9.2 Listening
46 Part 1
Good morning, everyone. I’m going to talk to you this morning about public health and, in particular, two very different public health issues that are affecting the health of the world today. I’m going to talk first about the topic of obesity, and I will outline some of the major issues related to this current phenomenon. Then I will go on and do the same for climate change and its impact on health. I’ll also give you a summary of the points we have covered. But before we begin, I have a little story to tell you.
Before becoming a lecturer, I worked for Médecins du Monde. For those of you that haven’t heard of it, it’s an international humanitarian organization that provides medical care both in France and in the developing world. I was based in Haiti, and it was a fantastic experience, at least from a personal point of view. I was working with children and young mothers, and the team was just great. But as you can imagine, the situation was far from ideal: medical supplies were low, and the conditions were just appalling. Consequently, there was a lot of frustration amongst the medical staff, as well as for the Haitians themselves. One of the biggest problems was corruption, the dishonesty of some of those in power. Of course, the fact that there wasn’t any real public health system in place didn’t help. It meant that supplies often didn’t get through, or they were hijacked on the way. And the ones that actually suffered the most were the kids … Of course, the point of that story is to illustrate the fact that the role of public health authorities in ensuring the health of a nation is crucial. So – to get back to the main part of my lecture … Now, to start with, it might be useful to look at
a definition of public health. Simply put, it’s about improving the health of the community as a whole, as opposed to treating the individual. The United Nations World Health Organization (WHO) defines health as ‘a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’. As we shall see, the focus of public health is to prevent rather than treat disease, and this is done by surveying cases and promoting healthy behaviour – on local and national levels as well as on an international level. It’s worth pointing out here that a key aim of public health is to eliminate healthcare inequality – healthcare is, after all, one of the fundamental basic human rights along with access to clean drinking water and education. In terms of access to healthcare, unfortunately there are disparities not only between people of different ethnicities but also different genders. Gender gaps related to access to and control over resources are widespread. Possible exposure to health risks is fundamentally different between men and women. What I’m going to focus on now is one particular
subject of concern that is greatly affecting Western nations today and that, in many countries, has become an issue of public health. OK, so to start with, let’s take a few moments to
consider what constitutes obesity. What is it exactly that differentiates someone who is simply a little overweight from someone who we would classify as obese? When measuring weight, we usually use the body mass index, known as the BMI. To calculate someone’s BMI, you take their weight in kilos and divide it by the square of their height in metres. Someone who is overweight would
have a BMI equal to or more than 25, while someone who is obese would have a BMI of 30 or more. Although, having said that, it could be argued that the risk of chronic disease does in fact increase progressively from a BMI of 21. Anyway, these are cut-off points that provide a benchmark by which to assess individuals – adults of all ages and of both sexes. However, BMI should only be taken as a rough guide. To measure childhood obesity, we refer to BMI centiles: a child with a BMI above the 98th
those above the 95th
centile is considered clinically obese, although centile are considered obese for
population monitoring purposes. So, moving on, there are three important aspects to
consider in terms of public health and obesity. The first point is related to the extent of the problem. Research has shown that in 2016, approximately 1.9 billion adults were considered overweight, and 650 million were classed as obese. And one really alarming statistic is the estimated 38.2 million children under the age of five who were overweight or obese in 2019. Looking to the future, World Obesity Federation projections for 2030 for children classed as obese is a staggering 250 million worldwide. Obesity was once considered a problem of high-income countries – the USA being the most obvious example. Increasingly, we find that now low- and middle- income countries are also falling victim to this epidemic. Malnutrition and obesity are as likely as not to be found side by side within the same country. Indeed, according to the WHO, developing countries are home to the ‘vast majority’ of overweight and obese children; and the rate of increase in childhood overweight and obesity has been over 30% higher in these countries. So, what causes obesity? Medically speaking, the
fundamental cause is an energy imbalance between calories consumed on the one hand and calories expended on the other hand. At a global level, there has been a shift in diet towards the intake of what we consider energy-dense foods – in other words, foodstuffs that are high in fat and sugar and low in vitamins, minerals and other micronutrients. Equally, intake of nutritional foodstuffs is falling. Coupled with this is the trend away from physical activity and the increasingly sedentary nature of our work. We can add to that a greater reliance on modes of transport – as opposed to walking or cycling – and urbanization, i.e., the move away from the countryside into towns and cities. Let’s look now at the health risks that obese people
run – in other words, the consequences of obesity. It’s probably fair to say that obesity and its related chronic diseases are largely preventable. And the risks people run are fairly well known. Common consequences of obesity include cardiovascular disease – strokes, heart attacks – which is the world’s premier cause of death; over 17 million people die of coronary heart disease worldwide annually. Also type 2 diabetes – the WHO predicts diabetes-related deaths will rise by more than 50% in the next few years. Another possible risk is osteoarthritis, as a result of carrying excess weight. Other musculoskeletal disorders are also common, as are certain types of cancer – cancer of the colon, even breast cancer. People suffering from obesity also run the risk of suffering from respiratory problems and sleep apnoea. When it comes to clinically obese children, premature death and disability in adulthood are the long-term risks. And now we come to the real question, which is – what exactly are nations doing to reduce levels of
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