A Prospective Analysis of Red and Processed Meat Intake in Relation to Colorectal Cancer in the Black Women's Health Study

Abstract

Background Black Americans have the highest incidence of colorectal cancer (CRC) of any racial/ethnic group in the US. High intake of red and processed meats has been associated with an increased CRC risk in predominately White populations. However, three prior studies in Black populations, who have been reported to have high intake of red and processed meats, have reported no association. Data on a possible association with CRC risk of saturated and monounsaturated fatty acids, the primary types of fat in red and processed meat, are inconclusive. Objective We prospectively assessed intakes of processed and unprocessed red meat and saturated and monounsaturated fatty acids in relation to CRC risk, utilizing data from the Black Women's Health Study (BWHS, 1995–2018). Methods Dietary data were derived from validated food frequency questionnaires completed in 1995 and 2001. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression. Results Among 52,695 BWHS participants aged 21–69 at baseline and followed for up to 22 years, 564 women developed incident CRC. Unprocessed red meat intake was associated with a 33% increased CRC risk per 100 g/d (HR = 1.33, 95%CI: 1.03–1.71). Examining CRC anatomic sites, unprocessed red meat was associated with 2-times increased rectal cancer risk (HR = 2.22, 95% CI: 1.15–4.26). There was no evidence of an interaction with age (pinteraction = 0.4), but unprocessed red meat intake was only associated with a significant increased risk of late-onset CRC (≥50 years of age, HR = 1.38, 95%CI: 1.04–1.83). Processed red meat and total saturated and monounsaturated fatty acid intakes were not associated with CRC risk. Conclusions Unprocessed red meat intake was associated with an increased CRC risk in the present study, the first positive evidence that red meat plays a role in the etiology of CRC in Black women. The findings suggest prevention opportunities.

Red and Processed Meat Consumption: What's at Stake?

“…In the current analysis of the Black Women's Health Study, a 100-g/d higher intake of (unprocessed) red meat, about 1 small steak, was associated with a 33% (95% CI: 3%, 71%) higher risk of colorectal cancer ( 4 ). The point estimate is somewhat higher—albeit with a fairly wide confidence interval—than the summary estimate from the meta-analysis used to inform the WCRF judgment [per 100-g/d higher intake of red meat: 12% (95% CI: 6%, 25%) higher risk of colorectal cancer, n = 6662 cases of colorectal cancer] ( 1 ).…”

“…Indeed, most of the nutritional epidemiology literature on various diet–disease relations comes from cohort studies in predominantly white populations, mostly from Europe and North America. The investigation of the relation between meat and colorectal cancer in the Black Women's Health Study by Yiannakou et al ( 4 ), in this issue of the Journal of Nutrition , is therefore a welcome addition to the body of evidence.…”

“…In 1995, >50,000 women were recruited into the Black Women's Health Study, which was set up to investigate risk factors for disease in US black women. Diet was assessed via Food Frequency Questionnaire (FFQ) at baseline, and women have been followed for >20 y, during which time 564 incident cases of colorectal cancer occurred ( 4 ). Diet was reassessed in 2001, and this second measurement was used in the analysis by Yiannakou et al ( 4 ) to reduce the impact of measurement error and true changes in intake over time.…”

“…Diet was assessed via Food Frequency Questionnaire (FFQ) at baseline, and women have been followed for >20 y, during which time 564 incident cases of colorectal cancer occurred ( 4 ). Diet was reassessed in 2001, and this second measurement was used in the analysis by Yiannakou et al ( 4 ) to reduce the impact of measurement error and true changes in intake over time. This is important as relying only on baseline measures of diet (or any exposure) tends to bias associations with disease toward the null ( 5 ).…”

“…For processed meat, the results from the Black Women's Health Study were null but with wide confidence intervals that encompass the summary estimate from the WCRF meta-analysis [Black Women's Health Study: per 50-g/d higher intake, ∼2 rashers of bacon: 1.02 (95% CI: 0.83, 1.26) ( 4 ); WCRF per 50-g/d higher intake: 1.16 (95% CI: 1.08, 1.26), n = 10,738 cases] ( 1 ).…”