Diet and colorectal cancer in UK Biobank: a prospective study.

Kathryn E Bradbury,Timothy J Key,Neil Murphy

doi:10.1093/ije/dyz064

Abstract

BackgroundMost of the previous studies on diet and colorectal cancer were based on diets consumed during the 1990s.MethodsWe used Cox-regression models to estimate adjusted hazard ratios for colorectal cancer by dietary factors in the UK Biobank study. Men and women aged 40–69 years at recruitment (2006–10) reported their diet on a short food-frequency questionnaire (n = 475 581). Dietary intakes were re-measured in a large sub-sample (n = 175 402) who completed an online 24-hour dietary assessment during follow-up. Trends in risk across the baseline categories were calculated by assigning re-measured intakes to allow for measurement error and changes in intake over time.ResultsDuring an average of 5.7 years of follow-up, 2609 cases of colorectal cancer occurred. Participants who reported consuming an average of 76 g/day of red and processed meat compared with 21 g/day had a 20% [95% confidence interval (CI): 4–37] higher risk of colorectal cancer. Participants in the highest fifth of intake of fibre from bread and breakfast cereals had a 14% (95% CI: 2–24) lower risk of colorectal cancer. Alcohol was associated with an 8% (95% CI: 4–12) higher risk per 10 g/day higher intake. Fish, poultry, cheese, fruit, vegetables, tea and coffee were not associated with colorectal-cancer risk.ConclusionsConsumption of red and processed meat at an average level of 76 g/d that meets the current UK government recommendation (≤90 g/day) was associated with an increased risk of colorectal cancer. Alcohol was also associated with an increased risk of colorectal cancer, whereas fibre from bread and breakfast cereals was associated with a reduced risk.

Highlights

Most of the previous studies on diet and colorectal cancer were based on diets consumed during the 1990s
The objective of the current study is to systematically examine the associations of colorectal-cancer risk with the intake of foods and food groups included in the short foodfrequency touchscreen questionnaire: meat, fish, fruit, vegetables, milk, cheese, alcohol, tea and coffee, as well as fibre intake, and to use re-measured dietary intakes to quantify the risk at actual levels of intake in UK Biobank
When we examined the source of fibre, intake of fibre from bread and breakfast cereals was associated with a reduced risk of colorectal cancer [hazard ratios (HRs) for the highest vs lowest fifth of intake 1⁄4 0.86 (0.76–0.98), Ptrend 1⁄4 0.005]

Summary

Introduction

Most of the previous studies on diet and colorectal cancer were based on diets consumed during the 1990s. Conclusions: Consumption of red and processed meat at an average level of 76 g/d that meets the current UK government recommendation (90 g/day) was associated with an increased risk of colorectal cancer. The evidence that red meat increases the risk and that dairy products, wholegrains and foods containing dietary fibre reduce risk was judged as probable. Many of the large previous studies were based on dietary intakes in the 1990s5–7 and food-supply data indicate that meat consumption has changed from the 1990s, with a much higher proportion of total meat supply in Europe and the USA coming from poultry as opposed to beef and pork.[8] it is not certain whether previous risk estimates are relevant to current eating patterns

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