Friday, September 13, 2013

Health changes since 1870

This week, we’ve been talking about the profound social transformations that have taken place since 1870. One of these is the vast increase in human lifespan and decrease in childhood mortality. Like the vast industrial progress we now take for granted, soaring numbers of human beings is also actually a relatively recent phenomenon. As positive as this trend is, it has led to the environmental crisis we now face, as we have ever larger numbers of people coupled with ever-increasing living standards.

Slate is currently running an excellent series of articles on human longevity. It’s worth taking a look at why we’re living longer today, since it is one of the hallmarks of progress that is pointed to most often. It’s true, the average person does live much longer today, but it little to do with all those gigantic hospitals and medical complexes that are springing up like dandelions all over the country:
To understand why people live so long today, it helps to start with how people died in the past. People died young, and they died painfully of consumption (tuberculosis), quinsy (tonsillitis), fever, childbirth, and worms. There’s nothing like looking back at the history of death and dying in the United States to dispel any romantic notions you may have that people used to live in harmony with the land or be more in touch with their bodies. Life was miserable—full of contagious disease, spoiled food, malnutrition, exposure, and injuries.

The vast majority of deaths before the mid-20th century were caused by microbes—bacteria, amoebas, protozoans, or viruses that ruled the Earth and to a lesser extent still do. It’s not always clear which microbes get the credit for which kills...The first European settlers to North America mostly died of starvation, with (according to some historians) a side order of stupidity. They picked unnecessary fights with Native Americans, sought gold and silver rather than planting food or fishing, and drank foul water...The slave trade killed more than 1 million Africans who were kidnapped, shackled, and shipped across the Atlantic. The slave trade introduced African microbes to North America; malaria and yellow fever were the ones that killed the most...Deadly diseases infiltrated North America faster than Europeans did. Native Americans had no exposure and thus no resistance to the common European diseases of childhood, and unimaginable pandemics of smallpox, measles, typhus, and other diseases swept throughout the continent and ultimately reduced the population by as much as 95 percent.

Global trade introduced new diseases around the world and caused horrific epidemics until the 1700s or so, when pretty much every germ had made landfall on every continent. Within the United States, better transportation in the 1800s brought wave after wave of disease outbreaks to new cities and the interior. Urbanization brought people into ideal proximity from a germ’s point of view, as did factory work. Sadly, so did public schools: Children who might have toiled in relative epidemiological isolation on farms were suddenly coughing all over one another in enclosed schoolrooms.
Why Are You Not Dead Yet? (Slate)

In the past people had large families. They had to, because a large amount of the children they did have never reached adulthood, and consequently never reached sexual maturity themselves. The amount of babies born who actually lived to reproductive age, managed to secure a mate, and produce enough children with that mate to propagate their parents’ genetic material forward must have been quite small. No doubt this had a profound genetic effect on our species, one of the reasons evolutionary biologists have increasingly come around to the view that humans are, in fact, continuing to evolve since the rise of civilization. Today we are at a point where the majority of children survive to adulthood and reproductive age. Interestingly, hominid lifespans seem to have increased in Paleolithic times, possibly because of the adaptive benefits of grandparents coupled with the ability of elders to serve as repositories of tribal knowledge as humans social relations became a principal survival strategy (Early hominid 'cared for elderly,' BBC)

This drastic decline in death rates often eventually leads to reduced birth rates - the so called demographic transition. Yet even with the demographic transition, the sheer number of people alive today is astonishing. And it gets worse, because the more people you have, the more potential breeding pairs you have meaning that population grows geometrically – the so-called demographic momentum. Getting down to replacement rate is tricky, getting below it even harder. These massive numbers are why even with the twentieth century’s massive wars and genocides, violent deaths per capita are very much lower than in the past.

In the past, as people got richer they had more children – thereby ensuring their chance of genetic survival through the bottlenecks of disease, famine and war. This caused an increase in population that drove overall living standards down. It also caused downward mobility for children of the wealthier classes, as they now occupied the slots formerly occupied by members of the lower classes who failed to reproduce themselves. By contrast, in modern societies, prosperity causes people to have less children, because infant mortality is so low (and only because of this). Wealthier couples can devote more resources to each individual child, as well as pass down their wealth undivided to a smaller number of children without having to worry about whether those children will make it to reproductive age or not.

