Body mass index and physical activity as risk factors for pancreatic cancer: the Multiethnic Cohort Study

Role of body mass index and weight change in the risk of cancer: A systematic review and meta-analysis of 66 cohort studies

Background

This study was designed to evaluate the effects of body mass index (BMI) and weight change on the risk of developing cancer overall and cancer at different sites.

Methods

We searched PubMed and other databases up to July 2023 using the keywords related to 'risk', 'cancer', 'weight', 'overweight', and 'obesity'. We identified eligible studies, and the inclusion criteria encompassed cohort studies in English that focused on cancer diagnosis and included BMI or weight change as an exposure factor. Multiple authors performed data extraction and quality assessment, and statistical analyses were carried out using RevMan and R software. We used random- or fixed-effects models to calculate the pooled relative risk (RR) or hazard ratio along with 95% confidence intervals (CIs). We used the Newcastle-Ottawa Scale to assess study quality.

Results

Analysis included 66 cohort studies. Compared to underweight or normal weight, overweight or obesity was associated with an increased risk of endometrial cancer, kidney cancer, and liver cancer but a decreased risk of prostate cancer and lung cancer. Being underweight was associated with an increased risk of gastric cancer and lung cancer but not that of postmenopausal breast cancer or female reproductive cancer. In addition, weight loss of more than five kg was protective against overall cancer risk.

Conclusions

Overweight and obesity increase the risk of most cancers, and weight loss of >5 kg reduces overall cancer risk. These findings provide insights for cancer prevention and help to elucidate the mechanisms underlying cancer development.

Registration

Reviewregistry1786.

Recent Developments in the Treatment of Pancreatic Cancer

Pancreatic duct adenocarcinoma is currently the sixth-leading cause of cancer death worldwide and the fourth in Europe, with a continuous increase in annual lethality in Portugal during the last two decades. Surgical en-bloc resection of the tumor with microscopic-negative margins and an adequate lymphadenectomy is the only possibility of long-term survival. As this type of cancer is a systemic disease, there is a high rate of recurrence even after curative resection, turning systemic therapy the core of its management, mostly based on chemotherapy. Neoadjuvant strategies for nonmetastatic disease showed significant improvement in overall survival compared with upfront surgery, namely in borderline resectable disease. Moreover, these strategies provided downstaging in several situations allowing R0 resections. Under these new oncologic strategies, several recent surgical issues were introduced, namely more aggressive vascular resections and even tumor resections in oligometastatic disease. This review revisits the state-of-the-art of surgical and oncological interventions in pancreatic duct adenocarcinoma and highlights recent advances in the field aiming to achieve higher survival rates.

Treatment optimization of locally advanced and metastatic pancreatic cancer (Review)

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant tumor types, being the sixth leading cause of mortality worldwide and the fourth in Europe. Globally, it has a mortality/incidence ratio of 98%, and the 5‑year survival rate in Europe is only 3%. Although risk factors, such as obesity, diabetes mellitus, smoking, alcohol consumption and genetic factors, have been identified, the causes of PDAC remain elusive. Additionally, the only curative treatment for PDAC is surgery with negative margins. However, upon diagnosis, ~30% of the patients already present with locally advanced disease. In these cases, a multidisciplinary approach is required to improve disease‑related symptoms and prolong patient survival. In the present article, a comprehensive review of PDAC epidemiology, physiology and treatment is provided. Moreover, guidelines on patient treatment are suggested. Among the different available therapeutic options for the treatment of advanced PDAC, results are modest, most likely due to the complexity of the disease, and so the prognostic remains poor. Molecular approaches based on multi‑omics research are promising and will contribute to groundbreaking personalized medicine. Thus, economic investment that promotes research of pancreatic cancer will be critical to the development of more efficient diagnostic and treatment strategies.

Racial/ethnic disparities in weight or BMI change in adulthood and pancreatic cancer incidence: The multiethnic cohort

INTRODUCTION

Compared to non-Hispanic Whites, Japanese Americans, Native Hawaiians, and African Americans have higher incidences of pancreatic cancer (PCa) that are not entirely explained by rates of obesity but may be explained by weight changes throughout adulthood.

METHODS

The multiethnic cohort is a population-based prospective cohort study that has followed 155,308 participants since its establishment between 1993 and 1996. A total of 1,328 incident cases with invasive PCa were identified through 2015. We conducted separate multivariable Cox proportional hazards models for self-reported weight-change and BMI-change (age 21 to cohort entry) to determine the association with PCa risk, adjusting for potential confounders including weight or BMI at age 21.

RESULTS

The mean age at cohort entry was 59.3 years (SD 8.9). An increased risk of PCa was associated with: 1) weight (HR per10 lbs = 1.06; 95% CI = 1.03-1.09) or BMI (HR per kg/m2  = 1.04; 95% CI = 1.02-1.05) at age 21; and 2) weight (HR per 10 lbs = 1.03; 95% CI = 1.01-1.05) or BMI (HR = 1.02; 95% CI = 1.00-1.03) at cohort entry. We found increased risk of PCa between weight (HR per 10 lbs = 1.03; 95% CI = 1.01-1.05) and BMI (HR per 5 kg/m2  = 1.08; 95% CI = 1.01-1.15) change from age 21 to baseline. There were significant interactions between race/ethnicity and weight (p = 0.008) or BMI (p = 0.03) at baseline, and weight (p = 0.02) or BMI (p = 0.02) change. Weight and BMI change through adulthood significantly increased the risk of PCa for Japanese Americans and Latinos, but not for African American, White, or Hawaiian participants.

CONCLUSION

Our findings indicate that weight or BMI gain has a significant and independent impact on PCa risk, specifically among Latinos and Japanese Americans.

Changes in diet quality and body weight over 10 years: the Multiethnic Cohort Study

High-quality diets have been found to be beneficial in preventing long-term weight gain. However, concurrent changes in diet quality and body weight over time have rarely been reported. We examined the association between 10-year changes in diet quality and body weight in the Multiethnic Cohort Study. Analyses included 53 977 African Americans, Native Hawaiians, Japanese Americans, Latinos and Whites, who completed both baseline (1993–1996, 45–69 years) and 10-year follow-up (2003–2008) surveys including a FFQ and had no history of heart disease or cancer. Using multivariable regression, weight changes were regressed on changes in four diet quality indexes, Healthy Eating Index-2015, Alternative Healthy Eating Index-2010, alternate Mediterranean Diet and Dietary Approaches to Stop Hypertension scores. Mean weight change over 10 years was 1·2 (sd 6·8) kg in men and 1·5 (sd 7·2) kg in women. Compared with stable diet quality (< 0·5 sd change), the greatest increase (≥ 1 sd increase) in the diet scores was associated with less weight gain (by 0·55–1·17 kg in men and 0·62–1·31 kg in women). Smaller weight gain with improvement in diet quality was found in most subgroups by race/ethnicity, baseline age and baseline BMI. The inverse association was stronger in younger age and higher BMI groups. Ten-year improvement in diet quality was associated with a smaller weight gain, which varied by race/ethnicity and baseline age and BMI. Our findings suggest that maintaining a high-quality diet and improving diet quality over time may prevent excessive weight gain.

Diabetes-Related Complications and Pancreatic Cancer Incidence in the Multiethnic Cohort

Background

People with diabetes are at an increased risk of developing pancreatic cancer. However, it is unclear whether diabetes-related complications are associated with risk of pancreatic cancer.

Methods

A nested matched case-control analysis was conducted among the fee-for-service Medicare participants of the prospective Multiethnic Cohort (n = ∼123 000). Between 2001 and 2014, 433 incident cases of pancreatic ductal adenocarcinoma were matched to 1728 controls by birth year, sex, race and ethnicity, and age at cohort entry. Participants were linked to data from the California and Hawaii cancer registries and Medicare claims. We used the diabetes complications severity index (DCSI) for the presence of 7 complications within 2 years prior to the diagnosis date of the index case. Multivariable conditional logistic regression was used to examine the association of DCSI with pancreatic cancer incidence.

