Determinants of salivary evening alpha-amylase in a large sample free of psychopathology

ObjectiveRecently, salivary alpha-amylase (sAA) has been proposed as a suitable index for sympathetic activity and dysregulation of the autonomic nervous system (ANS). Although determinants of sAA have been described, they have not been studied within the same study with a large sample size without potential disturbances of psychopathology. In this paper, we report about correlates of evening sAA in saliva.MethodsIn 487 participants (mean age = 42.9 years, 59.8% female) without lifetime psychiatric disorders from the Netherlands Study of Depression and Anxiety (NESDA), sociodemographic, health and sampling determinants of sAA levels were examined using multivariable linear regression analysis. sAA was measured in two saliva samples that participants collected in the late evening, at 22:00 h and 23:00 h, after which these were averaged.ResultsIn multivariate analysis, age (β = 0.20, p < 0.001) and daily alcohol intake (β = − 0.13, p = 0.01) were independent determinants of evening sAA levels. Gender, allergy or lung disease, and the use of oral contraceptives were univariate correlates, but no longer associated with sAA in the multivariate model.ConclusionsAge and alcohol use were identified as potential confounding factors that should be taken into account in epidemiologic studies that examine the ANS function using sAA.

► Salivary alpha-amylase (sAA) is an indicator of autonomous nervous system function.
► Determinants of evening sAA were examined in a large sample.
► Age and daily alcohol intake were independent determinants of evening sAA levels.
► sAA is highly sensitive to stress-related changes and relevant to psychology.