In 1970, the global population was about 3.7 billion. By the start of 2016, this had doubled to roughly 7.5 billion, and is expected to rise to around:
- 8.5 billion by 2030
- 9.2 billion by 2040
- and 9.7 billion by 2050
This is largely due to better quality of life, and increasing life expectancy:
- In 2010, global average life expectancy at birth was around 69.
- By 2050, according to UN estimates, this will have climbed to 76.
Advances in healthcare and better quality of life are the driving factors behind people living longer. However, lifestyles are changing too, partly in response to developing technology, and as we’ll discuss, this means that the prevalence of some illnesses is expected to rise.
In this post, we’ll explore how these trends may affect the global incidence of certain conditions over the course of the next 35 years, and some of the social factors that may make a difference; but we’ll also look at the worldwide prevalence of communicable illnesses, and how intervention methods may affect these over the coming decades.
In particular we'll look at:
- heart disease
- viral hepatitis
- visual impairment
- and erectile dysfunction.
In a recent post, we discussed the future of this condition with the International Diabetes Federation. They estimated the number of those living globally with diabetes in 2015 to be 415 million. By 2040, they estimate that this will have increased to 642 million.
Furthermore, they note that while in 2015 one in eleven adults had diabetes, this will rise to one in ten by 2040.
Type 1 diabetes, as we know, is autoimmune; it occurs when the immune system attacks pancreatic cells and inhibits the body’s ability to make insulin.
Type 2 typically manifests in those aged over 40, or who have one or more risk factors; the most significant of these is being overweight or obese. Type 2 accounts for the majority of cases (about 9 out of 10).
Unhealthy lifestyles, particularly those closely associated with urbanisation, are therefore often attributed to be the main cause of this rise. Calorie and sugar-dense diets, combined with an overall increase in occupations that are sedentary in nature, are major factors behind it.
Luckily awareness of how to reduce the risk of the condition is generally rising thanks to the work of organisations like the IDF, and some governments (such as in Mexico, France, Hungary and now the UK) are responding to calls for sugar levies to be imposed to reduce consumption of sugary products such as fizzy drinks.
But experts argue that more needs to be done to encourage healthy food choices and physical activity in order to curb the escalation of diabetes. Among these are urging supermarkets and producers to make health foods more accessible and affordable, and imposing limitations on the promotion of unhealthy, calorific snack items.
It is thought by many that cardiovascular conditions will see a rise in prevalence in the coming years, as they tend to be more common in older people and the ageing population is set to increase.
The extent of this rise, however, is subject to discussion.
- An Icelandic study from 2016 stated that heart failure in those aged 65 and over is set to more than double by 2040, and treble by 2060.
- One study by researchers Netherlands projected that the number of cardiovascular patients in that country would increase by 65 percent between 2011 and 2040.
- In 2012 a prominent Hong Kong doctor predicted that heart disease would increase by 50 percent globally by 2040.
- Figures quoted in a joint report compiled by the World Economic Forum and Harvard School of Public Health estimated that the total global cost of cardiovascular disease (which includes the cost of lost productivity as well as care) is set to increase from $863 billion in 2010 to $1,044 billion in 2030.
WHO baseline scenario projections seem to be somewhat consistent with these findings. They estimate that deaths caused by cardiovascular illnesses will rise from 17.9 million in 2015 to 22.2 million in 2030 (a 24 percent rise); and that globally, ischaemic heart disease will remain the leading cause of death (13.2 percent of global totals in both 2015 and 2030).
As with diabetes, overall awareness of how diet and lifestyle directly affect heart health is growing. But while the projected rise might largely be attributed to the increasing average age of the population, one has to believe that urbanisation and sedentary routines will likely play a role in this too.
To ease the growing burden on healthcare providers, prevention will remain key: once more, campaigning and education on the ramifications of unhealthy lifestyles are going to continue to be essential in the coming decades.
The number of people globally living with human immunodeficiency virus was estimated by UNAIDS in 2015 to be 36.7 million. They also estimated that since the epidemic began, 78 million had become infected with the virus, and 35 million had died from related causes.
In the same report, they noted that new cases of infection had fallen from roughly 3.2 million per year in 2000 to 2.1 million per year in 2015.
