NEW ORLEANS – Visceral adiposity, but not body mass index or total body fat, significantly correlated with elevated 24-hour ambulatory systolic blood pressure, greater systolic variability, and masked hypertension in a study from the University of Pennsylvania, Philadelphia.
Dr. Jordana B. Cohen
Subjects in the highest quartile of visceral fat had a 6.3-fold greater odds of masked hypertension – normal in the office, but high at home – compared with those in the lowest quartile (95% confidence interval, 1.2-33.1).
The study findings suggest that central obesity, in particular, should trigger 24-hour ambulatory blood pressure monitoring (ABPM). “Every obese person should get a 24-hour” ABPM, but “we really need to be pushing [it] in people who have central adiposity. These are the patients ... we really need to focus on” because of the risk of masked hypertension, a “ticking time bomb” that greatly increases the risk of cardiovascular events, said lead investigator Jordana B. Cohen, MD, an assistant professor of medicine at the university.
The study also helps explain why body mass index (BMI) hasn’t been consistently linked to masked hypertension in previous studies; some studies likely included subjects with high BMIs but not central obesity.
Waist circumference, a marker of visceral adiposity, also correlated with elevated 24-hour systolic pressure and greater variability, but a trend for masked hypertension was not statistically significant, Dr. Cohen reported at the joint scientific sessions of the American Heart Association (AHA) Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension.
It’s long been known that visceral fat – fat around the abdominal organs – is metabolically active and associated with greater cardiovascular risk, but its relationship to blood pressure hadn’t been well described, so Dr. Cohen and her team decided to take a look.
They ran whole body dual x-ray absorptiometry scans on 96 hypertensive adults on a stable dose of one antihypertensive drug for at least 2 months and correlated the findings with ABPM. Subjects were an average of 58 years old, almost 60% were women, almost half were black, and 54% were obese, with BMIs of at least 30 kg/m2.
After adjustment for age, sex, race, and antihypertensive class, the team found a significant, linear correlation between visceral fat and mean 24-hour systolic blood pressure. Patients with a visceral adiposity of about 0.1 kg/m2, for instance, had a mean pressure of around 130 mm Hg, compared with patients with more than 0.6 kg/m2, who had a mean of almost 150 mm Hg. Findings were similar for waist circumference over a range of 70-150 cm.
The correlations were weak (r = 0.3), but Dr. Cohen said they might improve with ongoing enrollment. Both measures also correlated with systolic variability.
Overall, the highest quartiles of waist circumference and visceral adiposity correlated with the highest mean systolic pressures and greatest variability, compared with the lowest quartiles. Visceral adiposity was the only measure significantly linked with masked hypertension. Trends in those directions for increasing BMI and total body fat mass were not statistically significant.
Mean BMI in the study was 31.7 kg/m2, and mean waist circumference was 104 cm. Mean 24-hour systolic blood pressure was 135 mm Hg and mean 24-hour systolic variability was 13 mm Hg. Almost 30% of the subjects had masked hypertension. Drug classes included beta-blockers, calcium channel blockers, diuretics, ACE-inhibitors, and angiotensin receptor blockers.
Dr. Cohen plans to investigate drug response versus visceral adiposity once the recruitment goal of 150 subjects is reached.
There was no external funding, and the investigators reported that they didn’t have any relevant disclosures.
SOURCE: Cohen JB et al. Joint Hypertension 2019, Abstract P2052.