Sex, Race Disparities in High Blood Pressure Begin to Emerge Early in Life

Disparities in the prevalence of high blood pressure (BP) between men and women and across racial/ethnic groups can be seen in children as young as 8 years old, a new analysis shows.

Researchers led by Shakia Hardy, MPH (University of North Carolina at Chapel Hill), found that between the ages of 8 and 30, African-Americans and males were more likely than white individuals and females to transition away from ideal BP levels, placing them at heightened risk of prehypertension or hypertension earlier in life. That lays the groundwork for race- and sex-based differences in the occurrence of elevated BP observed in older age groups.

“These findings invite a reassessment of the traditional approach that considers blood pressure as a risk factor that needs to be treated once people are hypertensive, at which point disparities are already apparent,” Hardy told TCTMD in an email. “As the saying goes, ‘prevention is better than cure.’ Primordial prevention beginning in childhood could prevent or delay the development of adverse levels of blood pressure and disparities.”

For the study, published online April 19, 2017, ahead of print in JAMA Cardiology, the investigators examined whether the likelihood of moving between BP categories (ideal BP, prehypertension, or hypertension) in a year’s time—measured as annual net transition probabilities, which take into account people moving into higher as well as lower categories—varied by race/ethnicity and sex.

“Previous studies characterizing blood pressure levels across the life course have relied on prevalence estimates at a given age or used longitudinal studies that are often inconsistent with current blood pressure trends,” Hardy said. “Our study was interested in identifying critical ages at which net transitions between levels of blood pressure occurred in contemporary populations.”

The analysis included data from three US National Health and Nutrition Examination Survey (NHANES) samples from 2007-2008, 2009-2010, and 2011-2012. There were 17,747 total participants who self-reported being white (50.1%), black (28.0%), or of Mexican ethnicity (21.9%). Other racial/ethnic groups were excluded because of small sample sizes.

At age 8 years, there were already disparities seen. Boys were less likely to have ideal BP and more likely to have prehypertension compared with girls, with the gaps widening through the teenage years.

Between 8 and 30 years, annual net transition probabilities from ideal to prehypertension were about twice as high in males as in females. The largest probabilities were found in black young men, of whom 2.9% of those with ideal BP transitioned to prehypertension a year later. The lowest probabilities, on the other hand, were seen in Mexican-American young women (0.6%).

At age 40, the likelihood of moving from ideal BP to prehypertension was roughly equal in men and women across racial/ethnic groups, but differences developed after that. Probabilities remained stable or declined for men and increased rapidly for women.

Disparities in the likelihood of transitioning from prehypertension to hypertension were seen early in life, as well. Probabilities were highest in white males at age 8, with a slight decline through age 60. Both male and female African-Americans had increasing probabilities into early adulthood, after which they began to fall. White females and Mexican-Americans of both sexes had probabilities that tended to increase throughout the adult years.

A Call for Primordial Prevention

The results suggest the need for more intensive efforts focusing on primordial prevention early in life to head off problems later on, as opposed to treating elevated BP after it has developed, the authors state.

But that might be easier said than done, Hardy indicated.

“The challenge of primordial prevention for clinical and public health professionals is developing and implementing effective sodium reduction, physical activity, and weight loss strategies that lead to sustained blood pressure reductions among diverse populations,” she said. “There’s a substantial missed opportunity in the pediatric population to educate children and their families about lifestyle factors and provide adequate school, community, and home-based support for lifestyle modifications. Public health and clinical efforts need to be properly timed at the right ages to reach those known to be vulnerable to early rises in blood pressure in culturally- and gender-appropriate settings.”

In an accompanying editorial, Herman Taylor, MD, MPH (Morehouse School of Medicine, Atlanta, GA), and colleagues cite some limitations of the study but also stress the importance of prevention early in life.

“For now, methodological imperfections should in no way detract from the important message delivered by the analysis of Hardy et al: if hypertension prevalence and disparities are to be eliminated, the attention of public health and primary care sectors must be directed emphatically toward the young,” they write. “The key is to get ahead of the transitions and attempt to modify social, behavioral, and clinical determinants of BP elevations before they occur.”