The number of people globally receiving treatment for the condition has grown, as accessibility has increased. According to figures published by AVERT, 3 percent of people with HIV globally in 2000 were accessing treatment. By 2015, this had risen to 46 percent.
HIV prevalence has thereby seen an overall rise, because people with the condition are getting the treatment they need and essentially living for longer. Consequently, it is expected that the number of people living with HIV will continue to rise over the coming years, while the number of those dying from related diseases as a percentage of this will likely decrease.
In 2013, WHO projected that HIV/AIDS would be responsible for 1.67 million deaths globally, equivalent to 2.9 percent, in 2015. In 2030, they estimate that the actual number of deaths attributable to HIV/AIDS is expected to rise to 1.79 million, equivalent to 2.6 percent of deaths.
However, how common the condition is years from now largely depends on the measures taken at international level to make testing and treatment accessible to patients.
Research undertaken at the British Columbia Centre for Excellence in HIV/AIDS back in 2006 suggested that the universal provision of antiretroviral therapy could reduce the global presence of the virus to just one million by 2050. While they argued that this provision would obviously come at a considerable financial cost at first, this would decrease with each passing year due to the falling number of new infections.
The economic landscape has changed considerably since then; but the theoretical argument remains that ending the virus is within our scientific means (even if it is not easily within our financial means).
Once again, intervention measures taken at a global level to tackle malaria are going to be crucial in the coming decades. As we’ve seen, the disease is capable of developing a resistance to medicine; which makes total eradication a more practical and economically viable option in the long term, than the perpetual development of new treatments.
Going back to WHO baseline scenario projections, they estimated in 2013 that malaria would cause 447,000 deaths globally in 2015, rising to 457,000 in 2030.
However, since these projections were made, WHO have implemented a ‘major scale-up’ of efforts to drastically reduce the presence of the disease, with the long-term goal of eradication. Their aim is to reduce malaria prevalence by 90 percent by 2030. With cooperation from all countries, total eradication by 2040 is thought to be possible.
You can find more information about malaria and the risk factors present in different countries by consulting our world map.
Mortality related to hepatitis B and C is on the rise, and a WHO report puts this down to poor access to treatment in some continental regions.
The 2016 publication noted that, globally, an estimated 240 million people are living with chronic hepatitis B, and 130-150 million with hepatitis C. It also noted that 1.46 million people died worldwide from viral hepatitis in 2013.
Without wider access to proper treatment, it went on to project that the disease would be responsible for 19 million further deaths worldwide between 2015 and 2030.
Vaccination and improved blood safety has helped to reduce the overall prevalence of viral hepatitis in recent years; and provided a combined prevention and treatment strategy is implemented, WHO argue that virtual eradication by 2030 is within our power.
Recently, after passing their Hepatitis C Elimination Programme, the Government of Georgia announced that they expected HCV (which affects 6.7 percent of the population in the country) to be ‘practically eradicated’ there by 2020.
As with the other communicable conditions already discussed, where we stand in 30 years time will depend largely on the success of these strategies, and the willingness of nations to cooperate in their implementation.
Experts believe that the overall prevalence of some allergic conditions is set to rise; and for people living in certain parts of the world, environmental factors may increase the severity of symptoms that those with allergies experience.
One study published in 2016 examined how the increasing presence of ragweed in Europe is expected to contribute towards a significant upsurge in both pollen concentration and airborne latency on the continent. This, they noted, would see the number of Europeans affected by sensitivity to ragweed rise: from 33 million today; to 77 million at some point between 2041 and 2060.
The study explains that for those with ragweed allergies living in Hungary and in the Balkan region, sensitivity symptoms (which include nasal congestion, sneezing, headaches and irritation in the throat and eyes) will rise; but the actual number of people susceptible to ragweed sensitivity will see its largest proportional increase in Northern European nations, such as France, Germany and Poland.
Figures from other organisations concur that a rise in allergy prevalence is imminent. A statement by the European Commission in 2010 estimated that, by 2050, around 50% of people living in the EU would have an allergic condition (compared with 35% back then).
Elsewhere, findings reported to the American College of Allergy, Asthma and Immunology in 2012 stated that pollen levels were expected to increase by 1.5 to two times their current levels in the US. The research stopped short of saying that an overall increase in allergy symptoms would be a foregone consequence of this, but stated that those with allergies could take action now by exploring immunotherapy treatment options.
