Impact of vitamin D and obesity on bladder cancer; Risk and survival
Project
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The project examines whether obesity and vitamin D levels affect the risk of developing bladder cancer.
Background
Bladder cancer is a common cancer among Norwegian men, occurring 3-4 times more frequently than among women. Smoking and occupational exposure are established risk factors. Over the past decades, both smoking and occupational exposure have decreased in Norway, yet the incidence of bladder cancer continues to rise. Other lifestyle-related factors may also influence the risk of developing this disease.
High body mass index (BMI), low physical activity, metabolic disorders such as high blood pressure, are associated with the risk of various cancers and may also have relevance to bladder cancer. Additionally, previous studies suggest that low levels of vitamin D may increase the risk of this disease.
Purpose
In this project, we investigate whether there are associations between different lifestyle-associated factors and the risk of developing bladder cancer, using data and serum samples from the Janus Serum Bank and the Cancer Registry. The project examines:
- Associations between BMI, physical activity, blood pressure, triglycerides, and cholesterol and the risk of bladder cancer.
- Whether serum levels of vitamin D influence the risk of bladder cancer.
Results
The results indicate an association between elevated blood pressure and increased risk of bladder cancer, but no associations for BMI, physical activity, triglycerides, or cholesterol. Generally, the observed associations between lifestyle and bladder cancer were strongest among men and non-smokers. This suggests that smoking may mask some of the associations among smokers. Future studies of associations between lifestyle-associated factors and the risk of bladder cancer should be conducted among non-smokers to ensure better confounding control.
In this project, we found that high levels of vitamin D were associated with reduced risk of bladder cancer, indicating that low levels of vitamin D may be a risk factor. However, we found no association for vitamin D-binding protein.
Furthermore, we found that having insufficient vitamin D levels prior to diagnosis predicted increased mortality from bladder cancer. The results were most pronounced for patients without muscle-invasive disease, which may indicate an important role of vitamin D in the early stages of the disease.
About the project
Project group:
- Trude Eid Robsahm, Project manager
- Randi Gislefoss, former project manager (retired from 1 July 2021)
- Helga Helseth Hektoen, Post doc
- Hilde Langseth, researcher
- Bettina Kulle Andreassen, researcher
- Jo S Stenehjem, researcher
- Ronnie Babigumira, data manager
REC: The project has been approved by the Regional Committees for Medical and Health Research Ethics (REK), reference 2016/2233 REC South-East B
Duration: 2016 - Ongoing
Funding: The project is funded by the Norwegian Cancer Society