What If Medical Science Cured All Diseases?

The top cause of death in wealthy countries is coronary heart disease (CHD), according to 2008 data from the World Health Organization. That fact is a product of the long life span and lifestyle characteristic of high-income nations. In our hypothetical world, there would be a cure for CHD. You could eat steak subs every day, but with the help of a pill, your arteries wouldn't clog.

Another pill would protect smokers, people with high blood pressure and diabetics from strokes, the second-largest killer in rich countries [source: WHO]. If you assume people are inherently pleasure seekers, you'd expect them to eat whatever they wanted, exercise less and smoke more in a world full of magical medical bullets.

More people also might light up because lung cancer and related cancers, the third leading cause of death in rich countries, would be curable [source: WHO]. Not that smokers necessarily would live excellent lives. Many would be diagnosed with lung cancer, take a pill and then get lung cancer again. They'd have to cyclically solicit treatments for their smoking-related problems.

So far, this hypothetical world looks pretty bad -- that is, until we consider modern incurable diseases. Children with cerebral palsy or muscular dystrophy could choose a different life, if they wanted. AIDS patients could swap a succession of hospital visits and expensive drugs for an immediate, sweeping fix.

Not only would our experiment imagine away the big burdens, but also the little annoyances, like colds, ear infections and the flu. Since all of these ailments are viral, today's best efforts typically center on treating the symptoms and waiting for your body to clear the infection [source: Fauci]. In our what-if world, you'd spend fewer days suffering and miss less work or school.

What if mental illnesses became curable? Sure, many mental illnesses are controllable, sometimes to the point that the people who have them don't notice them, but for the top three mental illnesses in the United States -- anxiety disorders, depression and attention deficit hyperactivity disorder -- there can be a period of chaos before control is achieved, and control can involve lifelong medication or worries about relapse [source: Kessler]. Cures could lead to a better quality of life. We also suspect that by alleviating mental illness two institutions would lose residents: hospitals and jails [source: Harcourt].

Rich countries have a tidy system of doctors, hospitals, pharmacies and emergency crews. How would it change if every disease had a cure? If the medical system were interested in keeping the most people healthy, it might expand screening. Medical establishments tend to invest in screening when catching a disease early really helps the patient, as with breast cancer. In our world of cures, doctors would be trying detect all diseases early, except no country could afford to do that. So, the public and every other interested party you could imagine would fight over how much to spend and which illnesses to include.

We'll take all these hypothetical cures to a low-income nation next.

As in wealthy countries, most people in poor countries die from curable illnesses, such as lung infections and diarrheal diseases [source: WHO]. That fact suggests that low-income nations need more than cures. They need preventions, like sanitation and health education. They also require the money to pay for treatments, and the experts and clinics to distribute them.

In our imaginary world, we'll pretend cures come for free and with the necessary infrastructure. If so, children would benefit first. Children die at much higher rates in poor countries than in rich ones. If you live in Chad, you're about 50 times more likely to die before age 5 than if you live in Denmark [source: WHO]. The youngest ones pass on as babies because they're premature, weigh too little, or the mother or baby suffers stress during birth [source: WHO]. The rest expire mostly from pneumonia and diarrheal diseases [source: WHO].If these killers never existed, women would need fewer pregnancies to have families of the same size, which could allow them to spend less time pregnant or grieving.

If these sicknesses suddenly disappeared, there'd be more babies and children running around the developing world, at least at first. To explore what a lower death rate would do for low-income countries in the long term, see our article on a world without illness.

Put away your malaria pills and suit up for a futuristic voyage of the HMS Beagle. We'll now predict what cures could mean for human evolution.

With a cure for every disease, our evolutionary future might change. To understand why, we need to talk about genes. Genes are like options on a car. Alleles, which are sequences of DNA, make choices for those options. Option: Sunroof. Choice: Leaky sunroof. Among humans, there are plenty of alleles that are bad for us, as a leaky sunroof is on a car.

Some alleles are bad for us because they kill us or prevent us from having children when we're young. People who have such alleles often don't pass them on to their children. They die, or their disease prevents reproduction, so their alleles don't become very prevalent in the population. In our hypothetical world, those people would be cured before they were stopped from having children, so they would pass on their alleles to future generations.

Other alleles cause debilitating diseases, but not necessarily ones that prevent reproduction. In the real world, couples who carry alleles for these diseases might choose not to have children. In our what-if scenario, they might opt to become parents, since rather than suffering, those children could be cured.

Overall, disease-related alleles would become more common.

It's possible that even with a cure for every disease, little would change. People might not pursue them, even if they were available. Some people wouldn't know or would refuse to admit that they were sick. Others would avoid doctors, for whatever beliefs keep them away now. Another faction would get the wrong diagnosis or the wrong cure or reject treatment due to expense. Lastly, cures might have side effects, leading some folks to decide that the side effects were intolerable and choose to live with the disease.

Keep reading for more related links you might like or leave a comment below on how you imagine a world cured of disease.