Fish Intake and Polyunsaturated Fatty Acids in Relation to Colorectal Cancer Risk in the Black Women's Health Study.

Background: Black Americans have the highest colorectal cancer (CRC) incidence and mortality rates of any racial/ethnic group in the United States. Diets high in fish consumption and long-chain n-3 (ω-3) polyunsaturated fatty acids (PUFAs) have been associated with reduced risk of CRC. Black Americans have higher overall fish consumption than White Americans but are more likely to consume fish that are lower in n-3 PUFAs.

Objectives: We prospectively assessed fish intake and PUFAs in relation to risk of CRC, using data from the Black Women's Health Study (1995-2021).

Methods: Dietary data were collected from validated food frequency questionnaires completed by participants in 1995 and 2001. Cox-proportional hazards regression models were utilized to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between fish/PUFA intake and incident CRC. Models were adjusted for total caloric intake, fruit/vegetable intake, and red meat intake, among other factors.

Results: Among 52,690 Black women aged 21-69 y at baseline, 687 women developed incident CRC over 24 y of follow-up. High intake of baked fish (>8.09 g/1000 kcal), compared with low intake (<0.38 g/1000 kcal), was associated with a 26% reduced risk of incident CRC (HR_{Q4 v Q1} = 0.74; 95% CI: 0.57, 0.96; P_trend = 0.058), which was notable for proximal colon cancer (HR_{Q4 v Q1} = 0.56; 95% CI: 0.36, 0.86; P_trend = 0.038). No associations between PUFA intakes and overall CRC risk were found. The HR for n-3 PUFA intake in relation to proximal colon cancer risk was 0.61 (95% CI_{Q4 v Q1}: 0.39, 0.93; P_trend = 0.025).

Conclusions: We found that high intake of baked fish was associated with a decreased CRC risk. This finding suggests that increasing baked fish intake could be a valuable strategy for CRC prevention among Black women.