Quality of diet and its determinants in people at increased risk of colorectal cancer

Unhealthy diet-related behaviour is linked to an increased risk of colorectal cancer (CRC) and therefore people at increased-risk of CRC are advised to follow healthy dietary recommendations. Assessing disparities in diet quality based on sociodemographic factors could help to tailor dietary interventions (1) . We aimed to determine the relationship between diet quality and sociodemographic factors in people at increased risk of CRC. This was a cross-sectional study including adults at increased risk of CRC due to a prior history of colorectal neoplasia and/or a known significant family history of CRC. Participants completed a survey including the Australian Eating Survey (AES) (2) , and collection of demographic characteristics including age, gender, education, and socioeconomic indices (SEI) from Oct 2023 to July 2024. The AES survey was used to calculate diet quality using the Australian Recommended Food Score (ARFS) (2) . The ARFS was calculated by summing the eight sub-scales that includes vegetables, protein foods, breads/cereals, dairy foods, water, and spreads/sauces. The total ARFS ranges from 0–73, with a higher score indicating a higher diet quality. Associations between diet quality and sociodemographic factors were determined using a log Poisson regression model with robust variance estimation. 1940 individuals (52% female) completed the survey. The median age was 67.44 years (IQR: 59.56 ± 72.66), with 11.49% (n = 223) aged under 50 years, 86.0% (n = 1669) aged 50–79 years and 2.5% (n = 48) aged over 79 years. The mean (± SD) ARFS was 28.76 ± 10.48 points. The ARFS did not significantly differ with gender (males: 29.0 ± 10.57; females: 28.6 ± 10.36), family history of CRC (family history: 28.7 ± 10.55; no family history: 28.8 ± 10.44), or SEI (higher tertile: 28.76 ± 10.41; lower tertile: 28.92 ± 10.65) (p > 0.05). Diet quality was associated with age, with ARFS lower in younger (18–49y) (28.72 ± 10.18) than older (80–89y) participants (31.19 ± 8.5) (p < 0.05). Regarding dietary components, dairy intake was lower in females than males (Relative Risk (RR) = 0.94, 95% confidence interval (CI) 0.90–0.99), while individuals with the middle SEI tertile had lower fruit intake compared with the highest tertile (RR = 0.94, 95% CI 0.84–0.99), and those left school before year 12 had lower vegetable intake, compared to those with tertiary education (RR = 1.07, 95% CI 1.01–1.13). This study has shown that individuals at elevated risk for CRC have a quality of diet that is poorer than the general population, with greater disparities seen in young individuals. Further differences were observed in dairy, vegetable and fruit intakes based on sex, education, and socioeconomic status. There is a need for further promotion of dietary interventions in people at elevated risk for CRC.