Oesophageal cancer risk related to higher genetically predicted coffee consumption

1st September 2022

Oesophageal cancer risk is causally associated with genetically-predicted coffee consumption and this effect might be temperature-related

Oesophageal cancer risk is associated with genetically predicted coffee consumption even after adjustment for factors such as body mass index (BMI), smoking initiation and alcohol intake according to the findings of a Mendelian randomisation study by UK and Swedish researchers.

Coffee drinking has been found to have a wide range of health benefits including a reduced risk of cardiovascular disease and cancer. Coffee contains a wide range of compounds, some of which including kahweol that has been reported to exert anti-cancer properties. Moreover, coffee has been associated with a significant decrease in the risk of colorectal cancer and colon cancer with a higher intake of the beverage also linked to a lower risk of prostate cancer. Nevertheless, much of the data has been derived from epidemiological studies which can be subject to confounding and reverse causality, i.e., where the direction of causality between to factors is the opposite of what might be expected. A Mendelian randomisation (MR) study is designed to avoid the problems due to confounding and reverse causality and assesses whether the genetically-predicted levels of a risk factor, for instance, coffee consumption, and a disease outcome, such as oesophageal cancer are associated. Since genetic variants are present at birth, MR studies reduce the potential for reverse causality and confounding and are therefore more likely to generate a causal interpretation.

In the present study, researchers investigated the association of genetically-predicted coffee consumption and the risk of 22 different cancers which, for example, included those affecting the ovary, thyroid and bladder. There were a total of 15 single nucleotide polymorphisms (SNPs) identified to be associated with coffee consumption although only 12 of these were used in the analysis. Most of the SNPs were in gene regions (one for example was near a locus linked to the smell/test perception of coffee) that were likely to affect coffee drinking behaviour or behaviour indirectly by altering the metabolism of caffeine. The researchers tested the association using data from the UK Biobank and also tested these for replication in the FinnGen consortium. The results were then adjusted for differences in genetically-predicted body mass index, smoking and alcohol consumption. The effect sizes of the associations between genetically-predicted coffee consumption and cancer risk were scaled to a 50% increase in coffee consumption.

Oesophageal cancer risk and coffee consumption

Using a sample of 367,561 European participants, 59,647 had one of the 22 site-specific cancers. However, genetically-predicted coffee consumption was not associated with the risk of any cancer in the main analysis (odds ratio, OR = 1.05, 95% CI 0.98 – 1.14, p = 0.183) even after adjustment for BMI, smoking and alcohol intake.

But when the team looked at digestive system cancers overall, there was an increased risk (OR = 1.28, 95% CI 1.09 – 1.51, P = 0.003) and which remained significant after adjustment for BMI, smoking initiation and alcohol consumption. This higher risk was largely driven by oesophageal cancer (OR = 2.79, 95% CI 1.73 – 4.50) in the Biobank and remained after adjustment for the effect of BMI, smoking and alcohol intake. In the FinnGen consortium, genetically predicted coffee consumption was associated with a non-significant increase in oesophageal cancer (OR = 2.01, 95% CI 0.57 – 7.05, p = 0.27) and which was attenuated after adjustment for BMI. Coffee consumption was also associated with an increased risk of multiple myeloma in the Biobank data (OR = 2.25) even after adjustment and a reduced risk of ovarian cancer.

Interestingly, when the researchers looked at coffee consumption and individual’s preferences for drinking, they found that a preference for drinking warm (OR = 2.74) and hot (OR = 5.45) coffee was also significantly associated with a higher risk of oesophageal cancer but, surprisingly, not for very hot. In a further subgroup analysis based on self-reported coffee intake, the risk of oesophageal cancer was similar among those drinking 1 – 3 cups/day compared with those who did not drink coffee and which the authors suggested might be due to consumption of tea.

The authors concluded that their study found evidence that coffee consumption was causally associated with a risk of oesophageal cancer and that there was some evidence that this was related to a temperature effect.

Citation
Carter P et al. Coffee consumption and cancer risk: a Mendelian randomisation study Clin. Nutr 2022

Study suggests increased coffee consumption lowers rate of kidney function decline in diabetics

11th May 2022

A higher level of coffee consumption in type 2 diabetics significantly reduces the rate of decline in estimated glomerular filtration rate

A greater coffee consumption in those with type 2 diabetes is significantly associated with a reduction in the rate of decline in the estimated glomerular filtration rate (eGFR). This was the key finding from a prospective study by researchers from the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

Chronic kidney disease (CKD) is a non-communicable disease and which usually develops as a consequence of diabetes and hypertension. Disease severity in CKD can be assessed by a low serum creatinine-based eGFR, which indicates excretory kidney function and by a raised urinary albumin. Lifestyle management is deemed to be a fundamental aspect of diabetes care and this encompasses self-management education and support, medical nutrition therapy, physical activity, smoking cessation counselling and psychosocial care. Nutritional therapy, however, does not just include what foods to eat but also what should be drunk. One commonly consumed beverage is coffee and a higher coffee consumption, as well as green tea, has been found to be associated with a reduction in all-cause mortality, particularly in patients with type 2 diabetes. Furthermore, some data suggests that a higher coffee consumption is associated with lower risk for incident CKD. Nevertheless, this finding is not consistent, with other work undertaken in men, find that there was no significant association between coffee consumption and CKD.

What remains unclear though, is if a higher level of coffee consumption in patients with type 2 diabetes would reduce the decline in kidney function. For the present study, the Japanese team carried out a prospective study of adult diabetic patients attending diabetic clinics throughout the country. They carried out a dietary survey which asked about coffee consumption but also had access to clinical measurements such as blood pressure and eGFR taken at the clinics. Coffee consumption was recorded as none, less than 1 cup/day, one cup/day or two or more cups/day. The primary outcome was set as a decline in eGFR to <60 mL/min/ 1.73 m2, based on two consecutive measures of eGFR during the follow-up period.

Coffee consumption and decline in eGFR rate

In total, 3,805 patients with type 2 diabetes and a mean age of 64.2 years (44.4% female) and eGFR ≥60ml/min/1.73 m2 were followed-up for a median of 5.3 years.

During the period of follow-up, 840 participants experienced a decline in eGFR of < 60 mL/min/1.73 m2. Using multivariate analysis, the researched found that compared to those who drank no coffee, the adjusted hazard ratio (aHR) for a decline in eGFR associated with drinking less than one cup/day was 0.77 (95% CI 0.63 – 0.97) and this increased slightly to 0.75 (95% CI 0.62 – 0.91) for those drinking two or more cups/day.

The mean eGFR change per year was -2.16ml/min/1.73 m2 with no coffee consumption, and -1.78ml/min/1.73 m2 with two or more cups per day (p for trend 0.03).

There was also no significant effect on coffee drinking and the decline in eGFR based on age, gender, body mass index, smoking status, those who exercised regularly or blood pressure.

The authors concluded that coffee consumption is significantly associated with a lower risk of a decline in eGFR, which suggested a progressive impairment in renal function, in patients with type 2 diabetes.

Citation
Komorita Y et al. Relationship of coffee consumption with a decline in kidney function among patients with type 2 diabetes: The Fukuoka Diabetes Registry J Diabetes Investig 2022