Modifiable risk factors for the prevention of bladder cancer: a systematic review of meta-analyses.
Study Goal
The researchers aimed to evaluate the association between cruciferous vegetable intake and the risk of primary bladder cancer.
Results Summary
The study found that higher intake of cruciferous vegetables was associated with a reduced risk of bladder cancer (RR 0.84), indicating a statistically significant protective effect.
Population
Individuals at risk of or diagnosed with bladder cancer, based on meta-analyses of primary studies.
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
current cigarette smoking | increase | primary bladder cancer risk | - | RR 3.14 | Statistically significant association | #1 |
former cigarette smoking | increase | primary bladder cancer risk | - | RR 1.83 | Statistically significant association | #2 |
pipe smoking | increase | primary bladder cancer risk | - | RR 1.9 | Statistically significant association | #3 |
cigar smoking | increase | primary bladder cancer risk | - | RR 2.3 | Statistically significant association | #4 |
antioxidant supplementation | increase | primary bladder cancer risk | - | RR 1.52 | Statistically significant association | #5 |
obesity | increase | primary bladder cancer risk | - | RR 1.10 | Statistically significant association | #6 |
higher physical activity levels | decrease | primary bladder cancer risk | - | RR 0.86 | Statistically significant association | #7 |
higher body levels of selenium | decrease | primary bladder cancer risk | - | RR 0.61 | Statistically significant association | #8 |
higher body levels of vitamin D | decrease | primary bladder cancer risk | - | RR 0.75 | Statistically significant association | #9 |
higher intakes of processed meat | increase | primary bladder cancer risk | - | RR 1.22 | Statistically significant association | #10 |
higher intakes of vitamin A | decrease | primary bladder cancer risk | - | RR 0.82 | Statistically significant association | #11 |
higher intakes of vitamin E | decrease | primary bladder cancer risk | - | RR 0.82 | Statistically significant association | #12 |
higher intakes of folate | decrease | primary bladder cancer risk | - | RR 0.84 | Statistically significant association | #13 |
higher intakes of fruit | decrease | primary bladder cancer risk | - | RR 0.77 | Statistically significant association | #14 |
higher intakes of vegetables | decrease | primary bladder cancer risk | - | RR 0.83 | Statistically significant association | #15 |
higher intakes of citrus fruit | decrease | primary bladder cancer risk | - | RR 0.85 | Statistically significant association | #16 |
higher intakes of cruciferous vegetables | decrease | primary bladder cancer risk | - | RR 0.84 | Statistically significant association | #17 |
occupation as tobacco worker | increase | primary bladder cancer risk | - | RR 1.72 | highest risk | #18 |
occupation as dye worker | increase | primary bladder cancer risk | - | RR 1.58 | highest risk | #19 |
occupation as chimney sweep | increase | primary bladder cancer risk | - | RR 1.53 | highest risk | #20 |
Each year, 430,000 people are diagnosed with bladder cancer. Due to the high recurrence rate of the disease, primary prevention is paramount. Therefore, we reviewed all meta-analyses on modifiable risk factors of primary bladder cancer. PubMed, Embase and Cochrane database were systematically searched for meta-analyses on modifiable risk factors published between 1995 and 2015. When appropriate, meta-analyses (MA) were combined in meta-meta-analysis (MMA). If not, the most comprehensive MA was selected based on the number of primary studies included. Probability of causation was calculated for individual factors and a subset of lifestyle factors combined. Of 1496 articles identified, 5 were combined in MMA and 21 were most comprehensive on a single risk factor. Statistically significant associations were found for current (RR 3.14) or former (RR 1.83) cigarette smoking, pipe (RR 1.9) or cigar (RR 2.3) smoking, antioxidant supplementation (RR 1.52), obesity (RR 1.10), higher physical activity levels (RR 0.86), higher body levels of selenium (RR 0.61) and vitamin D (RR 0.75), and higher intakes of: processed meat (RR 1.22), vitamin A (RR 0.82), vitamin E (RR 0.82), folate (RR 0.84), fruit (RR 0.77), vegetables (RR 0.83), citrus fruit (RR 0.85), and cruciferous vegetables (RR 0.84). Finally, three occupations with the highest risk were tobacco workers (RR 1.72), dye workers (RR 1.58), and chimney sweeps (RR 1.53). The probability of causation for individual factors ranged from 4 to 68 %. The combined probability of causation was 81.8 %. Modification of lifestyle and occupational exposures can considerably reduce the bladder cancer burden. While smoking remains one of the key risk factors, also several diet-related and occupational factors are very relevant.