Neuroendocrine biomarkers, social relations, and the cumulative costs of stress in Taiwan

Abstract

Allostatic load (AL) is thought to represent the physiological toll that builds up over the life course as a consequence of the body's response to stress. An important aim of this paper is to test this widely held -but little investigated -understanding of what AL represents. More specifically, using the Social Environment and Biomarkers of Aging Study (SEBAS), a nationally representative survey of Taiwan conducted in the year 2000, this paper scrutinizes the connection between stressful life histories and neuroendocrine allostatic load (NAL). The 2000 SEBAS is a cross-sectional survey with over 1,000 participants (of men and women) age 54-91 and contains both conventional social variables and a number of physiological measures. Stressful life histories are operationalized through the use of two sets of indicators: one set makes use of respondents' subjective interpretations of various life domains and the other makes use of non-subjective data about conditions that are expected to be stressful (e.g., widowhood, living alone, low education). NAL is an index of four neuroendocrine biomarkers (cortisol, dehydroepiandrosterone sulfate (DHEAS), epinephrine, norepinephrine) collected in blood and urine samples under resting, basal states.The major findings of this paper are twofold. First, there is little evidence to support the hypothesis that baseline levels of the neuroendocrine markers stem from stressful life histories. Second, report of current stress (among women only) is positively correlated with higher NAL levels. Taken together, these findings question whether the neuroendocrine markers of the AL construct reflect long-term processes over the life course. Indeed, evidence here suggests that the neuroendocrine markers may reflect the exact opposite -a transient state at the time of the study.

Allostatic load biomarkers of chronic stress and impact on health and cognition

“…Using the SEBAS cohort, concurrent and cumulative perceived stress-related to increased AL (high and low DHEA-S, glucose, and IL-6 levels) most strongly in women . Another analysis of stressful life histories (e.g., marital status, group participation, coresidence with married son) found no association with neuroendocrine AL parameters and, yet, current perceived stress was again found in women (Gersten, 2008a). This finding conflicts with AL theory stipulating that chronic stress is at the core of physiological dysregulations, but the findings may be due to limitations in the assessment of stress (Gersten, 2008b;Loucks et al, 2005) and cultural nuances (McDade, 2008).…”

Socioeconomic status over the life course and allostatic load in adulthood: results from the Northern Swedish Cohort

“…Considering the conceptually integral status of these mediators within the AL model, which presupposes neuroendocrine mediation of stressful circumstances, we had expected to find similar life-course influences on AL as on the circadian cortisol rhythm. Even though cumulative effects have been reported by others for life-course SES and cortisol levels,9 this inconsistency converges with a critique of the empirical status of neuroendocrine mediators within the AL model 1 34. Possibly, some of the inconsistencies in the literature might stem from the methodological challenges in assessing hypothalamic–pituitary–adrenal axis functioning.…”

Adult cognitive ability and socioeconomic status as mediators of the effects of childhood disadvantage on salivary cortisol in aging adults

“…elevated daytime cortisol, flat cortisol slopes). With regard to education, in four of six cross-sectional studies there was no association between participants' education and cortisol levels (Decker, 2000; Dowd and Goldman, 2006; Dowd et al, 2011; Gersten, 2008); findings were mixed in two studies (Brandtstadter et al, 1991; Fiocco et al, 2007). Education per se, however, is a poor indicator of SES or cognitive ability especially in older adults, minorities, or for women.…”