Results

Diabetes was present among 45.4% of cases and 34.1% of controls. Cases had higher DCSI score compared with controls (score ≥4: 32.8% in cases; 21.2% in controls). The most prevalent diabetes-related complications for cases were cardiovascular disease (61.2%), nephropathy (31.2%), and cerebrovascular disease (21.7%). Individuals with diabetes (odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.14 to 1.91), nephropathy (OR = 1.75, 95% CI = 1.32 to 2.33), cardiovascular disease (OR = 1.88, 95% CI = 1.45 to 2.44), and metabolic complications (OR = 6.61, 95% CI = 2.49 to 17.50) were at increased risk of pancreatic cancer. For every 1-unit increase in DCSI score, participants had 18% greater risk of pancreatic cancer (OR = 1.18, 95% CI = 1.11 to 1.25).

Conclusions

Participants with diabetes-related complications have an elevated risk of pancreatic cancer. Identifying diabetes-related complications may help identify high-risk groups who can be studied for development of early markers for this fatal cancer.

Pancreatic ductal adenocarcinomas from Mexican patients present a distinct genomic mutational pattern

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers in humans, with less than 5% 5-year survival rate. PDAC is characterized by a small number of recurrent mutations, including KRAS, CDKN2A, TP53, and SMAD4 and a long "tail" of infrequent mutated genes. Most of the studies have been performed in US and European populations, so new studies are needed to describe the mutational landscape of these tumors in other cohorts. The present study analyzed the exome and transcriptome of four PDAC tumors from Mexican patients. We found a paucity of the previously described recurrent mutations, with mutations in only three genes (HERC2, CNTNAP2 and HMCN1) previously reported in PDAC with a frequency > 1%. In addition, we discovered several recurrent putative copy number aberrations in SKP2, BRAF, CSSF1R, FOXE1, JAK2 and MET genes and in genes previously reported as putative drivers in PDAC, including KRAS, SF3B1, BRAF, MYC and MET. Although a larger cohort is needed to validate these findings, our results could be pointing toward potential differences in contributing factors for PDAC in Latin-American populations.

Physical Activity and Gastrointestinal Cancer Risk: A Review

Introduction: Western lifestyle characterized by increased consumption of red meat, fat, processed food, smoking, alcohol drinking, lower consumption of vegetables and physical inactivity has been associated with a higher gastrointestinal cancer risk. Digestive system cancers are diagnosed at late stages when they show poor response to treatment and are associated with a high mortality rate. Colorectal, gastric, esophageal and pancreatic cancers are among the most common cancers worldwide. Studies show that more than 50% of gastrointestinal cancers develop as a result of inappropriate lifestyle. An inverse association between physical activity and many chronic diseases has been proved so far. However, the association between physical activity and some gastrointestinal cancers is still controversial. This study was aimed to determine the association between physical activity and gastrointestinal cancers risk.

Methods: We conducted a comprehensive search of English and Persian databases from February 2007 till December 2017, for studies investigating the association of physical activity and risk of gastrointestinal cancers. Finally, after reading full text of articles, 123 studies were included.

Results: Physical activity can be helpful in reducing the risk of gastrointestinal cancer, especially colon and pancreatic cancers. The risk reduction is not similar for different types of gastrointestinal cancers and also among males and females.

Conclusion: Different types of physical activity are associated with a lower risk of gastrointestinal cancer. However, it is unknown which type and intensity of physical activity are associated with a protective effect against gastro-intestinal cancer.

Closing the Disparity in Pancreatic Cancer Outcomes: A Closer Look at Nonmodifiable Factors and Their Potential Use in Treatment

OBJECTIVES

African Americans (AAs) have disproportionately higher incidence and lower survival rates from pancreatic cancer compared with whites. Historically, this disparity has been attributed to modifiable risk factors. Recent studies suggest that nonmodifiable aspects may also play an important role. We review these new contributions as potential targets for closing the disparity.

METHODS

A PubMed search was conducted to review studies of nonmodifiable elements contributing to pancreatic cancer disparities in AAs.

RESULTS

Several nonmodifiable risks are associated with the racial disparity in pancreatic cancer. SSTR5 P335L, Kaiso, and KDM4/JMJD2A demonstrate differential racial expression, increasing their potential as therapeutic targets. Many social determinants of health and their associations with diabetes, obesity, and the microbiome are partially modifiable risk factors that significantly contribute to outcomes in minorities. Barriers to progress include the low minority inclusion in research studies.

CONCLUSIONS

Genomics, epigenetics, the microbiome, and social determinants of health are components that contribute to the pancreatic cancer disparity in AAs. These factors can be researched, targeted, and modified to improve mortality rates. Closing the disparity in pancreatic cancer will require an integrated approach of personalized medicine, increased minority recruitment to studies, and advanced health care/education access.

Obesity and Pancreatic Cysts in African American Patients

Objective

Obesity is one of the risk factors for pancreatic cancer and a prognostic factor for acute-chronic pancreatitis.

Aim

To explore the relationship and association between obesity and pancreatic cysts over a 25-year period in African American patients.

Methods

We reviewed the medical records of 207 patients diagnosed with pancreatic cysts via radiology and pathology data from January 1988 to December 2012. A control group was selected from a separate group of healthy patients without a history of pancreatic disease. The patients were evaluated in five groups according to the last 20 years of diagnosis in five-year intervals.

Results

Most patients with pancreatic cyst (73%) were overweight (defined as a body mass index (BMI) ≥ 25), and 53% had a history of chronic pancreatitis compared to patients in the control group. There was a significant difference between the two groups; 79% of patients group were overweight (BMI ≥ 25) vs. 66% in control group (p = 0.02). The incidence of obese and overweight patients was significant (85%) during the 2008 to 2012 interval for the test group (p = 0.009).

Conclusion

Given the increasing proportion of obese pancreatic cyst patients in recent decades compared to the proportion noted in the 1990s, obesity plays a large role in the formation of pancreatic cysts.

Obesity-Related Digestive Diseases and Their Pathophysiology

Obesity is a growing medical and public health problem worldwide. Many digestive diseases are related to obesity. In this article, the current state of our knowledge of obesity-related digestive diseases, their pathogenesis, and the medical and metabolic consequences of weight reduction are discussed. Obesity-related digestive diseases include gastroesophageal reflux disease, Barrett’s esophagus, esophageal cancer, colon polyp and cancer, nonalcoholic fatty liver disease, hepatitis C-related disease, hepatocellular carcinoma, gallstone, cholangiocarcinoma, and pancreatic cancer. Although obesity-related esophageal diseases are associated with altered mechanical and humoral factors, other obesity-related digestive diseases seem to be associated with obesity-induced altered circulating levels of adipocytokines and insulin resistance. The relationship between functional gastrointestinal disease and obesity has been debated. This review provides a comprehensive evaluation of the obesity-related digestive diseases, including pathophysiology, obesity-related risk, and medical and metabolic effects of weight reduction in obese subjects.

Physical Activity and Pancreatic Cancer Risk among Urban Chinese: Results from Two Prospective Cohort Studies

Background: Associations between physical activity and pancreatic cancer risk are unclear.Methods: In two prospective cohort studies, the Shanghai Women's Health Study and Shanghai Men's Health Study, physical activity and other information were collected at the baseline interview of 72,451 women and 60,037 men. Participants were followed up through annual linkage with a cancer registry in combination with in-person interviews taking place every 2 to 4 years.Results: We identified 225 female and 159 male cases during a median follow up of 16.1 and 10.3 years, respectively. Adult exercise participation was significantly associated with a decreased pancreatic cancer risk in men [hazard ratio (HR), 95% confidence interval (CI): 0.71 (0.50-1.00)]. Meeting the recommended minimum exercise threshold to achieve health benefits of 150 min/week of moderate-intensity or 75 min/week of vigorous-intensity exercise was associated with further decreased pancreatic cancer risk [HR (95% CI): 0.59 (0.40-0.87)]. We also observed an inverse association between adolescent physical activity and pancreatic cancer risk in men [HR (95% CI): 0.54 (0.33-0.90)]. Exercise throughout one's lifetime was associated with a 68% decrease in pancreatic cancer risk [HR (95% CI): 0.32 (0.16-0.66)]. No significant association was found in women. Adult non-exercise daily activity and occupational activity were not associated with pancreatic cancer risk in either men or women.Conclusions: Adult exercise and adolescent physical activity were significantly associated with a decreased pancreatic cancer risk in men but not in women.Impact: These findings underscore the importance of investigating the possible modification by sex on the exercise and pancreatic cancer risk association. Cancer Epidemiol Biomarkers Prev; 27(4); 479-87. ©2018 AACR.

