A new study from Japan [1].
A 1994 U.S. study found that education was a PCa risk factor [2]:
"education level was associated positively in an increasing trend ... up to an RR of 1.4 ... among men with postgraduate education."
In a 2007 Italian study [3]:
"A significantly increased risk was found for high education level (OR = 3.3 for 12 or more years versus less than 7 years)"
In a 2008 U.S. study [4]:
"lower education level was associated with a decreased risk of ... local prostate cancers (0.79 ...)."
In the new study:
"In white-collar industries, higher occupational class men tended to have lower a reduced risk for most common types of cancer, with the exception of professionals who showed an excess risk for prostate cancer."
I have always thought that the risk is due to the number of hours working indoors. The fact that PCa stands out in this regard, may indicate the importance of vitamin D for protection.
One might argue that well-educated men might be more inclined to screen, but the association was noted before the PSA era [5].
-Patrick
[1] ncbi.nlm.nih.gov/pubmed/306...
[2] ncbi.nlm.nih.gov/pubmed/751...
[3] ncbi.nlm.nih.gov/pubmed/181...