Blood pressure and cholesterol levels in adults over 40 with obesity are increasingly similar to those of adults with a normal body mass index (BMI), suggests a new study led by Imperial researchers.
The analysis, published in The Lancet, shows a significant shift in unhealthy cholesterol levels and blood pressure over the last three decades in several high-income countries, where older adults with obesity now have levels approaching, or lower than, people with a normal BMI.
According to the authors, the trend is likely due to increased use of cholesterol-lowering medications (such as statins) and blood pressure medication in people aged over 40 living with obesity in high-income countries.
However, the study found little change in the gap between blood pressure and unhealthy cholesterol levels in adults younger than 40 years old with obesity and those with normal BMI. The researchers believe this is likely because younger adults rarely receive cholesterol or blood pressure medication regardless of their BMI.
The researchers say that while the trend has reduced the cardiovascular risks for many older adults, the other risks associated with obesity remain, including diabetes, kidney and liver diseases, and cancers.
Professor Majid Ezzati, lead author from the School of Public Health at Imperial College London and Academic Director of Imperial Global Ghana, said: "Our study suggests that, in high-income countries, taking medication to lower blood pressure and cholesterol has helped middle-age and older adults with obesity lower their cardiovascular risk to levels that are similar to people with normal BMI.
"At a time that weight-loss medications are becoming more widely used, our results give a picture of the cardiovascular health of people likely to be prescribed them, which allows the healthcare system to understand how blood pressure and cholesterol treatments benefit the population alongside weight-loss medications."
Cardiovascular health
Obesity is known to increase blood pressure and unhealthy cholesterol levels, which can impact cardiovascular health and increase the risk of heart attack, heart failure, and stroke.
In the clinic, non-HDL cholesterol, or 'unhealthy' cholesterol, is a measure of how much 'bad' cholesterol is in the blood. It measures cholesterol carried on Low-Density Lipoprotein (LDLs), Very Low-Density Lipoprotein (VLDLs) and other particles known to cause plaque buildup in blood vessels. It doesn't include the 'good' (HDL) cholesterol. High levels of non-HDL are known to raise your risk of heart disease and stroke.
While the links between high blood pressure, unhealthy cholesterol and cardiovascular risk are well established, there has been little information on blood pressure and cholesterol levels, and how they have changed, for people with obesity compared with people with normal BMI.
In the latest study, researchers analysed data on blood pressure and cholesterol in people with obesity, overweight, and normal BMI from 110 health datasets including almost one million participants from 1990 to 2024 in seven high-income countries: England, USA, Japan, South Korea, Taiwan, Thailand and Finland.
They found that in the 1990s adults with obesity generally had higher blood pressure and high-density lipoprotein (non-HDL) cholesterol levels than people with a normal BMI.
Since 1990, in most of the countries studied (including England and the USA), blood pressure and unhealthy cholesterol fell more steeply among middle-aged and older adults (40–79 years old) with obesity and overweight than among those with normal BMI, narrowing the gap over time. The exceptions were Taiwan and Thailand, which did not see this convergence as universally as other countries.
The findings were most striking in older adults (60–79 years old). In England and the USA, older adults with obesity, and especially with severe obesity, had similar or even lower blood pressure and unhealthy cholesterol levels at the end of the study period than older adults with normal BMI.
Heart medicines driving change
Over the past three decades, people with obesity were more likely to be prescribed cholesterol-lowering medication (such as a statin) and blood pressure medication than those with a normal BMI.
This gap was especially pronounced in older adults. For example, in England and the USA, around 70–72% of older men with severe obesity (BMI ≥35) were taking cholesterol-lowering medication by the early 2020s, compared with 40–48% of older men with a normal BMI.
Lakshya Jain, a PhD student in the School of Public Health at Imperial, said: "This latest analysis suggests that the observed convergence in cholesterol and blood pressure levels between people aged over 40 with obesity and those with a normal BMI is largely due to statins and other widely accessible medications to reduce cardiovascular risk. That is a significant public health success story, and one we should not lose sight of as new weight-loss medications enter the picture."
However, in younger adults (under 40 years old), the study findings suggest little or no narrowing of the gap in blood pressure or cholesterol between those with obesity and those with a normal BMI. The data also suggests that use of cholesterol-lowering and blood pressure medication is low for this age group, adding further evidence that medication is the driver of the gap reduction in older adults.
Ysé d'Ailhaud de Brisis, a Research Assistant in Population Health from the School of Public Health at Imperial, said: "While good news for older adults with obesity, our results suggest that cardiovascular health risks remain higher for adults under 40 than for their counterparts with a normal BMI. Early lifestyle interventions, screening and, when appropriate, medication in this younger group should be considered to prevent long-term cardiovascular complications linked to obesity."
The researchers note some limitations of the study, including that their analysis was limited to seven countries which were all high-income, therefore the finding may not be applicable elsewhere, especially for low- and middle-income countries where the use of unhealthy cholesterol and blood pressure lowering medicines is likely to be lower. Additionally, it was not possible to look at the impact of different medication doses, which require data on prescriptions.
The study was funded by UK Medical Research Council and UK Research and Innovation. The studies were conducted by researchers from the NCD Risk Factor Collaboration (NCD-RisC) (for a full list of authors, see the paper).
This article is based on materials provided by The Lancet.
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'Metabolic traits in obesity and normal body-mass-index in industrialised countries: A multi-country analysis of national population-based studies' by Ysé d'Ailhaud de Brisis, Lakshya Jain, James E Bennett, et al. is published in The Lancet.
