New findings presented at SIU in Milan.
There are numerous PCa studies that associate obesity (BMI>30) with agressive disease & poorer outcome. This is unfortunate since men who are merely overweight might disregard the message.
I have written a number of posts about the dangers of a low-fat diet, high triglycerides, visceral fat & aggressive disease. There are several studies that admit that BMI is used as a surrogate for visceral fat. Some researchers prefer a hips to waist ratio, but there are no external measurement than can readily ascertain the amount of visceral fat. Only a scan can do that.
It's expensive to scan a large number of men for a study such as this, so the team used >= 3 components of metabolic syndrome as a definition of Metabolically Obese (MO).
I have mentioned previously that men lose weight on the 10% fat Dean Ornish diet because it is a high-fiber calorie restriction diet. But it usually raises triglycerides, which are preferentially deposited around internal organs. This can lead to the TOFI (thin outside, fat inside) phenomemenon. On the other hand, it is also possible to be a FOTI men (fat outside, thin inside). BMI is not a good indicator of risk in these men.
The study chose to combine overweight (BMI>25 but <30) with obese (BMI>30) in their definition of BMI obese.
"Interestingly, {Metabolically Obese but Normal Weight men} were at higher risk than {Metabolically Healthy and Obese men}, suggesting it is not obesity alone that increases risk." "Interesting" if one was not expecting it. Unlike subcutaneous fat, visceral fat is hormonally active.
There were over a million Metabolically Obese but Normal Weight men in the study (10% of study participants).
-Patrick
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SIU 2017: Different Incidence of Prostate Cancer According to Metabolic Health Status: A Nationwide Cohort Study
Lisbon, Portugal (UroToday.com) While many prior papers have looked at the effect of obesity and BMI with prostate cancer incidence and prognosis, within the field of metabolic health, there is now an understanding that patients with normal weight can still have metabolic syndrome. These patients with “metabolically obese, normal weight” have a high visceral/subcutaneous fat ratio and other metabolic derangements associated with metabolic syndrome. Recent studies have also demonstrated that in Asian patients, diabetes and heart disease may be more prevalent even in the absence of obesity.
With prostate cancer incidence rising in Korea, the authors assess the incidence of prostate cancer using the National Health Check-ups (NHC) database. There were 11.8 million men who participated between 2009 and 2012, amongst which there were 56,552 newly diagnosed cases of prostate cancer. Obesity was defined as patients with BMI > 25 in this study (though historically it is >30). Metabolically Obese (MO) was defined as anyone have >= 3 components of metabolic syndrome. This resulted in 4 categories: metabolically healthy and normal weight (MHNW), metabolically obese but normal weight (MONW), metabolically healthy and obese (MHO) and metabolically obese and obese (MOO). MV regression analysis was used to identify predictors of prostate cancer incidence.
While MHNW predominated the number of cases (6.1 million), there were 1.2 million MONW, and 2 million each of the obese patients. Importantly, MONW patients and MOO patients were older than their metabolically healthy counterparts. Diabetes, HTN, and HLP were all higher as expected in the metabolically obese and obese patients. Median follow-up was similar for all groups, approximately 5.3 years.
Compared to MHNW patients, all the other categories had a higher age-adjusted and multi-variable adjusted risk of prostate cancer. HR were 1.143 (MONW), 1.09 (MHO) and 1.25 (MOO). Interestingly, MONW were at higher risk than MHO, suggesting it is not obesity alone that increases risk.
As the number of metabolic components increased, so did the risk of developing prostate cancer!
Presented by: Hong Seok Park
Affiliation: Korea University, South Korea
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal