With all this crazy news about ObamaCare, a lot of facts (and “facts”) are being tossed around. Often, people will use big fancy health care words like “life expectancy” and while we all kind-of-sorta know what life expectancy is, I’m going to really get into it for you. Why? Because life expectancy is one of those things that seems to get twisted and used in all sorts of ways it was never intended.

So, we’ll start off with the basics. What is life expectancy? Life expectancy is defined as the the average (expected) number of years of life remaining at any given age.

When people say “life expectancy in _________” they are referring to the life expectancy of that country at birth, but you can define life expectancy in other ways as well. For example, life expectancy at age 1 (or at age 5) is often used in countries with very high levels of infant mortality. Why? Well, I have to get all mathy for this so I’m going to turn it into a footnote. Hover over it if you’re really interested.

So, we’ve defined it as an average. As with any average, this creates helpful comparisons between countries/cities/regions since it is independent of population size. Also with any average, it doesn’t really define the population. The life expectancy in the US just went up to it’s highest point in history at 77.9 years. That doesn’t mean you’re going to die exactly .1 years before your 78th birthday. In fact, it doesn’t even mean most people die right before their 78th birthday. It means some people died above 77.9, some below 77.9 and maybe a few at 77.9, but when you added them up and divided by the sample size, you get 77.9

So here comes the fun part. The United States ranked horribly when it comes to this. Horribly. We are ranked 35th–this puts us at slightly higher than Costa Rica and Cuba and well, well below Japan (82) or Australia (81.6) and even *gasp* Canada (81.2)! Essentially, this puts us below any industrialized country.

And that is often what gets touted. We have the lowest life expectancy of any industrialized country in the world.

This is, of course, true; however, it is also slightly misleading. You see, life expectancy is not the most robust measure of a country’s health care system. Cultural, environmental, geographical, social, structural, or legal differences can all affect this measure and health systems have a hard time countering that. It’s a great crude measure, but horrible for direct comparisons.

It’s this exact weakness that has conservatives pouncing all over the Obama plan. Specifically, there is a presentation–too often (mis-)cited by others–which claims that if we removed all violent crime and automobile accident deaths, we would actually be number 1 in the world in terms of life expectancy.

This is simply not correct. If any of those blogs that cited this presentation actually bothered to read the article, they would find that the regression the authors used removed automobile accidents and violent crimes and the US moved up to 17th. Then they “standardized” the US with the rest of the world by factoring in GDP. Given that the US a huge GDP compared to any other country in the world, this bumped us up to number 1 on the list.

So the idea is if we removed areas where America has a uniquely higher rate–driving accidents and murder–we’re not as bad as the rest of the world and this is a better reflection of the health care system. Now, I’ve got issues with that already, but my first question is why? Why are we suddenly developing this new metric? We already have a metric designed to reflect a good health care system–it’s called amenable mortality. Amenable mortality is the mortality rate of a country that could have been (theoretically) avoided with timely and proper medical attention.

So there you have it. Life expectancy is the tool being used in this war of ideologies and it’s about the dullest one in the box. Don’t be tricked by this “if you remove violent crime and automobile accidents” business. Complete garbage. Look for articles that cite something useful like amenable mortality, infant mortality, maternal mortality, measures involving access to care, etc.

Malaria kills about a million people a year (most are children in sub-Saharan Africa). The potential uses for GIS to concentrate and focus malaria prevention efforts are vast and the map shows about 2.4 billion people at risk for malaria infection. The good news is the map also shows about three-quarters of those are at a low-risk and the technical obstacles to address the situation are relatively small. The bad (if unsurprising) news is that sub-Saharan Africa still takes the brunt of malaria infections and deaths.

Click here for the official project website.

[Image by trebol a via flickr.]

Things only got worse when I read this NYTimes article. They cite this study (N=55,000!) which found that on days off work, people slept according to standard (non-DST) time. Which just makes sense–circadian rhythms don’t have dials. They go on to cite other studies that talk about the link between time changes and negative health outcomes. It’s a quick, easy read.

