It has been well documented that alcohol consumption is a strong risk factor for oral cancer, as well as other upper alimentary tract cancers, especially if it is combined with smoking. Alcoholic beverages are chronic irritants to the throat, specifically on the oral and pharyngeal mucosa, which leads to chronic inflammation and the release of problematic free radicals and cytokines. These free radicals can cause chain reactions with other compounds within the body, resulting in an increased risk for malignant tumors.
The ethanol in the alcoholic beverage, though alone is not dangerous, can metabolize and produce acetaldehyde, a mutagen and carcinogen, which binds directly to DNA and transcription factor proteins, which ultimately lead to tumor development and growth. Alcohol consumption also changes the metabolic and hormonal equilibrium in the body, sometimes with positive implications for human health. Mild to moderate alcohol consumption has been shown to reduce the prevalence of metabolic syndrome, Type-2 Diabetes, and cardiovascular disease.
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For post-menopausal women, moderate alcohol consumption has been shown to have cardiovascular health benefits, by decreasing coagulation activity, improving dyslipidemia and antioxidant capacity, in addition to improving estrogen levels in the body. For men (middle-aged), no alcohol or heavy alcohol consumption are risks for insulin resistant states, while moderate alcohol consumption decreases this risk following a U-like relationship. In the elderly, lifetime alcohol consumption is associated with increased risk of Type-2 Diabetes, cardiovascular disease, as well as other diseases in a U-shaped relationship. Conversely, in the elderly, moderate alcohol consumption is associated with a lower risk of morbidity and mortality (no or excessive consumption leads to a higher risk).
In regards to oral cancer, the disease is more frequent among those with insulin resistant Type-2 Diabetes. Some evidence has shown that moderate alcohol intake may reduce overall cancer risk in postmenopausal women by increasing insulin sensitivity, and maybe also increasing estrogen protection.
The aim of the study presented today, which was published last year, was to clarify the information in the literature regarding the dose-related risk of alcohol consumption for oral cancer by examining both male and female non-smoker patients.
Methods
A total of 608 non-smoking inpatients with histologically confirmed squamous cell oral carcinomas were included in this study (466 men and 142 women). 264 men and 142 women were used as tumor-free controls.
Data was collected via questionnaires and case reports.
For each female cancer patient, an aged-matched control was used (within 6 months of age difference). For each male cancer patient, an aged-matched control was used (within 1 year age difference).
Participants were considered as “non-smokers” if they had never smoked at all, or if they haven’t smoked in 10 or more years.
Alcohol consumption habits were recorded, including how much and what type of alcohol was consumed. Those drinking only on special occasions were considered non-drinkers. Participants were considered moderate consumers if they drank less than 25g of alcohol per day (1 bottle of beer, 2dl of wine, or 0.5dl of spirits). Participants consuming greater than 25g of alcohol per day were considered excessive drinkers.
Blood glucose levels were measured for all participants. Those with glucose levels of 5.6mmol or higher were considered insulin resistant. No Type-1 Diabetes patients participated in this study. For postmenopausal women, ratios of postmenopausal cases and the mean onset of menopause were calculated for both cancer and control groups.
Results
- The mean age of female cancer patients upon admission was significantly higher than the mean age of male cancer patients.
- In the male cancer group, 41.8% were excessive drinkers, and 7.1% were moderate drinkers.
- In the male control group, 23.4% were regular drinkers, though out of those, the majority were excessive drinkers.
o In men, excessive alcohol consumption was found to be a risk factor for oral cancer.
- In the female cancer group, the rate of regular alcohol consumption was significantly lower than the male cancer group (15.4% versus 48.9%).
- In the female cancer group, excessive consumption was predominant (12.6%) and moderate consumption was low (2.8%).
- In the female control group, excessive and moderate alcohol consumption rates were both low (2.1% and 4.2%).
o In women, excessive alcohol consumption was found to be a risk factor for oral cancer.
o In women, moderate alcohol consumption lowered the risk for oral cancer.
- Elevated blood glucose levels were similar between males with cancer and males in the control group.
- Elevated blood glucose levels were significantly higher for females with cancer compared with female controls (58.4% versus 42.2%).
o Elevated blood glucose levels are a risk factor for oral cancer in women.
- Mean age at menopause was significantly lower for females with cancer compared to their cancer-free controls (45.4 years versus 51.3 years).
Conclusions
The results of this study showed that in women, consumption of alcohol is a very important risk factor for oral cancer. At lower levels of alcohol consumption, the results showed that men retain a moderate risk of oral cancer, whereas women actually have a reduced risk of developing the disease. At higher levels of alcohol consumption, both men and women showed increased risk for oral cancer.
Why is there this difference between the sexes? The authors speculated that these differences may be explained by the menopausal and hormonal changes that occurred in the women of the cancer group. They claim that moderate alcohol consumption may reduce this risk of cancer in postmenopausal women by increased insulin sensitivity, or through increased estrogen levels. Since studies have shown that insulin resistance in a high cancer risk factor for women, particularly after menopause, then increased insulin sensitivity caused by moderate alcohol consumption may be a justified therapy for reducing the cancer risk.
One thing I would have liked to have seen from this study is a breakdown of the different types of alcohol consumed. Will any type of alcohol consumed moderately reduce the risk of oral cancer in postmenopausal women? Or do wine, beer, and/or spirits act differently in the body? The authors indicated that this data was collected; however, they never appeared to do any analysis with it. For example, we’ve seen from previous studies presented on this blog that different types of alcoholic beverages act differently in the body in regards to Alzheimer’s risk: specifically, those drinking mixed alcoholic beverages showed more negative effects on mental status than those consuming wine alone or beer alone. What about oral cancer and types of alcohol consumed?
I’d also be curious how these results change when compared with patients who are smokers. Does smoking change this supposed reduced risk of oral cancer found in postmenopausal women? Or does smoking “override” these benefits and there is increased risk no matter how much or how little alcohol is consumed?
I’d love to hear what you all think about this study, the results/methods/conclusions/what have you. Please leave your comments below (no html tags, please).
Source: Takács, D., Koppány, F., Mihályi, S., and Suba, Z. 2011. Decreased oral cancer risk by moderate alcohol consumption in non-smoker postmenopausal women. Oral Oncology 47: 537-540.
DOI: 10.1016/j.oraloncology.2011.04.003
I am not a health professional, nor do I pretend to be. Please consult your doctor before altering your alcohol consumption habits. Do not consume alcohol if you are under the age of 21. Do not drink and drive. Enjoy responsibly!