Connect the dots.

HealthDay News is running a story by reporter Amanda Gardner about the impact of obesity and insulin levels on survival of prostate cancer.  "Men who are overweight and who have high insulin levels when they are diagnosed with prostate cancer may be more likely to die from the disease, research shows."  The research is online at Lancet Oncology and will be formally published in the journal's November issue.

Gardner's reporting is good, but as a scientist reading this, I see connections that raise a different set of interpretations.

The reporting focuses on the impact that obesity has upon prostate cancer survival.  But beyond that, we could ask:  Is there a common factor that may simultaneously affect prostate cancer survival AND increase the risk of obesity and disregulation of insulin.

My first thought upon reading this is: "This result is totally predictable based upon recent scientific publications."  A series of studies from the University of Cincinnati have shown that the environmental contaminant bisphenol A (BPA) makes prostate cancer more aggressive and interferes with standard treatments for the disease. This work was done in vitro and then with human prostate tumors implanted into rats, some of the very tools that are used to develop pharmacological treatments for prostate cancer. And new epidemiological data published in none other than that Journal of the American Medical Association links BPA to metabolic syndrome, which includes Type 2 diabetes and obesity.  That result builds upon studies that tie BPA to obesity and failures in insulin metabolism. 

Both of these data sets are based upon research using levels of BPA well within the range of human exposures, indeed the epidemiological research is all about common, background levels of exposure to BPA.

These two data sets imply that BPA may both increase vulnerability to prostate cancer, and also increase the risk of obesity and metabolic syndrome.  Thus the result reported by HealthDay News could be taken further: Perhaps it's not that obesity alters the risk of prostate cancer aggressiveness, but that BPA exposure-- which is virtually ubiquitous in America because of its use in food cans-- is contributing both to the increased aggressiveness of prostate cancer and the increased risk of obesity and metabolic syndrome.  Teasing apart confounding variables like this is hellishly difficult for epidemiology.  And this is terrain that scientists in that field have barely started to mine.

BPA isn't driving all human disease.  Far from it.  But a large body of scientific data now tie it plausibly to a range of significant ailments.  This is new science, and it's unreasonable to imagine that working reporters can keep up with it all, connecting one field to another... in fact the pace of publication of new science in this arena defies anyone to be in complete command of the latest data. That's why it's so important for working scientists with expertise in issues like this to be available for reporters on deadline, and equally, for reporters to reach out to the scientific community for interpretation and context.  These two cultures need one another.