Globally, allergic diseases are thought to affect one billion people currently. However, this is expected to rise to around four billion by 2050 (by this time, 4 billion will constitute just over 40% of the world’s 9.7 billion population).
Food allergies and anaphylaxis
However, other types of allergies, not related to pollen, are thought to be on the increase too.
A UK study in 2007 noted that, since 1990, there had been a five-fold increase in hospital admissions due to food allergies, and a seven-fold increase in those due to anaphylactic reactions. Allergy UK reports that the number of hospitalisations for anaphylactic reactions between 2011-2 and 2015-6 increased in the UK by 19 percent.
Several factors are thought to be behind this trend. One consultant allergist noted in The Guardian that increased overall awareness is leading to a higher rate of diagnoses; but also that our lifestyles and diets, due to the way they influence our exposure to certain allergens, might be having an impact too.
Many new-onset cases of food allergies now develop in adulthood, opposed to early on in life. One theory put forward is that exposure to a certain type of food through unusual means can lead to late-onset sensitisation.
An example used in the above Guardian article by Tina Dixon, a consultant allergist based in Liverpool, is that of a chef she treats with a late-onset egg allergy. By breathing in and absorbing particles of egg over a long period, she theorises that the patient has developed a hypersensitivity to it.
The good news for those with allergies is that, as we come to better understand these conditions, allergy treatments will likely improve. For allergic rhinitis, researchers are currently investigating the efficacy of co-administering more than one treatment at a time. Low dose UVB is also an option being explored.
One piece of research suggested that sublingual administration of epinephrine in tablet form for anaphylactic patients may offer a more convenient alternative to the solution contained in injector pens (it theorised that tablets may be preferable for the needle-phobic, and that these wouldn’t need to be replaced as often as they would be less susceptible to degradation than the injectible solution). However testing for this form of epinephrine delivery is still in an early phase.
There are conflicting estimates of how prevalent asthma will be in the future.
Asthma UK reports that, in the UK, one in 11 people (or 5.4 million) are currently affected by the condition. However, they also state that the rate of increase has seemingly levelled off since the late 1990s.
(The number of people who have ever been diagnosed with asthma is higher at around 8 million; however many who are diagnosed with asthma during childhood ‘outgrow’ the condition, so the number of people with active asthma is smaller.)
The European Academy of Allergy and Clinical Immunology estimated in 2014 that asthma would be the most common chronic childhood illness by the year 2025. They cited the increase in prevalence in urban areas, mainly due to lifestyle and environmental factors, as the leading proponent in this rise.
So what are some of these environmental factors?
Indoor air pollution is one.
In 2015, one professor from Reading University said that energy efficiency in households essentially traps in exacerbating airborne pollutants from cooking, cleaning and applying cosmetics. Because more and more households are being built with energy efficiency in mind, he estimated this would lead to an 80% rise in asthma prevalence by 2050 (this would take the current affected population of the UK from 5.4 million to 9.7 million).
It’s perhaps unsurprising then given these projections that asthma prevalence is also expected to increase globally.
In 2007, the World Health Organisation stated that an estimated 300 million people worldwide were living with asthma, and that this would increase to at least 400 million by 2025.
According to an entry in the World Allergy Organisation Journal, asthma will affect 10%, or roughly a billion, of the world’s population by 2050.
It’s difficult to say. At present, it doesn’t seem as though an absolute cure for asthma will be discovered imminently. As with allergies, ongoing research is being undertaken to better understand the condition and what causes it. This will help scientists develop new ways to help patients manage the condition and keep attacks to a minimum.
A paper in the European Respiratory Review said on the subject that investigations into new ways of targeting the condition showed promise, and may have the potential to ‘cure mild asthma, and considerably improve the control and quality of life of the most severe patients.’
For instance, developing methods of isolating and stopping the IgE molecule (which triggers allergic asthmatic episodes) from being reproduced in the body is one such approach researchers are looking into.
One other theory is that allergic asthma is a reaction to a parasite which the immune system thinks is present, but is not; and therefore treatments in some way derived from parasitic worms may hold the key to lessening symptoms.
