@article {1266, title = {Higher serum free testosterone concentration in older women is associated with greater bone mineral density, lean body mass, and total fat mass: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {96}, year = {2011}, month = {2011 Apr}, pages = {989-96}, abstract = {

CONTEXT: The physiological importance of endogenous testosterone (T) in older women is poorly understood.

OBJECTIVE: The aim of the study was to determine the association of higher total and free T levels with bone mineral density (BMD), lean body mass, and fat mass in elderly women.

DESIGN: Total and free T were measured using sensitive assays in 232 community-dwelling women aged 67-94 yr who were enrolled in the Cardiovascular Health Study and had dual-energy x-ray absorptiometry scans. Cross-sectional analyses were performed to examine associations between total and free T and BMD and body composition.

RESULTS: In adjusted models, total T was directly associated with BMD at the lumbar spine (P = 0.04) and hip (P = 0.001), but not body composition outcomes, in all women, and after excluding estrogen users and adjusting for estradiol (P = 0.04 and 0.01, respectively). Free T was positively related to hip BMD, lean body mass, and body fat (all P < 0.05), with more than 10\% differences in each outcome between women at the highest and lowest ends of the free T range, with attenuation after excluding estrogen users and adjusting for estradiol.

CONCLUSIONS: In the setting of the low estradiol levels found in older women, circulating T levels were associated with bone density. Women with higher free T levels had greater lean body mass, consistent with the anabolic effect of T, and, in contrast to men, greater fat mass. Mechanistic studies are required to determine whether a causal relationship exists between T, bone, and body composition in this population and the degree to which any T effects are estrogen-independent.

}, keywords = {Adipose Tissue, Aged, Aged, 80 and over, Body Mass Index, Bone Density, Cardiovascular Physiological Phenomena, Cohort Studies, Female, Health, Humans, Organ Size, Osmolar Concentration, Osteoporosis, Postmenopausal, Testosterone, Thinness, Up-Regulation}, issn = {1945-7197}, doi = {10.1210/jc.2010-0926}, author = {Rariy, Chevon M and Ratcliffe, Sarah J and Weinstein, Rachel and Bhasin, Shalender and Blackman, Marc R and Cauley, Jane A and Robbins, John and Zmuda, Joseph M and Harris, Tamara B and Cappola, Anne R} } @article {1373, title = {The natural history of subclinical hypothyroidism in the elderly: the cardiovascular health study.}, journal = {J Clin Endocrinol Metab}, volume = {97}, year = {2012}, month = {2012 Jun}, pages = {1962-9}, abstract = {

CONTEXT: Studies of long-term outcomes of subclinical hypothyroidism have assessed only baseline thyroid function, despite natural transitions to euthyroidism and overt hypothyroidism over time.

OBJECTIVE: We provide estimates of persistence, resolution, and progression of subclinical hypothyroidism over 4 yr, stratified by baseline TSH, anti-thyroid peroxidase antibody (TPOAb) status, age, and sex.

DESIGN, SETTING, AND PARTICIPANTS: Participants were 3996 U.S. individuals at least 65 yr old enrolled in the Cardiovascular Health Study. Subclinical hypothyroidism was detected at baseline in 459 individuals not taking thyroid medication.

MAIN OUTCOME MEASURE: Thyroid function was evaluated at 2 and 4 yr and initiation of thyroid medication annually. Results were stratified by baseline TSH, TPOAb status, age, and sex.

RESULTS: Persistence of subclinical hypothyroidism was 56\% at 2 and 4 yr. At 2 yr, resolution was more common with a TSH of 4.5-6.9 mU/liter (46 vs. 10\% with TSH 7-9.9 mU/liter and 7\% with TSH >=10 mU/liter; P < 0.001) and with TPOAb negativity (48 vs. 15\% for positive; P < 0.001). Higher TSH and TPOAb positivity were independently associated with lower likelihood of reversion to euthyroidism (P < 0.05). TSH of 10 mU/liter or higher was independently associated with progression to overt hypothyroidism (P < 0.05). Transitions between euthyroidism and subclinical hypothyroidism were common between 2 and 4 yr. Age and sex did not affect transitions.

CONCLUSIONS: Subclinical hypothyroidism persists for 4 yr in just over half of older individuals, with high rates of reversion to euthyroidism in individuals with lower TSH concentrations and TPOAb negativity. Future studies should examine the impact of transitions in thyroid status on clinical outcomes.

}, keywords = {Age Distribution, Aged, Aged, 80 and over, Autoantibodies, Cardiovascular Diseases, Cohort Studies, Disease Progression, Female, Humans, Hypothyroidism, Iodide Peroxidase, Logistic Models, Longitudinal Studies, Male, Prevalence, Risk Factors, Seroepidemiologic Studies, Severity of Illness Index, Sex Distribution, Thyrotropin}, issn = {1945-7197}, doi = {10.1210/jc.2011-3047}, author = {Somwaru, Lily L and Rariy, Chevon M and Arnold, Alice M and Cappola, Anne R} }