Objective: A growing area in the study of population aging is the examination of stress, health, and mortality. Almost without exception such studies have focused on healthy older adults in the community. This study focuses on an important indicator of physiologic stress—salivary cortisol—in the physically and cognitively frail older population in response to an external challenge (transfer to new facility). The aims of the study are: 1) to obtain physiological measures of stress from a physically and cognitively impaired older population, and 2) to understand the differences between cognitively impaired and cognitively intact residents with respect to levels of stress hormones produced. Design: The study involves a unique, naturally occurring experimental design in which residents of the former Philadelphia Geriatric Center (PGC) were moved to a newly built nursing home facility. The first group of residents, which served as the experimental group, began preparation for their move in September 2001, and moved over a 3-month period from October 2001 through December 2001. The second group, which served as the control group will be moved from April 2002 through May 2002. Sample: The sample included 88 (mean age 88 years; 81% female) residents randomly assigned to either the experimental or control group. Variables studied: 1) affect (5-minute observations of mood using the Observed Emotion Rating Scale); 2) cognitive functioning (Folstein Mini Mental State Exam); 3) salivary-free cortisol; and 4) physiological status (blood pressure, pulse, height/weight, medications). Method: Participants were approached four times over the course of a day: on-awakening and thereafter 3-4, 6-7 and 9-10 hours from awakening, respectively. Measures were obtained at each interval based on the following schedule: one week before moving, one week after moving and 4 weeks after moving for the experimental group and at matched intervals for the control group. All samples were assayed for salivary cortisol using a high-sensitive enzyme immunoassay (Salimetrics, PA). Findings: We find that the collection of salivary cortisol in this population is a challenging task, primarily due to Xerostomia (dry mouth) linked to medication use and location within the facility. In our evaluation of missing data, we found non-compliance with the saliva protocol was unrelated to age, cognition, and physiologic status but higher among women and those on select medications. Basal cortisol levels were significantly higher among older subjects (p=. 05), with lower mental status (p=.04), and greater BMI (p=.03). Mean cortisol values in the sample demonstrated steep declines followed by a flattening, similar to those described in other studies of populations under chronic stress. However, individual rhythms did not mimic the group averages. Analysis of individual diurnal patterns among individuals proving four saliva samples revealed three distinct profiles: a monotonic decreasing pattern consistent with healthy elders (N=6, basal cortisol=.58, 80% female, MMSE=18.5); a u-shaped pattern with afternoon values exceeding morning readings (N=10, basal cortisol=.38, 80% female, MMSE=11.9); and an erratic pattern (N=6, basal cortisol=. 31, 80% male, MMSE=7.2). Significantly lower depression (p=.008) and anxiety (p=.03) symptoms existed in the erratic pattern group. Conclusions: Our findings suggest that cognition affects both basal cortisol and diurnal variation whereas physiologic measures are related to basal levels and mood and gender to overall pattern. In addition, the ability to provide saliva may offer an important window in the quality of care in nursing homes. Implications: These findings are among the first to examine links between diurnal hypothalamic-pituitary-adrenal (HPA) axis patterns, cognition and mood in this population and have important implications for a host of age-related processes that exhibit gender differences, most notably those related to brain and immune function. Further analysis is needed to establish whether diurnal cortisol rhythms predict a nursing home resident’s clinical course, including chances of survival and is the next step of our analysis. Supported by National Institute on Aging Grant No. R03 AG19896-01, by Penn State University’s College of Health and Human Development and Population Research Institute, and by Polisher Research Institute.
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