Chronic distress has been linked with premature aging and earlier development of cardiometabolic diseases and conditions (CMD) but identification of the biological mechanisms linking progression of these diseases with chronic distress remains limited. Moreover, in epidemiologic studies, it is often difficult to assess chronic distress comprehensively or to identify who is at higher risk for adverse physical health outcomes among those who are distressed. Therefore, it is of great interest to identify biomarkers that may help indicate a prolonged distress exposure and also provide insight into distress-linked biological alterations that are etiologically relevant. Recent advances have been made in high-throughput technologies that can simultaneously measure hundreds of small molecule metabolites in plasma (?metabolomics?). We hypothesize that chronic distress is associated with multiple changes in circulating levels of small molecule metabolites. Our three aims are to 1) evaluate specific plasma metabolite levels in women with and without chronic distress. We hypothesize chronic distress is associated with circulating levels of multiple metabolites, including positive associations with isoleucine and phenylalanine, and specific lysophosphatidylethanolamine and phosphatidylcholine lipids, and an inverse association with glycine; 2) derive and validate a plasma metabolomics score that separates women with and without chronic distress; 3) assess associations between the individual metabolites and metabolomics score with CMD risk. Our studies will utilize the rich questionnaire and biospecimen resources from three large cohorts of women, the Nurses? Health Study (NHSI), NHSII, and Women?s Health Initiative (WHI). We posit shared patterns of metabolic alterations across different forms of distress, and we will therefore consider several common forms of distress manifested by symptoms of depression, anxiety, or post-traumatic stress disorder (PTSD). For discovery, we will use two independent datasets with existing metabolomics profiles: 226 women from the NHSII Mind Body Substudy (MBS) and 328 women from WHI, all of whom completed detailed questionnaires on depression, anxiety, and key covariates and also provided a blood sample. For validation, we will utilize 3 independent data sets from NHSI and NHSII. We will compare metabolomic profiles among women without (n=360) and with chronic distress as characterized by PTSD (n=120), anxiety (n=120), or depression (n=120). Finally, in two prospective nested case-control studies, identified metabolites and derived metabolomic profiles will be evaluated in relation to risk of CHD (WHI, case n=1,105) and diabetes (NHS, case n=1,000). The use of multiple independent but complementary and detailed data sets in women for discovery and validation of distress-linked plasma metabolites/score will help ensure our findings are reliable and reproducible. Discovery of metabolic pathways dysregulated by chronic distress will help elucidate potential biologic pathways linking distress and CMD, thus generating new targets for intervention as well as provide an objective measure of chronic distress that can be used in other large prospective studies.
Chronic distress has long been linked with increased risk of premature mortality, accelerated aging, and cardiometabolic risk. However, few studies have been able to identify a pattern of biological change at the molecular level that occurs with distress and can explain how distress might influence development of chronic disease as people age. This study will identify metabolic mechanisms by which distress influences adverse health outcomes, suggest new ways to enhance early detection of risk, and also identify biological markers that indicate prolonged exposure to distress.
