Young adulthood and adulthood adiposity in relation to incidence of pancreatic cancer: a prospective study of 0.5 million Chinese adults and a meta-analysis

Exposure to Metal Mixtures and Overweight or Obesity Among Chinese Adults

Previous research has investigated the association between individual metal exposure and overweight/obesity (OW/OB). However, there is limited data about metal mixture exposure and OW/OB. This study aimed to explore the individual and joint effects of 21 metals on OW/OB and its metabolic phenotypes. A total of 4042 participants were enrolled in our study, and 51.0% of them were overweight/obese. We quantified 21 metal levels in the urine sample. OW/OB was defined as BMI ≥ 24 kg/m², while the metabolic phenotypes, including metabolic unhealthy overweight/obesity (MUOW/OB) and metabolic health overweight/obesity (MHOW/OB), were determined by BMI and metabolic state. We used logistic regression to analyze the effect of individual metal exposure on OW/OB and its metabolic phenotypes. Quantile g-computation was applied to evaluate the joint effect of metal exposure on OW/OB and its metabolic phenotypes. In logistic regression, zinc (Zn) was positively associated with OW/OB, with the odds ratio (OR) in the highest quartiles of 2.19 (95% confidence interval (CI), 1.74, 2.77; P trend < 0.001), while arsenic (As) and cadmium (Cd) were negatively associated with OW/OB (OR = 0.70 (0.56, 0.87) and 0.61 (0.48, 0.78), respectively). After adjustment for age, gender, education, cigarette smoking, alcohol drinking, physical activity, meat intake, and vegetable intake, Zn was positively associated with MUOW/OB, while As, Cd, nickel (Ni), and strontium (Sr) were negatively associated with MUOW/OB (all P trend < 0.05). Quantile g-computation showed a significantly negative association between metal mixture exposure and MUOW/OB. Our study suggested that metal mixture exposure might be negatively associated with OW/OB, particularly with MUOW/OB. Zn, As and Cd contributed most to the effect of the mixture. More prospective studies are warranted to confirm these findings and reveal the underlying mechanisms.

Body Mass Index Trajectories Across the Adult Life Course and Pancreatic Cancer Risk

BACKGROUND

Body mass index (BMI) during adulthood has been associated with pancreatic ductal adenocarcinoma (PDAC), however, patterns of body size across the adult life course have not been studied extensively. We comprehensively evaluated the association between adiposity across adulthood and PDAC.

METHODS

We conducted a prospective analysis of 269 480 (162 735 males, 106 745 females) National Institutes of Health-AARP Diet and Health Study participants, aged 50-71 years (1995-1996) who self-reported height and weight history. Participants were followed through December 31, 2011. We examined associations between BMI (kg/m2) at ages 18, 35, 50, and 50-71 (baseline) years, their trajectories determined from latent-class trajectory modeling, and incident PDAC. Cox proportional hazard models were used to calculate multivariable adjusted hazards ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During up to 15.2 years of follow-up, 3092 (2020 males, 1072 females) patients with incident PDAC were identified. BMI at all 4 ages were statistically significantly associated with increased PDAC (per 5-unit increase, HR = 1.09-1.13) with higher magnitude associations in males than females at ages 35 years and older (Pinteraction < .05). Four BMI trajectories were created. Compared with normal-weight maintainers, normal-to-overweight, normal-to-obese class I, and overweight-to-obese class III trajectories had hazard ratios of 1.15 (95% CI = 1.06 to 1.25), 1.39 (95% CI = 1.25 to 1.54), and 1.48 (95% CI = 1.18 to 1.87), respectively (Pinteraction by sex = .07).

CONCLUSIONS

High BMI and BMI trajectories that result in overweight or obesity during adulthood were positively associated with PDAC, with stronger associations among those with early onset adiposity and those with male sex. Avoidance of excess body weight throughout the adult life course may prevent PDAC.

Pancreatic Cancer and the Obesity Epidemic: A Narrative Review

Pancreatic cancer (PC) is one of the most frequent causes of death. It usually affects older individuals with incidence closely approaching mortality due to its early asymptomatic feature and highly metastatic nature. Multiple risk factors such as family history, smoking, and germline mutations are associated with PC development, with obesity being one of the controllable factors. This review article focuses on the compilation of various studies to help establish a correlation between obesity or an increased body mass index and PC development. Hence, in this review, we have summarised multiple biological mechanisms of PC development induced by obesity, including insulin resistance, inflammation, beta-cell dysfunction, and oxidative stress, to prove that their correlation when combined with other factors, such as smoking, alcohol and chronic pancreatitis, may increase its risk. We have also reviewed potential diagnostic and screening techniques, such as evaluating precancerous lesions in high-risk patients and management plans discussing upcoming advances in treatment tactics such as neoadjuvant therapy, to reduce post-operative complications.

