

CONCLUSIONS

Individual is suggested to maintain a normal BMI throughout adulthood to have greater longevity.

Diet-induced weight loss leads to a switch in gene regulatory network control in the rectal mucosa

BACKGROUND

Weight loss may decrease risk of colorectal cancer in obese individuals, yet its effect in the colorectum is not well understood. We used integrative network modeling, Passing Attributes between Networks for Data Assimilation, to estimate transcriptional regulatory network models from mRNA expression levels from rectal mucosa biopsies measured pre- and post-weight loss in 10 obese, pre-menopausal women.

RESULTS

We identified significantly greater regulatory targeting of glucose transport pathways in the post-weight loss regulatory network, including "regulation of glucose transport" (FDR=0.02), "hexose transport" (FDR=0.06), "glucose transport" (FDR=0.06) and "monosaccharide transport" (FDR=0.08). These findings were not evident by gene expression analysis alone. Network analysis also suggested a regulatory switch from NFΚB1 to MAX control of MYC post-weight loss.

CONCLUSIONS

These network-based results expand upon standard gene expression analysis by providing evidence for a potential mechanistic alteration caused by weight loss.

Trajectory of body shape in early and middle life and all cause and cause specific mortality: results from two prospective US cohort studies

OBJECTIVE

To assess body shape trajectories in early and middle life in relation to risk of mortality.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study and Health Professionals Follow-up Study.

POPULATION

80 266 women and 36 622 men who recalled their body shape at ages 5, 10, 20, 30, and 40 years and provided body mass index at age 50, followed from age 60 over a median of 15-16 years for death.

MAIN OUTCOME MEASURES

All cause and cause specific mortality.

RESULTS

Using a group based modeling approach, five distinct trajectories of body shape from age 5 to 50 were identified: lean-stable, lean-moderate increase, lean-marked increase, medium-stable/increase, and heavy-stable/increase. The lean-stable group was used as the reference. Among never smokers, the multivariable adjusted hazard ratio for death from any cause was 1.08 (95% confidence interval 1.02 to 1.14) for women and 0.95 (0.88 to 1.03) for men in the lean-moderate increase group, 1.43 (1.33 to 1.54) for women and 1.11 (1.02 to 1.20) for men in the lean-marked increase group, 1.04 (0.97 to 1.12) for women and 1.01 (0.94 to 1.09) for men in the medium-stable/increase group, and 1.64 (1.49 to 1.81) for women and 1.19 (1.08 to 1.32) for men in the heavy-stable/increase group. For cause specific mortality, participants in the heavy-stable/increase group had the highest risk, with a hazard ratio among never smokers of 2.30 (1.88 to 2.81) in women and 1.45 (1.23 to 1.72) in men for cardiovascular disease, 1.37 (1.14 to 1.65) in women and 1.07 (0.89 to 1.30) in men for cancer, and 1.59 (1.38 to 1.82) in women and 1.10 (0.95 to 1.29) in men for other causes. The trajectory-mortality association was generally weaker among ever smokers than among never smokers (for all cause mortality: P for interaction <0.001 in women and 0.06 in men). When participants were classified jointly according to trajectories and history of type 2 diabetes, the increased risk of death associated with heavier body shape trajectories was more pronounced among participants with type 2 diabetes than those without diabetes, and those in the heavy-stable/increase trajectory and with a history of diabetes had the highest risk of death.

CONCLUSIONS

Using the trajectory approach, we found that heavy body shape from age 5 up to 50, especially the increase in middle life, was associated with higher mortality. In contrast, people who maintained a stably lean body shape had the lowest mortality. These results indicate the importance of weight management across the lifespan.