Causal association of childhood obesity with cancer risk in adulthood: A Mendelian randomization study

Effect of weight loss following Roux-en-Y gastric bypass on cancer risk: A Mendelian randomization study

Cancer incidence and development are strongly correlated with obesity, however there is insufficient data to support a causal relationship between intentional weight loss and the prevention or promotion of cancer. We investigated the causal relationship between weight loss following Roux-en-Y gastric bypass (RYGB) and the incidence of 18 cancers using Mendelian randomization (MR). A genome-wide association studies (GWAS) data related to weight loss following RYGB from the GWAS catalog database were used as exposure, and GWAS data related to 18 cancers from the Medical Research Council integrative epidemiology unit open GWAS project were used as outcomes. In order to investigate the causal relationship between exposure and results, we used a two-sample MR approach. The primary analysis technique was inverse variance weighting, with weighted median, and MR-Egger regression utilized as supplemental techniques to confirm the findings. Heterogeneity and horizontal pleiotropy were investigated using a variety of sensitivity studies, including the Cochran Q test, MR-Egger regression pleiotropy test, MR pleiotropy residual sum and outlier, and leave-one-out analysis. We included a total of 4 single-nucleotide polymorphisms as instrumental variables through rigorous quality control screening. Under the limitations of Bonferroni correction threshold (P < 2.78 × 10-3), our results suggest that the weight loss following RYGB has a significant causal relationship with a reduced risk of breast (odds ratio [OR]: 0.784; 95% confidence interval [CI]: 0.762-0.808; P = 2.167e-58) and lung cancer (OR: 0.992; 95% CI: 0.987-0.997; P = .0023), and a potential causal relationship with a decreased risk of hematological cancer (OR: 0.9998462; 95% CI: 0.9997088-0.9999836; P = .028) and an increased risk of cervical cancer (OR: 1.000123; 95% CI: 1.0000313-1.000215; P = .009). Sensitivity analysis confirms the robustness of our analysis results. Genetically predicted weight loss following RYGB has significant causal effects in reducing the risk of breast and lung cancer. It also has potential benefits in lowering the risk of hemotological cancers and increasing the risk of cervical cancer. Considering the limitations of our study, the reliability of its results and the underlying mechanisms require further investigation.

Body mass index at birth and early life and colorectal cancer: A two-sample Mendelian randomization analysis in European and East Asian genetic similarity populations

BACKGROUND

Varying obesogenic inherited predisposition in early to later life may differentially impact colorectal cancer (CRC) development. Previous Mendelian randomization (MR) studies, conducted in populations of European genetic similarity, have not observed any significant associations between early life body weight with CRC risk. However, it remains unclear whether body mass index (BMI) at different early lifetime points is causally related with CRC risk in both Europeans and East Asian populations.

OBJECTIVES

We conducted a two-sample MR study to investigate potential causal relationships between genetically predicted BMI during early life (birth to 8 years old) and at specific periods (birth, transient, early rise and late rise) and CRC risk.

METHODS

Summary data were obtained from genome-wide association study (GWAS) of BMI in 28 681 children from the Norwegian Mother, Father and Child Cohort Study (MoBa) study and applied to CRC GWAS data from European and East Asian descent populations (102 893 cases and 485 083 non-cases).

RESULTS

There were no significant associations observed between early life BMI and CRC risk in European or East Asian populations. The effect estimates were similar in European studies (odds ratio [OR] per a 1-standard deviation [SD] increase: 1.01, 95% confidence interval [CI]: 0.95, 1.07) and in East Asians (OR per a 1-SD increase: 1.02, 95% CI: 0.91, 1.14). Similar nonsignificant associations were found between time of BMI measurement during childhood and cancer-site-specific analyses.

CONCLUSIONS

We found little evidence of any associations between early life adiposity on later life CRC risk.

