Ageing is the biggest risk factor for heart disease but why some people age faster than others isn’t fully understood.
The scientists leading the research say that visceral body fat could play an important role in accelerating ageing of the heart and blood vessels.
This type of fat is known to be harmful to health and this study now links it to faster heart ageing.
Sex differences
The study, led by scientists from the Medical Research Council (MRC) Laboratory of Medical Sciences, also found differences between men and women.
They discovered that fat around the hips and thighs could potentially slow heart ageing in women.
The scientists analysed data from 21,241 participants in UK Biobank, which includes whole body imaging to map the amount of fat and where it is located in the body.
The study was published in the ‘European Heart Journal’.
Determining an individual’s ‘heart age’
The UK Biobank data also includes detailed imaging of the heart and blood vessels.
Artificial intelligence (AI) was used to analyse these images to capture signs of organ ageing such as tissues becoming stiff and inflamed.
An individual was given a ‘heart age’ which can be compared to their actual age at the time of the scan.
The risks of hidden fat
The researchers found that faster heart ageing was linked to having more visceral adipose tissue.
Visceral adipose tissue is fat found deep inside the abdomen around organs such as the stomach, intestines, and liver.
This type of fat cannot be seen from the outside, and some people can have large amounts of visceral fat despite having a healthy weight.
Premature ageing
The researchers found signs on blood tests that visceral fat is linked to increased inflammation in the body, which is a potential cause of premature ageing.
They also found differences between the sexes.
Male-type fat distribution, which is fat around the belly and often called ‘apple-shaped’, was particularly predictive of early ageing in men.
The role of hormones
In contrast, a genetic predisposition to female-type fat, primarily fat on the hips and thighs, often called ‘pear-shaped’, was protective against heart ageing in women.
The researchers also found a link between higher oestrogen levels in pre-menopausal women and a slowing of heart ageing.
They suggested that this could indicate a role for hormones in protecting against heart ageing.
Increase healthy lifespan
Professor Declan O’Regan, who led the research at the MRC Laboratory of Medical Sciences and Imperial College London, said:
We have known about the apple and pear distinction in body fat, but it hasn’t been clear how it leads to poor health outcomes. Our research shows that ‘bad’ fat, hidden deep around the organs, accelerates ageing of the heart.
But some types of fat could protect against ageing, specifically fat around the hips and thighs in women.
We also showed that body mass index wasn’t a good way of predicting heart age which underscores the importance of knowing where fat is stored in the body and not just total body weight.
The goal of our research is to find ways to increase healthy lifespan. While being active is important, we found that hidden fat could still be harmful even in fit people.
In the future, we plan to investigate how drug therapies, such as GLP-1 inhibitors (for example, Ozempic) could improve not just diabetes and obesity but target the ageing effects of hidden visceral fat.
This study was funded by MRC, British Heart Foundation, and the National Institute for Health and Care Research Imperial Biomedical Research Centre.