TY - JOUR
T1 - Cortisol diurnal patterns, associations with depressive symptoms, and the impact of intervention in older adults
T2 - Results using modern robust methods aimed at dealing with low power due to violations of standard assumptions
AU - Wilcox, Rand R.
AU - Granger, Douglas A.
AU - Szanton, Sarah
AU - Clark, Florence
N1 - Funding Information:
The Well Elderly II study was supported by NIH grant R01 AG021108 .
PY - 2014/3
Y1 - 2014/3
N2 - Advances in salivary bioscience enable the widespread integration of biological measures into the behavioral and social sciences. While theoretical integration has progressed, much less attention has focused on analytical strategies and tactics. The statistical literature warns that common methods for comparing groups and studying associations can have relatively poor power compared to more modern robust techniques. Here we illustrate, in secondary data analyses using the USC Well Elderly II study (n=460, age 60-95, 66% female), that modern robust methods make a substantial difference when analyzing relations between salivary analyte and behavioral data. Analyses that deal with the diurnal pattern of cortisol and the association of the cortisol awakening response with depressive symptoms and physical well-being are reported. Non-significant results become significant when using improved methods for dealing with skewed distributions and outliers. Analytical strategies and tactics that employ modern robust methods have the potential to reduce the probability of both Type I and Type II errors in studies that compare salivary analytes between groups, across time, or examine associations with salivary analyte levels.
AB - Advances in salivary bioscience enable the widespread integration of biological measures into the behavioral and social sciences. While theoretical integration has progressed, much less attention has focused on analytical strategies and tactics. The statistical literature warns that common methods for comparing groups and studying associations can have relatively poor power compared to more modern robust techniques. Here we illustrate, in secondary data analyses using the USC Well Elderly II study (n=460, age 60-95, 66% female), that modern robust methods make a substantial difference when analyzing relations between salivary analyte and behavioral data. Analyses that deal with the diurnal pattern of cortisol and the association of the cortisol awakening response with depressive symptoms and physical well-being are reported. Non-significant results become significant when using improved methods for dealing with skewed distributions and outliers. Analytical strategies and tactics that employ modern robust methods have the potential to reduce the probability of both Type I and Type II errors in studies that compare salivary analytes between groups, across time, or examine associations with salivary analyte levels.
KW - Cortisol awakening response
KW - Depressive symptoms
KW - Robust statistical techniques
KW - Well Elderly II study
KW - Well-being
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U2 - 10.1016/j.yhbeh.2014.01.005
DO - 10.1016/j.yhbeh.2014.01.005
M3 - Article
C2 - 24468639
AN - SCOPUS:84896831660
SN - 0018-506X
VL - 65
SP - 219
EP - 225
JO - Hormones and Behavior
JF - Hormones and Behavior
IS - 3
ER -