Transitions to Family Caregiving and Latent Variables of Systemic Inflammation Over Time.

Circulating levels of inflammatory biomarkers may be influenced by chronic psychological stressors such as those experienced by family caregivers. However, previous studies have found mostly small and inconsistent differences between caregivers and control samples on individual measures of systemic inflammation. Latent variables of inflammation were extracted from six biomarkers collected from two blood samples over 9 years apart for 502 participants in a national cohort study. One-half of these participants transitioned into a sustained family caregiving role between the blood samples. Two latent factors, termed "up-regulation" and "inhibitory feedback," were identified, and the transition to family caregiving was associated with a lower increase over time on the inhibitory feedback factor indexed by interleukin (IL)-2 and IL-10. No caregiving effect was found on the up-regulation factor indexed primarily by IL-6 and C-reactive protein. These findings illustrate the advantages of using latent variable models to study inflammation in response to caregiving stress.