Determinants of childhood obesity in China

Over the past four decades, China has witnessed an important nutritional transition, characterised by a heightened overnutrition burden among children. The country now has the largest population of children with obesity globally. In this paper, we review the epidemiology of childhood obesity in China, its determinants, and risk factors, with a particular focus on school-aged children. Evidence unveils substantial variations across age, gender, and region. We describe multilevel obesogenic determinants, including macro-level social, cultural, and environmental factors; meso-level factors related to schools and communities; and micro-level factors tied to families and individuals from the perinatal-infant stage to childhood and adolescence. The primary drivers of childhood obesity appear to be rooted in the broader macro-level social, economic, and technological environment; obesogenic factors, which have affected school, community, and family environments; and accelerated unhealthy behaviour uptake. Identifying and characterising the catalysts behind the rise in childhood obesity in China is imperative for the development of scalable, effective, and tailored prevention, control, and intervention strategies.

Exploring the Link between Oxidative Stress, Selenium Levels, and Obesity in Youth

Obesity is a worldwide increasing concern. Although in adults this is easily estimated with the body mass index, in children, who are constantly growing and whose bodies are changing, the reference points to assess weight status are age and gender, and need corroboration with complementary data, making their quantification highly difficult. The present review explores the interaction spectrum of oxidative stress, selenium status, and obesity in children and adolescents. Any factor related to oxidative stress that triggers obesity and, conversely, obesity that induces oxidative stress are part of a vicious circle, a complex chain of mechanisms that derive from each other and reinforce each other with serious health consequences. Selenium and its compounds exhibit key antioxidant activity and also have a significant role in the nutritional evaluation of obese children. The balance of selenium intake, retention, and metabolism emerges as a vital aspect of health, reflecting the complex interactions between diet, oxidative stress, and obesity. Understanding whether selenium status is a contributor to or a consequence of obesity could inform nutritional interventions and public health strategies aimed at preventing and managing obesity from an early age.

Body Composition and Clinical Outcomes in Esophageal Cancer Patients Treated with Immune Checkpoint Inhibitors

BACKGROUND

Obesity is associated with increased mortality in various cancers, but the relationship between obesity and clinical outcomes in unresectable or recurrent esophageal cancer who receive immune checkpoint inhibitors (ICIs) remains unknown. This study investigated the association between body composition and clinical outcomes in patients with unresectable or recurrent esophageal cancer who received ICIs.

METHODS

Utilizing an unbiased database of 111 unresectable or recurrent esophageal cancers, we evaluated the relationships between body composition (body mass index, waist circumference, psoas major muscle volume, and subcutaneous and visceral fat areas) at the initiation of ICI treatment and clinical outcomes including the disease control rate and progression-free survival (PFS).

RESULTS

Waist circumference was significantly associated with the disease control rate at the first assessment (P = 0.0008). A high waist circumference was significantly associated with favorable PFS in patients treated with nivolumab. In an univariable model, for 5-cm increase of waist circumference in the outcome category of PFS, univariable hazard ratio (HR) was 0.73 (95% confidence interval [CI], 0.61-0.87; P = 0.0002). A multivariable model controlling for potential confounders yielded a similar finding (multivariable HR, 0.56; 95% CI, 0.33-0.94; P = 0.027). We observed the similar finding in esophageal cancer patients treated with pembrolizumab+CDDP+5-FU (P = 0.048). In addition, waist circumference was significantly associated with the prognostic nutritional index (P = 0.0073).

CONCLUSIONS

A high waist circumference was associated with favorable clinical outcomes in ICI-treated patients with unresectable or recurrent esophageal cancer, providing a platform for further investigations on the relationships among body composition, nutrition, and the immune status.

Light pollution during pregnancy influences the growth of offspring in rats

OBJECTIVE

To investigate the effects of excessive light exposure during gestation on intrauterine development and early growth of neonates in rats.

