Bioindicators in the MIDUS national study: protocol, measures, sample, and comparative context.

OBJECTIVES: Midlife in the United States (MIDUS) is a national study of health and aging among individuals aged 25 to 74 at baseline (1995-1996). Longitudinal survey assessments (2004-2005), were followed by biological assessments on a subsample (aged 35-85).To facilitate public use, we describe the protocol, measures, and sample. METHOD: Respondents traveled to clinics for a 2-day data-collection protocol that included fasting blood specimens, 12-hr urine specimen, medical history, physical exam, bone densitometry, and a laboratory challenge (heart rate variability, blood pressure, respiration, salivary cortisol). RESULTS: Response rates for the biological protocol (N = 1,255) were 39.3% or 43.1% (adjusting for those who could not be located or contacted). Reasons for nonparticipation were travel, family obligations, and being too busy. Respondents were comparable to the recruitment pool on most demographic characteristics and health assessments. DISCUSSION: Strengths of the protocol vis-à-vis similar studies include opportunities to link biological factors with diverse content from other MIDUS projects.

Coping and positive affect predict longitudinal change in glycosylated hemoglobin.

OBJECTIVE: This study investigated whether different psychosocial factors predicted levels of glycosylated hemoglobin (HbA1c) over time, after adjusting for covariates and baseline level of HbA1c. DESIGN: These questions were investigated with a longitudinal sample (N = 97, age = 61-91) of older women without diabetes. HbA1c levels and psychosocial measures were obtained at baseline and 2-year follow-up. MAIN OUTCOME MEASURES: Coping strategies, positive affect, medical history, and health behaviors were assessed using self-administered questionnaires. HbA1c were obtained during the respondents' overnight stay at the General Clinical Research Center (GCRC) at the University of Wisconsin-Madison. RESULTS AND CONCLUSION: Regression analyses showed that higher levels of problem-focused coping, venting, and positive affect predicted lower levels of HbA1c, after controlling for baseline HbA1c and sociodemographic and health factors. Furthermore, positive affect was found to moderate the effects of problemfocused coping (active, instrumental social support, suppressing competing activities). The pattern of interaction showed that the adverse effects of low problem-focused coping on cross-time changes in HbA1c were amplified among those who also had low levels of positive affect.

Psychological well-being and ill-being: do they have distinct or mirrored biological correlates?

BACKGROUND: Increasingly, researchers attend to both positive and negative aspects of mental health. Such distinctions call for clarification of whether psychological well-being and ill-being comprise opposite ends of a bipolar continuum, or are best construed as separate, independent dimensions of mental health. Biology can help resolve this query--bipolarity predicts 'mirrored' biological correlates (i.e. well-being and ill-being correlate similarly with biomarkers, but show opposite directional signs), whereas independence predicts 'distinct' biological correlates (i.e. well-being and ill-being have different biological signatures). METHODS: Multiple aspects of psychological well-being (eudaimonic, hedonic) and ill-being (depression, anxiety, anger) were assessed in a sample of aging women (n = 135, mean age = 74) on whom diverse neuroendocrine (salivary cortisol, epinephrine, norepinephrine, DHEA-S) and cardiovascular factors (weight, waist-hip ratio, systolic and diastolic blood pressure, HDL cholesterol, total/HDL cholesterol, glycosylated hemoglobin) were also measured. RESULTS: Measures of psychological well-being and ill-being were significantly linked with numerous biomarkers, with some associations being more strongly evident for respondents aged 75+. Outcomes for seven biomarkers supported the distinct hypothesis, while findings for only two biomarkers supported the mirrored hypothesis. CONCLUSION: This research adds to the growing literature on how psychological well-being and mental maladjustment are instantiated in biology. Population-based inquiries and challenge studies constitute important future directions.

Positive health: connecting well-being with biology.

Two key types of well-being, eudaimonic and hedonic, are reviewed. The first addresses ideas of self-development, personal growth and purposeful engagement, while the second is concerned with positive feelings such as happiness and contentment. How well-being varies by age and socio-economic standing is briefly summarized, followed by examination of its biological correlates (neuroendocrine, immune, cardiovascular, rapid eye movement (REM) sleep). Preliminary findings on a sample of ageing women showed that those with higher levels of eudaimonic well-being had lower levels of daily salivary cortisol, pro-inflammatory cytokines, cardiovascular risk, and longer duration REM sleep compared with those showing lower levels of eudaimonic well-being. Hedonic well-being, however, showed minimal linkage to biomarker assessments. Future research directions building on these initial findings are discussed.

Social relationships, gender, and allostatic load across two age cohorts.

OBJECTIVE: This article addresses the question of biological pathways through which social integration and support may affect morbidity and mortality risks. A new concept of cumulative biological risk, allostatic load, is used to test the hypothesis that social experiences affect a range of biological systems. Data from two community-based cohorts are examined to evaluate the consistency of findings across two different age groups. METHODS: One cohort included older adults aged 70 to 79 years (N = 765); the other cohort included persons aged 58 to 59 years (N = 106). Allostatic load was assessed using identical protocols in the two cohorts. Measures of social experience were similar but not identical, reflecting levels of social integration and support for the older cohort vs. childhood and adult experiences of loving/caring relationships with parents and spouse for the younger cohort. Gender-specific analyses were examined to evaluate possible gender differences in patterns of association. RESULTS: In the younger cohort, positive cumulative relationship experiences were associated with lower allostatic load for men and women. In the older cohort, men who were more socially integrated and those reporting more frequent emotional support from others had lower allostatic load scores; similar but nonsignificant associations were seen for women. CONCLUSIONS: Evidence from two cohorts provides support for the hypothesis that positive social experiences are associated with lower allostatic load. These findings are consistent with the hypothesis that social experiences affect a range of biological systems, resulting in cumulative differences in risks that in turn may affect a range of health outcomes.