Associations of Body Mass Index and Waist Circumference with the Risk of Head and Neck Cancer: A National Population-Based Study

Joint association of drinking alcohol and obesity in relation to cancer risk: A systematic review and data synthesis

BACKGROUND

Rates of alcohol consumption and obesity are increasing in many Western populations. For some cancer types, both heavy alcohol consumption and obesity are independently associated with increased risk. Whether combined exposure to both synergistically increases an individual's risk of cancer is unclear. We performed a systematic review to assess whether alcohol and obesity interact to confer higher risk for cancer than the additive sum of their effects.

METHODS

A systematic literature search was conducted from the inception date to 13 February 2024 of PubMed, Embase, Cochrane Library and Web of Science to identify studies of alcohol, obesity, and cancer risk. We aimed to undertake a meta-analysis if there were sufficient data.

RESULTS

The literature search identified 17,740 potentially eligible studies. After review, 24 studies were included. Eleven reported on the association between alcohol consumption and cancer risk in individuals according to their body mass index (BMI), nine reported on the association between BMI and cancer risk in individuals according to their alcohol consumption, and six studies examined potential synergistic interactions between alcohol consumption and obesity on cancer risk. However, there were insufficient data and significant heterogeneity in the cancers studied to undertake meta-analysis, therefore a systemic review and narrative synthesis was conducted. Overall, there was no consistent pattern of interaction between alcohol use and overweight/obesity on cancer risk across cancer types.

CONCLUSIONS

While alcohol and obesity are prevalent and important risk factors for a range of cancers, data are lacking on whether their combined exposure may synergistically increase an individual's risk for cancer. Further study across more cancer types is required to better understand the nature of interactions between alcohol use and obesity on cancer risk.

Association of Metabolic Syndrome with the Risk of Head and Neck Cancer: A 10-Year Follow-Up Study of 10 Million Initially Healthy Individuals

The aim of this national population-based retrospective study was to analyze the relationship between MetS and the incidence of HNC. In this Korean population-based cohort study, 9,598,085 subjects above the age of 20 were monitored from 1 January 2009 to 31 December 2018. In the study population, a total of 10,732 individuals were newly diagnosed with HNC during the 10-year follow-up. The hazard ratio (HR), after adjusting for age, gender, smoking status, alcohol intake, and exercise, indicated that participants with MetS were at a 1.06-fold (95% CI: 1.01-1.10) higher risk of having HNC than those without MetS. Participants with MetS showed an increased risk of developing oral cavity cancer (HR, 1.12; 95% CI, 1.03-1.23) and laryngeal cancer (HR, 1.18; 95% CI, 1.09-1.27). Among the components of MetS, elevated fasting glucose (HR = 1.04, 95% CI: 1.00-1.08) and elevated blood pressure (HR = 1.08, 95% CI: 1.04-1.13) were significantly associated with an increased HR for HNC in an adjusted multivariable model. The association between HNC and MetS remained significant even among individuals who had never smoked or were ex-smokers (HR: 1.09; 95% CI: 1.04-1.15), as well as those who did not drink or were mild drinkers (HR: 1.07; 95% CI: 1.02-1.12). The findings of this cohort study suggest MetS was associated with an increased risk for some types of HNCs. The results of this study could assist with etiological investigations and prevention strategies.

Obesity, the Adipose Organ and Cancer in Humans: Association or Causation?

Epidemiological observations, experimental studies and clinical data show that obesity is associated with a higher risk of developing different types of cancer; however, proof of a cause-effect relationship that meets the causality criteria is still lacking. Several data suggest that the adipose organ could be the protagonist in this crosstalk. In particular, the adipose tissue (AT) alterations occurring in obesity parallel some tumour behaviours, such as their theoretically unlimited expandability, infiltration capacity, angiogenesis regulation, local and systemic inflammation and changes to the immunometabolism and secretome. Moreover, AT and cancer share similar morpho-functional units which regulate tissue expansion: the adiponiche and tumour-niche, respectively. Through direct and indirect interactions involving different cellular types and molecular mechanisms, the obesity-altered adiponiche contributes to cancer development, progression, metastasis and chemoresistance. Moreover, modifications to the gut microbiome and circadian rhythm disruption also play important roles. Clinical studies clearly demonstrate that weight loss is associated with a decreased risk of developing obesity-related cancers, matching the reverse-causality criteria and providing a causality correlation between the two variables. Here, we provide an overview of the methodological, epidemiological and pathophysiological aspects, with a special focus on clinical implications for cancer risk and prognosis and potential therapeutic interventions.

Body fatness associations with cancer: evidence from recent epidemiological studies and future directions

This narrative review highlights current evidence linking greater body fatness to risk of various cancers, with focus on evidence from recent large cohort studies and pooled analyses of cohort studies as well as Mendelian randomization studies (which utilized genetic variants associated with body mass index to debrief the causal effect of higher body fatness on cancer risk). This review also provides insights into the biological mechanisms underpinning the associations. Data from both observational and Mendelian randomization studies support the associations of higher body mass index with increased risk of many cancers with the strongest evidence for digestive system cancers, including esophageal, stomach, colorectal, liver, gallbladder, and pancreatic cancer, as well as kidney, endometrial, and ovarian (weak association) cancer. Evidence from observational studies suggests that greater body fatness has contrasting effects on breast cancer risk depending on menopausal status and on prostate cancer risk depending on disease stage. Experimental and Mendelian randomization studies indicate that adiponectin, insulin, and sex hormone pathways play an important role in mediating the link between body fatness and cancer risk. The possible role of specific factors and pathways, such as other adipocytokines and hormones and the gut microbiome in mediating the associations between greater body fatness and cancer risk is yet uncertain and needs investigation in future studies. With rising prevalence of overweight and obesity worldwide, the proportion of cancer caused by excess body fatness is expected to increase. There is thus an urgent need to identify efficient ways at the individual and societal level to improve diet and physical activity patterns to reduce the burden of obesity and accompanying comorbidities, including cancer.