METHODS

Pregnant rats were randomly allocated to three groups: the constant light exposure group, non-light exposure group and control group. Blood samples were collected from the tail vein to analyze melatonin and cortisol levels. Weight, daily food and water consumption were recorded. Uterine weight, placental weight and placental diameter were measured on gestational day 19. Natural birth and neonate growth were also monitored. The expression of NR1D1(nuclear receptor subfamily 1 group D member 1) in offspring's SCN (suprachiasmatic nuclei), liver and adipose tissue was measured. Expression of NR1D1, MT1(melatonin 1 A receptor) and 11β-HSD2 (placental 11β-hydroxysteroid dehydrogenase type 2) in placenta was also measured. Finally, the expression of MT1 and 11β-HSD2 in NR1D1 siRNA transfected JEG-3 cells was evaluated.

RESULTS

There were no significant differences in maternal weight gain, pregnancy duration, uterine weight, placental body weight, placental diameter, fetal number among three groups. There were no significant differences in weights or lengths of offspring at birth. Compared to other two groups, constant light exposure group showed significantly more rapid growth of offspring in 21st day post-birth. The expression of NR1D1 in SCN, liver and adipose tissues of offspring was not significantly different among three groups. The maternal serum melatonin and cortisol levels of the constant light exposure group were lower and higher than other two groups, respectively. The expressions of NR1D1, MT1 and 11β-HSD2 were all decreased in placenta of the constant light exposure group. The expression of MT1 and 11β-HSD2 in JEG-3 cells were decreased after NR1D1 siRNA transfection.

CONCLUSION

Excessive light exposure during pregnancy results in elevated cortisol and reduced melatonin exposure to fetuses in uterus, potentially contributing to an accelerated early growth of offspring in rats.

Genetic predisposition to childhood obesity does not influence the risk of developing skin cancer in adulthood

The relationship between body mass index (BMI) and melanoma and other skin cancers remains unclear. The objective of this study was to employ the Mendelian randomization (MR) approach to evaluate the effects of genetically predicted childhood adiposity on the risk of developing skin cancer later in life. Two-sample MR analyses were conducted using summary data from genome-wide association study (GWAS) meta-analyses of childhood BMI, melanoma, cutaneous squamous cell carcinoma (cSCC), and basal cell carcinoma (BCC). We used the inverse-variance-weighted (IVW) methods to obtain a pooled estimate across all genetic variants for childhood BMI. We performed multiple sensitivity analyses to evaluate the potential influence of various assumptions on our findings. We found no evidence that genetically predicted childhood BMI was associated with risks of developing melanoma, cSCC, or BCC in adulthood (OR, 95% CI: melanoma: 1.02 (0.93-1.13), cSCC 0.94 (0.79-1.11), BCC 0.97 (0.84-1.12)). Our findings do not support the conclusions from observational studies that childhood BMI is associated with increased risks of melanoma, cSCC, or BCC in adulthood. Intervening on childhood adiposity will not reduce the risk of common skin cancers later in life.

Association between late bedtime and obesity in children and adolescents: a meta-analysis

Background

Short sleep duration has been related to obesity in children and adolescents. However, it remains unknown whether late bedtime is also associated with obesity and whether the association is independent of sleep duration. A meta-analysis was performed to address this issue.

Methods

In order to accomplish the aim of the meta-analysis, a comprehensive search was conducted on databases including PubMed, Embase, and Web of Science to identify observational studies. The cutoff to determine late bedtime in children in this meta-analysis was consistent with the value used among the included original studies. As for obesity, it was typically defined as a body mass index (BMI) > 95th percentile of age and sex specified reference standards or the International Obesity Task Force defined age- and gender-specific cut-off of BMI. The Cochrane Q test was employed to evaluate heterogeneity among the included studies, while the I2 statistic was estimated. Random-effects models were utilized to merge the results, considering the potential impact of heterogeneity.

Results

Tweleve observational studies with 57,728 participants were included. Among them, 6,815 (11.8%) were obese. Pooled results showed that late bedtime reported by the participants or their caregivers was associated with obesity (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 1.16-1.39, p < 0.001; I2 = 0%). Subgroup analysis showed consistent results in studies with (OR: 1.33, 95% CI: 1.04-1.70, p = 0.02) and without adjustment of sleep duration (OR: 1.27, 95% CI: 1.14-1.41, p < 0.001). Further subgroup analysis also showed that the association was not significantly affected by study location, design, age of the participants, or diagnostic methods for obesity (p for subgroup difference all >0.05).

