How obesity impacts cardiovascular health

In this article, a leading consultant cardiologist explains the relationship between obesity and cardiovascular health.

What is obesity, and how do we define it?

Obesity is more than just a cosmetic concern and certainly has nothing to do with ‘body shaming’. Medical advice is not judgmental but aims to optimise mental and physical health.

Obesity is a complex, chronic disease characterised by an excessive accumulation of body fat which poses significant health risks. While we may picture someone visibly overweight, it's important to remember that obesity is a spectrum.

To classify weight status, healthcare professionals use the Body Mass Index (BMI), a calculation based on your height and weight. A BMI between 20 and 25 is considered a healthy body weight, between 25 and 30 is the overweight range, and a BMI of 30 or higher generally falls within the obese range; over 40 is morbid obesity, with the highest health risk concern.

However, BMI alone does not take into account body composition, and cannot distinguish between muscle from fat or water content. It's also crucial to consider other factors like waist circumference, as fat concentrated around the abdomen is particularly harmful. In that regard, a body composition analysis, which measures the proportion of fat to muscle, can provide a more accurate assessment of an individual's health risk.  

Why would cardiologists be concerned about obesity?

I will answer this question, sharing what the European Society of Cardiology, the largest cardiology society in the world, has recently declared about obesity:

• Obesity is now a pandemic and has doubled since 1990 – almost 1 in 4 European adults (23%) living with obesity.
• People living with obesity have a 50%–100% increased risk of death from all causes compared to normal-weight individuals, and most of this increased risk - 67.5% - is due to cardiovascular disease (CVD).
• Governments and healthcare systems have failed to effectively curb the obesity pandemic, leading to a significant increase in preventable deaths from CVD.

• Obesity is highly prevalent among patients with CVD and significantly impacts both the course and prognosis of the condition. It is essential for cardiologists to actively engage in the management of obesity as an integral part of comprehensive patient care.
• While non-pharmacological measures remain first course of action, new drugs have recently become available that can significantly lower body weight; some of these drugs have been shown to improve cardiovascular prognosis yet expense and availability is an issue in all countries.
• Beyond its recognition as a high-risk condition that is causally linked to multiple chronic illnesses, many medical societies and health professionals consider obesity as a disease itself, resulting in impaired quality of life and reduced life expectancy.

What are the main health risks associated with obesity?

Obesity is a serious public health concern with wide-ranging consequences for individuals and healthcare systems. It significantly elevates the risk of cardiovascular diseases, including coronary artery disease (leading to angina, heart attacks, and necessitating interventions like angioplasty or bypass surgery), heart failure, cardiomyopathy, stroke, high blood pressure, and abnormal heart rhythms. Beyond its impact on the cardiovascular system, obesity disrupts metabolic processes, increasing the likelihood of developing type 2 diabetes and metabolic syndrome.

Furthermore, obesity is linked to an increased risk of certain cancers, including colon, breast, endometrial, and kidney cancer. It can also lead to liver disease with fat buildup in the liver, which can lead to liver damage, cirrhosis, and kidney disease. Pregnancy complications are also more common in obese individuals.

Obesity is also linked to sleep apnoea, a condition where breathing repeatedly stops and starts during sleep. The extra weight can put stress on your joints, contributing to osteoarthritis, a degenerative joint disease. And the impact extends beyond physical health; obesity can also take a toll on mental well-being, increasing the risk of depression and anxiety.

In essence, obesity acts as a catalyst for a multitude of health problems, compromising various bodily systems and overall quality of life. Recognising the seriousness of obesity and its far-reaching consequences is crucial for promoting effective prevention and management strategies.

What are the primary causes of obesity?

Obesity, a growing global health concern, arises from a complex interplay of factors that ultimately lead to an energy imbalance – where we take in more calories than we burn. While our individual susceptibility to weight gain is influenced by genes and biological processes, the alarming rise in obesity rates worldwide is largely fuelled by the environment we live in and the societal norms that shape our choices.

The modern food environment, with its abundance of inexpensive, highly processed foods laden with calories, unhealthy fats, and added sugars, encourages overconsumption and weight gain. Our increasingly sedentary lifestyles, characterised by limited physical activity and reliance on cars and public transport, further contribute to this energy imbalance by reducing calorie expenditure. Marketing and advertising also play a powerful role by influencing our dietary habits with persuasive campaigns for unhealthy food choices and sugary drinks. Moreover, urban environments often lack green spaces and recreational facilities, discouraging physical activity, while socioeconomic factors like poverty and food insecurity can limit access to healthy food options.

While environmental and societal factors are major drivers, our biology and genetics also contribute. Some individuals may be genetically predisposed to gain weight more easily or store fat in certain areas. Hormonal imbalances can disrupt appetite regulation and metabolism, making it harder to control weight. Even the composition of bacteria in our gut can influence how we process food and store energy. Sleep deprivation and certain medications can also tip the scales towards weight gain. Psychological factors, such as stress, emotional eating, and mental health conditions, further complicate the picture by influencing our eating habits and motivation for physical activity.

Addressing this complex issue requires a multi-pronged approach that tackles both individual behaviours and the broader environmental and societal influences that shape our choices.

What is the link between obesity and inflammation?

The link between obesity and inflammation is a crucial one to understand, as it underpins many of the health risks associated with excess weight. Essentially, obesity triggers a chronic, low-grade inflammatory state throughout the body, and this ongoing inflammation acts as a driving force behind various diseases, particularly cardiovascular disease.

