Testosterone and Cognitive Function

A study in the European Journal of Endocrinology says “Low endogenous levels of testosterone may be related to reduced cognitive ability, and testosterone substitution may improve some aspects of cognitive ability.”

Beauchet O. Testosterone and cognitive function: current clinical evidence of a relationship. Beauchet O. Eur J Endocrinol. 2006 Dec;155(6):773-81.

BACKGROUND: Testosterone levels decline as men age, as does cognitive function. Whether there is more than a temporal relationship between testosterone and cognitive function is unclear. Chemical castration studies in men with prostate cancer suggest that low serum testosterone may be associated with cognitive dysfunction. Low testosterone levels have also been observed in patients with Alzheimer’s disease (AD) and mild cognitive impairment (MCI). This paper reviews the current clinical evidence of the relationship between serum testosterone levels and cognitive function in older men.

METHODS: A systematic literature search was conducted using PubMed and EMBASE to identify clinical studies and relevant reviews that evaluated cognitive function and endogenous testosterone levels or the effects of testosterone substitution in older men.

RESULTS: Low levels of endogenous testosterone in healthy older men may be associated with poor performance on at least some cognitive tests. The results of randomized, placebo-controlled studies have been mixed, but generally indicate that testosterone substitution may have moderate positive effects on selective cognitive domains (e.g. spatial ability) in older men with and without hypogonadism. Similar results have been found in studies in patients with existing AD or MCI.

CONCLUSIONS: Low endogenous levels of testosterone may be related to reduced cognitive ability, and testosterone substitution may improve some aspects of cognitive ability. Measurement of serum testosterone should be considered in older men with cognitive dysfunction. For men with both cognitive impairment and low testosterone, testosterone substitution may be considered. Large, long-term studies evaluating the effects of testosterone substitution on cognitive function in older men are warranted.

Low Testosterone Levels and Mortality

Researchers writing in the Annals of Internal Medicine examined “whether low testosterone levels are a risk factor for mortality in male veterans.”

Shores MM, Matsumoto AM, Sloan KL, Kivlahan DR. Low serum testosterone and mortality in male veterans.
Arch Intern Med. 2006 Aug 14-28;166(15):1660-5.

BACKGROUND: Low serum testosterone is a common condition in aging associated with decreased muscle mass and insulin resistance. This study evaluated whether low testosterone levels are a risk factor for mortality in male veterans.

METHODS: We used a clinical database to identify men older than 40 years with repeated testosterone levels obtained from October 1, 1994, to December 31, 1999, and without diagnosed prostate cancer. A low testosterone level was a total testosterone level of less than 250 ng/dL (<8.7 nmol/L) or a free testosterone level of less than 0.75 ng/dL (<0.03 nmol/L). Men were classified as having a low testosterone level (166 [19.3%]), an equivocal testosterone level (equal number of low and normal levels) (240 [28.0%]), or a normal testosterone level (452 [52.7%]). The risk for all-cause mortality was estimated using Cox proportional hazards regression models, adjusting for demographic and clinical covariates over a follow-up of up to 8 years. RESULTS: Mortality in men with normal testosterone levels was 20.1% (95% confidence interval [CI], 16.2%-24.1%) vs 24.6% (95% CI, 19.2%-30.0%) in men with equivocal testosterone levels and 34.9% (95% CI, 28.5%-41.4%) in men with low testosterone levels. After adjusting for age, medical morbidity, and other clinical covariates, low testosterone levels continued to be associated with increased mortality (hazard ratio, 1.88; 95% CI, 1.34-2.63; P<.001) while equivocal testosterone levels were not significantly different from normal testosterone levels (hazard ratio, 1.38; 95% CI, 0.99%-1.92%; P=.06). In a sensitivity analysis, men who died within the first year (50 [5.8%]) were excluded to minimize the effect of acute illness, and low testosterone levels continued to be associated with elevated mortality.

CONCLUSIONS: Low testosterone levels were associated with increased mortality in male veterans. Further prospective studies are needed to examine the association between low testosterone levels and mortality.

