The utility and dynamics of salivary sex hormone measurements in the National Social Life, Health, and Aging Project, Wave 2

Abstract

Objectives: Sex hormones affect physical, mental, and social health, yet their role in mediating social effects on aging is understudied. To facilitate such analyses with the National Social Life, Health & Aging Project Wave 2, we summarize the conceptual background, collection protocols, laboratory assays, and data analysis strategies for biologically active (free) levels of testosterone, estradiol, progesterone, and dehydroepiandrosterone (DHEA).

Method: Saliva from passive drool was collected from returning Wave 1 respondents and non-respondents as well as their partners during an in-home interview. Specimens were frozen and sent to Dresden LabService GmbH for duplicate assays of biologically active steroids using identical assay kits from National Social Life, Health, and Aging Project (NSHAP) Wave 1 (SaliCap, Catalog No. RE69995). Overall, 2,772 testosterone, 2,504 estradiol, 2,714 progesterone, and 2,800 DHEA measurements are publically available for Wave 2 analyses. Through a series of weighted linear regressions, all 4 steroids are compared by gender and age and to Wave 1 measurements.

Results: Men had higher levels of both free testosterone and progesterone than women; women and men had the same levels of estradiol and DHEA. Both free testosterone and DHEA decreased with age. We also found significant wave effects for all 4 sex hormones.

Conclusion: NSHAP Waves 1 and 2 are the first U.S. probability sample studies to measure these 4 salivary sex hormones simultaneously, providing individual profiles 5 years apart. Wave 2 data demonstrate differences by gender and trends by age that are similar to those found in other saliva-based and serum-based studies of free steroid levels. The differences between waves arising from the change in assay laboratory need to be adjusted in future longitudinal analyses using NSHAP Wave 1 and Wave 2 steroid data.

Keywords: DHEA; Estradiol; Progesterone; Saliva collection; Sex hormones; Testosterone..

Figure 1.

The distributions of salivary sex hormone measurements (pg/mL) for women and men (columns) in NSHAP Waves 1 and 2 (rows). Notes. DHEA = dehydroepiandrosterone; NSHAP = National Social Life, Health, and Aging Project. ^aFor simplicity and graph visibility, two Wave 1 male respondents with DHEA > 1,000 pg/mL excluded.

Figure 2.

Documented measures of mean salivary sex hormones ± SEM (pg/mL)^a in older women and men sorted by increasing mean age of the sample and compared with NSHAP Wave 1 (*) and NSHAP Wave 2 (**). Notes. DHEA = dehydroepiandrosterone; M-D and A-H = Mirzaii-Dizgah and Agha-Hosseini; NSHAP = National Social Life, Health, and Aging Project; pg/mL = picograms per milliliter; SEM = standard error of mean. ^aWhen not specified in original source, means and standard errors are approximated from text, tables, or figures. bData in Wilcox, Granger, Szanton, and Clark (2014) are not presented separately for men and women.

Figure 3.

Sex differences in levels of salivary sex hormones by age in NSHAP Wave 2 (weighted to represent the U.S. population aged 62–90). Notes. CI = confidence interval; DHEA = dehydroepiandrosterone; NSHAP = National Social Life, Health, and Aging Project; pg/mL = picograms per milliliter.