Wednesday, November 11, 2009

Measuring Frailty - Does Testosterone Matter?

The results from a study titled Osteoporotic Fractures in Men, or a particular analysis of some of the measures (and men) in that study, was reported in the Journal of Clinical Endocrinology and Metabolism. I read an abbreviated report in Medscape this week.

Here is the bottom line as I understand it. [Men in the study were at least 65 years old with an average age of 75. They lived in communities, not nursing homes. The participants lived in several states across the country. The men were tested at baseline and four years later]

The scientists took certain biometric measures of the participants. This included their height, weight, BMI and fat percentage. Blood work was also completed. Specifically the men were tested for sex hormone levels and the sex hormone binding compound known as SHBG, the G stands for globulin.

The men were also put into categories based on five criteria. The categories were robust, intermediate and frail. The criteria for categorization were:
1) weakness - based on grip strength
2) slowness - based on walking speed
3) activity level- activity level was assessed for all men and the men in the lowest 20% met the criteria (you can see the criteria is for frailty not robustness!)
4) sarcopenia or shrinkage - meaning having a low lean body mass for their height and weight
5) and exhaustion - as measured by loss of breath or having to stop while walking short distances

If a man met three or more of the five he was said to be frail, if he met one or two then he was intermediate and the absence of any of the above meant he was robust.

The scientists expected to see some correlation between hormone levels and frailty. What they did find was that the men who met the frailty criteria at the start of the study, or at base line, WERE low in bioavailable testosterone.

No other hormone was related to frailty. Bioavailable testosterone is free or available for the body to use. Perhaps a lack of this BAT leads to muscle atrophy and weakness, but that was a hypothesis not a conclusion.

Four years later however, it wasn't testosterone levels that predicted frailty but having been frail OR older at the initial screening. If one is frail, he tends to stay frail and if he is older he is more likely to become frail. [this was not a study to see if frailty could be reversed, but I think it is possible that it could be]

From time one to time two, which was ONLY four years, about 11 % less men were robust, 5% less were intermediate and an additional 3% were frail. The most startling number of all, however, was that 12% had died.

I do not know what the prevention message can be except to say that some testosterone levels can be affected, i.e. lowered, by obesity, medications, injury and other conditions. If muscle strength and cardiovascular conditioning are the markers of frailty, then certainly, staying active and doing weight resistance exercises is paramount.

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