to Western countries. With wealth comes chronic ill-health. As developing countries play economic catch-up, the diseases of civilisation spread. What began as a Western problem threatens to engulf the rest of the planet. Obesity tends to lead the way, and has affected large swathes of the population already, including those in developing countries. Its collective of associated conditions such as heart disease and type 2 diabetes (an insensitivity to insulin, rather than a lack of it) are trailing not far behind. Allergic disorders, including asthma and eczema, are also at the forefront of the spread, with rises under way across middle-income countries in South America, Eastern Europe and Asia. Autoimmune diseases and behavioural conditions appear to lag the most, but are now particularly common in the upper-middle-income countries, including Brazil and China. Just as many of our modern illnesses reach a plateau in the wealthiest countries, these conditions begin their ascent elsewhere.
When it comes to twenty-first-century illnesses, money is dangerous. The size of your salary, the wealth of your neighbourhood and status of your country all contribute to your risk. But of course, simply being rich does not make you ill. Money may not buy happiness, but it does buy clean water, freedom from infectious disease, calorie-rich foods, an education, a job in an office, a small family, holidays to far-flung places, and many other luxuries besides. Asking Where? tells us not just the location of our modern plagues, but that it is money that’s bringing us chronic ill-health.
Intriguingly though, this relationship between increasing wealth and poorer health disconnects at the very richest end of the scale. The wealthiest people in the wealthiest countries appear to be better able to lift themselves clear of the chronic disease epidemic. What begins as a preserve of the rich (think tobacco, takeaway food and ready meals) ends as the staple of the poor. Meanwhile, the well-off gain access to the latest health information, the best health care, and the freedom to make choices that keep them well. Now, while the richest cohorts of society in developing countries gain weight and acquire allergies, it is the poorest in developed countries who are more and more likely to be overweight and to suffer from chronic ill-health.
Next, we must ask Who? Does wealth and a Western lifestyle bring ill-health to everyone, or are some groups affected more than others? It’s a pertinent question: in 1918, as many as 100 million people died from the flu pandemic that swept the globe after the First World War. Asking Who? provided an answer, that, with today’s medical knowledge, could potentially have considerably reduced the death toll. Whereas flu usually kills vulnerable members of society – the young, the old, and the already sick – the 1918 flu killed mainly healthy young adults. These victims, in the prime of their lives, are likely to have died not from the flu virus itself, but from the ‘cytokine storm’ unleashed by their immune systems in an attempt to clear the virus. The cytokines – immune messenger chemicals which ramp up the immune response – can inadvertently lead to a reaction that’s more dangerous than the infection itself. The younger and fitter the patients, the greater the storm their immune systems created, and the more likely they were to die from the flu. Asking Who? tells us something of what made this particular flu virus so dangerous, and would have enabled us to direct medical care not just at fighting the virus, but also towards calming the storm.
Who? is composed of three elements. What age are those affected by twenty-first-century illnesses? Are there differences in how these conditions affect people of different races? And are the sexes affected equally?
Let’s start with age. It’s easy to assume that diseases associated with developed, wealthy countries, where health care is good, are an inevitable consequence of our ageing population. Of course new diseases are on the rise! you might think. We live so long now! Surely so many of us living well into our seventies and eighties guarantees a whole host of new health challenges? Of course, as we release ourselves from the burden of death-by-pathogen, we will inevitably suffer from death-by-something-else, but many of the illnesses we face now are not simply diseases of old age, released by our longer life expectancy. Unlike cancer, whose rise is at least partly attributable to the cellular replacement process breaking down in older bodies, twenty-first-century illnesses are not all old-age-related. In fact, most of them show a preference for children and young adults, despite being relatively rare among these age groups during the age of infectious disease.
Food allergies, eczema, asthma and skin allergies often begin at birth or in the first few years of a child’s life. Autism typically presents itself in toddlers, and is diagnosed before the age of five. Autoimmune diseases can hit at any time, but many show themselves at a young age. Type 1 diabetes, for example, typically reveals itself in childhood and the early teens, though it can also crop up in adulthood. Multiple sclerosis, the skin condition psoriasis, and inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis, all typically attack in the twenties. And lupus usually affects people between the ages of fifteen and forty-five. Obesity too, is a disease that can start young, with around 7 per cent of American babies considered over the normal weight at birth, rising to 10 per cent by the time they are toddlers, and about 30 per cent becoming overweight later in childhood. Older people are not immune to twenty-first-century illnesses – almost all of them can strike suddenly at any age – but the fact that they so often affect the young suggests it is not the ageing process itself that triggers them.
Even among those diseases that kill people in the West in ‘old’ age – heart attacks, strokes, diabetes, high blood pressure and cancers – most have their roots in weight gain that begins in childhood or early adulthood. We can’t attribute deaths from these conditions to our longer lifespans alone, as even those people in traditional societies who make it to eighty or ninety years old very rarely die of this set of ‘age-related’ illnesses. Twenty-first-century illnesses are not limited by the burgeoning top tier of our demographic ranks, but rather are hitting us, like the 1918 flu, in what should be the prime of our lives.
On to race. The Western world – North America, Europe and Australasia – is a largely white place, so are our new health problems actually a genetic predisposition among white people? In fact, within these continents, whites do not consistently have the highest rates of obesity, allergies, autoimmunity or autism. Blacks, Hispanics and South Asians tend to have higher incidences of obesity than whites, and allergies and asthma disproportionately affect blacks in some areas and whites in others. No clear pattern emerges for autoimmune diseases, with some, such as lupus and scleroderma, affecting blacks more, and others, including childhood diabetes and multiple sclerosis, tending to prefer whites. Autism does not appear to affect races differently, though black children are often diagnosed later.
Could what seem like racial differences actually be largely due to other factors, such as wealth or location, rather than to the genetic tendencies of each race? In an elegantly designed statistical study, the higher rate of asthma in black American children than in other races was found to be due not to race itself, but the greater tendency of black families to live in inner-city urban locations, where asthma is more common in all children. Rates of asthma among black children growing up in Africa are, as in most less developed regions, low.
A neat way to untangle the effects of ethnicity and environment in bringing on twenty-first-century illnesses is to look at the health of migrants. In the 1990s, civil war led to a large exodus of families from Somalia to Europe and North America. Having escaped turmoil in their own country, the Somali diaspora faced a fresh battle. Whereas rates of autism are extremely low in Somalia, the incidence in children born to Somali migrants rapidly jumped to match that of non-migrant children. Among the large Somali community of Toronto, Canada, autism is referred to as ‘the Western disease’, as so many migrant families are affected by it. In Sweden too, children of immigrants from Somalia have three or four times the rate of autism as Swedish children. Race, then, seems far less important than location.
So what about the final aspect of Who?: sex. Do women and men suffer equally? That women have stronger immune systems may not come as a surprise to anyone who has witnessed a bout of ‘man flu’. But unfortunately, in this immune-mediated epidemic of chronic ill-health, women’s immune superiority proves a disadvantage. While men seem to succumb to the most benign of colds, women battle demons that only their immune systems can see.
Autoimmune diseases show the widest divergence, with the vast majority