It’s good to clear the air about lifespans prior to the modern age. Yes, infant mortality rates have skewed life expectancy numbers down to a deceptively low number, one that often gets unthinkingly tossed around. Yes, people frequently did live to be 70, 80, and even 90 years old in past societies. No, a 35 year-old was not considered "old" back then. But overall, it is  true that less people managed to live to a ripe old age prior to 1870 than in our modern industrial societies. In addition to children, there were a lot more deaths of 20, 30 and 40 year-olds than today, mostly thanks to disease, famine, war and childbirth in both agricultural and hunter-gatherer societies.

What changed after 1870? From the above article:
Clean water may be the biggest lifesaver in history. Some historians attribute one-half of the overall reduction in mortality, two-thirds of the reduction in child mortality, and three-fourths of the reduction in infant mortality to clean water...Closely related were technologies to move wastewater away from cities.

The germ theory of disease didn’t catch on all that quickly, but once it did, people started washing their hands. Soap became cheaper and more widespread, and people suddenly had a logical reason to wash up before surgery, after defecating, before eating. Soap stops both deadly and lingering infections; even today, kids who don’t have access to soap and clean water have stunted growth.

Housing, especially in cities, was crowded, filthy, poorly ventilated, dank, stinky, hot in the summer, and cold in the winter. These were terrible conditions to live in as a human being, but a great place to be an infectious microbe. Pretty much everyone was infected with tuberculosis (the main cause of consumption), the leading killer for most of the 19th century.

Contaminated food was one of the greatest killers, especially of infants; once they stopped breast-feeding, their food could expose them to typhoid fever, botulism, salmonella, and any number of microbes that caused deadly diarrhea in young children. Refrigeration, public health drives for pure and pasteurized milk, and an understanding of germ theory helped people keep their food safe. The Pure Food and Drug Act of 1906 made it a crime to sell adulterated food, introduced labeling laws, and led to government meat inspection and the creation of the Food and Drug Administration.

The earliest European settlers in North America suffered from mass starvation initially, but once the Colonies were established, they had more food and better nutrition than people in England. During the Revolutionary War era, American soldiers were a few inches taller than their British foes. In Europe, the wealthy were taller than the poor, but there were no such class-related differences in America—which means most people had enough to eat. This changed during the 1800s, when the population expanded and immigrants moved to urban areas.

People had started finding ways to fight disease epidemics in the early 1700s, mostly by isolating the sick and inoculating the healthy...Port cities instituted quarantines starting in the 19th century, preventing sailors from disembarking if there was any evidence of disease, and on land, quarantines separated contagious people from the uninfected.

In the early 1900s, antitoxins to treat diphtheria and vaccines against diphtheria, tetanus, and pertussis helped stop these deadly diseases, followed by vaccines for mumps, measles, polio, and rubella...Vaccines have been so effective that most people in the developed world don’t know what it’s like to watch a child die of pertussis or measles, but parents whose children have contracted these diseases because of anti-vaccine paranoia can tell them.

Some credit for the historical decrease in deadly diseases may go to the disease agents themselves. The microbes that cause rheumatic fever, scarlet fever, and a few other diseases may have evolved to become less deadly. Evolutionarily, that makes sense—it’s no advantage to a parasite to kill its own host, and less-deadly strains may have spread more readily in the human population. Of course, sudden evolutionary change in microbes can go the other way, too: The pandemic influenza of 1918–19 was a new strain that killed more people than any disease outbreak in history—around 50 million. In any battle between microbes and mammals, the smart money is on the microbes.
Later in the series, the author summarizes this information:
Public health measures get the credit for most of the increase in life expectancy that happened from the mid-1800s to mid-1900s. Clean water, safe food, comfortable housing, and a healthy respect for germs made the world a completely different place...Our world is full of life-saving luxuries: We turn on a tap and clean water comes out. Our diets are so rich and varied that almost nobody suffers from rickets or scurvy. We live in airy, spacious homes that aren’t clouded with the coughs of consumptives—and when we share a bed with someone, it’s due to desire rather than overcrowding….If you look at the top causes of death in the United States in 1900 and 2010, you might think you’re examining data from two entirely different species. In 1900, we died of tuberculosis, gastrointestinal infections, and diphtheria. In 2010, none of those diseases made it into the top 10.
Some salient points are in order here:

1.) Hunter-gatherers ate better diets and were more physically active, thus it stands to reason that people in hunter-gatherer societies were on average healthier than modern citizens of industrialized nations.

2.) Very sick and infirm children, or people with congenital diseases who did not live to breeding age were mostly eliminated from the gene pool preventing maladaptive genes from spreading. This probably meant a healthier human population overall, albeit by harsh measures.

3.) Many of the infectious diseases named above are epidemic and pandemic diseases only possible in dense populations such as those of settled agriculture. In addition, most zoonotic diseases emerge only with the rise of settled agricultural populations with domestic animals such as smallpox, influenza, bubonic plague, etc.

