@article {9487, title = {Factors Associated With Circulating Sex Hormones in Men : Individual Participant Data Meta-analyses.}, journal = {Ann Intern Med}, year = {2023}, month = {2023 Aug 29}, abstract = {

BACKGROUND: Various factors modulate circulating testosterone in men, affecting interpretation of testosterone measurements.

PURPOSE: To clarify factors associated with variations in sex hormone concentrations.

DATA SOURCES: Systematic literature searches (to July 2019).

STUDY SELECTION: Prospective cohort studies of community-dwelling men with total testosterone measured using mass spectrometry.

DATA EXTRACTION: Individual participant data (IPD) (9 studies; ~= 21 074) and aggregate data (2 studies; ~= 4075). Sociodemographic, lifestyle, and health factors and concentrations of total testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone, and estradiol were extracted.

DATA SYNTHESIS: Two-stage random-effects IPD meta-analyses found a nonlinear association of testosterone with age, with negligible change among men aged 17 to 70 years (change per SD increase about the midpoint, -0.27 nmol/L [-7.8 ng/dL] [CI, -0.71 to 0.18 nmol/L {-20.5 to 5.2 ng/dL}]) and decreasing testosterone levels with age for men older than 70 years (-1.55 nmol/L [-44.7 ng/dL] [CI, -2.05 to -1.06 nmol/L {-59.1 to -30.6 ng/dL}]). Testosterone was inversely associated with body mass index (BMI) (change per SD increase, -2.42 nmol/L [-69.7 ng/dL] [CI, -2.70 to -2.13 nmol/L {-77.8 to -61.4 ng/dL}]). Testosterone concentrations were lower for men who were married (mean difference, -0.57 nmol/L [-16.4 ng/dL] [CI, -0.89 to -0.26 nmol/L {-25.6 to -7.5 ng/dL}]); undertook at most 75 minutes of vigorous physical activity per week (-0.51 nmol/L [-14.7 ng/dL] [CI, -0.90 to -0.13 nmol/L {-25.9 to -3.7 ng/dL}]); were former smokers (-0.34 nmol/L [-9.8 ng/dL] [CI, -0.55 to -0.12 nmol/L {-15.9 to -3.5 ng/dL}]); or had hypertension (-0.53 nmol/L [-15.3 ng/dL] [CI, -0.82 to -0.24 nmol/L {-23.6 to -6.9 ng/dL}]), cardiovascular disease (-0.35 nmol/L [-10.1 ng/dL] [CI, -0.55 to -0.15 nmol/L {-15.9 to -4.3 ng/dL}]), cancer (-1.39 nmol/L [-40.1 ng/dL] [CI, -1.79 to -0.99 nmol/L {-51.6 to -28.5 ng/dL}]), or diabetes (-1.43 nmol/L [-41.2 ng/dL] [CI, -1.65 to -1.22 nmol/L {-47.6 to -35.2 ng/dL}]). Sex hormone-binding globulin was directly associated with age and inversely associated with BMI. Luteinizing hormone was directly associated with age in men older than 70 years.

LIMITATION: Cross-sectional analysis, heterogeneity between studies and in timing of blood sampling, and imputation for missing data.

CONCLUSION: Multiple factors are associated with variation in male testosterone, SHBG, and LH concentrations. Reduced testosterone and increased LH concentrations may indicate impaired testicular function after age 70 years. Interpretation of individual testosterone measurements should account particularly for age older than 70 years, obesity, diabetes, and cancer.

PRIMARY FUNDING SOURCE: Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).

