Dataset Information

Fiber Intake and Survival After Colorectal Cancer Diagnosis.

ABSTRACT:

Importance

Although high dietary fiber intake has been associated with a lower risk of colorectal cancer (CRC), it remains unknown whether fiber benefits CRC survivors.

Objective

To assess the association of postdiagnostic fiber intake with mortality.

Design, setting, and participants

A total of 1575 health care professionals with stage I to III CRC were evaluated in 2 prospective cohorts, Nurses' Health Study and Health Professionals Follow-up Study. Colorectal cancer-specific and overall mortality were determined after adjusting for other potential predictors for cancer survival. The study was conducted from December 23, 2016, to August 23, 2017.

Exposures

Consumption of total fiber and different sources of fiber and whole grains assessed by a validated food frequency questionnaire between 6 months and 4 years after CRC diagnosis.

Main outcomes and measures

Hazard ratios (HRs) and 95% CIs of CRC-specific and overall mortality after adjusting for other potential predictors for cancer survival.

Results

Of the 1575 participants, 963 (61.1%) were women; mean (SD) age was 68.6 (8.9) years. During a median of 8 years of follow-up, 773 deaths were documented, including 174 from CRC. High intake of total fiber after diagnosis was associated with lower mortality. The multivariable HR per each 5-g increment in intake per day was 0.78 (95% CI, 0.65-0.93; P = .006) for CRC-specific mortality and 0.86 (95% CI, 0.79-0.93; P < .001) for all-cause mortality. Patients who increased their fiber intake after diagnosis from levels before diagnosis had a lower mortality, and each 5-g/d increase in intake was associated with 18% lower CRC-specific mortality (95% CI, 7%-28%; P = .002) and 14% lower all-cause mortality (95% CI, 8%-19%; P < .001). According to the source of fiber, cereal fiber was associated with lower CRC-specific mortality (HR per 5-g/d increment, 0.67; 95% CI, 0.50-0.90; P = .007) and all-cause mortality (HR, 0.78; 95% CI, 0.68-0.90; P < .001); vegetable fiber was associated with lower all-cause mortality (HR, 0.83; 95% CI, 0.72-0.96; P = .009) but not CRC-specific mortality (HR, 0.82; 95% CI, 0.60-1.13; P = .22); no association was found for fruit fiber. Whole grain intake was associated with lower CRC-specific mortality (HR per 20-g/d increment, 0.72; 95% CI, 0.59-0.88; P = .002), and this beneficial association was attenuated after adjusting for fiber intake (HR, 0.77; 95% CI, 0.62-0.96; P = .02).

Conclusions and relevance

Higher fiber intake after the diagnosis of nonmetastatic CRC is associated with lower CRC-specific and overall mortality. Increasing fiber consumption after diagnosis may confer additional benefits to patients with CRC.

SUBMITTER: Song M

PROVIDER: S-EPMC5776713 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BACKGROUND & AIMS:Few studies have examined the association between coffee intake and survival after diagnosis of colorectal cancer (CRC). We performed a prospective study to investigate the association between coffee intake after a diagnosis of CRC and mortality. METHODS:We collected data from the Nurses' Health Study (1984-2012) and Health Professionals Follow-up Study (1986-2012), following 1599 patients diagnosed with stage 1, 2, or 3 CRC. CRC was reported on questionnaires and ascertained by review of medical records and pathology reports; intake of food and beverages was determined from responses to semi-quantitative food frequency questionnaires. Participants were asked how often during the previous year that they consumed coffee, with 1 cup as the standard portion size. The first questionnaire response collected at least 6 months but not more than 4 years after diagnosis was used for assessment of post-diagnostic intake (median time from diagnosis to the dietary assessment, 2.2 years). The last semi-quantitative food frequency questionnaire prior to diagnosis was used to assess pre-diagnostic dietary intake. RESULTS:During a median of 7.8 years of follow-up, we documented 803 deaths, of which 188 were because of CRC. In the multivariable adjusted models, compared with nondrinkers, patients who consumed at least 4 cups of coffee per day had a 52% lower risk of CRC-specific death (hazard ratio [HR] 0.48; 95% CI, 0.28-0.83; P for trend=.003) and 30% reduced risk of all-cause death (HR, 0.70; 95% CI, 0.54-0.91; P for trend <.001). High intake of caffeinated and decaffeinated coffee (2 or more cups/day) was associated with lower risk of CRC-specific mortality and all-cause mortality. When coffee intake before vs after CRC diagnosis were examined, compared with patients consistently consuming low amounts (less than 2 cups/day), those who maintained a high intake (2 or more cups/day) had a significantly lower risk of CRC-specific death (multivariable HR, 0.63; 95% CI, 0.44-0.89) and death from any cause (multivariable HR, 0.71; 95% CI, 0.60-0.85). CONCLUSIONS:In an analysis data from the Nurses' Health Study and Health Professionals Follow-up Study, we associated intake of caffeinated and decaffeinated coffee after diagnosis of CRC with lower risk of CRC-specific death and overall death. Studies are needed to determine the mechanisms by which coffee might reduce CRC progression.