Conclusion

Late bedtime is associated with obesity in children and adolescents, which may be independent of sleep duration.

Leveraging seasonality and timing to optimize pediatric weight management interventions: Novel directions for future research

National estimates suggest that more than 35% of American children, ages 2-19 years, are overweight or obese, which increases their risk for weight-related comorbidities including diabetes, cancer, cardiovascular disease risk factors, depression, and anxiety. While obesity prevention is most cost-effective, for youth with existing obesity, the United States Preventive Services Task Force recommends ≥26 h of comprehensive lifestyle intervention over 6-12 months. This include standard behavioral therapy, dietary counseling, and an emphasis on physical activity. Although such programs are effective in reducing weight status, there are many barriers to completing these programs. A novel consideration for both the prevention and treatment of childhood obesity is the recognition that the timing of intervention, both duration and time of the year, can impact family engagement and intervention effectiveness. This paper discusses the potential of targeting high-risk periods for weight gain and offering brief behavioral intervention, in hopes of inspiring research on novel approaches to the prevention and treatment of childhood obesity.

Obesity associated pancreatic ductal adenocarcinoma: Therapeutic challenges

Obesity is a prominent health issue worldwide and directly impacts pancreatic health, with obese individuals exhibiting a significant risk for increasing pancreatic ductal adenocarcinoma (PDAC). Several factors potentially explain the increased risk for the development of PDAC, including obesity-induced chronic inflammation within and outside of the pancreas, development of insulin resistance and metabolic dysfunction, promotion of immune suppression within the pancreas during inflammation, pre- and malignant stages, variations in hormones levels (adiponectin, ghrelin, and leptin) produced from the adipose tissue, and acquisition of somatic mutations in tumor once- and suppressor proteins critical for pancreatic tumorigenesis. In this manuscript, we will explore the broad impact of these obesity-induced risk factors on the development and progression of PDAC, focusing on changes within the tumor microenvironment (TME) as they pertain to prevention, current therapeutic strategies, and future directions for targeting obesity management as they relate to the prevention of pancreatic tumorigenesis.

Association of birth and childhood weight with risk of chronic diseases and multimorbidity in adulthood

BACKGROUND

Little is known about the relationship between early life body size and occurrence of life-course multiple chronic diseases (multimorbidity). We aim to evaluate associations of birth weight, childhood body size, and their changes with the risks of chronic diseases and multimorbidity.

METHODS

This prospective cohort study included 246,495 UK Biobank participants (aged 40-69 years) who reported birth weight and childhood body size at 10 years old. Birth weight was categorized into low, normal, and high; childhood body size was reported as being thinner, average, or plumper. Multimorbidity was defined as having two or more of 38 chronic conditions retrieved from inpatient hospital data until 31 December, 2020. The Cox regression and quasi-Poisson mixed effects models were used to estimate the associations.

RESULTS

We show that 57,071 (23.2%) participants develop multimorbidity. Low birth weight (hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.26-1.33), high birth weight (HR 1.02, 95% CI > 1.00-1.05), thinner (HR 1.21, 95% CI 1.18-1.23) and plumper body size (HR 1.06, 95% CI 1.04-1.09) are associated with higher risks of multimorbidity. A U-shaped relationship between birth weight and multimorbidity is observed. Changing to be thinner or plumper is associated with multimorbidity and many conditions, compared to changing to be average.

CONCLUSIONS

Low birth weight, being thinner and changing to have a thinner body size in childhood are associated with higher risks of developing multimorbidity and many chronic conditions in adulthood. Early monitoring and maintaining a normal body size in childhood could have life-course benefits for preventing multimorbidity above and beyond individual conditions.