Proton pump inhibitors on pancreatic cancer risk and survival

BACKGROUND

Hypergastrinemia may promote the development and progression of pancreatic cancer. Proton pump inhibitor (PPI) therapy is known to cause hypergastrinemia. We sought to determine the association between PPI therapy and the risk of developing pancreatic cancer as well as survival following pancreatic cancer diagnosis.

METHODS

We conducted a nested case-control study and a retrospective cohort study in The Health Improvement Network (THIN), a medical records database representative of the UK population. In the case-control study, each patient with incident pancreatic cancer was matched with up to four controls based on age, sex, practice site and both duration and calendar time of follow-up using incidence density sampling. The odds ratios (ORs) and 95% confidence intervals (CIs) for pancreatic cancer risk associated with PPI use were estimated using multivariable conditional logistic regression. The retrospective cohort study compared the survival of pancreatic cancer patients according to their PPI exposure at the time of diagnosis. The effect of PPI use on pancreatic cancer survival was assessed using a multivariable Cox regression analysis.

RESULTS

The case-control study included 4113 cases and 16,072 matched controls. PPI use was more prevalent in cases than controls (53% vs. 26% active users). Adjusting for diabetes, smoking, alcohol use and BMI, PPI users including both former users and active users with longer cumulative PPI use had a higher risk of pancreatic cancer compared to non-users. When assessing survival following pancreatic cancer diagnosis, only short-term, active users had a modest decrease in survival.

CONCLUSIONS

Long-term PPI therapy may be associated with pancreatic cancer risk. While PPI users recently started on treatment had a slightly worse survival, this result likely is from reverse causation.

Slowing BMI Growth Trajectories in Elementary School-Aged Children: The Northeast Iowa Food and Fitness Initiative

This project examines the Northeast Iowa Food and Fitness Initiative, a policy-, community-, and school-based effort to slow children's body mass index (BMI) growth over 6 years. Kindergarteners (K) to fifth graders (5) from 10 different school districts participated (N = 4101). Students with 0 to 1 years of initiative exposure showed greater growth in BMI compared with children who had 2 to 6 years of exposure, resulting in K-5 BMI savings of 1.5 points (6 lb) for median-height boys and girls. Results suggest that changes to policies, communities, and schools may provide effective obesity reduction in children.

The Effect of Body Mass Index on Surgical Outcomes in Patients Undergoing Pancreatic Resection: A Systematic Review and Meta-Analysis

OBJECTIVES

Previous studies that investigated the association between body mass index (BMI) and pancreatectomy outcomes have produced conflicting conclusions. We conducted this meta-analysis to assess the association between them.

METHODS

We searched PubMed, EMBASE, and Cochrane Library databases up to December 28, 2014. Patients were divided into high-BMI group (BMI ≥ 25 kg/m) and normal-BMI group (BMI < 25 kg/m). Postoperative and intraoperative outcomes were evaluated. Meta-regression and subgroup analysis were performed to evaluate any factors accountable for the heterogeneity. Meta-analysis was performed using a random-effect model.

RESULTS

We included 22 studies involving 8994 patients. Patients in the high-BMI group had significantly increased postoperative pancreatic fistula rate (odds ratio [OR],1.96; 95% confidence interval [CI], 1.43-2.67), delayed gastric emptying rate (OR, 1.62; 95% CI, 1.15-2.29), wound infection rate (OR, 1.43; 95% CI, 1.07-1.93), operation time (mean difference [MD],15; 95% CI, 13.40-16.60), blood loss (MD, 270.71; 95% CI, 248.93-292.49), and length of hospital stay (MD, 2.87; 95% CI, 1.51-4.24). For modest heterogeneity in postoperative pancreatic fistula, regional distribution tended to be the contributor.

CONCLUSIONS

High BMI not only increased the surgical difficulty but also decreased the surgical safety for pancreatectomy.

Investigating Physical Activity in the Etiology of Pancreatic Cancer: The Age at Which This Is Measured Is Important and Is Independent of Body Mass Index

OBJECTIVES

There are plausible biological mechanisms for how increased physical activity (PA) may prevent pancreatic cancer, although findings from epidemiological studies are inconsistent. We investigated whether the risk is dependent on the age at which PA is measured and if independent of body mass index (BMI).

METHODS

A total of 23,639 participants, aged 40 to 74 years, were recruited into the EPIC-Norfolk (European Prospective Investigation of Cancer) cohort study between 1993 and 1997 and completed validated questionnaires on PA. The cohort was monitored for pancreatic cancer development, and hazard ratios (HRs) were estimated and adjusted for covariates.

RESULTS

Within 17 years, 88 participants developed pancreatic cancer (55% female). There was no association between PA and risk in the cohort (HR trend, 1.06; 95% confidence interval [CI], 0.86-1.29). However, in participants younger than 60 years, higher PA was associated with decreased risk (highest vs lowest category HR, 0.27; 95% CI, 0.07-0.99). Higher PA was not inversely associated when older than 60 years (HR trend, 1.23; 95% CI, 0.96-1.57). Including BMI in all models produced similar estimates.

CONCLUSIONS

The reasons why PA in younger, but not older, people may prevent pancreatic cancer need to be investigated. Physical activity may operate through mechanisms independent of BMI. If this association is causal, 1 in 6 cases might be prevented by encouraging more PA.

The Association between Leisure Time Physical Activity and Pancreatic Cancer Risk in Adults: A Systematic Review and Meta-analysis

We conducted a meta-analysis of the association between leisure time physical activity (LTPA) and risk of pancreatic cancer to update previous analyses in light of newly published studies, to examine subgroups of interest and potential sources of heterogeneity. We searched the PubMed and MEDLINE databases for studies until February 2015. Study information was collected using a standardized form to abstract relevant data on study design, number of cases, participant and study characteristics, assessment of LTPA, risk estimates, and adjustments for confounding by two independent abstractors. We used random-effects models to pool estimates from included studies of lowest versus highest comparison of LTPA. The search identified 26 studies eligible for inclusion into the meta-analysis. The combined summary risk estimate was [relative risk (RR), 0.89; 95% confidence interval (CI), 0.82-0.96]. There was evidence of heterogeneity across studies (I(2) = 22.1%, Pheterogeneity = 0.130). Some of the heterogeneity could be explained by study design, with stronger protective effects observed among case-control studies (RR, 0.69; 95% CI, 0.59-0.81) compared with cohort studies (RR, 0.96; 95% CI, 0.91-1.02). Across study designs, age of population was a source of heterogeneity, with stronger effects observed among younger (<50 years) populations. The present meta-analysis supports a protective association between LTPA and pancreatic cancer with an 11% risk reduction observed. LTPA appears to have the strongest effect among young populations. Additional investigations are needed to provide insights regarding the impact of LTPA in healthy adult populations, to reduce the risk of pancreatic cancer and encourage increases in LTPA.

Impact of body mass index on complications following pancreatectomy: Ten-year experience at National Cancer Center in China

AIM: To examine the impact of body mass index (BMI) on outcomes following pancreatic resection in the Chinese population.

METHODS: A retrospective cohort study using prospectively collected data was conducted at the Cancer Hospital of the Chinese Academy of Medical Sciences, China National Cancer Center. Individuals who underwent pancreatic resection between January 2004 and December 2013 were identified and included in the study. Persons were classified as having a normal weight if their BMI was < 24 kg/m² and overweight/obese if their BMI was ≥ 24 kg/m² as defined by the International Life Sciences Institute Focal Point in China. A χ² test (for categorical variables) or a t test (for continuous variables) was used to examine the differences in patients’ characteristics between normal weight and overweight/obese groups. Multiple logistic regression models were used to assess the associations of postoperative complications, operative difficulty, length of hospital stay, and cost with BMI, adjusting for age, sex, and type of surgery procedures.