Osteoarthritis (where the joints in the body sustain progressive damage over time) is also set to rise in the coming years, and this is largely due to the expected increase in the ageing population.
In the UK, Arthritis Research states that 8.75 million people have sought treatment for osteoarthritis:
- 4.33 million of this population are aged between 45 and 64;
- 2.15 million are aged between 65 and 74;
- and 2.27 million are over the age of 75.
These figures constitute one third of people aged 45 and over; and just under half of those aged 75 and over.
The CDC reports that between 2010 and 2012, there were 52.5 million adults living in the US who had been diagnosed at some point with an arthritic condition; these included osteoarthritis, rheumatoid arthritis, lupus, gout and fibromyalgia. 30.3% of US adults aged 45-64 had received a diagnosis of some sort of arthritic condition, as had around half of persons over the age of 65.
According to a Canadian review of figures, total prevalence rates for osteoarthritis in Australia and Northern European countries such as Belgium, Norway and the Netherlands, ranged between 8% and 13%; which seems comparable to those in the UK (12.5%). However, diagnosis rates in southern Asian countries are lower (between 4 and 11%), and lower still in South American and the Middle-Eastern countries (between 2 and 4%).
Determining global prevalence for arthritis then is tricky; different countries have varying definitions of arthritic conditions, and it might be possible that symptoms potentially being underreported by patients may be a contributing factor behind the comparatively low diagnosis rates in South America and the Middle East.
We can deduce from the increasing average age of the population that the prevalence of osteoarthritis is going to rise; but to get an idea of how much it is going to rise by, it might be useful to look a 2007 study from Australia.
10 years ago, Arthritis Australia stated that 3.85 million Australians were living with some form of arthritis at that time. They cited research from Access Economics that by 2050 this number would have risen to 7 million.
If we use these projections for Australia (which has similar prevalence rates to the UK and other countries in Northern Europe) as a template, that would mean the prevalence of arthritic conditions would be set to almost double from their 2007 levels by 2050. For the UK, this would mean the number of people affected rising from 8.75 million to around 15-17 million.
One other US projection from 2007 forecasted a slightly less drastic but still significant upsurge, estimating that the number of adults in the US living with arthritis would rise from a 2005 total of 60 million to 96 million by 2050, which would constitute a 1.6-fold increase.
The causes of rheumatoid arthritis are thought to be both genetic and environmental in nature, and research aiming to better identify these is ongoing. Once more, a better understanding will help scientists to develop new treatments.
For osteoarthritis, there are several different options currently being explored. These include tissue regeneration technology, which could help to reform damaged bone and cartilage in affected joints. Another treatment method scientists are attempting to harness for osteoarthritis is nanotechnology; more specifically, nanoparticle injections which would be administered to a joint shortly after an injury to reduce inflammation, and limit degeneration.
However, determining trends for this condition is problematic, as prevalence data from previous years is sparse.
A 2016 report by WHO suggested that, from the limited data available, we can ascertain that psoriasis is becoming more commonly diagnosed:
- they noted that prevalence in China rose from 0.17% in 1984 to 0.59% in 1999;
- in Spain, it rose from 1.43% in 1998 to 2.31% in 2013;
- and that in the US, prevalence rose from 1.62% in 2004 to 3.1% in 2010.
Furthermore, as it is a condition more commonly diagnosed in older adults, the ageing global population is also expected to have an impact on overall prevalence in the coming decades. Increased awareness of the condition is also no doubt having an impact on the rate of diagnoses.
So while we cannot put a figure on the number of cases there may be in 2050, it is likely that there will be more known cases in the future than there are today.
Relatively little is known about why psoriasis develops. However new drugs for the management of psoriatic conditions are in development.
Two such examples, which are IL-17A and IL-23 inhibitors, work by stopping proteins from producing an anti-inflammatory response in the body. A spokesperson for the National Psoriasis Foundation Medical Board noted that these types of medication are promising due to their ‘very high response rates’.
Currently, there are thought to be 3 million people living with osteoporosis in the UK. The NHS notes that there are half a million hospital admissions in Britain for fragility fractures related to osteoporosis on an annual basis.
Worldwide, the International Osteoporosis Foundation estimates that there are 200 million people affected by the condition, and 30 percent of all postmenopausal women in the US and Europe have osteoporosis. Globally, there are 8.9 million fractures related to osteoporosis each year.
