HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: EJE-07-0873v1 159/4/459    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Lapauw, B Articles by Kaufman, J M PubMed PubMed Citation Articles by Lapauw, B Articles by Kaufman, J M

The decline of serum testosterone levels in community-dwelling men over 70 years of age: descriptive data and predictors of longitudinal changes

B Lapauw^1,2,*, S Goemaere^2,*, H Zmierczak², I Van Pottelbergh^1,, A Mahmoud¹, Y Taes¹, D De Bacquer³, S Vansteelandt⁴ and J M Kaufman^1,2

¹ Department of Endocrinology² , Unit for Osteoporosis and Metabolic Bone Diseases³ Department of Public Health, Ghent University Hospital, De Pintelaan 185, 6K12 I.E., B-9000 Ghent, Belgium⁴ Department of Applied Mathematics and Computer Science, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium

(Correspondence should be addressed to B Lapauw; Email: bruno.lapauw{at}ugent.be)

Objective: This study was designed to assess longitudinal changes in serum testosterone levels, explore relationships with aging, genetic-, health-, and lifestyle-related factors, and investigate predictors of changes in healthy elderly men.

Design: Population-based, longitudinal, 4-year observational study in 221 community-dwelling men aged 71–86 years at baseline.

Methods: Hormone levels assessed by immunoassay, anthropometry, questionnaires on general health, and genetic polymorphisms. Predictors of changes in testosterone levels explored using linear mixed-effects modeling for longitudinal analyses.

Results: Total testosterone (TT), free testosterone, and bioavailable testosterone (BioT) levels decreased with aging, decreases in BioT being most marked. No changes in sex hormone-binding globulin (SHBG) or estradiol (E₂), while LH and FSH levels increased during follow-up. Subjects who gained weight displayed a greater decline in TT levels, mainly due to decreasing SHBG levels. However, baseline body composition was not predictive of subsequent changes in testosterone levels. Baseline E₂ (P=0.023 to 0.004), LH (P=0.046 to 0.005), and FSH (P<0.002) levels were independently positively associated with a faster decline in testosterone fractions, although only FSH remained significant when adjusting for baseline testosterone (P=0.041–0.035). Carriers of a ‘TA’ haplotype of the estrogen receptor gene (ER) PvuII and XbaI polymorphisms displayed a slower decline of TT and BioT (P=0.041–0.007).

Conclusions: In elderly men with already low serum testosterone levels, a further decline was observed, independent of baseline age. The identification of FSH levels as a predictor of this decline appears to reflect the testicular mechanisms of aging-related changes in testosterone production, whereas associations with E₂ and ER polymorphisms are suggestive of estrogen-related processes, possibly related to changes in the neuroendocrine regulation of testosterone production.