Consumption of Whole-Grain Bread and Risk of Colorectal Cancer among Norwegian Women (the NOWAC Study).

Toril Bakken,Tonje Braaten,Eiliv Lund,Anja Olsen,Guri Skeie,Cecilie Kyrø

doi:10.3390/nu8010040

Toril Bakken, Tonje Braaten + Show 4 more

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https://doi.org/10.3390/nu8010040

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Abstract

There is evidence that consumption of foods containing dietary fiber decreases the risk of colorectal cancer (CRC). Whole grains contain dietary fiber, as well as a range of micronutrients and bioactive compounds, but the association between the consumption of whole grains and the risk of CRC remains less studied. The aim of the present study was to investigate the association between whole-grain bread consumption and CRC incidence among Norwegian women, using data from a prospective cohort study (the Norwegian Women and Cancer Study). Dietary intake was estimated from the food-frequency questionnaires of 78,254 women in the cohort (median age: 55 years), and these women were then followed up for CRC incidence. During the 9 years of median follow-up, 795 women were diagnosed with CRC (316 proximal, 193 distal, 218 rectal). Associations between whole-grain bread consumption and the risk of CRC (including colorectal subsites) were investigated using Cox proportional hazards regression models. When compared to the low consumption group, the hazard ratio for CRC was 0.89 (95% confidence interval (CI): 0.72–1.09) for the high consumption group and 0.86 (95% CI: 0.72–1.02) for the medium consumption group in a multivariable model. Overall, no association between whole-grain bread consumption and CRC was found.

Highlights

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men worldwide [1]
No association between whole-grain bread consumption and colorectal cancer (CRC) was found in this prospective cohort study of Norwegian women
When examining the colorectal subsites, whole-grain bread consumption tended to be weakly associated with risk of proximal colon cancer

Summary

Introduction

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men worldwide [1]. There is large geographical variation in CRC incidence across the world [1], with high incidence related to economic development [2]. In Norway, the incidence of colon cancer among women has almost tripled the last 55 years [3], and CRC incidence among women is one of the highest in the world [4]. Research Fund/American Institute for Cancer Research, there is convincing evidence that intake of foods containing dietary fiber decreases the risk of CRC [5], and studies have suggested that dietary fiber from cereal sources is especially associated with this lower risk [6,7]. While the association between dietary fiber intake and the risk of CRC has been investigated in many cohorts [5], the association with consumption of whole grains has been less studied. A meta-analysis [6] and a systematic review [11]

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