Low Testosterone and the Pro-Inflammatory State in Aging Men

Researchers writing in the Journal of Endocrinological Investigation “suggest that a close relationship exists between the development of a pro-inflammatory state and the decline in Testosterone levels” and that “observational and interventional studies suggest that Testosterone supplementation reduces inflammatory markers in both young and old hypogonadal men. ”

Maggio M, Basaria S, Ceda GP, Ble A, Ling SM, Bandinelli S, Valenti G, Ferrucci L. The relationship between testosterone and molecular markers of inflammation in older men. J Endocrinol Invest. 2005;28(11 Suppl 2):116-9.

Other Links
Testosterone for Men
Testosterone and Bone Loss in Elderly Men
Older Men and Testosterone
More Testosterone Research Concerning Older Men
Testosterone replacement therapy and the risk of prostate cancer
Testosterone, Estrogen and Bone Loss
Risk factors for testosterone loss in aging men

The medicinal value of testicles have been documented in the Bible, the writings of the ancient Egyptians and from India. Indeed, nearly every ancient culture believed that the testicles held some form of masculine power. From our Age Management Booklet…read more

Low Testosterone and Men Over 45

Researchers writing in the International Journal of Clinical Practice, studied the prevalence of hypogonadism (testosterone deficiency) in men age 45 and over and found that nearly 39% of men over 45 suffered from hypogonadism. They noted “Odds ratios for having hypogonadism were significantly higher in men with hypertension, hyperlipidaemia, diabetes, obesity, prostate disease and asthma or chronic obstructive pulmonary disease than in men without these conditions.”

Mulligan T, Frick MF, Zuraw QC, Stemhagen A, McWhirter C. Prevalence of hypogonadism in males aged at least 45 years: the HIM study. Int J Clin Pract. 2006 Jun 2

Risk Factors for Testosterone Loss in Aging Men

Ponholzer A, Plas E, Schatzl G, Struhal G, Brossner C, Mock K, Rauchenwald M, Madersbacher S. Relationship between testosterone serum levels and lifestyle in aging men. Aging Male. 2005 Sep-Dec;8(3):190-3.

From the article abstract: “The aim of this study was to evaluate the association between serum levels of testosterone and free testosterone to lifestyle in aging males. Methods. Men between 45 and 85 years were assessed regarding body mass index (BMI), nicotine and alcohol consumption, stress level, physical and social activity, and sleeping quality by a self-administered questionnaire.”

The researchers concluded that the following were risk factors:
“This prospective study of 375 men aged 45 to 85 years confirms the correlation between age, BMI and smoking with serum levels of testosterone and free testosterone, whereas the investigated variety of lifestyle factors did not show a significant association to serum androgen levels.”

Older Men and Testosterone

This study is sponsored by University Hospital of North Norway
From the study abstract: “Male hypogonadism is a clinical situation characterized by a low serum testosterone level in combination with a diversity of symptoms and signs such as reduced libido and vitality, decreased muscle mass, increased fat mass and depression. Similar symptoms in combination with subnormal testosterone levels are seen in some elderly men. Similar symptoms in combination with subnormal testosterone levels are seen in some elderly men. Low testosterone levels are associated with known cardiovascular risk factors, and men with diabetes and stroke have lower testosterone levels than healthy men. Even though several publications have suggested that testosterone treatment in hypogonadal men may have beneficial effects, it is still uncertain if testosterone substitution in the aging man is indicated. Despite this uncertainty the sale of testosterone has increased enormously the last few years.

We hypothesize that older men with subnormal testosterone levels have a varying degree of dysfunction/symptoms both physically and mentally, and that these dysfunction/symptoms can be improved with testosterone treatment.

Read more about this study at clinicaltrial.gov

Testosterone’s Favorable Effects on an Important Metabolic Component of Chronic Heart Failure

Researchers writing in the European Journal of Heart Failure say that testosterone improves fasting insulin sensitivity in men with chronic heart failure and may also increase lean body mass, these data suggest a favorable effect of testosterone on an important metabolic component of CHF.