RESULTS: A total of 362 consecutive patients with data available for BMI calculation underwent pancreatic resection for benign or malignant disease from January 1, 2004 to December 31, 2013. Of the 362 patients, 156 were overweight or obese and 206 were of normal weight. One or more postoperative complications occurred in 35.4% of the patients following pancreatic resection. Among patients who were overweight or obese, 42.9% experienced one or more complications, significantly higher than normal weight (29.6%) individuals (P = 0.0086). Compared with individuals who had normal weight, those with a BMI ≥ 24.0 kg/m² had higher delayed gastric emptying (19.9% vs 5.8%, P < 0.0001) and bile leak (7.7% vs 1.9%, P = 0.0068). There were no significant differences seen in pancreatic fistula, gastrointestinal hemorrhage, reoperation, readmission, or other complications. BMI did not show a significant association with intraoperative blood loss, operative time, length of hospital stay, or cost.

CONCLUSION: Higher BMI increases the risk for postoperative complications after pancreatectomy in the Chinese population. The findings require replication in future studies with larger sample sizes.

Varying social media post types differentially impacts engagement in a behavioral weight loss intervention

The purpose of this study was to examine whether different types of posts differentially affect participant engagement and if engagement with social media enhances weight loss. Data are a subanalysis from a randomized weight loss study with a 4-month follow-up support period via private Facebook groups and monthly meetings. Counselors posted five different post types/week based on social cognitive theory (weight-related, recipes, nutrition information, poll votes, or requests for suggestions). Types of participant engagement (likes, comments/poll votes, and views) were assessed. Poll votes were the most engaging (mean number of votes or comments/poll 14.6 ± 3.4, P < 0.01) followed by suggestions (9.1 ± 2.7 posts, P < 0.01) and weight-related posts (7.4 ± 3.1 posts, P < 0.01). Engagement with Facebook was significantly associated with weight loss during the 4-month maintenance period (B = -0.09, P = 0.04). The findings provide evidence for ways to provide social support during weight loss interventions using remote methodology.

High calorie intake is associated with worsening insulin resistance and β-cell function in Hispanic women after gestational diabetes mellitus

OBJECTIVE

To assess associations between dietary intake and rates of change in insulin resistance and β-cell function in Hispanic women with prior gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

Sixty-two nondiabetic Hispanic women with pregnancies complicated by GDM completed oral and intravenous glucose tolerance tests and bioelectrical impedance measurements of body fat every 12-15 months postpartum for up to 12 years. Self-reported dietary intake was collected at all visits by structured food frequency questionnaires developed for Hispanics. Mixed-effects models were used to assess the relationship between dietary intake and rates of change in metabolic outcomes during follow-up.

RESULTS

The median length of follow-up from the first postpartum evaluation was 8.0 years (interquartile range 4.5-10.8 years). At baseline, women were 32 ± 5.7 years old and had a median calorie intake of 2,091 kcal/day. Over the course of follow-up, dietary intake did not change significantly. Higher baseline calorie intake was associated with a faster decline in insulin sensitivity, measured by the insulin sensitivity index (SI) (P = 0.029), and β-cell compensation, measured by the disposition index (DI) (P = 0.027), over time. These associations remained after adjustment for baseline characteristics; changes in BMI, calorie intake, levels of physical activity; and additional pregnancies during the follow-up period. The median rates were -0.06 vs. -0.02 units/year for SI and -810 vs. -692 units/year for DI for women with baseline calorie intake above versus below the cohort median.

CONCLUSIONS

High calorie intake is associated with a faster decline in insulin sensitivity and β-cell compensation in Hispanic women who are at high risk for type 2 diabetes, independent of adiposity.

A pooled analysis of body mass index and pancreatic cancer mortality in african americans

BACKGROUND

Pancreatic cancer is a leading cause of cancer-related mortality in the United States and both incidence and mortality are highest in African Americans. Obesity is also disproportionately high in African Americans, but limited data are available on the relation of obesity to pancreatic cancer in this population.

METHODS

Seven large prospective cohort studies pooled data from African American participants. Body mass index (BMI) was calculated from self-reported height and weight at baseline. Cox regression was used to calculate HRs and 95% confidence intervals (CI) for levels of BMI relative to BMI 18.5-24.9, with adjustment for covariates. Primary analyses were restricted to participants with ≥5 years of follow-up because weight loss before diagnosis may have influenced baseline BMI in cases who died during early follow-up.

RESULTS

In follow-up of 239,597 participants, 897 pancreatic cancer deaths occurred. HRs were 1.08 (95% CI, 0.90-1.31) for BMI 25.0 to 29.9, 1.25 (95% CI, 0.99-1.57) for BMI 30.0 to 34.9, and 1.31 (95% CI, 0.97-1.77) for BMI ≥35.0 among those with ≥5 years of follow-up (Ptrend = 0.03). The association was evident among both sexes and was independent of a history of diabetes. A stronger association was observed among never-smokers (BMI ≥30 vs. referent: HR = 1.44; 95% CI, 1.02-2.03) than among smokers (HR = 1.16; 95% CI, 0.87-1.54; Pinteraction = 0.02).

CONCLUSION

The findings suggest that obesity is independently associated with increased pancreatic cancer mortality in African Americans.

IMPACT

Interventions to reduce obesity may also reduce risk of pancreatic cancer mortality, particularly among never-smokers.

Physical activity and risk of pancreatic cancer in a central European multicenter case-control study

PURPOSE

Findings from epidemiological studies examining physical activity in relation to pancreatic cancer risk have suggested decreased risks for physical activity; however, the results are inconsistent.

METHODS

The association between occupational and leisure-time physical activity and risk of pancreatic cancer was examined among 826 pancreatic cancer cases and 930 age-, sex- and center-matched controls from a large multicenter central European study in Czech Republic and Slovakia recruited between 2004 and 2012. Data on physical activity including type and dose (frequency, intensity, and duration) were examined using multivariable-adjusted logistic regression models.

RESULTS

Occupational physical activity was not significantly associated with risk of pancreatic cancer [odds ratio (OR) 0.90, 95 % confidence interval (CI) 0.71-1.15]. A 35 % decrease in risk of pancreatic cancer was observed for regular leisure-time physical activity (OR 0.65, 95 % CI 0.52-0.87). The risk estimates were significant for low and moderate intensity of activity with the strongest protective effect among individuals who exercised during more than 40 weeks per year. The results for cumulated leisure-time physical activity assessed 1 year prior to diagnosis achieved the same level of risk reduction. In addition, stronger risk estimates for leisure-time physical activity were observed among women (men: OR 0.74, 95 % CI 0.54-1.01; women: OR 0.53, 95 % CI 0.37-0.75). The findings for female participants were stronger for intensity and frequency of leisure-time physical activity, in particular for light and moderate activity (OR 0.43, 95 % CI 0.25-0.75; and OR 0.57, 95 % CI 0.37-0.88, respectively).

CONCLUSION

These results provide evidence for a decreased risk of pancreatic cancer associated with regular leisure-time physical activity.

Overweight, obesity and endometrial cancer risk: results from a systematic review and meta-analysis

AIM

Findings from recent studies suggest that obesity may be associated with an increased risk of endometrial cancer, but several earlier studies were less conclusive. Here we strive to estimate this relationship in a meta-analysis of published data.

METHODS

We searched Pubmed and Embase for studies on body mass index and the risk of endometrial cancer, published from 1989 to 2011. Data were independently extracted and analyzed using random or fixed effects meta-analysis depending on the degree of heterogeneity.

