Do diet and obesity increase the risk of bladder cancer?

Background

Bladder cancer is the 7th most common cancer, with approximately 260,000 new cases diagnosed each year in men and 76,000 in women. It is most common in Western Europe, North America and Australia. Most bladder cancers can be cured with treatment, but require ongoing monitoring as they often reappear; this means that, in the longer term, bladder cancer results in some of the highest medical costs per patient of all cancers.

Around 30% of bladder cancers are aggressive tumours that are less responsive to treatment. The strongest risk factors for bladder cancer are cigarette smoking, specific chemicals used frequently in the dye and rubber industries, and some poisons such as arsenic. Being more physically active is associated with a lower risk of bladder cancer.

Despite decades of research, it remains unclear whether bladder cancer is related to obesity and diet. Furthermore, little is known about whether your body size, or what you eat and drink, influences the type of bladder cancer you might develop (for example, a more aggressive tumour or a curable tumour). Men have up to four times higher risk of bladder cancer than women. Only part of this difference in risk is explained by the known risk factors, which suggests that diet and body size might have different effects for men than for women. They may also be different for smokers and non-smokers. The studies carried out to date have been too small to investigate these issues.

Aims and objectives

This study aims to determine whether:

1. your bladder cancer risk is influenced by your body size, how much alcohol and other drinks (soft drinks, tea, coffee) you drink, how much fruit and vegetables you eat, how much meat you eat, certain patterns of eating (such as a Mediterranean diet), or specific components of different types of food (such as certain types of fat).
2. the influence of these factors (plus physical activity, already known to influence bladder cancer risk) and how they differ between men and women, between smokers and non-smokers, or between the types of bladder cancer that people might develop.

How it will be done

We will use data from more than 3.5 million people (24,000 of whom have bladder cancer) participating in 30 high-quality studies from around the world. Our funding will allow us to combine the data from these 30 individual studies and combine and analyse them.

Potential impact

This project will bring together the world’s highest-quality data and expert researchers to generate the best evidence to inform the prevention of bladder cancer.