Lifestyle associated factors and risk of urinary bladder cancer: A prospective cohort study from Norway

Abstract

A number of lifestyle associated factors, such as high body mass index (BMI), low physical activity, and related metabolic disorders, are associated with increased risk of cancer at several sites. For urinary bladder cancer (BC), such studies show inconsistent results, which could result from inadequate adjustment for smoking and occupational exposure. In the population-based Janus Cohort (n = 292 851), we investigated the independent and combined impact of BMI, physical activity, blood pressure, and blood lipids on the risk of BC, by thorough adjustment for smoking and potential occupational exposure. We used cox proportional hazard regression to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the associations between the lifestyle associated factors and BC risk. The associations observed were dependent on smoking status and gender. Among men, diastolic blood pressure (DBP) (HR 1.07, 95% CI 1.02-1.12) and systolic blood pressure (SBP) (HR 1.04, 95% CI 1.01-1.07) were positively associated with BC risk. Stratification by smoking status revealed a positive association between DBP and BC risk in never smokers (HR 1.14, 95% CI 1.00-1.30), while no association was seen for current and former smokers. A risk score, integrating information across the lifestyle factors was positively associated with BC risk in men (p trend = 0.043). In women, physical activity was associated with a decreased BC risk, but only among never smokers (HR 0.65, 95% CI 0.45-0.94). In conclusion, relations between lifestyle associated factors and BC risk were most evident in never smokers, suggesting that smoking dominates the relation in current smokers.

Vitamin D and Vitamin D‐binding protein and risk of bladder cancer: A nested case‐control study in the Norwegian Janus Serum Bank Cohort

“…For instance high BMI is associated with low 25(OH) D concentrations, and have in some studies showed a tendency to be inversely related to BC risk. 7,36 In our analysis, when stratifying by BMI; a reduced BC risk for deficient 25(OH)D concentrations was only seen in the category of BMI ≥25.…”

“…Occupational working titles were categorized as high risk (yes or no) and was based on existing knowledge about chemical exposures in certain occupations that previously has shown to be related to BC risk. 7,29,30 More details about the categorization of high risk occupations are published previously. 7 Education was categorized as unknown, compulsory, upper secondary and college/university.…”

“…7,29,30 More details about the categorization of high risk occupations are published previously. 7 Education was categorized as unknown, compulsory, upper secondary and college/university.…”

“…2,3 The main alterable risk factors for BC are smoking and exposure to chemicals. [4][5][6] Other suggested risk factors include lifestyle-related factors such as body mass index (BMI), blood pressure, physical activity, and various dietary and nutritional factors, including vitamin D. [7][8][9] Vitamin D is synthesized in the skin by ultraviolet radiation from the sun, or obtained from food and supplements, and must undergo activation through two steps to become the biologically active hormone; first to form 25-hydroxyvitamin D (25(OH)D) in the liver and then to form 1-25-dihydroxyvitamin D (1,25OH 2 D) in the kidney. 10 The active hormonal form of vitamin D is vital for maintaining bone health, but does also regulate several other biological functions, including mechanisms involved in carcinogenesis, such as cell growth and differentiation.…”

The Impact of Physical Activity on Risk and Health-Related Quality of Life in Bladder Cancer

“…An awareness of the benefits of of PA appears encourage people to have healthy lifestyle habits [17,30]. Indeed, the more frequently people engage in PA, better their lifestyle habits will be acquired.…”