RESULTS

Seven cohort studies and 11 case-control studies were included in the meta-analysis. Overall, the conditions of excess body weight ([EBW] defined as body mass index [BMI] ≥25 kg/m²), obesity (BMI ≥30 kg/m²) and overweight (25< BMI <30 kg/m²) were associated with an increased risk of endometrial cancer (relative risk [RR] for EBW=1.62, 95% confidence interval [CI], 1.39-1.89; for obesity RR=2.54, 95% CI, 2.11-3.06; for overweight RR=1.32, 95% CI, 1.16-1.50). Subgroup analyses showed that the positive associations were independent of study design, geographic locations, self-reported BMI, alcohol use, smoking habit, history of diabetes, hormone therapy, age at menarche, age at menopause, parity, and age at first full term pregnancy. However, there was no statistically significant association between EBW and endometrial cancer risk for measured BMI (for EBW RR=1.29, 95% CI, 0.66-2.53).

CONCLUSIONS

The findings from this meta-analysis strongly support that the conditions of EBW, overweight, and obesity are all associated with an increased risk of endometrial cancer. Also, the strength of the association increases with increasing BMI.

Obesity and pancreatic cancer

BACKGROUND

Pancreatic cancer is an invariably fatal malignancy. Cigarette smoking and diabetes are established risk factors, but over the last two decades studies have shown that excess adiposity is an additional independent risk factor with 30-50% of cases thought to be attributed to nutritional factors. The aim of this narrative review is to analyze all the epidemiological evidence on the topic and possible pathophysiology.

METHODS

We searched PubMed, Embase, Cochrane Library and Medline, and all available evidence was included. We firstly analyze meta- and pooled analysis. Then we discuss individual studies to identify sources of discrepancies between studies and attempt to delineate pathophysiology.

RESULTS

It is estimated that obese individuals have a relative risk (RR) ranging between 1.19 and 1.47, when compared with those of normal weight, regardless of diabetes or smoking status. No significant differences were found between gender.

CONCLUSION

There is a measurable increased risk of developing pancreatic cancer in obese individuals, and excess adiposity is related to the condition with a "dose-response" curve. Hyperinsulinemia and possibly hyperestrogenism secondary to a metabolic syndrome, and independently from diabetes status, appear to be the key elements of the pathogenesis in pancreatic cancer secondary to excess body fat. Increased efforts should therefore be made in tackling the epidemic levels of obesity in the Western world countries.

Body mass index and risk of pancreatic cancer in a Chinese population

Few studies have examined the association between body mass index (BMI: kg/m²) and pancreatic cancer risk in Asian populations. We examined this relationship in 51,251 Chinese men and women aged 45–74 who enrolled between 1993 and 1998 in the population based, prospective Singapore Chinese Health Study. Data were collected through in-person interviews. By December 31, 2011, 194 cohort participants had developed pancreatic cancer. A Cox proportional hazards model was used to estimate hazard ratios (HR) and their 95% confidence intervals (95% CI). We hypothesized the association between BMI and pancreatic cancer risk may vary by smoking status (ever v. never) and there was evidence for this as the interaction between BMI and smoking status was significant (p = 0.018). Among ever smokers, being classified as underweight (BMI <18.5 kg/m²), was associated with a significantly elevated risk of pancreatic cancer relative to smokers with a BMI of 21.5–24.4 kg/m² (HR = 1.99, 95% CI  =  1.03–3.84). This association was strengthened after exclusion of the first three years of follow-up time. Among never smokers, there was no association between BMI and pancreatic cancer risk. However, after excluding pancreatic cancer cases and person-years in the first three years of follow-up, never smokers with a BMI ≥ 27.5 kg/m² showed a suggestive increased risk of pancreatic cancer relative to never smokers with a BMI of 21.5–24.4 kg/m² (HR  =  1.75, 95% CI  =  0.93–3.3). In conclusion, Singaporean Chinese who were underweight with a history of smoking had an increased risk of developing pancreatic cancer, whereas there was no significant association between BMI and pancreatic cancer in never smokers.

Longitudinal changes in insulin sensitivity and beta cell function between women with and without a history of gestational diabetes mellitus

AIMS/HYPOTHESIS

The aim of the study was to compare longitudinal changes in insulin sensitivity (SI) and beta cell function between women with and without a history of gestational diabetes mellitus (GDM).

METHODS

The prospective follow-up cohort included 235 parous non-diabetic Mexican-American women, 93 with and 142 without a history of GDM. The participants underwent dual-energy x-ray absorptiometry, OGTTs and IVGTTs at baseline and at a median of 4.1 years follow-up. The baseline values and rates of change of metabolic measures were compared between groups.

RESULTS

At baseline, women with prior GDM (mean age 36.3 years) had similar values of SI but higher percentages of body fat and trunk fat (p ≤ 0.02), a lower acute insulin response and poorer beta cell compensation (disposition index [DI]) (p < 0.0001) than women without GDM (mean age 37.9 years). During the follow-up, women with GDM had a faster decline in SI (p = 0.02) and DI (p = 0.02) than their counterparts without GDM, with no significant differences in changes of weight or fat (p > 0.50). Adjustment for baseline age, adiposity, calorie intake, physical activity, age at first pregnancy, additional pregnancies and changes in adiposity during follow-up increased the between-group differences in the rates of change of SI and DI (p ≤ 0.003).

CONCLUSIONS/INTERPRETATION

Mexican-American women with recent GDM had a faster deterioration in insulin sensitivity and beta cell compensation than their parous counterparts without GDM. The differences were not explained by differences in adiposity, suggesting more deleterious effects of existing fat and/or reduced beta cell robustness in women with GDM.

Dietary energy balance modulation of Kras- and Ink4a/Arf+/--driven pancreatic cancer: the role of insulin-like growth factor-I

New molecular targets and intervention strategies for breaking the obesity-pancreatic cancer link are urgently needed. Using relevant spontaneous and orthotopically transplanted murine models of pancreatic cancer, we tested the hypothesis that dietary energy balance modulation impacts pancreatic cancer development and progression through an insulin-like growth factor (IGF)-I-dependent mechanism. In LSL-Kras(G12D)/Pdx-1-Cre/Ink4a/Arf(lox/+) mice, calorie restriction versus overweight- or obesity-inducing diet regimens decreased serum IGF-I, tumoral Akt/mTOR signaling, pancreatic desmoplasia, and progression to pancreatic ductal adenocarcinoma (PDAC), and increased pancreatic tumor-free survival. Serum IGF-I, Akt/mTOR signaling, and orthotopically transplanted PDAC growth were decreased in liver-specific IGF-I-deficient mice (vs. wild-type mice), and rescued with IGF-I infusion. Thus, dietary energy balance modulation impacts spontaneous pancreatic tumorigenesis induced by mutant Kras and Ink4a deficiency, the most common genetic alterations in human pancreatic cancer. Furthermore, IGF-I and components of its downstream signaling pathway are promising mechanistic targets for breaking the obesity-pancreatic cancer link.

High-fat diet is associated with obesity-mediated insulin resistance and β-cell dysfunction in Mexican Americans

Consumption of energy-dense, nutrient-poor foods has contributed to the rising incidence of obesity and may underlie insulin resistance and β-cell dysfunction. Macronutrient intake patterns were examined in relation to anthropometric and metabolic traits in participants of BetaGene, a family-based study of obesity, insulin resistance, and β-cell dysfunction in Mexican Americans. Dietary intake, body composition, insulin sensitivity (SI), and β-cell function [Disposition Index (DI)] were assessed by food-frequency questionnaires, dual-energy X-ray absorptiometry, and intravenous glucose-tolerance tests, respectively. Patterns of macronutrient intake were identified by using a K-means model based on the proportion of total energy intake per day attributable to carbohydrate, fat, and protein and were tested for association with anthropometric and metabolic traits. Among 1150 subjects aged 18-65 y (73% female), tertiles of fat intake were associated with greater adiposity and lower SI, after adjustment for age, sex, and daily energy intake. Moreover, 3 distinct dietary patterns were identified: "high fat" (35% fat, 44% carbohydrate, 21% protein; n = 238), "moderate fat" (28% fat, 54% carbohydrate, 18% protein; n = 520), and "low fat" (20% fat, 65% carbohydrate, 15% protein; n = 392). Compared with the low-fat group, the high-fat group had higher age- and sex-adjusted mean body mass index, body fat percentage, and trunk fat and lower SI and DI. Further adjustment for daily energy intake by matching individuals across dietary pattern groups yielded similar results. None of the observed associations were altered after adjustment for physical activity; however, associations with SI and DI were attenuated after adjustment for adiposity. These findings suggest that high-fat diets may contribute to increased adiposity and concomitant insulin resistance and β-cell dysfunction in Mexican Americans.

