Specific botanical groups of fruit and vegetable consumption and liver cancer and chronic liver disease mortality: a prospective cohort study

Background: Beyond alcohol and coffee, the relationship between other dietary factors, including specific vegetables and fruits, and liver outcomes remains poorly understood.

Objective: To evaluate the associations between fruit and vegetable intake with the risk of liver cancer and chronic liver disease (CLD) mortality.

Methods: This study was based on the National Institutes of Health-American Association of Retired Persons Diet and Health Study, including 485,403 participants aged 50-71 y from 1995 to 1996. Fruit and vegetable intake was estimated using a validated food frequency questionnaire. Cox proportional hazards regression was used to estimate the multivariable hazard ratios (HR) and 95% confidence intervals (CI) for liver cancer incidence and CLD mortality.

Results: During a median follow-up of 15.5 y, 947 incident liver cancers and 986 CLD deaths (other than liver cancer) were confirmed. A higher intake of total vegetables was associated with a lower risk of liver cancer (HR_{Quintile 5 vs. Quintile 1} = 0.72, 95% CI: 0.59, 0.89; P_trend < 0.001). When further subclassified into botanical groups, the observed inverse association was mainly driven by lettuce and the cruciferous family (broccoli, cauliflower, cabbage, etc.) (P_trend < 0.005). Additionally, higher total vegetable intake was associated with a lower risk of CLD mortality (HR_{Quintile5 vs. Quintile1} = 0.61, 95% CI: 0.50, 0.76; P_trend < 0.001). Inverse associations were observed for lettuce, sweet potatoes, cruciferous vegetables, legumes, and carrots with CLD mortality (all P_trend < 0.005). In contrast, total fruit intake was not associated with liver cancer or CLD mortality.

Conclusions: Higher intakes of total vegetables, especially lettuce and cruciferous vegetables, were associated with lower liver cancer risk. Higher intakes of lettuce, sweet potatoes, cruciferous vegetables, legumes, and carrots were associated with a lower risk of CLD mortality.