Large-scale study finds that as weight increases, blood pressure may also rise

New research has found that increases in body mass index are associated with increases in blood pressure. (AFP Relaxnews pic)

Carried out by researchers at the Yale Center for Outcomes Research and Evaluation (CORE), the ongoing large-scale study looked at more than 1.7 million Chinese men and women aged 35 to 80 taking part in the larger China Patient-Centered Evaluative Assessment of Cardiac Events (PEACE) Million Persons Project.

The project records data such as age, sex, race/ethnicity, geography and occupation, looking at more than 20,000 subgroups in total, as well as other important information such as whether subjects are taking antihypertensive medication.

After measuring participants’ BMI and blood pressure, the researchers found that there was an increase of between 0.8 to 1.7 mm Hg (kg/m2) in blood pressure per additional unit of BMI for 95% of the subgroups not taking antihypertensive medication.

However, the association between BMI and blood pressure was substantially weaker in those who were taking antihypertensive medication.

Although the researchers note that they cannot establish a causal association between BMI and blood pressure, they said the association is still robust, as well as being consistent across tens of thousands of subgroups.

“The enormous size of the dataset — the result of an unprecedented effort in China — allows us to characterize this relationship between BMI and blood pressure across tens of thousands of subgroups, which simply would not be possible in a smaller study,” explained George Linderman, first author of the study.

The results are concerning as high blood pressure already affects one-third of Chinese adults, and only about one in 20 of those with hypertension have the condition under control, according to an earlier Yale-CORE study.

Rates of obesity are expected to more than triple in Chinese men — from 4.0% in 2010 to 12.3% in 2025 — and more than double in women — from 5.2% in 2010 to 10.8% in 2025.

The researchers said that these trends in increasing BMI may lead to increases in blood pressure and an increased risk of cardiovascular events.

“If trends in overweight and obesity continue in China, the implication of our study is that hypertension, already a major risk factor, is likely to become even more important,” said Harlan Krumholz, MD, senior author on the study. “This paper is ringing the bell that the time is now to focus on these risk factors.”

The researchers advise that China and countries in a similar situation focus on preventing the increase of BMI and also make an effort to improve diagnosis and treatment of high blood pressure with antihypertensive drugs and lifestyle measures.

The results were published in the journal JAMA Network Open.