Researchers attribute the trend largely to the increased and more intensive use of cholesterol-lowering drugs, such as statins, and blood pressure medications among adults aged 40 and above living with obesity.
Obesity is a major risk factor for high blood pressure and unhealthy cholesterol levels, both of which increase the likelihood of cardiovascular diseases, including heart attack, heart failure and stroke. However, until now, little was known about how these risk factors have evolved over time in people with obesity compared with those with a normal BMI.
"Our study suggests that, in high-income countries, taking medication to lower blood pressure and cholesterol has helped middle-aged and older adults lower their cardiovascular risk to levels that are similar to people with normal BMI," said Professor Majid Ezzati of the School of Public Health at Imperial College London.
He added that the findings provide valuable context as weight-loss medications become more widely available, helping healthcare systems better understand how conventional cardiovascular treatments complement newer obesity therapies.
Nearly one million participants studied
The researchers analysed blood pressure and cholesterol data from nearly one million participants collected between 1990 and 2024 across 110 health datasets in seven high-income countries—England, the United States, Japan, South Korea, Taiwan, Thailand and Finland.
In the 1990s, adults with obesity generally had higher blood pressure and levels of non-high-density lipoprotein (non-HDL) cholesterol than those with a normal BMI.
Over the following three decades, however, blood pressure and unhealthy cholesterol declined more rapidly among overweight and obese adults aged 40 to 79 than among people with a normal BMI in most of the countries studied, particularly England and the United States. Taiwan and Thailand were notable exceptions, where the trend was less consistent.
The convergence was most pronounced among adults aged 60 to 79. By the end of the study period, older adults with obesity—and particularly those with severe obesity—in England and the United States had blood pressure and unhealthy cholesterol levels that were similar to, or in some cases even lower than, those of older adults with a normal BMI.
Medication use appears to be the key factor
The researchers found that people with obesity were consistently more likely than those with a normal BMI to receive cholesterol-lowering and blood pressure medications over the past three decades.
The difference was especially striking among older adults. In England and the United States, around 70% to 72% of older men with severe obesity (BMI of 35 or higher) were taking cholesterol-lowering medication by the early 2020s, compared with 40% to 48% of older men with a normal BMI.
Lead author Lakshya Jain of Imperial College London said the findings suggest that the convergence in cardiovascular risk factors is largely driven by the widespread availability and use of statins and other heart-protective medications.
"This is a significant public health success story, and one we should not lose sight of as new weight-loss medications enter the picture," Jain said.
Younger adults remain at greater risk
The study found little evidence of a similar improvement among adults younger than 40 years.
Researchers observed that younger adults with obesity continued to have higher blood pressure and unhealthy cholesterol levels than their peers with a normal BMI, while the use of cholesterol-lowering and blood pressure medications remained relatively low in this age group.
Ysé d'Ailhaud de Brisis, another author from Imperial College London, said the findings underscore the need for early lifestyle interventions, routine screening and, where appropriate, timely medication to reduce the long-term cardiovascular risks associated with obesity.
The researchers cautioned that the findings may not be applicable to low- and middle-income countries, where access to cholesterol- and blood pressure-lowering medications is generally lower. They also noted that the study could not assess the effects of different medication dosages due to a lack of prescription-level data.
In an accompanying commentary, Dr Yuan Lu of Yale School of Medicine, who was not involved in the research, said the study highlights that obesity-related cardiovascular risk is influenced not only by excess body weight but also by access to treatment, healthcare engagement and timely intervention.
She noted that while medications can reduce some of the cardiovascular risks associated with obesity, they do not eliminate the broader health consequences of the condition, particularly among younger adults, underscoring the need for comprehensive prevention strategies.