Navigation Links
Testosterone Levels in Men Decline Over Past Two Decades

Testosterone levels in American men have been declining steadily over the past two decades, a new study in the Journal of Clinical Endocrinology and Metabolism concludes. //

The reasons for this decline are unclear; the study suggests that neither aging nor changes in certain health factors, such as obesity or smoking, can completely explain the phenomenon.

“Male serum testosterone levels appear to vary by generation, even after age is taken into account,” said Thomas G. Travison, Ph.D., of the New England Research Institutes (NERI) in Watertown, Mass., and lead author of the study. “In 1988, men who were 50 years old had higher serum testosterone concentrations than did comparable 50-year-old men in 1996. This suggests that some factor other than age may be contributing to the observed declines in testosterone over time.”

Testosterone is the primary male sex hormone. It is important for maintaining bone and muscle mass throughout life. Insufficient levels of testosterone have been linked to diabetes, low libido, and other medical conditions. Typically, testosterone levels in men peak around their late 20s, and then begin a gradual decline from age 30 onward. Testosterone also is present in women, but at significantly lower levels.

Travison and colleagues based their study on data from the Massachusetts Male Aging Study (MMAS). The MMAS comprised three separate data-collection periods over 17 years (1987-89, 1995-97, and 2002-04). The study involved collecting blood samples, as well as health and biographical data, from approximately 1,500 randomly selected men residing in the greater Boston area.

During each phase of the study, the researchers analyzed the subjects’ blood samples to measure total testosterone, from which they also calculated the amount of “bio-available” testosterone. Bio-available testosterone includes both free testosterone (unbound to proteins) and testosterone weakly bound to proteins (especially albumin); as its name implies, it is available to tissues to support various functions within the body.

The NERI team carefully analyzed the data to compare men of similar ages during each phase of the study. After accounting for age and additional factors such as obesity, smoking, and medications, the researchers found that, each year, the subjects’ total and bio-available testosterone decreased an average of 1.2 and 1.3 percent, respectively.

For men 65-69 years of age in this study, average total testosterone levels fell from 503 ng/dL (nanograms/deciliter) in 1988 to 423 ng/dL in 2003. A normal, healthy adult male usually has blood total testosterone concentrations that range anywhere from 300-1000 ng/dL.

Travison acknowledged that hormone concentrations in the blood are difficult to measure, primarily due to normal daily fluctuations. To ensure these changes did not bias the results, two samples were obtained at each visit, and all were taken early in the morning, when testosterone levels are at their highest.

In addition, each MMAS data collection period utilized the same laboratory and the same technology to analyze subjects’ blood.

“Nevertheless,” said Travison, “time and technology march on, so it’s impossible to completely rule out the influence of subtle changes in the way the samples were obtained or processed. That being said, our results appear to be consistent across the various waves of the study.”

The researchers point out that, although subjects’ current health was taken into account as part of the analysis, it is impossible to account for certain health or environmental influences that may have impacted the subjects’ testosterone levels prior to enrolling in the study.

“This analysis deals with men who were born between 1915 and 1945,” said Travison, “but our baseline data were not obtained until the late 1980s, when the elder subjects were about 70 y ears old, and the youngest about 45. Events occurring in earlier decades could certainly help explain our results, if their effects persisted into recent years.” It is also possible that current, but unmeasured, health or environmental factors could be the root cause of the observed declines.

Souce-Newswise
SRM
'"/>




Related medicine news :

1. Testosterone Replacement Therapy Safe If Monitored Appropriately
2. Low Testosterone Levels the Cause Of Depression In Men
3. The Use Of Testosterone Replacement Therapy Questioned
4. Depression In Men Could Be To Low Testosterone Levels
5. Testosterone patch for women Rejected For safety Reasons
6. Testosterone Patches Found To Increase Sexual Desire In Menopausal Women
7. Testosterone Therapy can improve sexual function in postmenopausal women
8. Fatherhood Found To Tame Men by Reducing Testosterone Levels
9. Testosterone levels could serve as a marker for determining risk of SIDS
10. Males Lifespan Shortened By Elevated Levels Of Testosterone
11. Study Indicates An Increased Risk Of Breast Cancer In Women Undertaking Estrogen and Testosterone Therapy
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:5/24/2016)... VA (PRWEB) , ... May 24, 2016 , ... Controlling ... smarter - with the launch of the Aquanta Water Heater Controller , a ... smart phone or web-enabled device. As the Nest thermostat does for HVAC systems, ...
(Date:5/24/2016)... WI (PRWEB) , ... May 24, 2016 , ... ... In Milwaukee , Out patient Services To Begin In June , Aloria Health, ... pleased to announce the opening of Aloria Milwaukee, its first treatment facility for ...
(Date:5/24/2016)... NJ (PRWEB) , ... May 24, 2016 , ... The ... that’s causing the problem. A common injury that’s often misunderstood, whiplash should be swiftly ... MD, a Harvard-trained, orthopedic spine surgeon at Atlantic Spine Center . , ...
(Date:5/24/2016)... ... May 24, 2016 , ... ... successful implementation of protocols designed to reduce bleeding complications from percutaneous coronary intervention ... Angiography and Interventions (SCAI) in Orlando, FL, document a 40% reduction in risk-adjusted ...
(Date:5/24/2016)... ... May 24, 2016 , ... ... Essette Dashboard, its highly anticipated, web-based software module. The cutting-edge feature provides ... “secret sauce”? Integration with Izenda’s self-service business intelligence solution and its analytics ...
Breaking Medicine News(10 mins):
(Date:5/19/2016)... According to a new market research report "Sunitinib Malate ... Germany , France , U.K., ... Japan )", published by MarketsandMarkets, The market is projected to ... from 2016 to 2021.      (Logo: http://photos.prnewswire.com/prnh/20160303/792302 ... through 26 Pages and in-depth TOC on "Sunitinib Malate ...
(Date:5/19/2016)... AVIV, Israel , May 19, 2016 ... or the "Company"), an emerging global ophthalmic company focused ... product candidates which address ophthalmic conditions, announced today that ... Italy ) for the manufacturing, distribution, ... product for the treatment of dry eye syndrome (DES) ...
(Date:5/19/2016)... May 19, 2016 At the 18 ... Meeting in Amsterdam , (May 15-19), Elekta ... clinically-proven radiosurgery system available, has been used in the ... brain tumors, vascular malformations and functional disorders. ... 75,000 patients every year in hundreds of leading hospitals ...
Breaking Medicine Technology: