Several correlations have been reported between men's testosterone (T) and other characteristics, e.g., T declines during the day, declines with obesity, and declines with advancing age. We asked if these relationships hold in older men when T is assayed from saliva.Here seven familiar correlations are tested among older American men, their salivary T measured by enzyme immunoassay (EIA). Some correlations can also be tested among older British men, their salivary T assayed by liquid chromatography-tandem mass spectroscopy (LC-MS/MS), a technique noted for its specificity. Most of our attempts at replication failed in the American data but succeeded in the British data. We conclude that failure to replicate in Americans is likely due to inaccuracy of EIA values for T, and that most T correlations hold true in older men when salivary T is accurately measured by LC-MS/MS. 3 central regulator of crucial body functions, these alterations can be translated in significant clinical sequelae" (Diamanti-Kandarakis et al. 2017).Here we ask if seven previously-reported correlates of T, usually measured from serum, are still seen in older men when T is assayed from saliva. We tested these correlations in two large datasets, one American and one British. American data were collected by the National Social Life, Health & Aging Project (NSHAP), a two-wave panel (years 2006 and 2011) of older Americans ranging in age from 57 to 85 at Wave 1. T was measured in each wave by enzyme immunoassay (EIA) of saliva samples collected at the time of interview.British data were collected in a single wave of the National Survey of Sexual Attitudes and Lifestyles: 2010-2012 (Natsal-3), which assayed salivary T by liquid chromatography-tandem mass spectroscopy (LC-MS/MS), a technique noted for its specificity. Natsal-3 did not include all the variables used from NSHAP so not as many correlations could be tested.Several validation studies show salivary T to be correlated with "free" T in serum, i.e., with that small portion of total T not bound to protein and thus physiologically active (Shirtcliff et al. 2002;Keevil et al. 2014;Fiers et al. 2014). Biobehavioral researchers increasingly collect saliva rather than blood since saliva is cheaper and easier. Among several assay techniques, EIA has become a workhorse of behavioral studies because it is quick, convenient, inexpensive, and does not require radioactive material. Recently, however, Welker et al. (2016) presented results that question the accuracy of EIA for measuring salivary T.
PREVIOUSLY REPORTED CORRELATES OF MALE TWithout presenting a full literature review, we note correlations previously reported, which can be tested on one or both of our datasets. For example, it is now well established 4 that in men, T has a diurnal rhythm, that low T is associated with obesity, and that T usually declines as men age. These head the list of propositions tested here in older men, which also contains other T correlations reported less frequently or consistently:1. Diurnal: Male T has a diurnal rh...