Once more, the ageing population is likely to cause an upsurge in prevalence in the coming years. Hip fractures in men are expected by the IOF to increase by 310% on their 1990 levels by 2050; and by 240% on their 1990 levels in women.
It goes without saying that the more we learn about osteoporosis and the better we understand the condition, the more action people as a whole will be able to take to prevent it. Calcium and vitamin D are vital in offsetting the development of osteoporosis, so a diet containing a healthy amount of these nutrients is essential. Undertaking regular exercise plays an important role in reducing risk too.
Several different types of treatment for osteoporosis are currently available. Some work to lessen the rate at which bone density breaks down over time, and others work by redressing hormone levels (a hormonal imbalance is often a cause of bone density reduction).
Research into treatments which work specifically on bone cell pathophysiology is underway. A Swiss paper from 2012 discussed how new treatments may target specific molecules which regulate bone cell function. It is also hoped that more advanced diagnostic tools, which help doctors to identify precursive bone degeneration patterns in adolescence and adulthood, may also enable preventative treatment to be initiated earlier.
Last year, dementia overtook heart disease as the leading cause of death in England and Wales. The Office for National Statistics reported that in 2015, 11.6% of all registered deaths were caused by dementia or Alzheimer's; whereas ischaemic heart disease was the cause of 11.5%.
This, according to statistician Elizabeth McLaren, was partly due to a change in rules in determining cause of death (leading to an increase in dementia being identified as an underlying cause) but also due to the fact that detection rates have improved, and that people are living for longer.
As a result of the projected rise in the ageing population, it’s expected that the number of those affected by dementia will continue to rise dramatically in the next 35 years.
According to the Alzheimer's Society, the number of people in the UK affected currently is around 850,000. They estimate that this number will rise to more than 1 million by 2025, and to 2 million by 2051.
Globally, they report that there an estimated 46.8 million people living with dementia currently, and that this figure will rise to 115.4 million by 2050.
The Alzheimer’s Society stresses the importance of increasing funding and research into the condition. They estimate that delaying the development of dementia by five years would help to cut the number of deaths caused by the condition in half.
Currently, research is focusing on the changes that take place in the brain which experts think are behind the progression of dementia; and developing treatments to stop these or slow them down.
Among them are beta amyloid aggression inhibitors, which could help to prevent the formation of plaques in the brain; and drugs which target brain inflammation (which can be a contributing factor in the condition).
Two million Brits live with some form of sight loss, according to NHS Choices. Just under one fifth of these (360,000) are registered blind or partially sighted.
Once more, the rising ageing population is likely to cause this figure to exponentially increase by 2050; but it is thought that the rise in certain underlying factors in sight loss, such as obesity and diabetes, will also contribute towards this.
It is thought that age-related macular degeneration (AMD) will account for the largest portion of this increase (rising from 313,000 in 2010 to 887,000 by 2050).
The percentage of sight loss cases caused by glaucoma and diabetic retinopathy are set to drop, but the actual number of cases will rise in absolute terms: from 98,000 in 2010 to 200,000 in 2050 for glaucoma; and from 64,000 in 2010 to 93,000 in 2050 for diabetic retinopathy.
One recent projection from the US was somewhat consistent with these UK figures. Researchers at the Roski Eye Institute in California estimated that the number of people in the US living with visual impairment or blindness would double between 2015 and 2050.
They projected that the number of people who were legally blind would rise from one million to two million; and that the number of Americans with VI would rise from 3.2 million to 6.95 million. Again, the ageing population was cited as the major contributing factor.
As for the rest of the world? The World Health Organisation estimated in 2014 that 285 million worldwide were living with visual impairment. Of these, 39 million were blind.
If we applied UK and US projections to these global figures, in theory, visual impairment would be set to double to around 570 million, and the number of blind people to around 78 million.
Promoting the prevention of ocular injuries, increasing awareness of the importance of regular eye testing, and increasing access to treatment for those with low vision are among the strategies discussed by Access Economics and the RNIB in their 2009 report entitled Future Sight Loss, to try and tackle this expected rise.
Research on new types of treatment for visual impairment is being undertaken; for example stem cell tissue regeneration is one such route currently being explored. Retinal prosthesis is another avenue which may one day prove to life-changing for patients who have already lost their sight.