}, issn = {1539-3704}, doi = {10.7326/M23-0342}, author = {Marriott, Ross J and Murray, Kevin and Adams, Robert J and Antonio, Leen and Ballantyne, Christie M and Bauer, Douglas C and Bhasin, Shalender and Biggs, Mary L and Cawthon, Peggy M and Couper, David J and Dobs, Adrian S and Flicker, Leon and Handelsman, David J and Hankey, Graeme J and Hannemann, Anke and Haring, Robin and Hsu, Benjumin and Karlsson, Magnus and Martin, Sean A and Matsumoto, Alvin M and Mellstr{\"o}m, Dan and Ohlsson, Claes and O{\textquoteright}Neill, Terence W and Orwoll, Eric S and Quartagno, Matteo and Shores, Molly M and Steveling, Antje and Tivesten, {\r A}sa and Travison, Thomas G and Vanderschueren, Dirk and Wittert, Gary A and Wu, Frederick C W and Yeap, Bu B} } @article {9804, title = {Sociodemographic, lifestyle, and medical factors associated with calculated free testosterone concentrations in men: individual participant data meta-analyses.}, journal = {Eur J Endocrinol}, volume = {191}, year = {2024}, month = {2024 Oct 29}, pages = {523-534}, abstract = {

OBJECTIVE: Sociodemographic, lifestyle, and medical variables influence total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations. The relationship between these factors and "free" T remains unclear. We examined 21 sociodemographic, lifestyle, and medical predictors influencing calculated free T (cFT) in community-dwelling men across ages.

DESIGN: This is a cross-sectional analysis in 20 631 participants in the Androgens in Men Study.

METHODS: Individual participant data (IPD) were provided by 9 cohorts. Total T was determined using mass spectrometry, SHBG using immunoassays, and cFT using the Vermeulen formula. Associations were analyzed using 2-stage random effects IPD meta-analyses.

RESULTS: Cohort median ages ranged from 40 to 76 years and median cFT concentrations from 174.3 to 422.8 pmol/L. In men aged 17-99 years, there was a linear inverse association of cFT with age (-57.2 pmol/L [95\% confidence interval, -69.4, -44.9] per 1 SD increase in age). Calculated free T increased with increasing baseline body mass index (BMI) among men with BMI < 23.6 kg/m2, but decreased among men with BMI > 23.6 kg/m2 (-24.7 pmol/L [-29.1, -20.3] per 1 SD increase in the 25.4-29.6 kg/m2 BMI range). Calculated free T was lower in younger men, who were married or in a de facto relationship (-18.4 pmol/L [-27.6, -9.3]) and in men who formerly smoked (-5.7 pmol/L [-8.9, -2.6]), were in poor general health (-14.0 pmol/L [-20.1, -7.8]), and had diabetes (-19.6 pmol/L [-23.0, -16.3]), cardiovascular disease (-5.8 pmol/L [-8.3, -3.2]), or cancer (-19.2 pmol/L [-24.4, -14.1]).

CONCLUSIONS: Calculated free T was most prominently associated with age and BMI. The linear, inverse association with age, nonlinear association with BMI, and presence of diabetes, cancer, and sociodemographic factors should be considered when interpreting cFT values.

}, keywords = {Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Body Mass Index, Cohort Studies, Cross-Sectional Studies, Humans, Life Style, Male, Middle Aged, Sex Hormone-Binding Globulin, Sociodemographic Factors, Socioeconomic Factors, Testosterone, Young Adult}, issn = {1479-683X}, doi = {10.1093/ejendo/lvae133}, author = {Narinx, Nick and Marriott, Ross J and Murray, Kevin and Adams, Robert J and Ballantyne, Christie M and Bauer, Douglas C and Bhasin, Shalender and Biggs, Mary L and Cawthon, Peggy M and Couper, David J and Dobs, Adrian S and Flicker, Leon and Hankey, Graeme J and Hannemann, Anke and Wilkening, Robin and Martin, Sean A and Matsumoto, Alvin M and Ohlsson, Claes and O{\textquoteright}Neill, Terence W and Orwoll, Eric S and Shores, Molly M and Steveling, Antje and Travison, Thomas G and Wittert, Gary A and Wu, Frederick C W and Antonio, Leen and Vanderschueren, Dirk and Yeap, Bu B} }