Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men
The association between aging-related testosteronedeficiency and late-onset hypogonadism in men remains a controversialconcept. In this recently published article in the New England Journal of Medicine, the authors sought evidence-based criteria for identifying late-onsethypogonadism in the general population on the basis of an associationbetween symptoms and a low testosterone level. They surveyed a random population sample of 3369 men betweenthe ages of 40 and 79 years at eight European centers. Usingquestionnaires, they collected data with regard to the subjects'general, sexual, physical, and psychological health. Levelsof total testosterone were measured in morning blood samplesby mass spectrometry, and free testosterone levels were calculatedwith the use of Vermeulen's formula. Data were randomly splitinto separate training and validation sets for confirmatoryanalyses. The results showed in the training set, symptoms of poor morning erection,low sexual desire, erectile dysfunction, inability to performvigorous activity, depression, and fatigue were significantlyrelated to the testosterone level. Increased probabilities ofthe three sexual symptoms and limited physical vigor were discerniblewith decreased testosterone levels (ranges, 8.0 to 13.0 nmolper liter [2.3 to 3.7 ng per milliliter] for total testosteroneand 160 to 280 pmol per liter [46 to 81 pg per milliliter] forfree testosterone). However, only the three sexual symptomshad a syndromic association with decreased testosterone levels.An inverse relationship between an increasing number of sexualsymptoms and a decreasing testosterone level was observed. Theserelationships were independently confirmed in the validationset, in which the strengths of the association between symptomsand low testosterone levels determined the minimum criterianecessary to identify late-onset hypogonadism. From the above results the authors concluded that late-onset hypogonadism can be defined by the presenceof at least three sexual symptoms associated with a total testosteronelevel 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).
REFERENCE:
Frederick C.W. Wu, M.D., Abdelouahid Tajar, Ph.D., Jennifer M. Beynon, M.B., Stephen R. Pye, M.Phil., Alan J. Silman, M.D., Joseph D. Finn, B.Sc., Terence W. O'Neill, M.D., Gyorgy Bartfai, M.D., Felipe F. Casanueva, M.D., Ph.D., Gianni Forti, M.D., Aleksander Giwercman, M.D., Ph.D., Thang S. Han, M.D., Ph.D., Krzysztof Kula, M.D., Ph.D., Michael E.J. Lean, M.D., Neil Pendleton, M.D., Margus Punab, M.D., Ph.D., Steven Boonen, M.D., Ph.D., Dirk Vanderschueren, M.D., Ph.D., Fernand Labrie, M.D., Ph.D., Ilpo T. Huhtaniemi, M.D., Ph.D., for the EMAS Group. Identification of Late-Onset Hypogonadism in Middle-Aged and Elderly Men. NEJM 2010; 363:123-135