4.) Settled agricultural societies have less access to meat and the basic diet for most people centers around simple carbohydrates. This leads to poorer health, vitamin deficiency, and less resistance to diseases, as well as tooth decay.

5.) The crowded conditions in the urban slums of the early Industrial Revolution made people a lot sicker than before, which is alluded to in the article.

6.) Pollution in the Industrial Revolution was much more severe, leading to new diseases such as asthma and black lung. Thousands of new chemicals were dumped into water supplies, adding carcinogens into the environment along with the bacteria and parasites.

7.) Machines killed and maimed huge numbers of people, including children (as they still do today in the case of automobiles).

8.) Monotonous, repetitive work such as the stoop labor of agriculture, or the factory work of the Industrial Revolution, wears down the body and leads to crippling chronic physical maladies.

So for much of recorded human history, our life expectancy and living standards got worse before it got better. It’s only very recently – since 1870 – that things got a lot better leading to the lengthy lives we enjoy and take for granted today.

It’s important to note that, when it comes to longer life spans, high technology has done very little for us in this regard. Note that most of these are scientific advances in understanding, coupled with political centralization. In the Middle Ages, there was little political centralization. Trading cities might be able to enforce a quarantine, but not isolated manors or small duchies. Centralized nation-states can do the type of enforcement described in the article. Wealthy societies can undertake social provisions such as water filtration, public health services, vaccinations, and enforcing strict housing standards. It's undeniable that the much-derided “nanny state” seems to be a big contributor to life expectancy. Even inventions such as mechanical ventilation, window screens and air conditioning can save lives.

Similarly, increasing scientific knowledge, coupled with better instrumentation such as the microscope, have led to the other advances such as antibiotics, sterilization, water filtration, pasteurization, and the like. It is also worth noting that both science and the state are under constant attack, especially in the United States. The same science that saves lives also describes climate change, pollution and species extinction. The same state that enforces regulations and vaccinations and provides basic sanitation and public health campaigns also taxes the wealthy to pay for them. Thus, there has been a dramatic push to discredit both on the part of the sociopathic elite, leading to the rise of Neofeudalism. Already living standards and life expectancy are starting to wane for people on the lowest end of the socioeconomic ladder in the U.S.

But note that most of the beneficial changes have been 1.) cultural changes or 2.) a result of an abundance of resources (food, shipping, etc.). High tech medicine seems to be increasingly focused on keeping sick people alive as long as possible and gaining profits rather than curing disease. How often do you see fundraisers and collection banks dedicated to raising money for researching disease cures?

So keeping this in mind, if we want to keep expanding lifespans, it seems to me that the low hanging fruit isn’t more expensive gadgets and pills from the medical-industrial complex, it’s things like:

1. Dealing with suicide and mental illness. Suicide has overtaken cancer as a cause of death in industrial societies. Why? Let’s think about how dysfunctional our social systems are and build new ones. Let's think about the Roseto effect.

2. Our dependence on automobiles. Getting rid of the cars will save a lot of lives. Cars kill more people than all the world’s wars combined. Let’s invest in public transportation and biking and live in walkable neighborhoods instead of getting everyone in their cars

3. As the article points out, sitting is killing us. Desk jobs are profoundly unhealthy. Even exercise does not undo the bad effects of sitting all day long, which has been likened to smoking a pack of cigarettes. Sadly, a lot of these jobs are also unnecessary. We need to curtail sedentary jobs. Let’s start by working less hours, which we should be doing anyway.

4. Most deleterious to public health has been the rise of a heavily subsidized for-profit processed food industry that peddles junk food by manipulating our evolutionary proclivities for salt fat and sugar and spends millions of dollars in advertising that food. We used to rely on what can be produced by farmers and ranchers. I imagine if we banned all sweeteners, or at least treated them the way we now treat tobacco (heavily taxed, anti-smoking campaigns, subsidizing quitting). It is politically unthinkable, true, but it would probably have as big an effect as curtailing smoking had. Where American-style fast food goes, diabetes, heart disease and obesity follow.

5. Reducing pollution – lead, carcinogens, flame retardants, plasticizers, sulfur in the air, mercury in the water, and so on. Right now we’re all guinea pigs for industry. A lot of these things are unnecessary. We’ve cleaned up the air, now let’s do more.

The above measures will do far more to increase lifespans than all the money currently being spent on relatively rare diseases, not that such research is not beneficial as well.

Related: Men's average height 'up 11cm since 1870s' (BBC)

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