Effectiveness of a Worksite-Based Lifestyle Intervention on Employees' Obesity Control and Prevention in China: A Group Randomized Experimental Study

Background: This study was to culturally adapt a lifestyle intervention for employees’ obesity control and prevention using a participatory process, and evaluate the effectiveness of the project at worksites. Methods: A group randomized experimental study included four worksites (two intervention, two control) in the Yangtze River Delta in China was conducted. A total of 388 participants (216 in the intervention worksites and 172 in the control worksites) were finally recruited from 955 employees at the four worksites (464 in the intervention worksites and 491 in the control worksites). The final evaluation was completed by two hundred and seventy-eight employees (159 in the intervention worksites and 119 in the control worksites, respectively). Data of demographic information, weight, BMI, waist circumference, hip circumference and weight-related behaviors including diary behaviors and physical activities were collected before and after a 12-month intervention and analyzed using descriptive statistics, t-test, chi-square test, linear mixed regression and logistic mixed regression. Results: Although the intervention worksites had a reduction in body mass index (23.21 to 22.95, p < 0.01), hip circumference (95.97 to 95.28, p = 0.03) and waist-to-height ratio (0.49 to 0.48, p = 0.01), the differential changes compared to those of the control group were not statistically significant. The frequency of sweet beverages (−1.81, 95%CI: −0.52, −3.11), frequency of vegetable intake (5.66, 95%CI: 1.59, 9.74), daily servings of vegetables (0.53, 95%CI: 0.24, 0.82), frequency of fruit intake (3.68, 95%CI: 1.25, 6.12), daily servings of fruit (0.26, 95%CI: 0.44, 0.92), daily servings of vegetables and fruit (0.79, 95%CI: 0.43, 1.16), daily steps (863.19, 95%CI: 161.42, 1564.97) and self-efficacy to change physical activity (OR = 1.91, 95%CI: 1.02,3.60) were more improved in the intervention group than were those measures in the control group. Conclusions: The worksite-based lifestyle intervention project for obesity control and prevention improved several employees’ dietary behaviors and physical activities at worksites in China in a short time. Long-term intervention with larger samples in more worksites should be further examined.

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.

The Role of Dysfunctional Adipose Tissue in Pancreatic Cancer: A Molecular Perspective

Pancreatic cancer (PC) is a lethal malignancy with rising incidence and limited therapeutic options. Obesity is a well-established risk factor for PC development. Moreover, it negatively affects outcome in PC patients. Excessive fat accumulation in obese, over- and normal-weight individuals induces metabolic and inflammatory changes of adipose tissue microenvironment leading to a dysfunctional adipose “organ”. This may drive the association between abnormal fat accumulation and pancreatic cancer. In this review, we describe several molecular mechanisms that underpin this association at both local and systemic levels. We focus on the role of adipose tissue-derived circulating factors including adipokines, hormones and pro-inflammatory cytokines, as well as on the impact of the local adipose tissue in promoting PC. A discussion on potential therapeutic interventions, interfering with pro-tumorigenic effects of dysfunctional adipose tissue in PC, is included. Considering the raise of global obesity, research efforts to uncover the molecular basis of the relationship between pancreatic cancer and adipose tissue dysfunction may provide novel insights for the prevention of this deadly disease. In addition, these efforts may uncover novel targets for personalized interventional strategies aimed at improving the currently unsatisfactory PC therapeutic options.

Socioeconomic Status in Relation to Risks of Major Gastrointestinal Cancers in Chinese Adults: A Prospective Study of 0.5 Million People

BACKGROUND

Low socioeconomic status (SES) is associated with higher risk of certain gastrointestinal (e.g., colorectal, pancreatic, and liver) cancers in Western populations. Evidence is very limited in China, where correlates and determinants of SES differ from those in the West.

METHODS

The prospective China Kadoorie Biobank recruited 512,715 adults (59% women, mean age 51 years) from 10 (5 urban, 5 rural) regions. During 10 years of follow-up, 27,940 incident cancers (including 3,061 colorectal, 805 pancreatic, and 2,904 liver) were recorded among 510,131 participants without prior cancer at baseline. Cox regression was used to estimate adjusted HRs for specific cancers associated with area-level (e.g., per capita gross domestic product, disposable income) and individual-level (e.g., education, household income) SES.

RESULTS

Area-level SES and household income showed positive associations with incident colorectal and pancreatic cancers and inverse associations with liver cancer (P _trend < 0.05). Education showed no association with colorectal cancer but inverse associations with pancreatic and liver cancers, with adjusted HRs comparing university to no formal schooling being 1.05 [95% confidence interval (CI), 0.85-1.29], 0.49 (95% CI, 0.28-0.85), and 0.61 (95% CI, 0.47-0.81), respectively. Potential risk factors (e.g., smoking, alcohol) partly explained the inverse associations of education with pancreatic and liver cancers (17.6% and 60.4%), respectively.

