**Abstract**

Hair cortisol is increasingly becoming a reliable measure of long-term cortisol concentration and is thought to be a suitable biomarker for chronic stress. Further, a growing amount of scientific literature links elevated hair cortisol concentration with well-known cardiometabolic risk factors such as hypertension, obesity, dyslipidemia, and diabetes. This has important implications for the prognosis, treatment, and prevention of cardiovascular disease. This review focuses on the association between increased hair cortisol and stress-related cardiometabolic risk factors for cardiovascular disease. While the evidence for the relationship between cardiometabolic risk and elevated hair cortisol is clear and compelling, the data is inconsistent. Further studies are needed to support the use of hair cortisol as a biomarker of cardiometabolic risk in cardiovascular disease.

**Keywords:** cardiovascular disease, hair cortisol, cardiometabolic risk, obesity, hypertension, dyslipidemia, diabetes

## **1. Introduction**

Cardiovascular disease (CVD) continues to be the primary cause of morbidity and mortality worldwide [1]. In 2019, approximately 17.9 million people died from CVDs, representing 32% of all global deaths [2]. Eighty-five percent of CVD deaths resulted from heart attack and stroke. These high numbers are especially concerning since most CVDs are preventable or modifiable by addressing behavioral risk factors, such as a sedentary lifestyle, unhealthy diet, tobacco use, and harmful use of alcohol [1–3]. Early detection is essential in eradicating or in beginning management of cardiovascular disease with counseling and medications.

Cardiometabolic risk (CMR) refers to the risk factors that increase the likelihood of experiencing cardiovascular events or developing metabolic disease [4]. Besides the traditional cardiovascular risk factors (age, gender, family history, hypertension, diabetes, and smoking), CMR factors include abdominal obesity, insulin resistance, inflammation, unhealthy eating habits, and a sedentary lifestyle (**Figure 1**). Several cross-sectional clinical studies have shown a positive association between cortisol and cardiometabolic risk factors. With stress being an integral part of modern life that has become a significant health problem [5, 6], the importance of biomarkers that can assist in the treatment of stress-related diseases should only increase.

In particular, hair cortisol concentration (HCC) is gaining interest as a promising biomarker for cardiometabolic risk [7]. However, research investigating the direct association between HCC and cardiometabolic risk factors is still in its infancy, and more extensive prospective cohort studies are needed to gain further insight into the relationship between HCC, CMR, and the development of CVD. Unhealthy lifestyles such as physical inactivity, smoking, and excessive alcohol use also result in elevated cortisol levels and are associated with cardiometabolic risk and cardiovascular disease [4]. However, this review focuses on biological factors linked to high cortisol levels and stress that are activated through the hypothalamic-pituitary-adrenal (HPA) axis pathway, including hypertension, obesity, dyslipidemia, and diabetes.
