Metabolic Syndrome, Vitamin D and Prostate Cancer
Jacob Schor, ND
November 1, 2007
Every once in awhile I'll be paging through abstracts at the library and find myself muttering out loud, “Wow, put your finger on that page and reread this later”
Of course, these pages are on computer, the library is the National Library of Medicine in Washington , DC , and I'm not flipping pages but doing quick searches of the peer reviewed scientific literature via their search engine, PubMed.
This happened yesterday. Let me explain the situation. I was following up with a patient who was treated for prostate cancer early this past summer. I wanted to talk to him about diet. For years, we have felt it imperative to suggest a low glycemic diet for prostate cancer. There is a long standing notion that insulin may stimulate prostate cancer cell growth. This is best explained in Bob Arnodt's book, The Prostate Cancer Diet.
(Which appears to have been revised and retitled since my copy was published and is now called: The Prostate Cancer Protection Plan : The Foods, Supplements, and Drugs that Can Combat Prostate Cancer. Whatever)
Since this patient had a history of elevated blood lipids, higher than desired blood sugars, and truncal fat deposits, I had planned to talk to him about what is now called Metabolic Syndrome. In past years this ‘syndrome' has also been referred to as syndrome X, hyperinulinemia and probably a few other names I've forgotten. At one point it was one of those ‘alternative medicine' things, kind of like ‘candida' but now it seems quite mainstream. A google search on metabolic syndrome will turn up articles on the Mayo Clinic's website and other ‘respectable' sources of medical information. Put simply, this Metabolic Syndrome refers to the interrelationship of high insulin production, high blood fats and increased risk of a number of chronic diseases.
Medicine and the science supposedly behind medical interventions is evolving so rapidly these days that what was true yesterday may have been amended before the coffee's brewed this morning. I've developed a time consuming habit of double checking what I tell patients via a quick check of PubMed. This allows me to quickly scan new publications on a specific topic looking for evidence that contradicts the ‘current understanding'. Usually I simply find information that supports our contention and this is helpful in convincing the patient that what I am telling him isn't just made up.
So yesterday, I bumped into a fascinating paper published earlier this year on metabolic syndrome and the risk for prostate cancer. Published last February in Cancer Epidemiology Biomarkers Prevention, seven Finnish researchers (I would write their names but experience tells me that I cannot pronounce Finnish so why bother) wrote about their investigations.
They pulled data out of the Helsinki Heart Study which tracked the health of 18,939 middle aged Finnish men. They pulled out information on 132 prostate cancer cases and 456 matched controls and analyzed the data in detail.
The data revealed several interesting conclusions. First, “men in the highest quartiles of body mass index and systolic blood pressure showed a modest increase in risks of prostate cancer, with ORs of 1.37” Translated, that means that fat guys with high blood pressure had a better chance of getting prostate cancer than guys without high blood pressure who are not fat. The increased risk was not huge, about 40% greater than average. Having low HDL level alone, that's what everyone calls ‘good cholesterol', didn't make things worse.
But here is where it gets interesting. Guys with all three risk factors, being fat with high blood pressure and a low HDL, had more than triple the risk for getting prostate cancer.
And here was what stopped me and got me to lean over my computer to reread what was on the screen, “…..with all three factors present ….. jointly with low vitamin D, the OR was 8.03.”
In other words for fat guys with high blood pressure and low HDL cholesterol who were also low on vitamin D, the risk for getting prostate cancer was eight times the average.
Eight times the average, that stopped me.
Being fat, having high blood pressure aren't good for these guys. No question. That the vitamin D deficiency would have such a huge effect caught even me by surprise. Here is a little detail that will only add to this. The Finnish definition of low vitamin D levels was “<or=40 nmol/L”
Our labs in the United States have only recently raised their definition of low vitamin D from <15 to <20. Many men in the US who may be told that their vitamin D levels are just fine would still be defined as deficient by the Finnish standards.
If you are male, are on the heavy side and have high blood pressure and have low HDLs, you had better make the effort to either change one or more of those risk factors or spend a lot of time with your shirt off at the beach.
And with this patient, although focus on treating metabolic syndrome is still relevant, my top priority became testing his vitamin D levels. Intervention and treating vitamin D deficiency now appears to be the most effective way to lower risk of prostate cancer.
Interaction of factors related to the metabolic syndrome and vitamin D on risk of prostate cancer.
Medical School , University of Tampere , Department of Clinical Chemistry, Tampere University Hospital , Finland . Pentti.Tuohimaa@uta.fi
BACKGROUND: Factors related to the metabolic syndrome and low levels of vitamin D have been implicated as risk factors for prostate cancer. Insofar, no studies have assessed their joint effects on prostate cancer risk. METHODS: We studied (a) the associations of vitamin D with the metabolic syndrome factors body mass index, systolic and diastolic blood pressure, and high-density lipoprotein cholesterol (HDL-C) and (b) the prostate cancer risk associated with these factors and especially their joint effects with vitamin D on risk of prostate cancer. We did a longitudinal nested case-control study on 132 prostate cancer cases and 456 matched controls from a cohort of 18,939 Finnish middle-aged men from the Helsinki Heart Study. The odds ratios (OR) of prostate cancer were assessed via conditional logistic regression analysis. RESULTS: Apart from HDL-C, there was no linear association between the metabolic syndrome factors and vitamin D levels. In univariate analysis, men in the highest quartiles of body mass index (>28 kg/m(2)) and systolic blood pressure (>150 mmHg) showed a modest increase in risks of prostate cancer, with ORs of 1.37 (P = 0.16) and 1.53 (P = 0.05) when compared with the three lower quartiles, but low HDL-C entailed no prostate cancer risk. However, with all three factors present, the OR was 3.36 (P = 0.02), and jointly with low vitamin D (<or=40 nmol/L), the OR was 8.03 (P = 0.005) compared with those with no metabolic syndrome factors and intermediate levels of vitamin D. There was an interaction between vitamin D and the metabolic syndrome factors so that a clustering of these factors entailed high risk of prostate cancer but only if vitamin D level was low (<or=40 nmol/L). If it was at intermediate levels, the metabolic syndrome factors entailed no prostate cancer risk. CONCLUSIONS: We conclude that the prostate cancer risk associated with factors related to the metabolic syndrome is strongly conditioned by levels of vitamin D.
PMID: 17301263 [PubMed - indexed for MEDLINE]