Estimating the rates of STIs in the future is tricky; not least because cases have risen and fallen so erratically in previous decades.
The most recent figures from Public Health England report a 4% drop in overall STI diagnoses in England between 2015 and 2016. However, as we discussed in a recent post, some commentators have attributed this to fewer tests being carried out, and to cuts in public services.
The number of reported chlamydia diagnoses in England reached 211,372 in 2013. It dropped to 202,451 in 2015 and rose very slightly to 202,546 in 2016.
Since 2012, gonorrhoea has risen markedly, from 26,880 cases to 36,244 cases in 2016.
Between 2012 and 2016, the number of syphilis cases in the UK has nearly doubled, from 3,001 to 5,920.
The way STI figures were collated in England changed in 2012, which makes analyses of STI trends over a longer period problematic.
In the US, chlamydia rates have gradually increased since the current standard of surveillance began in 1984. There were 1.5 million cases reported in 2015, which is 478.8 persons per 100,000 of the population (to provide a comparison, the rate in England in 2016 was 366.5 per 100,000).
Gonorrhoea rates in the US peaked in the mid 1970s (464.1 diagnoses per 100,000 of the population), but dropped to an all-time low in 2009 (98.1 per 100,000). Since then, they’ve started to climb again (123.9 per 100,000 in 2015).
Since recent records began, syphilis (all stages) in the US was most prevalent in 1943 (447 cases per 100,000) but also fell dramatically in the decades that followed; to as low as 11.2 per 100,000 in 2000 and 2005. Once more, cases have risen again since, more than doubling to 23.4 per 100,000 in 2015.
On a worldwide basis, WHO estimates that there are 131 million chlamydia infections, 78 million gonorrhoea infections and 5.6 million syphilis infections each year.
These three STIs are treated with antibiotics; but how well the antibiotics that we currently have will continue to function in coming years is in serious doubt. As we’ve discussed previously, gonorrhoea has a capacity to quickly develop resistance to antibiotic drugs. Resistance in syphilis and chlamydia is not as common but, as noted by WHO, it does exist.
The extent to which this could affect those experiencing bacterial STIs - or any bacterial infection with resistant qualities - in the coming decades is therefore difficult to estimate.
Superbugs of all kinds resistant to antibiotics could cause as many as 10 million deaths per year by 2050, according to one report.
Research into new antibiotic candidates is ongoing, and how successful this research is will undoubtedly play a crucial role in how easy STIs are to treat. Now and during the coming years, the conservation of the antibiotics we do have will continue to be vitally important. And again, promoting awareness and education of these conditions, and of safe sex practices, will be a significant determining factor in their future prevalence.
Predicting how common erectile dysfunction will be in 35 years is, as you would expect, a tricky exercise for a number of reasons; but chiefly because it’s difficult to determine with any real certainty how common it is now.
Erectile dysfunction can be acute or chronic, and many men who have the condition short-term may not need to seek treatment; so instances of the condition may go entirely unreported. In other cases, where the condition is chronic, many men may be unwilling to see a doctor about the condition, and not seek treatment at all.
The NHS estimates that ED affects half of all men over 40 in some way. A report from 2013 estimated that only one out of every four men with newly diagnosed ED is under 40.
Taking this into account, one would presume that erectile dysfunction is likely to increase in overall prevalence, due to the estimated rise in the ageing population: the ONS estimated in 2015 that there were 32.8 million people (men and women) in the UK over the age of 40. They estimate that this number will rise to 39.4 million by 2035.
We should also keep in mind that the prevalence of other contributing factors in ED, such as obesity and diabetes, are on the rise.
Besides those already available, other oral and topical treatments for ED are in development. Uprima and Topiglan are examples of medicines currently under investigation.
But another possibility being explored, as reported by WebMD, is gene therapy. The idea is that this form of treatment helps the development of certain proteins in the body: proteins that aren’t working as they should in men affected by impotence. This form of treatment, although in its very early stages, has reportedly shown promise in clinical trials.
We’ve written before that there are several factors which can contribute towards ED, both physical and psychological. Treatment aside, the more we learn about these factors, the easier it will be for men who might be susceptible to erection problems to manage and prevent ED.