@article {7249, title = {Testosterone, Dihydrotestosterone, Sex Hormone Binding Globulin and Incident Diabetes among Older Men: the Cardiovascular Health Study.}, journal = {J Clin Endocrinol Metab}, year = {2016}, month = {2016 Oct 12}, pages = {jc20162623}, abstract = {

CONTEXT: Although sex hormone binding globulin (SHBG) and testosterone (T) have been inversely associated with risk of diabetes, few studies have examined dihydrotestosterone (DHT), a more potent androgen than T, or older adults, whose glycemic pathophysiology differs from younger adults.

OBJECTIVE: To determine the associations of SHBG, T, and DHT with insulin resistance and incident diabetes in older adult men.

DESIGN: In a prospective cohort study, we evaluated baseline levels of SHBG, T, and DHT using liquid chromatography-tandem mass spectrometry among 852 men in the Cardiovascular Health Study free of diabetes and cardiovascular disease in 1994.

MAIN OUTCOME: Insulin resistance estimated by HOMA-IR and insulin sensitivity estimated by the Gutt index in 1996, and incident diabetes (n=112) ascertained over a mean follow-up of 9.8 years.

RESULTS: In linear regression models adjusted for demographics, alcohol consumption, current smoking, body-mass index, and other androgens, SHBG (HOMA-IR 0.30 units lower per doubling; 95\% confidence interval [CI], 0.08-0.52; p=0.01) and total DHT (HOMA-IR 0.18 units lower per doubling; 95\% CI 0.06-0.30; p=0.01), but not free T (p=0.33) were inversely associated with insulin resistance. In corresponding Cox proportional hazards models, total DHT was again inversely associated with risk of diabetes (adjusted hazard ratio per doubling 0.69; 95\% CI, 0.52-0.92; p=0.01), but SHBG (hazard ratio 1.09; 95\% CI, 0.74-1.59; p=0.66) and free T (hazard ratio 1.15; 95\% CI, 0.92-1.43; p=0.23) were not.

CONCLUSIONS: Among older men, higher levels of DHT are inversely associated with insulin resistance and risk of diabetes over the ensuing 10 years, while levels of T are not. Future studies are still needed to clarify the role of SHBG in risk of diabetes in this population.

}, issn = {1945-7197}, doi = {10.1210/jc.2016-2623}, author = {Joyce, Katherine E and Biggs, Mary L and Djouss{\'e}, Luc and Ix, Joachim H and Kizer, Jorge R and Siscovick, David S and Shores, Molly M and Matsumoto, Alvin M and Mukamal, Kenneth J} }