news about low testosterone

We collect and will post testosterone news and news about andropause or low testosterone on this page as it is published.

Sex Hormones Associated with Broken Bones in Older Men

August 3, 2009—Low levels of estradiol or high levels of sex hormone binding globulin (SHBG) are associated with an increased risk of osteoporotic fracture in older men, according to a new study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM). The study also finds that men with low levels of testosterone combined with high levels of SHBG are also at higher risk for bone fracture.

Testosterone is the predominant male sex hormone and estradiol is a sex hormone that provides most estrogen effects in both men and women. SHBG, a protein that binds to estradiol and testosterone in the blood, is known to reduce circulating sex steroid concentrations and has also been associated with fracture risk.

Previous studies have shown that with aging, sex hormone concentrations decline and fracture rates increase. Until now, few studies have adequately assessed the nature of the association of sex hormones with bone fracture risk or how measuring sex hormones might be useful in clinical practice.

This new study followed 1,436 men aged 65 years or older, for approximately five years. Researchers measured sex steroid levels using liquid chromatography/mass spectrometry, a highly accurate chemistry technique used for the specific detection and potential identification of chemicals in the presence of other chemicals in a complex mixture. The results of the study clearly demonstrate that estradiol and SHBG levels were most predictive of fracture risk, and men with the combination of low estradiol, low testosterone and high SHBG levels were at even higher risk for fracture—more than three times as high as men with average levels.

“In clinical practice today, estradiol and SHBG levels are not commonly measured when assessing skeletal health or fracture risk in men,” said Eric Orwoll, MD of Oregon Health and Science University and co-author of the study. “This practice should be revised. The results from our study strongly suggest that the measurement of both sex hormones, estradiol and testosterone, as well as SHBG levels in older men may help identify men at higher risk.”

Dr. Orwoll pointed out that many of the study participants were aged 80 years or older, a segment of the population that is expanding and is at higher fracture risk but has not been previously studied in this context.

Other researchers working on the study include Erin LeBlanc, Carrie Nielson, Lynn Marshall and Jodi Lapidus of Oregon Health and Science University in Portland; Elizabeth Barrett-Connor and Gail Laughlin of the University of California in San Diego; Kristine Ensrud of the University of Minnesota in Minneapolis; Andrew Hoffman of Stanford University in Palo Alto, Calif.; and Claes Ohlsson of the Shlgrenska Academy in Göteborg, Sweden.

The article, “The effects of serum testosterone, estradiol and sex hormone binding globulin levels on fracture risk in older men,” will appear in the September 2009 issue of JCEM.

Source: The Endocrine Society

Testosterone Decreases after Ingestion of Sugar (Glucose)

June 13, 2009—Men with low testosterone should have their hormone levels retested after they fast overnight because eating may transiently lower testosterone levels, a new study concludes. The results were presented at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.

“Both the incidence of low testosterone, or hypogonadism, in men and the annual number of testosterone prescriptions are increasing, likely as a result of the obesity epidemic and our aging population,” said study co-author Frances Hayes, MD, an endocrinologist at St. Vincent’s University Hospital in Dublin, Ireland, who did the research at Massachusetts General Hospital, Boston. “The decision to prescribe testosterone therapy is based on the result of a blood sample, so obtaining an accurate measurement of testosterone is key to making a correct diagnosis of hypogonadism.”

In current guidelines for evaluating men with hypogonadism, The Endocrine Society recommends measuring blood levels of testosterone—the major male sex hormone—on two or more occasions in the morning, when testosterone is highest. However, no guidelines exist on when to draw a testosterone sample in relation to food intake, Hayes said.

Past research shows that a high level of insulin, the hormone primarily secreted after eating, is related to low testosterone levels. Like eating, glucose intake causes blood glucose (sugar) levels to rise, which stimulates secretion of insulin. Hayes and her colleagues examined the impact of a standard dose of glucose on testosterone levels in 74 men. The researchers administered the oral glucose tolerance test, a screening test for diabetes that involves drinking a sugary solution (75 grams of pure glucose) and then measuring blood sugar levels.

Of the 74 men, 42 had normal glucose tolerance on the test, 23 had impaired glucose tolerance (also called prediabetes) and 9 had newly diagnosed type 2 diabetes.

The authors found that the glucose solution decreased blood levels of testosterone by as much as 25 percent, regardless of whether the men had diabetes, prediabetes or normal glucose tolerance.

Two hours after glucose administration, the testosterone level remained much lower than before the test in 73 of the 74 men, a statistically significant difference, the authors reported. Of the 66 men who had normal testosterone levels before the test, 10 (15 percent) became hypogonadal at one or more time points during the test.

The results did not differ by changes in insulin levels, according to the abstract. Other hormones that could change testosterone measurements also did not appear to affect results. Hayes said more research is needed to find the factor or factors responsible for this drop in testosterone.

Because glucose intake, and likely food, decreases testosterone, she said, “This research supports the notion that men found to have low testosterone levels should be reevaluated in the fasting state.”

Testosterone Replacement for Men with Low Testosterone Improves Liver Function, Metabolic Syndrome

June 12, 2009—In middle-aged and older men with low testosterone levels, long-term testosterone replacement therapy greatly improves their fatty liver disease and their risk factors for cardiovascular disease and diabetes, a new study found. The results were presented at The Endocrine Society’s 91st Annual Meeting in Washington, D.C.

Testosterone deficiency, which becomes more common with age, is linked not only to decreased libido but also to a number of medical problems. These include the metabolic syndrome—a cluster of metabolic risk factors that increase the chances of developing heart disease, stroke and type 2 diabetes. Nonalcoholic fatty liver disease, also called a fatty liver, commonly co-occurs with the metabolic syndrome and may aggravate the metabolic problems. To receive a diagnosis of the metabolic syndrome, patients must have three of the following five risk factors: abdominal obesity (a large waist line), low HDL (“good”) cholesterol, high triglycerides (fats in the blood), high blood pressure and high blood sugar.

“Physicians often are reluctant to prescribe testosterone for conditions not related to sexual function,” said the study’s co-author, Farid Saad, PhD, of Berlin-headquartered Bayer Schering Pharma. “However, our study shows that testosterone has a much wider therapeutic role than just for improving sexual desire and erectile function.”

The study included 122 testosterone-deficient men, ages 36 to 69 years (mean age: 59.5). Results showed that restoring testosterone to normal levels led to major and progressive improvements in many features of the metabolic syndrome over the 2 years of treatment. Specifically, the men’s weight, waist line and body mass index (a measure of body fat) continued to decline over the full study period. The other metabolic risk factors also significantly improved during the first year of testosterone treatment. Of the 47 men who met the criteria for a diagnosis of the metabolic syndrome at the beginning of the study, 36 (77 percent) no longer had the diagnosis after 2 years of treatment, the authors reported.

Furthermore, liver function significantly improved during the first 12 to 18 months of therapy and stabilized for the remainder of the study period. Treatment also greatly decreased blood levels of C-reactive protein, a measure of inflammation that is linked to increased risk of cardiovascular disease.

“We conclude that testosterone therapy in men with testosterone deficiency can largely improve or even remedy the metabolic syndrome, which will most likely decrease their risk of diabetes and cardiovascular disease,” Saad said.

Study participants received treatment in Bremerhaven, Germany. Treatment used a slow-release, injectable form of the male hormone (testosterone undecanoate) that is not yet available in the United States.

Saad is an employee of Bayer Schering, which makes a brand of testosterone undecanoate.