Prostate Cancer Incidence is Correlated to Total Meat Intake– a Cross-National Ecologic Analysis of 172 Countries

Abstract

Objective: To examine the association of total meat (animal flesh) consumption to prostate cancer incidence<br />(PC61) at population level. Subjects and Methods: Data from 172 countries were extracted for analysis. Associations<br />between country specific per capita total meat intake and PC61 incidence at country level were examined using<br />Pearson's r and Spearman rho, partial correlation, stepwise multiple linear regression analyses with ageing, GDP, Is<br />(index of magnitude of prostate cancer gene accumulation at population level), obesity prevalence and urbanization<br />included as the confounding factors. Countries were also grouped for regional association analysis. The data were<br />log-transformed for analysis in SPSS. Microsoft Excel, and ANOVA Post hoc Scheffe tests were applied to calculate<br />and compare mean differences between country groupings. Results: Worldwide, total meat intake was strongly and<br />positively associated with PC61 incidence in Pearson's r (r= 0.595, p<0.001) and Spearman rho (r= 0.637, p<0.001)<br />analyses. This relationship remained significant in partial correlation (r= 0.295, p<0.001) when ageing, GDP, Is, obesity<br />prevalence and urbanization were kept statistically constant. GDP was weakly and insignificantly associated with PC61<br />when total meat intake was kept statistically constant. Stepwise multiple linear regression identified that total meat<br />was a significant predictor of PC61 with total meat intake and all the five confounders included as the independent<br />variables (R2=0.417). Post hoc Scheffe tests revealed nine significant mean differences of PC61 between the six WHO<br />regions, but all disappeared when the contributing effect of total meat on PC61 incidence rate was removed. GDP was<br />not identified as the statistically significant predictor of PC61 in either of the models including or excluding total meat<br />as the independent variable. Conclusions: Total meat intake is an independent predictor of PC61 worldwide, and the<br />determinant of regional variation of PC61. The longitudinal cohort studies are proposed to explore the association further.