first, it is not just in old people as was thought--see
Pharmacotherapy 19(8):951-956, 1999
http://www.medscape.com/viewarticle/418019_2
Reductions in total testosterone are not usually observed in men until the sixth decade; however, decline in free concentrations are seen earlier, at a rate of approximately 1% per year between ages
40 and 70 years.[5] This is explained by increasing SHBG concentrations at a rate of about 1.2% per year. As the number of testosterone-binding sites on SHBG increases, the unbound fraction of the hormone decreases. As a result of declines in both Leydig cell function and HPG axis sensitivity, aging men appear unable to compensate for the reduction in circulating testosterone.[6] In fact, 7% of men aged 40-60 years, 20% of those 60-80 years, and 35% over 80 years have total concentrations below the lower limit of normal (350 ng/dl).[
but the results in trt in old guys is pretty significant
there a whole bunch on studies that are in process or just finsihed re: TRT and men 60+---a little does little, a whole bunch does little-
1, somewhere in between and the results are just remarkable
3: concentration, perception, reasoning, and higher level logical reasoning.
and, of course, increase in strength/balance/ect
http://ajpendo.physiology.org/cgi/reprint/00362.2001v1.pdf
1. 250/tested after 5 days (but qualified that spatial cognition may take longer to retrun)
Testosterone and cognition in elderly men: a single testosterone injection blocks the practice effect in verbal fluency, but has no effect on spatial or verbal memory . Biological Psychiatry , Volume 47 , Issue 7 , Pages 650 - 654
O . Wolf
http://linkinghub.elsevier.com/retrieve/pii/S0006322399001456
2. can't find the srticle--it is a 2007/8 J.Andrololgy i think
3. SCOTT D. MOFFAT (2005) Effects of Testosterone on Cognitive and Brain Aging in Elderly Men Annals of the New York Academy of Sciences 1055 (1) ,
80–92 doi:10.1196/annals.1323.014 (100-150/week)
Abstract
Older age is associated with functional declines throughout the body, including some aspects of cognitive performance. While dementia develops in only some elderly individuals, declines in cognitive functioning have an impact on daily living for many others. There are individual differences in age-related cognitive changes, however, and the factors that contribute to this variability have not been well-characterized. Recent evidence suggesting that age-related alterations in the endocrine environment may modulate cognitive changes has generated considerable interest. Currently, there is a discordance between the rapidly expanding number of studies of the possible neuroprotective effects of estrogens in postmenopausal women, and the relative dearth of analogous research on the putative effects of testosterone on cognitive and brain function in older men. This paper reviews the extant literature and reports new findings on the effects of testosterone loss and supplementation on cognitive and brain function in elderly men. Preliminary evidence suggests that testosterone loss may be a risk factor for cognitive decline and possibly for dementia. Conversely, the maintenance of higher testosterone levels either endogenously or through exogenous supplementation may prove beneficial for cognitive and brain function in elderly men. However, most studies are associational in nature and the intervention studies are of short-duration testosterone exposure in small samples of subjects. Large-scale placebo-controlled intervention studies are required to resolve ambiguities in the literature. Testosterone intervention to ameliorate cognitive decline may be warranted only when the efficacy and safety of longer-term use is firmly established.
even as an aid for alzheimers see
http://www.sciencedaily.com/releases/2005/12/051214083816.htm
NEUROLOGY 2005;64:2063-2068
© 2005 American Academy of Neurology
Testosterone improves spatial memory in men with Alzheimer disease and mild cognitive impairment
Objective: To determine the efficacy of testosterone (T) supplementation on cognition in a sample of men with Alzheimer disease (AD) or mild cognitive impairment (MCI).
Methods: Fifteen patients with AD and 17 patients with MCI aged 63 to 85 years completed a randomized, double-blind, placebo-controlled study. Nineteen participants received weekly intramuscular (IM) injections of 100 mg T enanthate and 13 participants received weekly injections of placebo (saline) for 6 weeks. Cognitive evaluations using a battery of neuropsychological tests were conducted at baseline, week 3, and week 6 of treatment and again after 6 weeks of washout.
Results: Peak serum total T levels were raised from baseline an average of 295% in the active treatment group. Improvements in spatial memory (p < 0.05) and constructional abilities (p < 0.05) and verbal memory were evident in the T group. No changes were noted for selective and divided attention or language. Prostate specific antigen did not significantly change during this brief treatment.
Conclusion: Testosterone supplementation may benefit selective cognitive functions in men with Alzheimer disease and mild cognitive impairment.
Effects of Testosterone on Cognition and Mood in Male Patients With Mild Alzheimer Disease and Healthy Elderly Men
Arch Neurol. 2006;63:177-185. Published online December 12, 2005 (doi:10.1001/archneur.63.2.nct50002). Context There is a compelling need for therapies that prevent, defer the onset, slow the progression, or improve the symptoms of Alzheimer disease (AD).
