Introduction
The consumption of alcohol is associated with over 200 health conditions, injuries and diseases globally. Cited as one of the drugs with the greatest disease, economic and social burden, alcohol use subjects light to moderate users to the risk of cancer of the upper and lower aerodigestive system such as that of the rectum, colon, larynx, pharynx and oral cavity (Klein et al., 2020). The constant use of alcohol can also lead to the manifestation of cancer in the liver and heighten the risk of breast cancer in females. Rumgay et al. (2021) report highlights that at least 23,000 new cases are recorded annually, with 13% of the new health conditions attributed to alcohol-induced cancer. The types of cancer contribute to 6.3 million cases, with at least 3.3 million patients succumbing to the health condition globally (Rehm et al., 2017). People who consume at least 10 g per day of alcohol contribute to at least a third of new cancer cases. The changing patterns of alcohol consumption also indicate new distributions in terms of alcohol-related cancer risks, with countries such as India, China and sub-Saharan Africa showing increased cancer incidents (Rumgay et al., 2021).
Further evidence suggests that increased consumption and duration heighten the risks of suffering from cancer incidences associated with alcohol. This includes binge drinkers and those that indulge in more than one drink daily. However, the risks differ depending on other factors such as sex, age and geographical location. The discourse will expound on the association between alcohol consumption and cancer risk. The paper will also describe the epidemiology of cancer depending on the level of consumption. Lastly, the report will also make causal inferences based on cancer incidences and alcohol consumption while highlighting the limitations of studies incorporated in this text.
Summary of Debate on Alcohol Consumption and Cancer Incidences
Several longitudinal, cross-sectional and cohort studies have sought to identify the association between alcohol consumption and cancer incidences. There is strong evidence of a correlation between alcohol consumption and different types of cancer. In a cohort study by Rumgay et al. (2021), alcohol-related cancer accounts for 4.1% of the total cancer incidents reported globally in 2020, with at least 741 300 reported one of the strains. The study further elucidates that more males reported the condition compared to women, with 76.7% compared to 23.3% in the same year. Most alcohol drinkers reported cancer of the Oesophagus and oral cavity.
The changes in alcohol consumption highlight changing trends regarding alcohol-attributable cancer outcomes. Rovira and Rehm (2020) argued that countries in the European Union report chronic cancer cases because of alcohol, even amongst light to moderate drinkers (<10g). Younger adults show varying levels of risk exposures compared to older individuals, as they remain more susceptible to cancer incidence, with 13.5% of the deaths associated with alcohol-attributed cancer (Rumgay et al., 2021). Additionally, vulnerable and disadvantaged ethnic minorities are more prone to alcohol-inclined cancer. Rumgay et al. (2020) study further explored patterns of alcohol consumption and the changing trends across different geographical locations. The findings highlight that the consumption of alcohol per capita has decreased significantly in the majority of European countries. The decrease in the consumption rate insinuates a possible decrease in relative risks associated with cancer.
A study by Wood et al. (2018) provided a threshold for a minimum alcoholic content that reduces the risks of alcohol-induced cancer. The study suggested that an alcohol content of about 100 g per week remains the recommended level to reduce the risks of cancer. The threshold differs significantly depending on the region and gender, as individuals who reduce their consumption to at least 100 g per week or lower tend to have a higher life expectancy, especially after age 40. Individuals prone to consume spirits/beer or indulge in regular binge drinking sessions are at a higher risk of alcohol-attributed cancer.
The Epidemiology of Cancer Risk by Alcohol Consumption Level
Laryngeal and oral cavity cancers occur in the upper aerodigestive system and are common among individuals that consume at least 10 g daily. Consuming this amount of alcohol daily increases the overall risk by 15%, especially in the case of oral cavity cancer. According to Bagnardi et al. (2014), increasing alcohol consumption by 12.5 g on a daily basis further infuriated the risk of laryngeal and pharyngeal cancer by 5.13 in the case of light and moderate drinking.
Oesophageal cancer is another outcome associated with increased alcohol consumption resulting in a type referred to as squamous cell carcinoma. Compared to non-drinkers, individuals consuming alcohol are 1.3 times and fivefold more prone to exposure to oesophageal cancer for both light and heavy drinkers, respectively. Bagnardi et al. (2014) highlighted differences in risk exposures based on factors such as geographical location as drinkers from Europe, North America and Asia showed high risks of squamous cell carcinoma. Individuals with a deficiency of the metabolic enzyme aldehyde dehydrogenase 2 also have higher risks of this type of cancer, especially if they indulge in drinking. The majority of the population in Eastern Asia tends to have the aldehyde dehydrogenase 2 variant, allele that escalates the risks of oesophageal cancer compared to those with carriers of the first variant common in other regions.
