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

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