Objective To evaluate the effects of testosterone therapy on cognition, neuropsychiatric symptoms, and quality of life in male patients with mild AD and healthy elderly men.
Design Twenty-four–week, randomized, double-blind, placebo-controlled, parallel-group study.
Setting Memory disorders clinics as well as general neurology and medicine clinics from University of California medical centers at Los Angeles, San Francisco, and Irvine.
Patients or Other Participants Sixteen male patients with AD and 22 healthy male control subjects. Healthy elderly control men were recruited from the community through advertisements as well as through the university-based clinics.
Intervention Testosterone and placebo, in the form of hydroalcoholic gel (75 mg), were applied daily to the skin of the participants.
Main Outcome Measures Instruments assessing cognitive functioning (Alzheimer’s Disease Assessment Scale–Cognitive Subscale, California Verbal Learning Test, Block Design Subtest, Judgment of Line Orientation, Developmental Test of Visual-Motor Integration), neuropsychiatric symptoms (Neuropsychiatric Inventory), global functioning (Clinician’s Interview-Based Impression of Change), and quality of life (Quality of Life–Alzheimer Disease Scale).
Results For the patients with AD, the testosterone-treated group had significantly greater improvements in the scores on the caregiver version of the quality-of-life scale (P = .01). No significant treatment group differences were detected in the cognitive scores at end of study, although numerically greater improvement or less decline on measures of visuospatial functions was demonstrated with testosterone treatment compared with placebo. In the healthy control group, a nonsignificant trend toward greater improvement in self-rated quality of life was observed in the testosterone-treated group (P = .09) compared with placebo treatment. No difference between the treatment groups was detected in the remaining outcome measures. Testosterone treatment was well tolerated with few adverse effects relative to placebo.
Conclusions Results suggest that testosterone replacement therapy improved overall quality of life in patients with AD. Testosterone had minimal effects on cognition
BUt as usual, the establishment is hypercautious....
Hypogonadism of ageing - does low testosterone in ageing men require treatment?
In the healthy ageing male, a number of studies have shown that blood levels of the male hormone, testosterone, falls by a modest 1-2% annually from the age of 40 onwards. The rate and extent of this fall in testosterone varies between individuals and usually brings the levels to around the lower part of the normal range for young men eg 8-11nmol/l, in whom the reference testosterone range for blood sampled at 09.00am is 10-30nmol/l. The clinical significance of this downward trend is unclear.
Ageing is associated with increased fat (particularly abdominal fat), decreased muscle bulk, muscle strength and restricted physical activity, a decrease in bone mineral density, and a greater fracture risk, and diminished / poorer quality sexual function. Although these non-specific clinical features can occur in many chronic illnesses, they do share an uncanny resemblance to some of the key symptoms of hypogonadism - testosterone deficiency resulting from diseases in the testis or pituitary gland. There has been an assumption by many physicians that these symptoms must be caused by testosterone deficiency, and the term ‘andropause’ (or ‘male menopause’ in the popular media) has been used in this context. However, a cause and effect relationship has not been established by any means and, at present, it is uncertain how many of the symptoms and changes encountered in the ageing male might be reversed by restoration of blood testosterone levels to those seen in younger men. In some relatively small studies, testosterone administration to middle-aged and elderly men with muscle weakness and poor bone density and low or low normal testosterone, testosterone supplementation has been shown to increase bone density and muscle mass with a slight reduction in fat mass.
Whether these physiological changes also lead to physical and psychological improvements and enhanced quality of life is still uncertain. Furthermore, there may also be significant side effects to testosterone supplementation in elderly men, which may lead to an increase in sleep related problems (eg sleep apnoea: a situation where normal breathing during sleep is interrupted by pauses leading to lack of oxygenation of the blood, a rise in blood pressure etc), prostate enlargement, progression of previously undiagnosed prostate cancer, and an inappropriate increase in circulating red cell numbers (this can thicken the blood and make a patient more prone to thrombosis).
While patients with symptomatic and unequivocal biochemical deficiency of testosterone due to hypogonadism will clearly benefit from testosterone replacement, the potential benefits and risks of treating low testosterone in ageing men are currently unknown. To resolve the growing uncertainties, there is an urgent need for large properly designed studies to investigate the risk to benefit effects of testosterone supplementation in symptomatic ageing men with low normal testosterone levels. There are several such studies underway, and results are likely to become available in 2006/2007.
Until the results of such studies become available, testosterone supplementation should be withheld from healthy ageing men and administered to symptomatic ageing men only where there is clinical and biochemical evidence of androgen deficiency according to criteria established in the management of younger patients with hypogonadism. In the interim, patients concerned about potential symptoms of hypogonadism should consult their GP, who will be best positioned to make the initial assessment and, where appropriate, carry out the necessary blood tests. An onward referral to an endocrinologist is occasionally required. Some patients experiencing the symptoms described above may benefit from a change in lifestyle – for example increasing exercise, weight loss – or from diagnosis and treatment of mild depression.
PMGB 21.1.05.