Malkin CJ, Jones TH, Channer KS. The effect of testosterone on insulin sensitivity in men with heart failure. Eur J Heart Fail. 2006 Jul 5

Other Articles
Researchers in Sweden writing in the Journal of Bone and Mineral Research, say “not only estrogens but also androgens are of importance for bone health in elderly men.”

Older Men and Testosterone
From the study abstract: “Male hypogonadism is a clinical situation characterized by a low serum testosterone level in combination with a diversity of symptoms and signs such as reduced libido and vitality, decreased muscle mass, increased fat mass and depression.

Testosterone replacement therapy and the risk of prostate cancer
The article says “The belief that testosterone increases the risk of prostate cancer is so widely accepted that study after study that tries to show it and can’t keeps getting repeated over and over,” says Dr. Abraham Morgentaler, a Boston urologist and author of the 2004 review. “People don’t believe it.”

Risk factors for testosterone loss in aging men
“The aim of this study was to evaluate the association between serum levels of testosterone and free testosterone to lifestyle in aging males”

Testosterone, Diabetes, and Cardiovascular Disease

New research says Testosterone may have a protective role in the development of metabolic syndrome and subsequent diabetes mellitus and cardiovascular disease in aging men.

Svartberg J. Epidemiology: testosterone and the metabolic syndrome Int J Impot Res. 2006 Jul 20.

From the study abstract:
Low levels of testosterone, hypogonadism, have several common features with the metabolic syndrome.

In a population-based health survey, testosterone levels were inversely associated with anthropometrical measurements, and the lowest levels of total and free testosterone were found in men with the most pronounced central obesity.

Total testosterone was inversely associated with systolic blood pressure, and men with hypertension had lower levels of both total and free testosterone.

Furthermore, men with diabetes had lower testosterone levels compared to men without a history of diabetes, and an inverse association between testosterone levels and glycosylated hemoglobin was found.

Thus, there are strong associations between low levels of testosterone and the different components of the metabolic syndrome.

In addition, an independent association between low testosterone levels and the metabolic syndrome itself has recently been presented in both cross-sectional and prospective population-based studies.

Thus, testosterone may have a protective role in the development of metabolic syndrome and subsequent diabetes mellitus and cardiovascular disease in aging men. However, clinical trials are needed to confirm this assumption.

 From Our Booklet: Age Management

TESTOSTERONE FOR MEN
The medicinal value of testicles have been documented in the Bible, the writings of the ancient Egyptians and from India. Indeed, nearly every ancient culture believed that the testicles held some form of masculine power.

The use of testosterone as a means of restoring vitality can be traced in the modern era to the work of famed medical researcher Charles Edouard Brown-Séquard (1817-1894). Brown-Séquard had been hailed as a medial pioneer for his ability to treat difficult and previously untreatable disorders of the nervous system. At the age of 72, when he noticed his declining vitality, he injected himself with the extracts of crushed testicles from dogs and guinea pigs and increased his physical strength and intellectual abilities and announced his results to his colleagues.

Brown-Séquard’s work sparked an influx of research and medical use of testicles, however, technology could not, at that time, substantiate his claims. Read more

Testosterone replacement therapy and the risk of prostate cancer. Is there a link?

An article by Susan Brink of the Los Angeles Times recently appeared in newspapers around the country discussing the link between testosterone and prostate cancer.

The article says “The belief that testosterone increases the risk of prostate cancer is so widely accepted that study after study that tries to show it and can’t keeps getting repeated over and over,” says Dr. Abraham Morgentaler, a Boston urologist and author of the 2004 review. “People don’t believe it.”

Here is a press release from the Harvard Medical School.

“Boston–January 2004, Harvard Medical School affiliate Beth Israel Deaconess Medical Center–A retrospective analysis by researchers at Beth Israel Deaconess Medical Center published in The New England Journal of Medicine found no causal relationship between testosterone replacement and prostate cancer or heart disease risk. The comprehensive review of 72 studies, addresses the current controversy about testosterone replacement therapy and its potential health risks to men.”

« Previous Page