Sex-specific markers of hypertension

https://doi.org/10.1038/s41371-022-00772-z

Introduction:

The leading risk factor for cardiovascular disease is high blood pressure/hypertension (BP). This research paper focuses on the effect of biological sex on BP development in midlife, the period within which BP tends to escalate, especially in women. In this health study, participants were examined at baseline for 6 years using inflammatory markers and BP levels. Levels of inflammatory markers are tests for inflammation in the blood, which occurs when chemicals from white blood cells enter the body against pathogens during an infection, thereby raising blood flow.

Previous Research:

It is known that T-cells, a part of the adaptive immune system, play an integral role in regulating blood pressure response, which could lead to hypertension. The adaptive immune system is activated differently in males and females. While the causes for sex differences in BP haven’t been identified, some experimental studies suggested that this varied activation may be the culprit.

Summary:

The correlation between sex and hypertension was studied using markers of inflammation in the body. Systolic BP measures the pressure in the arteries during a heartbeat. Diastolic BP measures the pressure in the arteries between heartbeats. In women, it was found that higher levels of C-reactive proteins, proteins found in blood plasma that are markers for inflammation, were associated with higher levels of systolic and diastolic BP. In men, higher levels of C-reactive proteins were not associated with either systolic or diastolic levels of BP. C-reactive protein, which is found in blood plasma, indicates high blood pressure when found in abundance both in men and women. Therefore, the interaction between C-reactive proteins and sex was determined. This suggests that the relationship between C-reactive proteins is correlational and not causal.

The study also focused on the effect of antihypertensive medication on markers of inflammation. It was discovered that women had an increased association between antihypertensive medication and markers of inflammation. In men, the association between antihypertensive medication and markers of inflammation was weaker, as it was only present between the medication and C-reactive proteins. It is known that healthy young women have a lower average systolic and diastolic BP than men, however, there is a far steeper increase in BP during the ageing process, beginning in their thirties. The study did not have the power to look at individual medications, so the results were generalised to the effect of all antihypertensive medications.

Conclusion:

The results of this study indicate that in midlife, there is a sex-specific interaction between inflammation in the veins and the arteries and BP. It was found that the systolic BP in women increased, whereas men had decreasing levels of BP over 6 years in their forties. In this study, the correlation between C-reactive proteins and BP was independent of body mass index, as weight tends to be a coexisting condition along with hypertension. This supports the evidence that age-associated blood pressure increase differs in women and men. In early life, women have a lower BP, until their third decade, which usually sees a steep increase. Additionally, BP is a more potent risk factor for coronary heart disease in women than it is in men. This is because the risk begins at a lower BP threshold in women.

Sources:

Kringeland, Ester, et al. “Inflammation, Sex, Blood Pressure Changes and Hypertension in Midlife: The Hordaland Health Study.” Journal of Human Hypertension, vol. 37, no. 8, Aug. 2023, pp. 718–25, https://doi.org/10.1038/s41371-022-00772-z. Accessed 1 Sept. 2023.

Sylvester, Megan A., and Heddwen L. Brooks. “Sex-Specific Mechanisms in Inflammation and Hypertension.” Current Hypertension Reports, vol. 21, no. 7, May 2019, https://doi.org/10.1007/s11906-019-0959-2. Accessed 5 Jan. 2021.

‌MedlinePlus. “C-Reactive Protein (CRP) Test: MedlinePlus Lab Test Information.” Medlineplus.gov, 2018, medlineplus.gov/lab-tests/c-reactive-protein-crp-test/.

‌

‌