Self-reported physical activity is associated with β-cell function in Mexican American adults

OBJECTIVE

To examine the association between self-reported physical activity (PA) and diabetes-related quantitative traits.

RESEARCH DESIGN AND METHODS

The observational cohort was 1,152 Mexican American adults with dual-energy X-ray absorptiometry, oral and intravenous glucose tolerance tests, and self-reported dietary and PA questionnaires. PA was categorized into three mutually exclusive groups according to the U.S. Department of Health and Human Services PA guidelines for Americans: low (vigorous <75 min/week and moderate <150 min/week), moderate (vigorous ≥75 min/week or moderate ≥150 min/week), and high (vigorous ≥75 min/week and moderate ≥150 min/week). Trends in PA groups were tested for association with metabolic traits in a cross-sectional analysis.

RESULTS

The participants' mean age was 35 years (range, 18-66 years), mean BMI was 29.6 kg/m(2), and 73% were female. Among them, 501 (43%), 448 (39%), and 203 (18%) were classified as having low, moderate, and high PA, respectively. After adjustment for age, a higher PA was significantly associated with lower 2-h glucose, fasting insulin, and 2-h insulin and greater β-cell function (P = 0.001, 0.0003, 0.0001, and 0.004, respectively). The association did not differ significantly by sex. Results were similar after further adjustment for age, sex, BMI, or percent body fat.

CONCLUSIONS

An increasing level of PA is associated with a better glucose and insulin profile and enhanced β-cell function that is not explained by differences in BMI or percent body fat. Our results suggest that PA can be beneficial to β-cell function and glucose regulation independent of obesity.

The pathobiological impact of cigarette smoke on pancreatic cancer development (review)

Despite extensive efforts, pancreatic cancer remains incurable. Most risk factors, such as genetic disposition, metabolic diseases or chronic pancreatitis cannot be influenced. By contrast, cigarette smoking, an important risk factor for pancreatic cancer, can be controlled. Despite the epidemiological evidence of the detrimental effects of cigarette smoking with regard to pancreatic cancer development and its unique property of being influenceable, our understanding of cigarette smoke-induced pancreatic carcinogenesis is limited. Current data on cigarette smoke-induced pancreatic carcinogenesis indicate multifactorial events that are triggered by nicotine, which is the major pharmacologically active constituent of tobacco smoke. In addition to nicotine, a vast number of carcinogens have the potential to reach the pancreatic gland, where they are metabolized, in some instances to even more toxic compounds. These metabolic events are not restricted to pancreatic ductal cells. Several studies show that acinar cells are also greatly affected. Furthermore, pancreatic cancer progenitor cells do not only derive from the ductal epithelial lineage, but also from acinar cells. This sheds new light on cigarette smoke-induced acinar cell damage. On this background, our objective is to outline a multifactorial model of tobacco smoke-induced pancreatic carcinogenesis.

Obesity and pancreatic cancer: overview of epidemiologic evidence and biologic mechanisms

In the United States, pancreatic cancer is characterized by a low 5-yr survival rate of approximately 6%, fewer than 10% of patients diagnosed with localized disease and thus candidates for "curative" surgical resection, increasing incidence and few established risk factors. Similar statistics are observed for other industrialized nations. With new evidence to suggest that pancreatic cancer develops over a number of years, markers that can better identify high risk patients and are applicable to earlier diagnosis hold promise for improving these dire statistics. Obesity is one of the few modifiable risk factors that has been associated with increased risk of pancreatic cancer and also is related to increased risk of diabetes, a condition that in turn has been associated with pancreatic cancer development. Given recent data that nearly 70% of United States adults are overweight or obese, a clarification of the complex association between obesity and pancreatic cancer may disclose targets for prevention and intervention to decrease incidence and improve prognosis of this highly fatal disease. An overview of the current epidemiology and hypothesized biological mechanisms involved in the obesity-pancreatic cancer association are presented.

Physical activity, body mass index and bone mineral density-associations in a prospective population-based cohort of women and men: the Canadian Multicentre Osteoporosis Study (CaMos)

BACKGROUND

Physical activity (PA) is an important modifiable risk factor for both bone mineral density (BMD) and body mass index (BMI). However, BMI is itself strongly predictive of BMD. Our aim was to determine the association between PA and BMD, with consideration of BMI as a potential mediating factor.

METHODS

The Canadian Multicentre Osteoporosis Study (CaMos) is a population-based prospective cohort study of Canadian women and men. PA was determined from interviewer-administered questionnaires at baseline and Year 5 and summarized as daily energy expenditure in total metabolic equivalents of the task multiplied by minutes/day (MET*m/d). Height, weight, and total hip and lumbar spine BMD were measured at baseline and Year 5. General linear models assessed relationships between PA and BMD, both cross-sectionally (baseline PA with baseline BMD) and longitudinally (average PA and change in PA with change in BMD). BMI was considered as a mediating factor. Potential confounders included age, center, education, caffeine intake, alcohol exposure, smoking history, history of weight-cycling, age at menarche, past use of oral contraceptives, history of >3 months missed menstruation, menopausal status, and antiresorptive use, as relevant.

RESULTS

The study included 2855 men and 6442 women. PA was inversely associated with BMI at baseline, and an increase in PA between baseline and Year 5 was associated with a decrease in BMI, with 0.41 (95% CI: 0.22, 0.60) kg/m(2) loss per 1000 MET*m/d increase (in men) and 0.40 (95% CI: 0.23, 0.57) kg/m(2) loss per 1000 MET*m/d increase (in women). BMI was strongly associated with BMD, both cross-sectionally and longitudinally. However, increased PA was associated with a small increase in total hip BMD, 0.004 (95% CI: 0.000-0.008) g/cm(2) per 1000 MET*m/d (in men) and 0.003 (95% CI: 0.000-0.007) g/cm(2) per 1000 MET*m/d (in women). Average PA was associated with an increase in lumbar spine BMD in women, but not in men; it was not associated with change in total hip BMD in either sex.

CONCLUSION

Increased PA is associated with an increase in BMD and a concomitant decrease in BMI. These findings suggest that population-level interventions to increase PA would favorably impact bone and other health outcomes.

Physical activity, energy restriction, and the risk of pancreatic cancer: a prospective study in the Netherlands

BACKGROUND

Because of their influence on insulin concentrations, we hypothesized that both physical activity and energy restriction may reduce the risk of pancreatic cancer.

OBJECTIVE

We examined the associations between physical activity, proxies for energy restriction, and pancreatic cancer risk.

DESIGN

The Netherlands Cohort Study consisted of 120,852 individuals who completed a baseline questionnaire in 1986. After 13.3 y of follow-up, 408 cases were available for analysis. Self-reported information on physical activity was collected. Three indicators were used as proxies for energy restriction: father's employment status during the Economic Depression (1932-1940) and place of residence during the World War II years (1940-1944) and the Hunger winter (1944-1945).

RESULTS

For past sports activities, we observed a significantly decreased risk of pancreatic cancer (HR: 0.80; 95% CI: 0.64, 0.99). Proxies for energy restriction were not related to pancreatic cancer risk. When the results for energy restriction were stratified by height, a significant multiplicative interaction was observed for the Economic Depression period (P = 0.002). Shorter individuals (height less than the sex-specific median adult height) with an unemployed father during the Economic Depression period had a significantly lower cancer risk (HR: 0.31; 95% CI: 0.14, 0.66) than did taller individuals with an employed father. No significant interactions were observed for exposure to energy restriction during the World War II years and the Hunger winter.

