Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk.
Level 4 - case-series / case-control
Hospital-based case-control study
PubMed 18398034 · doi:10.1158/1055-9965.EPI-07-2502
What was done
This hospital-based case-control study evaluated 275 individuals with incident primary bladder cancer and 825 cancer-free controls. Researchers assessed prediagnostic dietary intake of raw and cooked cruciferous vegetables, total vegetables, and fruit. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression adjusted for smoking status and other bladder cancer risk factors.
What was found
Raw cruciferous vegetable consumption was significantly inversely associated with bladder cancer risk (adjusted OR for highest vs. lowest category = 0.64; 95% CI, 0.42–0.97; P for trend = 0.003). In contrast, no significant associations were found for fruit, total vegetable intake, or total cruciferous vegetable intake. Similar inverse associations were observed for individual raw crucifers. Among current smokers and heavy smokers consuming three or more servings per month of raw cruciferous vegetables, risk was significantly reduced (adjusted OR = 0.46, 95% CI, 0.23–0.93 for current smokers; adjusted OR = 0.60, 95% CI, 0.38–0.93 for heavy smokers).
Why it matters
These findings suggest that preparation method influences the chemopreventive potential of cruciferous vegetables, consistent with biological mechanisms where cooking degrades bioactive isothiocyanates.
Limits
The hospital-based retrospective case-control design is susceptible to recall bias and selection bias. Dietary intake was self-reported retrospectively, and residual confounding from unmeasured lifestyle or nutritional factors cannot be ruled out.
Cited by
- supports Epidemiological studies indicate that higher intake of raw cruciferous vegetables is associated with a greater reduction in cancer risk (such as breast and lung cancer) than cooked cruciferous vegetables.