CONCLUSIONS

Among Chinese adults, the associations of SES with gastrointestinal cancers differed by cancer type and SES indicator. Potential risk factors partially explained the inverse associations of education with pancreatic and liver cancers.

IMPACT

The different associations between SES with gastrointestinal cancers may inform cancer prevention strategies.

Pancreatic cancer and obesity: epidemiology, mechanism, and preventive strategies

The prevalence of obesity has seen a global increase in the past decades, escalating to one of the major epidemiological challenges today. Global economic growth has caused changes in dietary and physical activity patterns fueling obesity across age, gender, and income groups. The implications are many, as obesity has been associated with numerous serious health conditions, ultimately affecting morbidity and mortality. There is a growing recognition of the risk a high body mass index confers on the development and outcome of several malignancies, including pancreatic cancer. Pancreatic cancer is a highly lethal disease with exceptionally poor outcome, with incidences rising worldwide. Due to vague symptoms and no screening recommendations, a vast majority of patients are diagnosed at late stages, with already advanced disease and no opportunity for surgical intervention. Obesity mediates risk for pancreatic cancer through insufficiently understood mechanisms, possibly including inflammation and hormonal misbalance. As excess abdominal adiposity is among the few modifiable risk factors for pancreatic cancer onset, enduring weight loss could manifest an effective preventive measure. Lifestyle modifications on a population level aimed to reduce obesity could also scale down the grim pancreatic cancer rates. In cases when these measures alone are insufficiently effective, bariatric surgery can be an advantageous alternative. Extremely obese patients exhibit many health benefits following bariatric surgery along with weight loss, consequently reducing the chances of pancreatic cancer, especially if additionally adopting healthy lifestyle habits.

A review of lifestyle, metabolic risk factors, and blood-based biomarkers for early diagnosis of pancreatic ductal adenocarcinoma

We aimed to review the epidemiologic literature examining lifestyle and metabolic risk factors, and blood-based biomarkers including multi-omics (genomics, proteomics, and metabolomics) and to discuss how these predictive markers can inform early diagnosis of pancreatic ductal adenocarcinoma (PDAC). A search of the PubMed database was conducted in June 2018 to review epidemiologic studies of (i) lifestyle and metabolic risk factors for PDAC, genome-wide association studies, and risk prediction models incorporating these factors and (ii) blood-based biomarkers for PDAC (conventional diagnostic markers, metabolomics, and proteomics). Prospective cohort studies have reported at least 20 possible risk factors for PDAC, including smoking, heavy alcohol drinking, adiposity, diabetes, and pancreatitis, but the relative risks and population attributable fractions of individual risk factors are small (mostly < 10%). High-throughput technologies have continued to yield promising genetic, metabolic, and protein biomarkers in addition to conventional biomarkers such as carbohydrate antigen 19-9. Nonetheless, most studies have utilized a hospital-based case-control design, and the diagnostic accuracy is low in studies that collected pre-diagnostic samples. Risk prediction models incorporating lifestyle and metabolic factors as well as other clinical parameters have shown good discrimination and calibration. Combination of traditional risk factors, genomics, and blood-based biomarkers can help identify high-risk populations and inform clinical decisions. Multi-omics investigations can provide valuable insights into disease etiology, but prospective cohort studies that collect pre-diagnostic samples and validation in independent studies are warranted.

Smoking, alcohol, and diet in relation to risk of pancreatic cancer in China: a prospective study of 0.5 million people

In China, the incidence of pancreatic cancer (PC) has increased in recent decades. However, little is known about the relevance to PC risk of lifestyle and behavioral factors such as smoking, alcohol drinking, and diet. The China Kadoorie Biobank prospective study recruited 512,891 adults (210,222 men, 302,669 women) aged 30–79 (mean 52) years from 10 diverse areas during 2004–08. During ~9 years of follow‐up, 688 incident cases of PC were recorded among those who had no prior history of cancer at baseline. Cox regression yielded adjusted hazard ratios (HR) for PC associated with smoking, alcohol and selected dietary factors. Overall, 74% of men were ever‐regular smokers and 33% of men drank at least weekly, compared with only 3% and 2% of women, respectively. Among men, current regular smoking was associated with an adjusted HR of 1.25 (95% CI 1.08–1.44) for PC, with greater excess risk in urban than rural areas (1.46 [1.19–1.79] vs 1.04 [0.86–1.26]). Heavy, but not light to moderate, alcohol drinking (i.e. ≥420 g/week) was associated with significant excess risk (1.69 [1.21–2.37]), again more extreme in urban than rural areas (1.93 [1.29–2.87] vs 1.35 [0.74–2.48]). Overall, regular consumption of certain foodstuffs was associated with PC risk, with adjusted daily vs never/rare consumption HRs of 0.66 (0.56–0.79) for fresh fruit and 1.16 (1.01–1.33) for red meat. In China, smoking and heavy alcohol drinking were independent risk factors for PC in men. Lower fresh fruit and higher red meat consumption were also associated with higher risk of PC.