Being overweight or obese creates directly damaging changes to the structure of the heart, according to research led by Queen Mary University of London (QMUL). The new research uses UK Biobank data to reveal – for the first time – the direct damage that carrying extra weight has on the heart's weight and size, and implicates a range of other modifiable risk factors including high blood pressure.
The British Heart Foundation-funded research, which included academics from University of Oxford, used cardiac magnetic resonance imaging to carefully study the structure and function of the hearts of 4,561 people from the UK Biobank database – an international health resource following the health and well-being of 500,000 volunteer participants.
After adjusting for risk factors that can't be modified, the team were able to measure the effects of a range of lifestyle risk factors, including blood pressure, smoking status, body mass index (BMI), exercise, cholesterol, alcohol intake and diabetes, on the four chambers of the heart. They showed that risk factors could all have varying effects on the heart, but an overall increased heart weight was linked to overweight and obese individuals.
Previous studies have definitively proven the link between high BMI and heart disease but have predominantly shown how it increases blood pressure, cholesterol and the risk of developing diabetes, which are all independent risk factors for heart disease. This new study was able to see and measure the direct damage that modifiable risk factors have on the structure and function of the heart.
Professor Steffen Petersen, lead author at QMUL's William Harvey Research Institute, said: "We all know that our lifestyle has a big impact on our heart health – particularly if we're overweight or obese. But researchers haven't fully understood how exactly the two things are linked.
"With this research, we've helped to show how an unhealthy lifestyle increases your risk of heart disease. BMI and blood pressure in particular led to heavier and bigger hearts, which increases the risk of heart problems, including heart attacks."
Professor Sir Nilesh Samani, medical director of the British Heart Foundation, said: "This research shows the silent impact of being overweight and having high blood pressure on the structure and function of the heart, which over time may lead to heart disease and heart failure.
"The important message is that these are things we have the power to change before they result in irreversible heart damage."
Aims: The UK Biobank is a large-scale population-based study utilising cardiovascular magnetic resonance (CMR) to generate measurements of atrial and ventricular structure and function. This study aimed to quantify the association between modifiable cardiovascular risk factors and cardiac morphology and function in individuals without known cardiovascular disease.
Methods: Age, sex, ethnicity (non-modifiable) and systolic blood pressure, diastolic blood pressure, smoking status, exercise, body mass index (BMI), high cholesterol, diabetes, alcohol intake (modifiable) were considered important cardiovascular risk factors. Multivariable regression models were built to ascertain the association of risk factors on left ventricular (LV), right ventricular (RV), left atrial (LA) and right atrial (RA) CMR parameters.
Results: 4,651 participants were included in the analysis. All modifiable risk factors had significant effects on differing atrial and ventricular parameters. BMI was the modifiable risk factor most consistently associated with subclinical changes to CMR parameters, particularly in relation to higher LV mass (+8.3% per SD [4.3 kg/m2], 95% CI: 7.6 to 8.9%), LV (EDV: +4.8% per SD, 95% CI: 4.2 to 5.4%); ESV: +4.4% per SD, 95% CI: 3.5 to 5.3%), RV (EDV: +5.3% per SD, 95% CI: 4.7 to 5.9%; ESV: +5.4% per SD, 95% CI: 4.5 to 6.4%) and LA maximal (+8.6% per SD, 95% CI: 7.4 to 9.7%) volumes. Increases in SBP were associated with higher LV mass (+6.8% per SD, 95% CI: 5.9 to 7.7%), LV (EDV: +4.5% per SD, 95% CI: 3.6 to 5.4%; ESV: +2.0% per SD, 95% CI: 0.8 to 3.3%) volumes. The presence of diabetes or high cholesterol resulted in smaller volumes and lower ejection fractions.
Conclusions: Modifiable risk factors are associated with subclinical alterations in structure and function in all four cardiac chambers. BMI and systolic blood pressure are the most important modifiable risk factors affecting CMR parameters known to be linked to adverse outcomes.
Steffen E Petersen, Mihir M Sanghvi, Nay Aung, Jackie A Cooper, José Miguel Paiva, Filip Zemrak, Kenneth Fung, Elena Lukaschuk, Aaron M Lee, Valentina Carapella, Young Jin Kim, Stefan K Piechnik, Stefan Neubauer
[link url="http://www.qmul.ac.uk/media/news/items/smd/200075.html"]Queen Mary University of London material[/link]
[link url="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185114"]PLOS One abstract[/link]