Inflammatory cytokines and chemokines in obese adolescents with antibody against to adenovirus 36

Obesity in adolescents has reached epidemic proportions and is associated with the inflammatory response and viral infections. The aim of this study was to understand the profile of inflammatory cytokines and chemokines associated with the inflammatory response and metabolic syndrome (MetS) in obese adolescents with positive serology for adenovirus 36 (ADV36). Thirty-six overweight, 36 obese, and 25 severe obesity adolescents aged 10 to 16 years were included in the study. The following variables were analyzed: sex, age, body mass index (BMI), blood pressure, total cholesterol and fractions, triglycerides, glucose, serum cytokine concentrations, and ADV36 antibodies. Cytokines and chemokines were quantified by cytometry and ADV36 serology was determined by enzyme-linked immunosorbent assay (ELISA). The results showed higher levels of the cytokines interleukin-1beta (IL-1β), IL-6, IL-10 and of the chemokine interferon-gamma-inducible protein 10 (IP-10) in severe obesity adolescents compared to the obese and overweight groups, as well as in the group with MetS compared to the group without this syndrome. The frequency of ADV36-positive individuals did not differ between groups. The findings revealed differences in BMI between the obese and severe obesity groups versus the overweight group in the presence of positivity for ADV36, suggesting an association with weight gain and possibly MetS installation.

Childhood body mass index trajectories, adult-onset type 2 diabetes, and obesity-related cancers

BACKGROUND

Elevated childhood body mass index (BMI), commonly examined as a "once-only" value, increases the risk of cancer and type 2 diabetes (T2D) in adulthood. Continuous exposure to adiposity during childhood may further increase cancer risk. We examined whether longitudinal childhood BMI trajectories were associated with adult obesity-related cancer and the role of adult-onset T2D in these associations.

METHODS

Five sex-specific latent class BMI trajectories were generated for 301 927 children (149 325 girls) aged 6-15 years from the Copenhagen School Health Records Register. Information on obesity-related cancers and T2D was obtained from national health registers. Incidence rate ratios (IRR), cumulative incidences, and confidence intervals (CI) were estimated using Poisson regressions.

RESULTS

Compared with the average childhood BMI trajectory (containing approximately 40% of individuals), the rate of obesity-related cancer (excluding breast cancer) increased with higher childhood BMI trajectories among women. The highest rates occurred in the overweight (IRR = 1.27, 95% CI = 1.17 to 1.38) and obesity (IRR = 1.79, 95% CI = 1.53 to 2.08) BMI trajectories. Similar patterns were observed among men. In contrast, women with the obesity childhood BMI trajectory had the lowest rate of pre- and postmenopausal breast cancer (IRR = 0.59, 95% CI = 0.43 to 0.80, and IRR = 0.41, 95% CI = 0.30 to 0.57, respectively). For all trajectories, the cumulative risk of obesity-related cancer increased with adult-onset T2D.

CONCLUSION

Consistent childhood overweight or obesity may increase the rates of adult obesity-related cancer and decrease the rates of breast cancer. Adult-onset T2D conferred additional risk for obesity-related cancer, but the effect did not differ across childhood BMI trajectories.

Separating the effects of early and later life adiposity on colorectal cancer risk: a Mendelian randomization study

BACKGROUND

Observational studies have linked childhood obesity with elevated risk of colorectal cancer; however, it is unclear if this association is causal or independent from the effects of obesity in adulthood on colorectal cancer risk.

METHODS

We conducted Mendelian randomization (MR) analyses to investigate potential causal relationships between self-perceived body size (thinner, plumper, or about average) in early life (age 10) and measured body mass index in adulthood (mean age 56.5) with risk of colorectal cancer. The total and independent effects of body size exposures were estimated using univariable and multivariable MR, respectively. Summary data were obtained from a genome-wide association study of 453,169 participants in UK Biobank for body size and from a genome-wide association study meta-analysis of three colorectal cancer consortia of 125,478 participants.

