Tuesday, September 6, 2011

Testosterone vs Diabetes: What's the Link?

In a study published last month in the Journal of Clinical Endocrinology & Metabolism, the authors performed a literature review of the data extant from 1970 to March 2011 and concluded that there is a modest link between low testosterone (hypogonadism) and type 2 diabetes (T2DM).  

Cross-sectional studies consistently demonstrated that total testosterone (TT) is lower in diabetic men compared to their non-diabetic controls, regardless of age, body fat, body mass index, waist circumference, etc.  While obesity accounted for a large percentage of the association, the link was still present after taking it into account.

In prospective studies, low TT was noted to be associated with a greater risk of developing T2DM than those with higher or even normal TT.  Furthermore, low TT was found to precede development of metabolic syndrome even prior to developing T2DM.

However, these are just observational studies and, as such, cannot prove cause & effect, just an association.  Interventional studies offering testosterone to T2DM patients have been inconsistent in their results.  Some studies have demonstrated benefit, while others have not.  The theory is that the studies thus far have not been of adequate duration, although most have been promising.

The biggest concern raised was that of safety, given that potentially large numbers of men will be exposed with minimal benefit to be gained.  Traditional medicine is still feeling the sting of the Women's Health Initiative when it attempted to prove the benefit of conjugated equine estrogens (CEE) +/- medroxyprogesterone acetate (MPA) based upon observational studies only.  However, without said observational studies, I doubt that we would ever have discovered the issues now demonstrated by CEE +/- MPA.  At the same time, I would encourage us not to lump CEE & MPA with estradiol & progesterone as these chemicals & hormones are quite distinct in their actions.

Likewise, it's important that, prior to putting testosterone into the water, we should investigate and prove that its benefits greatly outweigh its risks.  Unfortunately, this takes time and some of us don't even buy green bananas.  For those of you unwilling to wait for definitive answers (and who are open to exploring the cutting, if not bleeding, edge of medicine with testosterone's attendant risks w/o guarantee of benefits), I would point you towards physicians who have taken an interest in the growing field of andrology and men's health.  Not everyone is well-versed in the latest findings and too often, a very expensive cookie cutter is used, rather than less expensive but viable options.

One last point - current (controversial) guidelines for initiating testosterone supplement range from as low as <200ng/dL to as high as <300ng/dL but as noted in yesterday's post, non-obese healthy 19-40yo men have an average of TT of 724ng/dL with most (95%) having values greater than 348ng/dL.  Therefore, if we refuse to offer a trial of testosterone supplementation to the clinically symptomatic obese diabetic male with a TT of 301ng/dL, I would liken it to refusing to tutor a student who's getting D's in his mid-terms until he fails his final exams.  Does everyone want a tutor?  No!  But let's offer assistance to those who're reaching out for help.

In the meantime, while you mull over whether testosterone is right for you or not, there is no controversy regarding the need to eat nutritious food and to exercise regularly, even as little as 15min/d.