An analysis of the link between alcohol consumption and risk of cancer

Is it safe for someone to drink alcohol while undergoing cancer chemotherapy? Alcohol is produced by the fermentation of sugars and starches by yeast. Alcohol is also found in some medicines, mouthwashes, and household products including vanilla extract and other flavorings. This fact sheet focuses on cancer risks associated with the consumption of alcoholic beverages.

An analysis of the link between alcohol consumption and risk of cancer

Those levels specified corresponded to approximately two, four, and eight standard drinks per day, respectively. The effects of gender and differences i.

The RR indicates the strength of the relationship between alcohol consumption and a given type of cancer. A RR greater than 1. The greater the value over 1. The percent confidence intervals indicate the range of RR that is 95 percent likely to show a true RR.

An analysis of the link between alcohol consumption and risk of cancer

A statistically significant heterogeneity level indicates that results varied greatly among the various studies analyzed and that, therefore, an overall summary of average effect across studies must be interpreted with caution.

The RR describes the strength of the relationship between a variable e. The RR for the disease in people without the variable e. A RR among the people with the variable e. The greater the value, the greater the risk.

The curves shown here were obtained by fitting certain statistical models to the data from several studies i. Blue dotted lines indicate percent confidence intervals; that is, the range of RR that is 95 percent likely to show a true RR. For most of the tumor types included in the studies, the analysis found a dose- dependent increase in risk from alcohol consumption-that is, greater alcohol consumption was associated with a greater increase in risk.

Appreciably smaller, although still statistically significant at the 5-percent level,4 4Statistically significant means that the observed result would occur by chance under hypothesized conditions less than a specified proportion of the time usually 5 percent.

For all these types of cancer, significant increases in risk existed even at the lowest consumption level studied here i. In contrast, no significant relationship existed between alcohol consumption and the risk for pancreas, endometrial, and bladder cancers.

An analysis of the link between alcohol consumption and risk of cancer

With the exceptions of cancers of the ovary, prostate, and bladder, significant heterogeneity across studies existed for each type of cancer; this means that results vary greatly among the various studies analyzed, so an overall summary of average effect across studies must be taken with caution.

The researchers also investigated whether gender modified the effect of alcohol intake on the risk for each type of cancer. Statistically significant gender differences existed only for esophageal and liver cancer-where the alcohol-related risk was higher in women than in men-but not for other types of cancer.

The results of eight appropriate studies were pooled to determine the relationship between alcohol consumption and the risk of cancer at all sites combined.

This analysis found that alcohol consumption of at least 50 grams i. One limitation is that for most types of cancer included, the estimates of alcohol's effects tended to vary widely among the individual studies, making interpretation of the pooled data more difficult.

Part of this variability may result from differences in the characteristics of the subjects included in the studies. For example, the gender of the study participants may play a role because potential differences in alcohol breakdown i.

To control for this possibility, the investigators included separate analyses for men and women in their statistical models, where feasible. However, gender explained a significant portion of the observed variability in study results only for esophageal and liver cancer, but not for other types of cancers.

Another limitation of this and other meta-analyses is that alcohol consumption levels may have been systematically underreported in several studies, leading to biased RR estimates. The statistical power of this meta-analysis also is somewhat limited because, although it included more thancases, the numbers of cases for certain types of cancers e.

Similarly, for certain cancers, there were only a few cases with certain levels of alcohol consumption e. Furthermore, biases resulting from confounding factors may have affected the pooled estimates.

A confounding factor is a variable that is related to both the exposure variable e. For example, alcohol intake may appear to be positively associated with lung cancer but the actual association may be confounded by cigarette smoking, which is related with both alcohol intake because people who smoke also tend to drink and the risk of lung cancer.

One of the strengths of this meta-analysis is that the investigators performed a separate analysis of studies that also reported estimates adjusted for tobacco use, which contributes to various forms of cancer, prominently lung cancer.

Such analyses were conducted for most cancers of the upper airways and digestive tract, as well as for lung and bladder cancer. These analyses found that tobacco use had a substantial modifying effect not only on the alcohol-related risks for lung and bladder cancer but also on the risk for laryngeal cancer.

For example, when the investigators considered only studies reporting RRs not adjusted for tobacco use, the pooled RR for lung cancer at the highest level of alcohol consumption was 6.

When they excluded such studies from the analysis and considered only studies reporting estimates adjusted for tobacco use, however, the pooled RR declined to 1. This finding indicates that alcohol itself only weakly increases the risk for lung cancer and that lung cancer risk primarily results from tobacco use, which is common in heavy drinkers.

For laryngeal cancer, tobacco use also substantially influences the risk, though a strong association with alcohol consumption, indicated by a RR of 3.

The association between various levels of alcohol consumption and an increased risk of liver cancer remains difficult to interpret even with the pooled data used in this meta-analysis. This difficulty results from the fact that, as discussed earlier, the association between alcohol consumption and liver cancer is only indirect.

This change in consumption levels may lead to an underestimate of the real association.Link Policy context Effective interventions Policy priorities Position statements Evidence of a link between alcohol and cancer type.

Type of cancer Association with alcohol A meta-analysis of alcohol consumption and the risk of . 29 rows · Alcohol consumption has been linked to an increased risk for various types of cancer. A . Alcohol consumption has been linked to an increased risk for various types of cancer.

A combined analysis of more than studies assessing . Moderate alcohol consumption has been linked to an approximate % increased risk in breast cancer. Case-control and cohort studies have consistently observed this modest increase.

We highlight recent evidence from molecular epidemiologic studies and studies of intermediate markers like. 29 rows · Alcohol consumption has been linked to an increased risk for various types .

Feb 03,  · Alcohol is a risk factor for cancer of the oral cavity, pharynx, oesophagus, colorectum, liver, larynx and female breast, whereas its impact on other cancers remains controversial. A total of studies, including cancer cases, were identified. Relative risks (RRs) for heavy drinkers.

Alcohol Consumption and the Risk of Cancer