The Paper of the Month for January is from the British Journal of Nutrition and is entitled 'Joint association of alcohol consumption and adiposity with alcohol- and obesity-related cancer in a population sample of 399,575 UK adults'  by Elif Inan-Eroglu and Peter Sarich.

Excess body weight and alcohol consumption are both modifiable risk factors for many adverse health outcomes, including cancer. Alcohol is classified as Group 1 carcinogen by the International Agency for Research on Cancer (IARC), and alcohol consumption is associated with a higher incidence of seven cancer types. Excess body weight is also associated with at least 13 cancer types. Although these factors have been known to be linked with cancer for many years, very few studies have investigated the joint association between alcohol consumption and excess body weight with cancer risk.

As part of a collaboration between the Charles Perkins Centre and the Daffodil Centre at the University of Sydney, we aimed to investigate the joint effect of alcohol consumption and adiposity on the risk of cancer using the UK Biobank. We used a sample of almost 400,000 participants aged between 40-69 years who did not have cancer at baseline. Alcohol consumption at baseline was self-reported as the number of UK units consumed per week and the participants were grouped as never drinkers, previous drinkers, within guideline drinkers (up to 14 units per week) and above guideline drinkers (greater than 14 units per week). We measured three different markers of excess body weight: body fat percentage, waist circumference and body mass index.

Over a follow-up period of 12 years, 61,898 participants developed cancer - 17,617 were alcohol-related cancers and 20,214 were obesity-related cancers. Participants who drank alcohol above the level recommended by UK guidelines, and who were classified as overweight or obese, had the highest risk of developing cancer overall. We found that across all markers of excess body weight, participants with higher adiposity levels who drank more than the recommended guidelines, were at greater risk of cancer. Compared to participants who never drank alcohol and had the lowest body fat percentage, those in the highest body fat percentage tertile who drank within the recommended alcohol guidelines were 53% more likely to develop alcohol-related cancers; while those who drank above alcohol guidelines were at 61% greater risk.

Regardless of alcohol intake, we identified a dose-response relationship between higher waist circumference and the risk of developing obesity-related cancer. People with larger waistlines who drank more than the recommended alcohol level had a 17% greater risk of developing obesity-related cancer compared to those with a healthy waist measurement (< 80 cm for women, < 94 cm for men) who never drank; while risk for participants in the group with the highest waist circumference who drank above alcohol guidelines, was 28% higher.

We found that excess body weight may exacerbate the harmful effect of alcohol on cancer risk, strengthening the evidence for the importance of limiting consumption of alcohol and maintaining a healthy weight to reduce cancer risk. This effect was above and beyond the impact of each risk factor individually. The World Cancer Research Fund (WCRF) recommends that for cancer prevention, it is best not to consume alcohol, and that if people choose to drink, to follow the national guidelines of no more than 14 drinks per week, spread over at least three days. The WCRF also recommends that for cancer prevention, people should keep their weight within the healthy weight range (body mass index 18.5 to 24.9 kg/m2, and waist circumference of < 80 cm for women and < 94 cm for men) and avoid weight gain in later life.

This study is now published in the British Journal of Nutrition: Inan-Eroglu E, Huang B, Sarich P, Nassar N, Stamatakis E. Joint associations of alcohol consumption and adiposity with site-specific cancer in a population sample of 399,575 UK adults. Br J Nutr. 2022.

Elif Inan-Eroglu and Peter Sarich.