Diet, Body Size, Physical Activity And Risk Of Prostate Cancer: An Umbrella Review Of The Evidence

George MARKOZANNES, University of Ioannina School of Medicine, Greece
TZOULAKI I. 1,2 , KARLI D. 1 , ABAR L. 2 , AUNE D. 2 , CHAN D. 2 , NAVARRO ROSENBLATT D. 2 , STEVENS C. 2 , VIEIRA A. 2 , VINGELIENE S. 2 , EVANGELOU E. 1 , NTZANI E. 1 , GUNTER M. 3 , NORAT T. 2 , IOANNIDIS J. 4 , TSILIDIS K. 1,2

1 Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece
2 Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom
3 International Agency for Research on Cancer, Lyon, France
4 Department of Medicine, Department of Health Research and Policy, Department of Statistics, Stanford Prevention Research Center, Stanford School of Medicine, Stanford University School of Humanities and Sciences, Stanford, California, USA

Purpose: The literature evidence on the relationship of diet, body size, physical activity and risk of prostate cancer was summarised by the World Cancer Research Fund (WCRF) Continuous Update Project (CUP). We conducted an umbrella review using data from the CUP to further evaluate the robustness of the evidence.

Methods: The robustness of the evidence was evaluated using several criteria addressing evidence strength and validity, such as the statistical significance of the random effects summary estimate and of the largest study in a meta-analysis, the number of prostate cancer cases, between-study heterogeneity, 95% prediction intervals, small-study effects bias, excess significance bias and sensitivity analyses with credibility ceilings.

Results: A total of 248 meta-analyses were extracted from the CUP, which studied associations of 23 foods, 31 nutrients, 8 indices of body size and 3 indices of physical activity with risk of total prostate cancer development, mortality or cancer development by stage and grade. Of the 176 meta-analyses that used a continuous scale to measure the various exposures, no association presented strong evidence by satisfying all the aforementioned criteria. Only the association of height with total prostate cancer incidence and/or mortality presented highly suggestive evidence with a 4% higher risk per 5cm greater height (95% CI, 1.03-1.05). Seven associations of five exposures, including body mass index (BMI), weight, height, dietary calcium and spirits intake, were supported by suggestive evidence. The strongest association of those was for BMI and prostate cancer mortality, where an 11% higher risk per 5 kg/m2 greater BMI was observed (95% CIs, 1.06-1.17). The grading of the evidence was similar in the 72 meta-analyses with a categorical exposure assessment.

Conclusions: The association of diet, body size and physical activity with prostate cancer risk has been extensively studied, but no association was graded with strong evidence.

Funding source: WCRF 2014/1180