RESULTS

Genetically predicted early life body size was estimated to increase odds of colorectal cancer (odds ratio [OR] per category change: 1.12, 95% confidence interval [CI]: 0.98-1.27), with stronger results for colon cancer (OR: 1.16, 95% CI: 1.00-1.35), and distal colon cancer (OR: 1.25, 95% CI: 1.04-1.51). After accounting for adult body size using multivariable MR, effect estimates for early life body size were attenuated towards the null for colorectal cancer (OR: 0.97, 95% CI: 0.77-1.22) and colon cancer (OR: 0.97, 95% CI: 0.76-1.25), while the estimate for distal colon cancer was of similar magnitude but more imprecise (OR: 1.27, 95% CI: 0.90-1.77). Genetically predicted adult life body size was estimated to increase odds of colorectal (OR: 1.27, 95% CI: 1.03, 1.57), colon (OR: 1.32, 95% CI: 1.05, 1.67), and proximal colon (OR: 1.57, 95% CI: 1.21, 2.05).

CONCLUSIONS

Our findings suggest that the positive association between early life body size and colorectal cancer risk is likely due to large body size retainment into adulthood.

Obesity, diabetes mellitus, and pancreatic carcinogenesis: Correlations, prevention, and diagnostic implications

The prevalence of obesity, diabetes mellitus (DM), and pancreatic cancer (PC) has been consistently increasing in the last two decades worldwide. Sharing various influential risk factors in genetics and environmental inducers in pathogenesis, the close correlations of these three diseases have been demonstrated in plenty of clinical studies using multiple parameters among different populations. On the contrary, most measures aimed to manage and treat obesity and DM effectively reduce the risk and prevent PC occurrence, yet certain drugs can inversely promote pancreatic carcinogenesis instead. Most importantly, an elevation of blood glucose with or without a reduction in body weight, along with other potential tools, may provide valuable clues for detecting PC at an early stage in patients with obesity and DM, favoring a timely intervention and prolonging survival. Herein, the epidemiological and etiological correlations among these three diseases and the supporting clinical evidence of their connections are first summarized to favor a better and more thorough understanding of obesity- and DM-related pancreatic carcinogenesis. After comparing the distinct impacts of different weight-lowering and anti-diabetic treatments on the risk of PC, the possible diagnostic implications of hyperglycemia and weight loss in PC screening are also addressed in detail.

Associations between early-life growth pattern and body size and follicular lymphoma risk and survival: a family-based case-control study

BACKGROUND

The influence of early-life growth pattern and body size on follicular lymphoma (FL) risk and survival is unclear. In this study, we aimed to investigate the association between gestational age, growth during childhood, body size, changes in body shape over time, and FL risk and survival.

METHODS

We conducted a population-based family case-control study and included 706 cases and 490 controls. We ascertained gestational age, growth during childhood, body size and body shape using questionnaires and followed-up cases (median=83 months) using record linkage with national death records. We used a group-based trajectory modeling approach to identify body shape trajectories from ages 5-70. We examined associations with FL risk using unconditional logistic regression and used Cox regression to assess the association between body mass index (BMI) and all-cause and FL-specific mortality among cases.

RESULTS

We found no association between gestational age, childhood height and FL risk. We observed a modest increase in FL risk with being obese 5 years prior to enrolment (OR=1.43, 95 %CI=0.99-2.06; BMI ≥30 kg/m²) and per 5-kg/m² increase in BMI 5 years prior to enrolment (OR=1.14, 95 %CI=0.99-1.31). The excess risk for obesity 5 years prior to enrolment was higher for ever-smokers (OR=2.00, 95 %CI=1.08-3.69) than never-smokers (OR=1.14, 95 %CI=0.71-1.84). We found no association between FL risk and BMI at enrolment, BMI for heaviest lifetime weight, the highest categories of adult weight or height, trouser size, body shape at different ages or body shape trajectory. We also observed no association between all-cause or FL-specific mortality and excess adiposity at or prior to enrolment.

CONCLUSION

We observed a weak association between elevated BMI and FL risk, and no association with all-cause or FL-specific mortality, consistent with previous studies. Future studies incorporating biomarkers are needed to elucidate possible mechanisms underlying the role of body composition in FL etiology.