CONCLUSIONS

Our results suggest a modestly decreased risk of pancreatic cancer associated with past sports activity. With respect to proxies for energy restriction, our findings suggest that shorter individuals exposed to energy restriction during adolescence may have a reduced risk, whereas taller individuals may not.

Main dietary compounds and pancreatic cancer risk. The quantitative analysis of case-control and cohort studies

OBJECTIVE

Estimation of the role of main dietary compounds in the risk of developing pancreatic cancer.

RESEARCH METHODS AND PROCEDURES

Literature published till 2010 was reviewed and selected for further analysis. The used terms were: red meat, minced meat, ham, bacon, sausages, white meat, poultry, vegetables, fish, eggs, fruits, lifestyle, diet, pancreatic cancer and pancreatic neoplasm. The collected data were meta-analysed with calculation of combined relative risk and 95% confidence interval as well as studies heterogeneity.

RESULTS

A meta-analysis of 11 case-control studies indicates that red meat ingestion elevates pancreatic cancer risk by 48% (95% CI=1.25-1.76). The vegetables and fruit reduce the risk by 38% (95% CI=0.54-0.73) and 29% (95% CI=0.59-0.84), respectively. The pooled analyses of 10 cohort studies do not show significant relations between main dietary compound ingestion and pancreatic cancer risk.

CONCLUSION

The red meat intake is associated with elevated risk of pancreatic cancer in contrast to vegetables and fruit ingestion. The ingestion of red meat, vegetables and fruit in cohort studies was not influenced on pancreatic cancer risk. The role of fish, poultry and eggs was not significant in both case-control and cohort studies, thus further studies were needed.

Body mass index, abdominal fatness and pancreatic cancer risk: a systematic review and non-linear dose-response meta-analysis of prospective studies

BACKGROUND

Questions remain about the shape of the dose-response relationship between body mass index (BMI) and pancreatic cancer risk, possible confounding by smoking, and differences by gender or geographic location. Whether abdominal obesity increases risk is unclear.

METHODS

We conducted a systematic review and meta-analysis of prospective studies of the association between BMI, abdominal fatness and pancreatic cancer risk and searched PubMed and several other databases up to January 2011. Summary relative risks (RRs) were calculated using a random-effects model.

RESULTS

Twenty-three prospective studies of BMI and pancreatic cancer risk with 9504 cases were included. The summary RR for a 5-unit increment was 1.10 [95% confidence interval (CI) 1.07-1.14, I(2) = 19%] and results were similar when stratified by gender and geographic location. There was evidence of a non-linear association, P(non-linearity) = 0.005; however, among nonsmokers, there was increased risk even within the 'normal' BMI range. The summary RR for a 10-cm increase in waist circumference was 1.11 (95% CI 1.05-1.18, I(2) = 0%) and for a 0.1-unit increment in waist-to-hip ratio was 1.19 (95% CI 1.09-1.31, I(2) = 11%).

CONCLUSIONS

Both general and abdominal fatness increases pancreatic cancer risk. Among nonsmokers, risk increases even among persons within the normal BMI range.

Body mass index and outcomes from pancreatic resection: a review and meta-analysis

INTRODUCTION

There are 1.6 billion adults worldwide who are overweight, with body mass indices (BMI) between 25 and 30, while more than 400 million are obese (BMI >30). Obesity predicts the incidence of and poor outcomes from pancreatic cancer. Obesity has also been linked to surgical complications in pancreatectomy, including increased length of hospital stay, surgical infections, blood loss, and decreased survival. However, BMI's impact on many complications following pancreatectomy remains controversial.

METHODS

We performed a MEDLINE search of all combinations of "BMI" with "pancreatectomy," "pancreatoduodenectomy," or "pancreaticoduodenectomy." From included studies, we created pooled and weighted estimates for quantitative and qualitative outcomes. We used the PRISMA criteria to ensure this project's validity.

RESULTS

Our primary cohort included 2,736 patients with BMI <30, 1,682 with BMI >25, and 546 with BMI between 25 and 30. Most outcomes showed no definitive differences across BMIs. Pancreatic fistula (PF) rates ranged from 4.7% to 31.0%, and four studies found multivariate association between BMI and PF (range odds ratio 1.6-4.2). Pooled analyses of PF by BMI showed significant association (p < 0.05).

CONCLUSION

BMI increases the operative complexity of pancreatectomy. However, with aggressive peri- and post-operative care, increases in BMI-associated morbidity and mortality may be mitigated.

Body mass index and body size in early adulthood and risk of pancreatic cancer in a central European multicenter case-control study

The relationship between two measures of excess body weight, body mass index (BMI) and body size score, and risk of pancreatic cancer was examined among 574 pancreatic cancer cases and 596 frequency-matched controls from the Czech Republic and Slovakia enrolled between 2004 and 2009. Analyses using multivariable logistic regression showed an increased risk of pancreatic cancer associated with elevated quartiles of BMI at ages 20 [fourth quartile: odds ratio (OR) = 1.79, 95% confidence interval (CI): 1.23, 2.61] and 40 (fourth quartile: OR = 1.57, 95% CI: 1.09, 2.27) compared to the lowest quartile. Consistent results were observed for body size score at ages 20 (high versus low: OR = 1.66, 95% CI: 1.08, 2.57) and 40 (medium versus low: OR = 1.36, 95% CI: 1.00, 1.86), but no association was found for BMI and body size score at 2 years before the interview. Stronger risk estimates for BMI were observed in males than females, particularly at age 20, but the analysis of body size yielded similar estimates by sex. When considering excess body weight at both ages 20 and 40 jointly, the highest risk estimates were observed among subjects with elevated levels at both time periods in the analysis of BMI (OR = 1.86, 95% CI: 1.32, 2.62) and body size (OR = 1.53, 95% CI: 1.09, 2.13). These findings, based on two different measures, provide strong support for an increased risk of pancreatic cancer associated with excess body weight, possibly strongest during early adulthood.

Smoking and risk of amyotrophic lateral sclerosis: a pooled analysis of 5 prospective cohorts

BACKGROUND

Cigarette smoking has been proposed as a risk factor for amyotrophic lateral sclerosis (ALS), but epidemiological studies supporting this hypothesis have been small and mostly retrospective.

OBJECTIVE

To prospectively examine the relation between smoking and ALS in 5 well-established large cohorts.

DESIGN

Five prospective cohorts with study-specific follow-up ranging from 7 to 28 years.

SETTING

Academic research.

PATIENTS

Participants in the Nurses' Health Study, the Health Professionals Follow-up Study, the Cancer Prevention Study II Nutrition Cohort, the Multiethnic Cohort, and the National Institutes of Health-AARP (formerly known as the American Association of Retired Persons) Diet and Health Study.

MAIN OUTCOME MEASURES

Amyotrophic lateral sclerosis deaths identified through the National Death Index. In the Nurses' Health Study and the Health Professionals Follow-up Study, confirmed nonfatal incident ALS was also included.

RESULTS

A total of 832 participants with ALS were documented among 562,804 men and 556,276 women. Smokers had a higher risk of ALS than never smokers, with age- and sex-adjusted relative risks of 1.44 (95% confidence interval, 1.23-1.68; P < .001) for former smokers and 1.42 (95% confidence interval, 1.07-1.88; P = .02) for current smokers. Although the risk of ALS was positively associated with pack-years smoked (P < .001), duration of smoking (9% increase for each 10 years of smoking, P = .006), and the number of cigarettes smoked per day (10% increase for each increment of 10 cigarettes smoked per day, P < .001), these associations did not persist when never smokers were excluded. However, among ever smokers, the risk of ALS increased as age at smoking initiation decreased (P = .03).

CONCLUSIONS

Results of this large longitudinal study support the hypothesis that cigarette smoking increases the risk of ALS. The potential importance of age at smoking initiation and the lack of a dose response deserve further investigation.

How to reduce your cancer risk: mechanisms and myths

Cancer prevention continues to be a high research priority and the most optimal way to ultimately lower the economic and psychological burden of cancer. Many known risk factors associated with cancer are related to dietary and lifestyle factors and can be avoided. These risk factors include among others, smoking, obesity, alcohol, physical inactivity, and carcinogens in diet. This article reviews the biological mechanisms leading to cancer in association with these factors, highlights important achievable cancer prevention methods, addresses commonly asked questions about lifestyle and cancer, and dispels some of the myths about cancer prevention.

