Background and aims: The risk of developing colorectal cancer (CRC) can be modified by diet- and lifestyle related factors such as intake of red meat, dietary fiber and alcohol, as well as obesity. These risk factors may also increase the risk of recurrence, secondary cancers and comorbidity. The prevalence of obesity and the habitual diet of CRC patients directly prior to diagnosis is, however, not well characterized. Thus, the aim of this thesis was to characterize BMI and dietary intake of red meat, dietary fiber and alcohol in CRC patients prior to diagnosis, in order to provide new knowledge about secondary prevention in CRC survivors.
Methods: This thesis comprises interim analyses from a large clinical trial in CRC survivors aged 50-75 years. All patients included in this trial between March 2012 and February 2013, who completed the dietary assessment, were included in this thesis (n = 26, (10 men and 16 women)). Anthropometrics and dietary data were assessed pre-surgery. Dietary data were assessed by a semi-quantitative food frequency questionnaire, and subsequently compared to the current Norwegian dietary guidelines and an age-matched reference group. Also, correlation coefficients were calculated between dietary intake, BMI and participant characteristics.
Results: Median BMI of 27.9 kg/m2 was significantly higher in the CRC group compared to an age-matched healthy Norwegian population (p<0.05). These differences in BMI were most prominent in men. The median waist-hip ratio met the definition of abdominal obesity in both genders, and 62 % and 23 % of the patients were classified as overweight and obese, respectively, according to BMI. CRC patients had a higher consumption of non-processed red meat (p<0.05), dietary fiber (p<0.05) and alcohol (p<0.001) compared to the reference population. Furthermore, the intake of red meat was higher than recommended in the current Norwegian dietary guidelines, while intake of dietary fiber was within the recommended range. Intake of alcohol was under the maximum recommendation for 77% of the CRC population.
Conclusion: In our CRC population, a large proportion of the patients were classified as overweight or obese, the intake of red meat was high, while the intake of dietary fiber was generally within recommendations, and the intake of alcohol was high only for a subgroup of the population. These results indicate that overweight and intake of red meat might be the most important risk factors to target in follow-up and lifestyle interventions in Norwegian CRC patients.