Fig 5. Cluster analysis of eight factors potentially related to core variable associated with a dyadic vulnerability index.

The cluster analysis demonstrates the factors that promote maternal cortisol decrements include lighter, more subordinate mothers with lighter infants at the time of VFD onset, with reduced maternal-infant dyadic distance suggesting an association between socioecological vulnerability and cortisol suppression. The cluster analysis suggests a “core” of vulnerability variables (in red outlined area) that are closely associated. The black arrow indicates that core variables were each less than 50 Euclidian Linkage Units from each other. However, given that the VFD group mean cortisol remains stable, cortisol decrements are evidently exquisitely matched by cortisol increments in relatively advantaged, yet equivalently challenged, dyads, hence the concept of social allostasis. Abbreviations: PRECORT = maternal pre-VFD cortisol (ug/dl), DOM, = social rank score, MOMSWT = maternal weight measured prior to VFD exposure, HFDPROX = maternal-infant proximity aggregated score obtained from the final high foraging demand two week epoch, z cortdiff = standardized z-score of post—pre-VFD cortisol in response to maternal VFD, KIDWT = infant weight at the time of onset of VFD exposure (kg), VFDONSET = age in days at onset of VFD, CRFPRE = maternal CSF CRF concentrations (pg, ml) obtained prior to VFD exposure.