[Image by MaestroBen.]

The University of Glasgow studied over 40 million people living in England and the death records of over 350,000 people. Using some sort of measure for exposure to green space, they found an association with income, overall mortality, and cause-specific mortality. They also noticed that the gap between the lowest- and highest-income individuals was about half as large in areas with “ample” green space.

It makes sense. We can speculate that green space probably helps reduce health disparities by providing a place for residents to become physically active, reduce stress, feel more empowered, etc. Or it could be something completely different… perhaps green spaces have more markets with healthy (and cheap) foods? Perhaps low income individuals in areas with park space are there because they have more active lifestyles and prefer living closer to a park. Who knows? I haven’t actually read the article yet, but it looks promising.

[Photo: mine.]

Now, I can blame my obsessive-compulsive irrationality on something scientifically sound. Trials done at the University of Southamptom found that items with a copper surface had 95% fewer micro-organisms than their stainless steel counterparts. Sure, this is good news for hospitals with a much cheaper and effective way of reducing the exposures to potential infection, but this is much better news for my own neuroticism.

A press release of the study can be read here.

Interesting Public Health Fact #1.

(My parents and friends ask me what I learn in school and I tell them about all the interesting things, but I never convey it in its absolute fullness and often end up getting polite “ohh… right… ok…” responses. I’ve decided to start a new category called “Interesting Public Health Facts” so I can put up the interesting things I read and learn so I can just point people in this direction instead of boring them with my inadequate attempts to articulate the awesomeness of public health.)

It’s been long established that loneliness (or “social isolation” in hip, public health speak) has really bad effects on your health.

You can use social isolation to predict mortality and morbidity in the general population, and it is especially good at predicting coronary heart disease. And the thing is, it is just a deficiency of social relationships that really matters — that’s to say that after a certain threshold of relationships, an increase in relationships does not lead to an increase in health. Or put more simply, being alone is bad for your health, but being popular is not necessarily better for your health than just having an average number of social contacts.

There are a lot of hypotheses on why this is the case. Some are pretty common sense (but inadequate)–such as having more friends will likely lead you to engaging in less self-destructive activities and support you in sleeping right, diet, exercise, alcohol consumption, etc etc. But none of the current theories really explain this in great detail and a lot of it has to do with just the difficulty of finding data. Imagine trying to find people and interview them and test them and talk to them and engage them when they really to be left alone or have been left alone for so long.

Before we go further, I should probably note that social isolation is not the same as solitude. A person who is socially isolated and a person who is seeking solitude may both be alone, but only the socially isolated person perceives loneliness.

Ok. So what?

Maybe I haven’t piqued your interest yet, but how about this: Did you know that feelings of loneliness may literally make you feel cold? Two psychologists from the University of Toronoto conducted a psychology study where they divided a group into two and asked them to recall either a time they were rejected or a time they were accepted into a group and then asked them to estimate the temperature of the room. They found people who recalled rejection often perceived a colder temperature. They then conducted an experiment with a computer game where some of the volunteers were purposely left out of the game and then asked each for a preference for snack and found the unpopular volunteers preferred “cold day” snacks such as hot coffee or soup.

Or did you know a group of UCLA researchers found that social isolation leads to effects on the immune system on a genetic level? They found that “feelings of social isolation are linked to alterations in the activity of genes that drive inflammation, the first response of the immune system” while at the same time “key gene sets were under-expressed”. In normal people speak, feeling lonely not only has psychological or medical implications but it has a genetic factor as well. Feeling lonely fundamentally alters our immune system.

Think about the impact this has on our approach to heart disease or mental disorders like depression. This changes the framework for a lot of policy–maybe we should focus more on helping older populations maintain social networks (Facebook for the elderly?). Maybe one day we’ll see really thin sweaters with happy thoughts on them and that’ll be enough to keep you warm–ok, maybe not. Still, it is profound how much of our health is dependent on our relationships with other people and our mental state.

[Photo by Grandhi via Flickr.]