Deciphering the Association Between Hypothalamus‐Pituitary‐Adrenal Axis Activity and Obesity: A Meta‐Analysis

Abstract

Objective Both the cortisol awakening response (CAR; corresponding to the state measurement) and hair cortisol concentration (HCC; corresponding to the trait measurement) are considered reliable markers of hypothalamus‐pituitary‐adrenal axis activity. Because cortisol has long been associated with adiposity, this systematic review and meta‐analysis aims to summarize and compare the literature around CAR and HCC and their association with obesity or fat distribution indices. Methods The PubMed, Web of Science (Web of Science Core Collection and Medline), EBSCO Information Services, Embase, and PsycNET databases were searched, and full‐text articles investigating the association between CAR or HCC and markers of adiposity in humans were included. Meta‐analyses were then performed to compare studies associating CAR or HCC with BMI (a marker of general adiposity) and waist circumference (a marker of fat distribution). Results The results of this review highlight inconsistencies in cortisol sampling and CAR computation, which makes comparisons between studies difficult. It was found that adiposity indices are not associated with CAR but that they correlate significantly and positively with HCC. The subgroup analysis hinted to possible age differences in the magnitude of the association between HCC and BMI. Conclusions Trait rather than state measurement of the hypothalamus‐pituitary‐adrenal axis activity is associated with increased general and abdominal adiposity in humans.

Eight Weeks of Lifestyle Change: What are the Effects of the Healthy Lifestyle Community Programme (Cohort 1) on Cortisol Awakening Response (CAR) and Perceived Stress?

“…While results on the CAR are inconsistent, hair cortisol has been consistently associated with chronic stress, obesity and NCDs, for example cardiovascular disease, recent myocardial infarction, and Diabetes Mellitus (DM) 16,28,80–83 . The measure is less prone to methodological errors 16,80 and due to its non-invasive sampling, being independent of the time of day, it may be a reliable indicator in studying the effects of chronic stress on health.…”

“…24 Results on the CAR and metabolic diseases are controversial: a blunted CAR has been linked to an unfavourable metabolic and cardiovascular risk profile, 25–27 while others found adiposity indices to not be associated with the CAR. 28…”

“…24 Results on the CAR and metabolic diseases are controversial: a blunted CAR has been linked to an unfavourable metabolic and cardiovascular risk profile, [25][26][27] while others found adiposity indices to not be associated with the CAR. 28 Also, psychological stress states may be indicated by the CAR 23,29,[30][31][32][33] , but again, results are inconsistent: a meta-analysis of 147 studies found a higher CAR to be linked to psychosocial stress, 34 while other studies, found a blunted CAR in participants with high levels of psychological stress. [35][36][37] Hence, different psychosocial factors may have a different effect on the CAR.…”

Effect of moderate continuous aerobic training versus cryolipolysis on stress hormone and aerobic capacity in central obesity

“…Appetite is stimulated by high levels of NPY and CRH, and leptin. Suppression of high cortisol levels during longterm exercise may disrupt this vicious cycle, reducing hunger, improving eating habits, and increasing refusal of highcalorie meals, resulting in weight loss [15]. Stress habituation occurs when repeated exposure to the same stressor (such as prolonged repetitive exercise) occurs.…”

Adipose Tissue Compartments, Inflammation, and Cardiovascular Risk in the Context of Depression

“…Additionally, an association of cortisol and obesity is consistently indicated in the literature. A recent meta-analysis that reviewed studies in humans regarding cortisol awakening response as a state measure for HPA axis activity and hair cortisol as a trait measure found that trait rather than state measures were associated with general and abdominal adiposity in humans ( 102 ). Therefore, HPA axis dysfunction might constitute a critical factor that links obesity and depression.…”