Detection of Leptin Using Electrocatalyst Mediated Impedimetric Sensing

Obesity is a complex disorder associated with immense health consequences including high risk of cardiovascular diseases, diabetes, and cancer. Abnormality in the thyroid gland, genetics, less physical activity, uptake of excessive diet, and leptin resistance are critical factors in the development of obesity. To determine the treatment strategy, understanding the pathophysiology of obesity is crucial. For instances, leptin resistance mediated obesity defined by the presence of excessive leptin hormone (Lep) in the systemic circulation is very common in diet induced obesity. Therefore, our hypothesis is that quantitative measurement of Lep from blood can help to identify individuals with Lep resistant mediated obesity and thereby guide toward a proper treatment strategy. In this work, we aim to utilize an electrochemical immunosensing platform for diagnosis of obesity by measuring the Lep content in systemic circulation. A porous carbon confined FeNi bimetallic system was synthesized with three different ratios of Fe and Ni ions using high temperature pyrolysis technique. The suitability of the sensor for detecting Lep was studied using both CV and EIS techniques. The limit of detection (LOD) for GCE was recorded as 157.4 fg/mL with a wide linear concentration range of 500 fg/mL to 80 ng/mL, while for SPCE the LOD was 184.9 fg/mL with a linear range of 500 fg/mL to 50 ng/mL. Finally, the feasibility and applicability of the sensor for Lep detection was tested with serum collected from high fat diet induced obese rats. The selectivity, sensitivity, storage, and experimental stability and reproducibility tests showed potential for this biosensor platform as a point-of-care Lep detection device.

Body Size at Different Ages and Risk of 6 Cancers: A Mendelian Randomization and Prospective Cohort Study

It is unclear if body weight in early life affects cancer risk independently of adult body weight. To investigate this question for 6 obesity-related cancers, we performed univariable and multivariable analyses using 1) Mendelian randomization (MR) analysis and 2) longitudinal analyses in prospective cohorts. Both the MR and longitudinal analyses indicated that larger early life body size was associated with higher risk of endometrial (odds ratioMR = 1.61, 95% confidence interval = 1.23 to 2.11) and kidney (odds ratioMR = 1.40, 95% confidence interval = 1.09 to 1.80) cancer. These associations were attenuated after accounting for adult body size in both the MR and cohort analyses. Early life body mass index (BMI) was not consistently associated with the other investigated cancers. The lack of clear independent risk associations suggests that early life BMI influences endometrial and kidney cancer risk mainly through pathways that are common with adult BMI.

Obesity and Pancreatic Cancer: Insight into Mechanisms

Simple Summary

Obesity is recognized as a chronic progressive disease and risk factor for many human diseases. The high and increasing number of obese people may underlie the expected increase in pancreatic cancer cases in the United States. There are several pathways discussed that link obesity with pancreatic cancer. Adipose tissue and adipose tissue-released factors may thereby play an important role. This review discusses selected mechanisms that may accelerate pancreatic cancer development in obesity.

Abstract

The prevalence of obesity in adults and children has dramatically increased over the past decades. Obesity has been declared a chronic progressive disease and is a risk factor for a number of metabolic, inflammatory, and neoplastic diseases. There is clear epidemiologic and preclinical evidence that obesity is a risk factor for pancreatic cancer. Among various potential mechanisms linking obesity with pancreatic cancer, the adipose tissue and obesity-associated adipose tissue inflammation play a central role. The current review discusses selected topics and mechanisms that attracted recent interest and that may underlie the promoting effects of obesity in pancreatic cancer. These topics include the impact of obesity on KRAS activity, the role of visceral adipose tissue, intrapancreatic fat, adipose tissue inflammation, and adipokines on pancreatic cancer development. Current research on lipocalin-2, fibroblast growth factor 21, and Wnt5a is discussed. Furthermore, the significance of obesity-associated insulin resistance with hyperinsulinemia and obesity-induced gut dysbiosis with metabolic endotoxemia is reviewed. Given the central role that is occupied by the adipose tissue in obesity-promoted pancreatic cancer development, preventive and interceptive strategies should be aimed at attenuating obesity-associated adipose tissue inflammation and/or at targeting specific molecules that mechanistically link adipose tissue with pancreatic cancer in obese patients.