The multiplicative capability of cancer occurring in the upper section of the aerodigestive system is more profound amongst individuals consuming both cigarettes and alcohol compared to those indulging in alcohol alone. According to Wood et al. (2014), the risk of cancer is 14 times higher, especially amongst individuals that smoked at least 20 cigarettes and 3 alcoholic drinks daily compared to those that live healthy lifestyles. Individuals consuming alcohol and smoking cigarettes risk exposure to oesophageal cancer by 8 times compared to those that have never smoked or consumed at least 5 g of drinks daily.
The epidemiology of liver cancer suggests that regular heavy drinkers are at risk of getting intrahepatic cholangiocarcinoma and hepatocellular carcinoma type of cancer. The threshold of consumption from this type of risk is 10 g daily, which increases the risks, two times compared to individuals that refrain from alcohol. However, light and moderate drinkers, especially those that stick to a non-linear dosage, are at lower risks of exposure to liver cancer, especially when the consumption is lower than 10 g daily (Rumgay et al., 2021).
Increased alcohol intake increases the risks of breast cancer among people indulging in binge drinking on a daily basis. The case is similar for light to moderate drinkers as the risk escalates compared to non-drinkers. Rumgay et al. (2021) argued that moderate and heavy drinkers are most likely to increase their risk exposure to colorectal cancer by 1.2 and 1.5 times higher compared to their non-drinking counterparts.
Causal Inferences In Relation To Alcohol Consumption and Cancer
Overcoming the deterrents highlighted in the observational studies, Rumgay et al. (2021) proposed the need to incorporate the Mendelian randomization approach by integrating several genetic variants to identify the causal relationship between disease outcomes and the extent of exposures. Such a causal relationship test assumes that all the genetic variants are randomly distributed during birth, eliminating reverse causality. A Mendelian randomization approach using genetic information of 6000 patients with oropharyngeal and oral cavity cancer incorporated 6600 control tests to identify the existence of a relationship between alcohol consumption and cancer risk exposure. The findings showed a positive causal relationship between alcohol exposure and cancer risks (Gormley et al., 2020). However, the results also indicate that the estimates on the test for causality elicited some degree of exaggeration, especially in the association between oropharyngeal and oral cancer concerning alcohol consumption. A UK Biobank research based on a Mendelian randomization test elucidates that drinking alcohol above the stipulated threshold > 14 units weekly showed a causal relationship for breast, neck and head cancer (Ingold et al., 2019). Larsson et al. (2020) study used data drawn from the UK Biobank and failed to establish any relationship between exposure to alcohol and cancer, although the study highlighted minute variances emanating from the presence of single nucleotide polymorphism. Ong et al. (2020) did not find any significance in terms of the association between breast cancer and an increase of alcohol consumption on a daily basis.
Limitations of the Study
Several studies have sought to understand the association between alcohol consumption and the risks of occurrence of cancer incidences. According to Ronksley et al. (2011), observation from such research has identified predominant reverse causality, especially after the inclusion of the category of non-drinkers who were formally indulging in alcohol consumption still at the exposure of cancer risks. Other limitations in the research are associated with the adjustment of high risks behavior, such as the use of tobacco and alcohol consumption concurrently, which elevate the risk of laryngeal and oral cavity cancers. Rumgay et al. (2021) noted consistent limitations and concerns relating to the accuracy of data on alcohol exposure, which elicits a high degree of bias owing to the underreporting by the test subjects and lack of inclusion of heavy drinkers.
The study by Rumgay et al. (2021) identifies several limitations associated with the effects of the synergy between tobacco and alcohol consumption and the clinical manifestation of cancer, especially in the case of laryngeal and oral cavity cancers. For instance, the occurrence of liver cancer is not always attributable to alcohol consumption as it might arise from the influence of other elements such as aflatoxin exposure and infection such as hepatitis C or B. In Mongolia, at least 46% of liver cancer cases were associated with hepatitis B and C as opposed to alcohol consumption. Obesity is another co-factor that elevates the risk of cancer, although conditions such as hepatocellular carcinoma emanate from the interaction between obesity and alcohol (Rumgay et al., 2021). However, there is imperative we investigate the influence of social inequalities and other social determinants that heighten the risk of liver cancer. The elimination of relative risks that are population specific might have yielded skewed results in terms of cancer burden, especially for populations with the ALDH2*2 enzyme, which is popular in Eastern Asia.
