Scalp hair cortisol concentrations show virtually no association with cardiac structure or function among middle-aged adults, according to a study published on October 7 in Heart, though researchers observed a minor link to left atrial volume.
Led by Simon Söderholm of Linköping University in Linköping, Sweden, the observational cross-sectional study evaluated whether long-term cortisol exposure indicated by hair samples correlates with heart measurements. Investigators analyzed 3,005 participants aged 50 to 64 years from a Swedish imaging-based cohort, where 64% of the participants were women and the mean age was 56.9 years. The research team measured cortisol concentrations in the proximal portions of scalp hair to reflect exposure over several months, comparing those levels against 19 echocardiographic measures grouped into broader cardiac phenotypes.
Decoding Chronic Stress Markers and Heart Mechanics
While elevated hair cortisol has frequently been linked to an increased risk of cardiovascular disease in epidemiological literature, this new investigation challenges the assumption that chronic stress alters core heart structure directly. The researchers statistically categorized 19 individual echocardiographic measures into three primary phenotypes: structural and volumetric remodeling, cardiac output and flow, and diastolic function and myocardial mechanics. Together, these categories accounted for 45.5% of the overall variation across the measured metrics.
After adjusting the statistical models for age, sex, body mass index (BMI), smoking status, alcohol intake, and physical activity levels, the analysis revealed no meaningful association between hair cortisol concentrations and the three broad heart phenotypes. Most of the 19 individual echocardiographic measures displayed negligible effects and no clear dose-response relationship with cortisol levels.
The single exception emerged in left atrial end-systolic volume. In the adjusted analysis, each one-unit higher log10-transformed concentration of cortisol in hair corresponded with a 0.178 standard deviation higher left atrial end-systolic volume index. When translated across the interquartile range of hair cortisol concentrations, this predicted difference amounted to a modest 0.734 mL/m2. Sensitivity analyses confirmed these findings, showing no consistent evidence of interactions influenced by sex.
In Plain English: The Clinical Takeaway
- Measuring Long-Term Stress: Testing the proximal portion of scalp hair allows clinicians to gauge systemic cortisol exposure over several months rather than capturing a momentary stress spike.
- Limited Cardiac Impact: Despite common assumptions that chronic stress physically damages the heart muscle, the study found no broad connection between hair cortisol and major structural heart phenotypes in generally healthy middle-aged adults.
- Atrial Volume Shift: The only measurable effect was a very minor increase in left atrial volume, suggesting that if chronic stress influences heart disease risk, it likely operates through pathways outside of basic cardiac remodeling.
“Although elevated hair cortisol has been associated with increased CVD risk, the present findings do not support a relationship with echocardiographic measures of cardiac structure or function in the studied population, suggesting that any such effects may be mediated through alternative physiological pathways,” the study authors wrote.
Methodological Boundaries and Funding Transparency
Because the study relied on a cross-sectional design, investigators could not establish definitive cause-and-effect relationships between cortisol levels and cardiac metrics. Furthermore, the methodology depended on self-reported data regarding participant smoking habits, alcohol consumption, and physical activity levels, introducing potential recall bias. The cohort consisted exclusively of middle-aged adults who were generally healthy at baseline, which restricts the generalizability of these findings to younger populations, elderly cohorts, or individuals with pre-existing cardiovascular pathologies.
Financial backing for the research came from multiple institutional and private entities. Three study authors reported acting as fellows or associated clinical fellows of the Wallenberg Centre for Molecular Medicine and received funding from the Knut and Alice Wallenberg Foundation. Additional financial support was provided by Dr P Håkanssons Foundation, while the specific hair cortisol laboratory analyses received grants from Swedish AFA Insurance and the County Council of Östergötland. The authors declared no competing interests relating to the work.
References
- Association of hair cortisol with cardiac structure and function in a Swedish cohort. Heart.
