Among Black Women, Hypertension Before Age 30 Years May Triple Risk of Later Stroke

Among Black women who develop elevated blood pressure before the age of 35 years, the odds of stroke may triple, according to striking findings presented at the American Stroke Association’s International Stroke Conference 2024, February 7 – 9, 2024 in Phoenix, AZ. Further, developing hypertension before age 45 years could double the risk of having a subsequent stroke.¹

The results are even more concerning given they are based on analyses controlled for multiple potential confounding variables including smoking, weight, diabetes status, and geographic region—primarily residence in the country’s so-called Stroke Belt.¹

The data come from the Black Women’s Health Study (BWHS) which includes 59 000 participants from across the US who have been followed since 1995.¹ The rate of hypertension in Black adults in the US is among the highest in the world—approximately 58% of Black women are affected compared with 43% of White women, 38% of Asian women, and 35% of Hispanic women, according to the most recent American Heart Association statistics.²

“This research was motivated by the glaring disparity I have seen in my own practice. Strokes are occurring at younger ages among my patients who identify as Black and among women,” said lead study investigator Hugo J Aparicio, MD, MPH, an associate professor of neurology at Boston University Chobanian and Avedisian School of Medicine, in Boston, MA, in an AHA statement.² “Early onset stroke, particularly at midlife, is even more tragic because these patients often have families or are caretakers for sick family members.”

Tapping data collected by the BWHS, Aparicio and colleagues investigated how early-life hypertension may influence risk for a “potentially disabling" stroke in later life.²

BWHS participants respond to biennial questionnaires that collect information related to reproductive health, lifestyle, medication use, finances, mental health, demographics, family history and psychosocial factors. The baseline year for the current analysis was the questionnaire administered in 1999.¹

Investigators identified 46 754 women with no history of stroke and who were younger than age 65 years when they completed the 1999 questionnaire. The mean age of the cohort was 42.6 years (range, 26-64 years). Participants were followed from 1999 until whichever occurred first: incident stroke, death, loss to follow-up, or the end of study follow-up on December 31, 2019). Mean length of follow-up was 17.1 years.¹

To estimate risk of midlife stroke, Aparicio et al compared participants with and without treatment for hypertension before age 45 years, between 45 and 64 years of age, and within 10-year age intervals from 1999 to 2019 using Cox proportional hazard models.¹ They determined a history of hypertension by participant self-report using as a definition “physician diagnosed hypertension with use of an antihypertensive medication or diuretic or use of an antihypertensive medication alone.”¹

FINDINGS¹

The researchers documented baseline hypertension in 2980 (10.5%) of participants younger than age 45 years and among 7147 (38.7%) of those aged 45-64 years. Over up to 23 years of follow-up, 1485 (3.2%) experienced stroke.

When they compared BWHS participants who experienced a stroke with Black women with no stroke history, the researchers found that women with a history of treatment for hypertension before age 45 years were at a significantly 2.2 times greater risk of midlife stroke (hazard ratio 2.23; 95% CI, 1.79-2.78) after multivariable adjustment for age, neighborhood socioeconomic status, residence in Stroke Belt states, smoking, body mass index, and diabetes.

Aparicio and colleagues reported the greatest increase in risk for mid-life stroke, at more than 3-fold, was among study participants with youngest age of hypertension onset, those aged 24 to 34 years (HR, 3.15; 95% CI, 1.92-5.16). The risk among women who developed hypertension at midlife (age 45 to 64 years) was more than 1.5 time greater (HR, 1.69; 95% CI, 1.47-1.95).

“We expected to see an association between having high blood pressure at a younger age and having a stroke during midlife and later life, however, we were surprised and concerned to see the magnitude of the relationship, especially for women who were taking antihypertension medications before age 35,” Aparicio said.²

He added, “My hope is that health care professionals are persuaded to pay special attention to high blood pressure screening and treatment over the life course for African American women, such as during child-bearing years and both before and at the start of middle age. Health care policy changes are needed so that primary prevention is promoted and funded because by the time a Black woman has a stroke at middle age, it is often too late,” Aparicio concluded.

References:

1. Aparicio HJ, Lioutas V, Shulman JG, et al. Early onset hypertension increases risk of midlife stroke among Black women. Abstract presented at: International Stroke Conference 2024; February 7 – 9, 2024; Phoenix, AZ. Accessed February 2, 2023. https://www.ahajournals.org/doi/10.1161/str.55.suppl_1.101
2. Black women with high blood pressure before age 35 may have triple the risk of a stroke. News release. American Heart Association. February 1, 2024. Accessed February 2, 2024. https://newsroom.heart.org/news/black-women-with-high-blood-pressure-before-age-35-may-have-triple-the-risk-of-a-stroke