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Context: The androgen receptor (AR) gene exon 1 CAG repeat length has been proposed to be a determinant of between-individual variations in androgen action in target tissues, which might regulate phenotypic differences of human ageing. However, findings on its phenotypic effects are inconclusive. Objective: To assess whether the AR CAG repeat length is associated with longitudinal changes in endpoints that are influenced by testosterone (T) levels in middle-aged and elderly European men. Design: Multinational European observational prospective cohort study. Participants: A total of 1887 men (mean ± s.d. age: 63 ± 11 years; median follow up: 4.3 years) from centres of eight European countries comprised the analysis sample after exclusion of those with diagnosed diseases of the hypothalamic-pituitary-testicular (HPT) axis. Main outcome measures: Longitudinal associations between the AR CAG repeat and changes in androgen-sensitive endpoints (ASEs) and medical conditions were assessed using regression analysis adjusting for age and centre. The AR CAG repeat length was treated as both a continuous and a categorical (6-20; 21-23; 24-39 repeats) predictor. Additional analysis investigated whether results were independent of baseline T or oestradiol (E2) levels. Results: The AR CAG repeat, when used as a continuous or a categorical predictor, was not associated with longitudinal changes in ASEs or medical conditions after adjustments. These results were independent of T and E2 levels.Conclusion: Within a 4-year time frame, variations in the AR CAG repeat do not contribute to the rate of phenotypic ageing, over and above, which might be associated with the age-related decline in T levels. [ABSTRACT FROM AUTHOR]

Objective: Interrelationships between hormones of the hypothalamic-pituitary-testicular (HPT) axis, hypogonadism, vitamin D and seasonality remain poorly defined. We investigated whether HPT axis hormones and hypogonadism are associated with serum levels of 25-hydroxyvitamin D (25(OH)D) in men. Design and methods: Cross-sectional survey of 3369 community-dwelling men aged 40-79 years in eight European centres. Testosterone (T), oestradiol (E2) and dihydrotestosterone were measured by gas chromatography-mass spectrometry; LH, FSH, sex hormone binding globulin (SHBG), 25(OH)D and parathyroid hormone by immunoassay. Free T was calculated from total T, SHBG and albumin. Gonadal status was categorised as eugonadal (normal T/LH), secondary (low T, low/normal LH), primary (low T, elevated LH) and compensated (normal T, elevated LH) hypogonadism. Associations of HPT axis hormones with 25(OH)D were examined using linear regression and hypogonadism with vitamin D using multinomial logistic regression. Results: In univariate analyses, free T levels were lower (P=0.02) and E2 and LH levels were higher (P<0.05) in men with vitamin D deficiency <25(OH)D !50 nmol/l). 25(OH)D was positively associated with total and free T and negatively with E2 and LH in age- and centre-adjusted linear regressions. After adjusting for health and lifestyle factors, no significant associations were observed between 25(OH)D and individual hormones of the HPT axis. However, vitamin D deficiency was significantly associated with compensated (relative risk ratio (RRR)=1.52, P=0.03) and secondary hypogonadism (RRR=1.16, P=0.05). Seasonal variation was only observed for 25(OH)D (P<0.001). Conclusions: Secondary and compensated hypogonadism were associated with vitamin D deficiency and the clinical significance of this relationship warrants further investigation. [ABSTRACT FROM AUTHOR]

Objective: To assess the influence of sex hormones on markers of bone turnover and to explore the association between these markers and bone health in middle-aged and elderly European men. Design: A cross-sectional population-based survey. Methods: Men aged 40-79 years were recruited from population registers in eight European centres. Subjects completed a postal questionnaire which included questions concerning lifestyle and were invited to undergo quantitative ultrasound (QUS) of the calcaneus and to provide a fasting blood sample from which the bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (b C-terminal cross-linked telopeptide (b-cTX)), total testosterone, total oestradiol (E2), sex hormone-binding globulin (SHBG) and insulin-like growth factor 1 (IGF1) were measured. Dualenergy X-ray absorptiometry (DXA) of the hip and lumbar spine was performed in two centres Results: A total of 3120, mean age 59.9 years (S.D.Z11.0) were included. After adjustment for centre, age, height, weight, lifestyle factors, season and other hormones, total and free E2 were negatively associated with &bgr;-cTX but not P1NP while SHBG, IGF1 and parathyroid hormone (PTH) were positively associated with both &bgr;-cTX and P1NP. Total or free testosterone was not independently associated with either bone marker. After the same adjustments, higher levels of both bone markers were significantly associated with lower QUS parameters and lower DXA-assessed bone density at the total hip and lumbar spine. Conclusions: E2, SHBG, IGF1 and PTH contribute significantly to the regulation/rate of bone turnover in middle-aged and older European men. Higher rates of bone remodelling are negatively associated with male bone health. [ABSTRACT FROM AUTHOR]