Conclusion
Medical practitioners have identified at least 200 injuries, diseases and health conditions associated with alcohol attributed consumption. Despite having a great social and economic burden, mild to moderate alcohol consumption also escalates the risk of the upper and lower aerodigestive system, such as that of the rectum, colon, larynx, pharynx and oral cavity. Breast cancer and liver cancer can also emerge amongst women owing to the continued use of alcohol. At least 23,000 new cases are recorded annually, with 13% of the new health conditions attributed to alcohol-induced cancer. People who consume at least 10 g per day of alcohol contribute to at least a third of new cancer cases. The changing patterns of alcohol consumption also indicate new distributions in terms of alcohol-related cancer risks, with countries such as India, China and sub-Saharan Africa showing increased cancer incidents. Vulnerable and disadvantaged ethnic minorities are more prone to suffer from alcohol-inclined cancer.
The most common aerodigestive tract cancers, such as that of the laryngeal and oral cavity, are more prone amongst individuals consuming > 10 g daily. Consuming this amount of alcohol on a daily basis increases the overall risk by 15%, especially in the case of oral cavity cancer. The intrahepatic cholangiocarcinoma and hepatocellular carcinoma strains of liver cancer are predominant amongst heavy drinkers. The threshold for this cancer type is >10 g daily, with higher consumption rates resulting in extreme cases of liver cancer. Individuals consuming alcohol and smoking cigarettes risk exposure to oesophageal cancer by 8 times compared to those that have never smoked or consumed at least 5 g of drinks daily. The limitation in the research is associated with the adjustment of high risks behavior, such as the use of tobacco and alcohol consumption concurrently, which elevate the risk of laryngeal and oral cavity cancers.
References
Bagnardi, V., Rota, M., Botteri, E., Tramacere, I., Islami, F., Fedirko, V., & La Vecchia, C. (2015). Alcohol consumption and site-specific cancer risk: a comprehensive dose–response meta-analysis. British journal of cancer, 112(3), 580-593.
Gormley, M., Dudding, T., Sanderson, E., Martin, R. M., Thomas, S., Tyrrell, J., & Richmond, R. C. (2020). A multivariable Mendelian randomization analysis investigating smoking and alcohol consumption in oral and oropharyngeal cancer. Nature Communications, 11(1), 6071.
Ingold, N., Amin, H. A., & Drenos, F. (2019). Alcohol causes an increased risk of head and neck but not breast cancer in individuals from the UK Biobank study: A Mendelian randomisation analysis. medRxiv, 19002832.
Klein, W. M., Jacobsen, P. B., & Helzlsouer, K. J. (2020). Alcohol and cancer risk: clinical and research implications. Jama, 323(1), 23-24.
Larsson, S. C., Carter, P., Kar, S., Vithayathil, M., Mason, A. M., Michaëlsson, K., & Burgess, S. (2020). Smoking, alcohol consumption, and cancer: a mendelian randomisation study in UK Biobank and international genetic consortia participants. PLoS medicine, 17(7), e1003178.
Ong, J. S., Derks, E. M., Eriksson, M., An, J., Hwang, L. D., Easton, D. F., & MacGregor, S. (2021). Evaluating the role of alcohol consumption in breast and ovarian cancer susceptibility using population‐based cohort studies and two‐sample Mendelian randomization analyses. International Journal of Cancer, 148(6), 1338-1350.
Rehm, J., Gmel Sr, G. E., Gmel, G., Hasan, O. S., Imtiaz, S., Popova, S., & Shuper, P. A. (2017). The relationship between different dimensions of alcohol use and the burden of disease—an update. Addiction, 112(6), 968-1001.
Ronksley, P. E., Brien, S. E., Turner, B. J., Mukamal, K. J., & Ghali, W. A. (2011). Association of alcohol consumption with selected cardiovascular disease outcomes: a systematic review and meta-analysis. Bmj, 342, d671.
Rovira, P., & Rehm, J. (2021). Estimation of cancers caused by light to moderate alcohol consumption in the European Union. European Journal of Public Health, 31(3), 591-596.
Rumgay, H., Shield, K., Charvat, H., Ferrari, P., Sornpaisarn, B., Obot, I., & Soerjomataram, I. (2021). Global burden of cancer in 2020 attributable to alcohol consumption: a population-based study. The Lancet Oncology, 22(8), 1071-1080.
Wood, A. M., Kaptoge, S., Butterworth, A. S., Willeit, P., Warnakula, S., Bolton, T., & Thompson, S. (2018). Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies. The Lancet, 391(10129), 1513-1523.
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