1. Adipose tissue dysfunction: Fat tissue, also known as adipose tissue, isn't just a storage depot for excess calories. It's an active endocrine organ that releases hormones and signalling molecules. In obesity, fat cells become enlarged and dysfunctional. They start producing an excess of pro-inflammatory molecules (like cytokines) and reduce the production of anti-inflammatory ones.
2. Immune system activation: This imbalance in signalling molecules triggers a chronic inflammatory response, with immune cells infiltrating the fat tissue. Macrophages, a type of immune cell, accumulate in the fat and release further inflammatory mediators.
3. Systemic inflammation: This inflammation isn't confined to fat tissue. It spills over into the bloodstream, affecting other organs and systems throughout the body. This chronic, low-grade inflammation contributes to the development of insulin resistance, leading to type 2 diabetes; atherosclerosis, plaque buildup in the arteries, increasing the risk of heart attack and stroke, endothelial dysfunction (impaired function of the blood vessel lining, contributing to high blood pressure and blood clots) and heart failure.

Inflammation and obesity become intertwined in a vicious cycle. Inflammation can worsen insulin resistance, further promoting fat accumulation and weight gain. This, in turn, perpetuates the inflammatory state, creating a self-reinforcing loop.

What are the most effective ways to treat obesity?

Obesity is a complex health condition requiring a comprehensive and individualized approach to treatment. Lifestyle interventions form the cornerstone of obesity treatment and should always be the first line of attack.

This includes dietary modification to create a sustainable calorie deficit, focusing on whole foods like fruits, vegetables, and lean protein while limiting processed foods, refined sugar, and unhealthy fats. Regular physical activity is also crucial, with at least 150 minutes of moderate-intensity exercise per week recommended, along with efforts to increase daily movement. Behavioural therapy, such as cognitive behavioural therapy (CBT) and mindful eating techniques, can help individuals identify and modify unhealthy thoughts and behaviours related to eating and exercise.

For some individuals, medications can be valuable in addition to lifestyle changes. These are typically considered for people with a BMI ≥30 kg/m² or ≥27 kg/m² with obesity-related complications. Several medications are available, including GLP-1 receptor agonists (like semaglutide and liraglutide) that mimic a natural hormone to regulate appetite and blood sugar, and orlistat, which reduces fat absorption.

In cases of severe obesity (BMI ≥40 kg/m² or ≥35 kg/m² with complications) where lifestyle changes and medication have not been effective, bariatric surgery may be an option. Common procedures include gastric bypass, sleeve gastrectomy, and adjustable gastric banding. These surgeries can lead to significant weight loss and improvement in obesity-related health issues.

Obesity management often involves a multidisciplinary team of healthcare professionals, including physicians, dietitians, psychologists, and exercise specialists, working together to provide comprehensive care. Ultimately, successful obesity management requires ongoing support and a long-term commitment to lifestyle changes.

What is the role of GLP-1 receptor agonists in treating obesity and reducing cardiovascular risk?

GLP-1 receptor agonists are a relatively new class of medications that are showing great promise in the treatment of obesity and related conditions. Originally developed for type 2 diabetes, these drugs have shown remarkable success in helping individuals achieve significant weight loss and improve their heart health. They mimic a natural hormone called GLP-1 which plays a key role in regulating appetite, blood sugar levels, and insulin secretion.

By activating GLP-1 receptors, these medications help to decrease appetite, increase feelings of fullness, improve blood sugar control, and slow gastric emptying. This leads to reduced food intake, weight loss, and better blood sugar management. Beyond their metabolic effects, GLP-1 receptor agonists also offer impressive cardiovascular benefits. Studies have shown they can reduce the risk of major adverse cardiovascular events like heart attacks and strokes, lower blood pressure, improve cholesterol levels, and reduce inflammation.

Currently, semaglutide is the only weight loss intervention with proven outcomes in patients with cardiovascular disease and without diabetes, while other medications such as liraglutide are also approved for patients with concomitant diabetes. This class of drug offers a promising new approach to improving both metabolic and cardiovascular outcomes, addressing a critical need in the fight against obesity and its associated health consequences.

What are the risks and the side effects of this class of medications? Can any patient with obesity take them?

While generally safe and well-tolerated, GLP-1 receptor agonists do have potential side effects: the most common are gastrointestinal issues like nausea, vomiting, and diarrhoea, which usually subside over time. Less common but more serious side effects include pancreatitis and gallbladder problems. These medications are contraindicated in individuals with a history of pancreatitis, type 1 diabetes, medullary thyroid carcinoma, or multiple endocrine neoplasia syndrome type 2. They should also be avoided during pregnancy and breastfeeding.

It's essential to discuss the potential benefits and risks of GLP-1 receptor agonists with your doctor to determine if they are a suitable treatment option for you.

What are some of the challenges in treating obesity?

Treating obesity can be challenging for several reasons. One of the biggest hurdles is weight regain after initial weight loss. Our bodies have a natural tendency to defend a certain weight, making it difficult to maintain weight loss over the long term. Another challenge is the stigma associated with obesity. People with obesity often face discrimination and negative stereotypes, which can make it harder to seek help and make positive changes. Access to care can also be a barrier, as not everyone has equal access to the resources and support needed for effective weight management.

What can be done to prevent obesity at the individual and societal levels?

Preventing obesity requires a multi-pronged approach that addresses both individual behaviour and the environment in which we live. At the individual level, promoting healthy lifestyle habits from a young age is crucial. This includes encouraging healthy eating, regular physical activity, and adequate sleep. At the societal level, we need to create environments that support healthy choices. This could involve policies that promote access to healthy foods and safe places to be active, as well as regulations on the marketing of unhealthy foods. Addressing the root causes of obesity will require a collaborative effort from individuals, families, communities, and policymakers.

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