The Importance of Considering Sex and Gender in Cardiovascular Research

A review of the historical use of sex as a biological variable in the American Journal of Physiology-Heart and Circulatory Physiology

Despite National Institute of Health (NIH) mandates requiring sex as a biological variable (SABV), female underrepresentation persists in research, driving the American Journal of Physiology-Heart and Circulatory Physiology (Am J Physiol-Heart Circ) to publish SABV expectations in 2021. To determine progress within the Am J Physiol-Heart Circ, this mini-review evaluated SABV during the first 6 mo of each decade from 1980 to 2020, and 2019, to mitigate pandemic influence. Of the 1,205 articles published, 1,087 articles were included in this review (articles without original research subjects were excluded), of which 72.9% identified subjects. There were consistently fewer female human participants than males, except within 2019 (1980: females n = 3, males n = 5; 1990: females n = 70, males n = 199; 2000: females n = 305, males n = 355; 2010: females n = 186, males n = 472; 2019: females n = 1,695, males n = 1,550; 2020: females n = 1,157, males n = 1,222) and fewer female animals than males (1980: females n = 58, males n = 1,291; 1990: females n = 447, males n = 2,628; 2000: females n = 590, males n = 3,083; 2010: females n = 663, males n = 4,517; 2019: females n = 338, males n = 1,340; 2020: females n = 1,372, males n = 1,973). Only 16 (12.3%) articles including humans discussed SABV from 1980 to 2020. There are persistent SABV disparities within Am J Physiol-Heart Circ with some improvements in recent years. It is imperative that organizations such as the American Physiological Society and NIH foster an expectation of SABV as the norm, not the exception.

Biology, Bias, or Both? The Contribution of Sex and Gender to the Disparity in Cardiovascular Outcomes Between Women and Men

Purpose of Review

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity worldwide for both men and women. However, CVD is understudied, underdiagnosed, and undertreated in women. This bias has resulted in women being disproportionately affected by CVD when compared to men. The aim of this narrative review is to explore the contribution of sex and gender on CVD outcomes in men and women and offer recommendations for researchers and clinicians.

Recent Findings

Evidence demonstrates that there are sex differences (e.g., menopause and pregnancy complications) and gender differences (e.g., socialization of gender) that contribute to the inequality in risk, presentation, and treatment of CVD in women.

Summary

To start addressing the CVD issues that disproportionately impact women, it is essential that these sex and gender differences are addressed through educating health care professionals on gender bias; offering patient-centered care and programs tailored to women’s needs; and conducting inclusive health research.

Resting Heart Rate and Heart Rate Variability in the Year Following Acute Coronary Syndrome: How Do Women Fare?

BACKGROUND

Women experience poorer health outcomes following acute coronary syndrome (ACS). Heart rate (HR) and heart rate variability (HRV) have emerged as sensitive and cost-effective markers of autonomic function and prognostic risk factors of poor cardiac outcomes. The aim of the current study was to investigate whether sex-specific differences existed across HR and five parameters of HRV, at 1 and 12 months following ACS diagnosis.

METHODS

Between January 2013 and June 2014, a sample of 416 ACS patients was enrolled in the Anxiety Depression & Heart Rate Variability in cardiac patients: Evaluating the impact of Negative emotions on functioning after Twenty four months (ADVENT) longitudinal cohort study. At 1 and 12 months following discharge, patient HR and HRV (root mean square of successive differences [RMSDD], standard deviation of RR intervals [SDRR], high frequency power [HF], low frequency power [LF], very low frequency power [VLF]) was measured via three-lead electrocardiogram.

RESULTS

At 1 month post-ACS, sex was a significant predictor of HR and VLF power in fully- adjusted models. At 12 months post-ACS, sex was a predictor of HR, SDRR and VLF power in fully-adjusted models.

CONCLUSION

Sex-specific differences in resting HR and HRV were observed in the year following ACS, whereby women had higher HR and lower HRV, suggestive of poorer autonomic function. Further large-scale cohort studies examining autonomic function as a driver of sex-specific outcomes following ACS are required.

How Does Mental Health Impact Women's Heart Health?

From adolescence until old age, women are more vulnerable to common mental disorders (CMDs; depression and anxiety) than men at all stages of the life course. By middle age, women who have clinical depression are at twice the risk of having an incident cardiovascular disease (CVD) than those without. This has important implications for the way we prevent, identify and treat both CMDs and coronary heart disease in women. In this paper, we discuss the various genetic, biological, ethnic/racial, and psychological pathways by which women's vulnerability to CMDs elevate their CVD risk and recovery from a cardiac event. We review the evidence from trials that have, to date, failed to show that treating depression can reduce or delay the onset or recurrence of CVD events, especially for female patients. We discuss the value of lifestyle-based therapies for treating depression, to which women may be more responsive, and finish by discussing how population-based approaches including risk factor assessment could be tailored to consider these factors.