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| 62. |
- Wu, Frederick C W, et al.
(författare)
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Hypothalamic-pituitary-testicular axis disruptions in older men are differentially linked to age and modifiable risk factors: The European Male Aging Study
- 2008
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 93:7, s. 2737-2745
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT The cause of declining testosterone (T) in aging men and their relationships with risk factors are unclear. OBJECTIVE To investigate the relationships between lifestyle and health with reproductive hormones in aging men. DESIGN Baseline cross-sectional survey on 3200 community - dwelling men aged 40 - 79 yr from a prospective cohort study in 8 European countries. RESULTS Four predictors were associated with distinct modes of altered function:- Age: lower free T (FT) (-3.12 pmol/L/ yr, p<0.001) with raised luteinizing hormone (LH) suggesting impaired testicular function. Obesity: lower total T (TT) (-2.32 nmol/L) and FT (-17.60 pmol/L) for BMI >/=25 - <30 kg/m(2) and lower TT (-5.09 nmol/L,) and FT (-53.72 pmol/L) for BMI >/=30 kg/m(2) (p <0.001 - 0.01, referent: BMI <25 kg/m(2)) with unchanged/decreased LH, indicating hypothalamus/pituitary dysfunction. Co-morbidity: lower TT (-0.80 nmol/L, p <0.01) with unchanged LH in younger men but higher LH in older men. Smoking: higher sex hormone binding globulin (SHBG) (5.96 nmol/L, p <0.001) and LH (0.77 U/L, p <0.01) with increased TT (1.31 nmol/L, p<0.001) but not FT, compatible with a resetting of T-LH negative feedback due to elevated SHBG. CONCLUSIONS Complex multiple alterations in the hypothalamic-pituitary-testicular axis function exist in ageing men against a background of progressive age-related testicular impairment. These changes are differentially linked to specific risk factors. Some risk factors operate independently of but others interact with age, in contributing to the T decline. These potentially modifiable risk factors suggest possible preventative measures to maintain T during in aging men.
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| 63. |
- Wu, Frederick C. W., et al.
(författare)
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Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men
- 2010
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 363:2, s. 123-135
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Konferensbidrag (refereegranskat)abstract
- BACKGROUND The association between aging-related testosterone deficiency and late-onset hypogonadism in men remains a controversial concept. We sought evidence-based criteria for identifying late-onset hypogonadism in the general population on the basis of an association between symptoms and a low testosterone level. METHODS We surveyed a random population sample of 3369 men between the ages of 40 and 79 years at eight European centers. Using questionnaires, we collected data with regard to the subjects' general, sexual, physical, and psychological health. Levels of total testosterone were measured in morning blood samples by mass spectrometry, and free testosterone levels were calculated with the use of Vermeulen's formula. Data were randomly split into separate training and validation sets for confirmatory analyses. RESULTS In the training set, symptoms of poor morning erection, low sexual desire, erectile dysfunction, inability to perform vigorous activity, depression, and fatigue were significantly related to the testosterone level. Increased probabilities of the three sexual symptoms and limited physical vigor were discernible with decreased testosterone levels (ranges, 8.0 to 13.0 nmol per liter [2.3 to 3.7 ng per milliliter] for total testosterone and 160 to 280 pmol per liter [46 to 81 pg per milliliter] for free testosterone). However, only the three sexual symptoms had a syndromic association with decreased testosterone levels. An inverse relationship between an increasing number of sexual symptoms and a decreasing testosterone level was observed. These relationships were independently confirmed in the validation set, in which the strengths of the association between symptoms and low testosterone levels determined the minimum criteria necessary to identify late-onset hypogonadism. CONCLUSIONS Late-onset hypogonadism can be defined by the presence of at least three sexual symptoms associated with a total testosterone level of less than 11 nmol per liter (3.2 ng per milliliter) and a free testosterone level of less than 220 pmol per liter (64 pg per milliliter).
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