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Jason A DeCaro
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ABSTRACT: Salivary alpha-amylase recently has been identified as a stress-related biomarker for autonomic nervous system activity. This study addresses sample collection and handling considerations for field researchers. Saliva was collected by unstimulated passive drool from 14 adults and pooled. Incubation of pooled saliva at 22 or 37 degrees C for 21 days did not diminish amylase activity. However, sodium azide added at concentrations <or=1.12 mg/ml to pooled saliva artificially inflated activity. After dosing cotton rolls within Salivette saliva collection devices with 0.25 to 1.5 ml of unpooled passive drool saliva from six additional adults, recovery of amylase activity was significantly below 100% at all volumes, with increased variance in recovery when the cotton was incompletely saturated (<or=1.0 ml). Hence, collection by passive drool instead of cotton-containing devices for amylase determinations is recommended, particularly whenever it is impossible to ensure full, uniform cotton saturation, and azide should be avoided as a preservative.
American Journal of Human Biology 05/2008; 20(5):617-9. · 2.27 Impact Factor
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ABSTRACT: The measurement of cardiovascular functioning targets an important bridge between social conditions and differential well-being. Nevertheless, the biocultural, psychosocial processes that link human ecology to cardiovascular function in children remain inadequately characterized. Childrearing practices shaped by parents' cultural beliefs should moderate children's affective responses to daily experience, and hence their psychophysiology. The present study concerns interactions among family ecology, the normative social challenge of entry into kindergarten, and parasympathetic (vagal) cardiac regulation in US middle-class children (N = 30). Although parents believed children must be protected from overscheduling to reduce stress and improve socio-emotional adaptation, maternal rather than child schedules predicted parasympathetic regulation during a nonthreatening social engagement task following school entry. Children of busier married mothers, but less busy single mothers, showed the context-appropriate pattern of parasympathetic regulation, low respiratory sinus arrhythmia (RSA). These findings are expected if: maternal and family functioning, rather than the scheduling of the child's daily life, principally drive young children's cardiovascular responsiveness to a normative challenge; and busy schedules represent high family functioning with married mothers, but not under single-parent conditions wherein adult staffing is uniquely constrained. Family ecology is shaped by culture, and in turn shapes the development of children's cardiovascular responses. Appropriately fine-grained analysis of daily experience can illustrate how culturally driven parenting practices may have unintended consequences for child biological outcomes that vary by family structure.
American Journal of Human Biology 05/2008; 20(5):572-83. · 2.27 Impact Factor
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ABSTRACT: This study examines everyday family life as a social regulator of child adrenocortical activity during the normative challenge of return to school. If positive family function facilitates child adaptation, we expected that mother-child relationships following school entry would predict individual differences in evening cortisol, a context-sensitive marker for the response to concurrent demands. Among 28 children followed longitudinally, late in pre-kindergarten those living with single and/or employed mothers had higher evening cortisol. Yet early during the following school year, children with poorer mother-child relationships had higher evening cortisol. Cortisol awakening response, a comparatively stable marker of anticipated demands, was higher with maternal employment, single parents, and busier child schedules before school re-entry, and with maternal employment afterwards. We argue for a layered ecological approach to social regulation, recognizing that family structure, family functioning, and proximal features of everyday life within the family moderate child adrenocortical activity differently across contexts.
Developmental Psychobiology 04/2008; 50(2):183-95. · 2.98 Impact Factor
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PARENTING: SCIENCE AND PRACTICE. 01/2007; 7(2):177-203.
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ABSTRACT: This study examines sex differences in vulnerability among children experiencing rapid culture change that may reflect distinct microecologies driven by differential parental investment and/or sex-specific life history strategies. Apparent female growth canalization may be a life history strategy favoring growth over maintenance but also may reflect sex-differentiated selection for resilience based on unequal treatment during early life.
Stature, weight, and serum measures of C-reactive protein (CRP, an inflammation marker) and Epstein-Barr Virus antibodies (EBV, a humoral immune response marker) were collected longitudinally among children/adolescents ages 5-20 years (N = 65), 5-9 years after sustained contact in a fringe highland hunter-horticulturalist group from the Schrader Range in Papua New Guinea exhibiting male preference and sex-biased survival. It was hypothesized that girls would exhibit canalization, with better nutritional status than boys; lower maintenance investment would yield lower female immune activation; and because of differential survivorship, females would appear increasingly canalized as early conditions for girls worsened relative to boys.
Girls had greater arm circumference z-scores than boys, less frequent stunting, and lower CRP despite high pathogen load. Average nutritional status for girls improved over time as the sex ratio became increasingly male biased and the condition of female infants reportedly worsened.
Both canalization and survivorship effects were found. Although a life history perspective on female canalization can help explain developmental outcomes in populations undergoing rapid culture change amid adversity, possible sex differences in the strength of survivorship effects that select for resiliency should not be ignored.
American Journal of Human Biology 22(5):657-66. · 2.27 Impact Factor