Does body mass index/morbid obesity influence outcome in patients who undergo pancreatoduodenectomy for pancreatic adenocarcinoma?

INTRODUCTION

The obesity epidemic coupled with epidemiologic evidence of the link between pancreatic cancer and obesity has raised the interest in the impact of body mass index (BMI) on outcomes for resected pancreatic cancer.

METHODS

All patients who underwent pancreatoduodenectomy (PD) for pancreatic adenocarcinoma from 1981 to 2007 were categorized into four groups according to their BMI (<25, 25 to <30, 30 to <35, and ≥35). Associations of these BMI groups with perioperative (operating time, blood loss, complications, in-hospital mortality), pathologic (tumor diameter, tumor stage, differentiation, lymph node status, R0 status) features and long-term patient outcome were evaluated using Kruskal-Wallis and chi-square tests, logistic regression, and Cox proportional hazards regression. A second set of analyses were performed by dichotomizing patients into morbidly obese (BMI ≥ 35) in comparison to the rest.

RESULTS

Of the 586 consecutive patients studied, there were 232 (39.6%) with BMI <25, 232 (39.6%) with BMI 25 to <30, 89 (15.2%) with BMI 30 to <35, and 33 (5.6%) with BMI ≥ 35. Operating time (P = 0.003) and intraoperative blood loss (P < 0.001) increased with BMI, although none of the remaining perioperative features differed significantly among the BMI groups. Similarly, there were no significant associations between BMI group and the pathological features studied, particularly lymph node status (P= 0.98). BMI was not associated with lymph node status even after adjusting for tumor diameter. All analyses were repeated for the morbidly obese. Cox regression did not demonstrate an impact of BMI or morbid obesity on overall or disease-free survival.

CONCLUSIONS

BMI (and morbid obesity) does not appear to influence long-term outcomes for patients undergoing PD. Surgeons should be vigilant of the greater risk of perioperative blood loss with increasing BMI.

Anthropometric measures, body mass index, and pancreatic cancer: a pooled analysis from the Pancreatic Cancer Cohort Consortium (PanScan)

BACKGROUND

Obesity has been proposed as a risk factor for pancreatic cancer.

METHODS

Pooled data were analyzed from the National Cancer Institute Pancreatic Cancer Cohort Consortium (PanScan) to study the association between prediagnostic anthropometric measures and risk of pancreatic cancer. PanScan applied a nested case-control study design and included 2170 cases and 2209 control subjects. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression for cohort-specific quartiles of body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]), weight, height, waist circumference, and waist to hip ratio as well as conventional BMI categories (underweight, <18.5; normal weight, 18.5-24.9; overweight, 25.0-29.9; obese, 30.0-34.9; and severely obese, > or = 35.0). Models were adjusted for potential confounders.

RESULTS

In all of the participants, a positive association between increasing BMI and risk of pancreatic cancer was observed (adjusted OR for the highest vs lowest BMI quartile, 1.33; 95% CI, 1.12-1.58; P(trend) < .001). In men, the adjusted OR for pancreatic cancer for the highest vs lowest quartile of BMI was 1.33 (95% CI, 1.04-1.69; P(trend) < .03), and in women it was 1.34 (95% CI, 1.05-1.70; P(trend) = .01). Increased waist to hip ratio was associated with increased risk of pancreatic cancer in women (adjusted OR for the highest vs lowest quartile, 1.87; 95% CI, 1.31-2.69; P(trend) = .003) but less so in men.

CONCLUSIONS

These findings provide strong support for a positive association between BMI and pancreatic cancer risk. In addition, centralized fat distribution may increase pancreatic cancer risk, especially in women.

Can physical activity modulate pancreatic cancer risk? a systematic review and meta-analysis

Numerous epidemiological studies have examined the association between physical activity and pancreatic cancer; however, findings from individual cohorts have largely not corroborated a protective effect. Among other plausible mechanisms, physical activity may reduce abdominal fat depots inducing metabolic improvements in glucose tolerance and insulin sensitivity, thereby potentially attenuating pancreatic cancer risk. We performed a systematic review to examine associations between physical activity and pancreatic cancer. Six electronic databases were searched from their inception through July 2009, including MEDLINE and EMBASE, seeking observational studies examining any physical activity measure with pancreatic cancer incidence/mortality as an outcome. A random effects model was used to pool individual effect estimates evaluating highest vs. lowest categories of activity. Twenty-eight studies were included. Pooled estimates indicated a reduction in pancreatic cancer risk with higher levels of total (five prospective studies, RR: 0.72, 95% CI: 0.52-0.99) and occupational activity (four prospective studies, RR: 0.75, 95% CI: 0.59-0.96). Nonsignificant inverse associations were seen between risks and recreational and transport physical activity. When examining exercise intensity, moderate activity appeared more protective (RR: 0.79, 95% CI: 0.52-1.20) than vigorous activity (RR: 0.97, 95% CI: 0.85-1.11), but results were not statistically significant and the former activity variable incorporated marked heterogeneity. Despite indications of an inverse relationship with higher levels of work and total activity, there was little evidence of such associations with recreational and other activity exposures.

Body mass index, effect modifiers, and risk of pancreatic cancer: a pooled study of seven prospective cohorts

OBJECTIVE

To investigate whether the positive association of body mass index (BMI, kg/m(2)) with risk of pancreatic cancer is modified by age, sex, smoking status, physical activity, and history of diabetes.

METHODS

In a pooled analysis of primary data of seven prospective cohorts including 458,070 men and 485,689 women, we identified 2,454 patients with incident pancreatic cancer during an average 6.9 years of follow-up. Cox proportional hazard regression models were used in data analysis.

RESULTS

In a random-effects meta-analysis, for every 5 kg/m(2) increment in BMI, the summary relative risk (RR) was 1.06 (95% confidence interval (CI) 0.99-1.13) for men and 1.12 (95% CI 1.05-1.19) for women. The aggregate analysis showed that compared with normal weight (BMI: 18.5 to <25), the adjusted RR was 1.13 (95% CI 1.03-1.23) for overweight (BMI: 25 to <30) and 1.19 (95% CI 1.05-1.35) for obesity class I (BMI: 30 to <35). Tests of interactions of BMI effects by other risk factors were not statistically significant. Every 5 kg/m(2) increment in BMI was associated with an increased risk of pancreatic cancer among never and former smokers, but not among current smokers (P-interaction = 0.08).

CONCLUSION

The present evidence suggests that a high BMI is an independent risk factor of pancreatic cancer.

Plasma 25-hydroxyvitamin D levels and the risk of colorectal cancer: the multiethnic cohort study

Vitamin D is obtained from the diet and synthesized in skin exposed to sunlight. Vitamin D status, assessed by circulating 25-hydroxyvitamin D [25(OH)D], has been associated with a reduced risk of colorectal cancer in previous studies. To complement existing evidence, we conducted a case-control study nested within the Multiethnic Cohort including men and women of Japanese, Latino, African-American, White, and Native Hawaiian ancestry. Using a direct competitive chemiluminescence immunoassay, 25(OH)D level was determined in plasma drawn before diagnosis from 229 cases and 434 controls matched to cases by area (Hawaii, Los Angeles), sex, ethnicity, birth year, blood draw date and time, and hours fasting. Odds ratios (OR) were estimated with conditional logistic regression. An inverse trend was observed (OR per doubling of 25(OH)D, 0.68; 95% confidence interval, 0.51-0.92; P = 0.01), but when examined in categories, relative to the first quintile (<16.8 ng/mL), the ORs in all other quintiles were quite similarly reduced between 37% and 46%. The association was not significantly heterogeneous among the four largest ethnic groups (P(heterogeneity) = 0.46). In summary, this study provides evidence of an association between vitamin D status and reduced risk of colorectal cancer in an ethnically diverse population.