Since I have been focused on the waste and corruption within the U.S. healthcare, pharmaceutical and medical industry, and since the U.S. is such an obvious negative outlier in terms of longevity, I am especially interested in possible reasons for the U.S.' underperformance and possible reasons why. Is the underperformance of the U.S. because of common and well-known negative health factors or perhaps due to more unique factors affecting Americans? Well-recognized and possible health factors affecting the health of citizens around the world to different degrees include diet and nutrition, exercise habits, obesity, smoking, alcohol, pollution, sleep habits and many others. With so many possible contributing factors to health (and sickness and disease) it is impossible to isolate a single cause to explain differences between the relative success and failures of individual countries. However, we can look at whether or not and to what extent potential health factors correlate with health outcomes, positively or negatively. While correlation does not prove causation, without correlation between possible explanatory variables and health outcomes then we must look elsewhere for possible factors.
Smoking and Life Expectancy
The extent of smoking within a country is an often discussed as a highly determining health factor, that is said to be severely negatively affecting health outcomes within populations and explaining differences across them. For decades, smoking has been blamed as the culprit behind high rates of disease and death in the U.S. Even today, on the U.S. Centers for Disease Control and Prevention (CDC) website, 480,000 deaths a year in the U.S. are attributed to cigarette smoking. It cites significantly higher deaths rates among smokers from coronary heart disease, cancer, respiratory diseases and others. It states that smoking is the leading preventable cause of the death in the U.S., causing one in five deaths, and that smoking cuts “at least” 10 years from smokers' lifespans.
Is it high smoking rates then, that explains the roughly four to six years of longevity underperformance for Americans compared to other developed nations (adjusted for healthcare spending)? Such a claim seems unlikely given the fact that U.S. citizens have steadily cut their rate of smoking for four decades now and more than most other countries. The U.S. now has one of the lowest smoking rates in the world, with a combined (male and female) smoking rate of adults now below 15%. And with an increased share of moderate smokers compared to heavy smokers, the rate of per capita cigarette consumption in the U.S. has fallen even more sharply, to less than a fourth the level of 1970, and barely half of what it was just 15 years ago (see graph below, though average cigarette consumption has fallen since the timeline of this graph).
It is interesting to note that there is actually not a high correlation between smoking rates and longevity across countries. I examined World Health Organization data on smoking rates for men and women for the 90 highest longevity countries in which smoking data was available. The overall conclusion is that there is extremely low correlation between smoking rates of a country and longevity. In fact, countries with higher female smoking rates correlate to higher female life expectancy. This is in large part due to the fact that richer countries, such as those in Europe, tend to have higher female smoking rates. The opposite is true for men, whereby they tend to smoke more in poorer countries. (Overall, average smoking rates across countries are fairly consistent regardless of wealth levels.)
Comparing male-female smoking rates (generally much higher for men, averaging about 20 percentage points higher) to female-male lifespans (averaging about 5 years higher for women) within countries, results in just a very slight correlation (see graph below). So in countries where the male-female smoking gap is larger than average, the life expectancy gap between women and men was affected very little.
On the CDC's website it states that smoking increases the risk of coronary heart disease by two to four times, stroke by the same amount, lung cancer by 25 times (for both men and women), COPD death by 12 to 13 times, and increases the risk of nearly every other type of major cancer including colon, kidney, liver, pancreas, and stomach.. The CDC also states that if no one in the U.S. smoked cancer rates would fall by a third.
So another puzzle to the premise that the health problems plaguing Americans are in large part due to high smoking rates is the small or non-existent improvement in health problems said to be triggered by smoking. Even with the proportion of smokers cut by more than half and total cigarette consumption by three-quarters, we have not seen age-adjusted incidence rates for these diseases decline as much as officials predicted. The death rate, and certainly the incidence, of heart disease and cancer has generally not declined in the U.S. despite sharp declines in smoking over the last 40 years. Below are two graphs from the CDC. The first shows that while heart disease death rates have generally fallen in the U.S., cancer death rates in the U.S. have continued to climb. It's all the more remarkable since more successful treatment for both cancer and heart disease have improved longevity after diagnosis. So the higher incidence of these diseases has more than offset the improvements from lower death rates after diagnosis. The second graph projects higher incidence and death rates for cancer in the coming years, despite much lower smoking rates.
The rate of smoking by U.S. women has now fallen by more than two-thirds since the 1970s yet their rates of lung cancer incidence have more than doubled during the same time (see graph below). According to the World Cancer Research Fund, the U.S. ranks 4th (highest, worst) in the world in terms of age-adjusted incidence of cancer, with U.S. women ranking a dismal second, despite rates of smoking below that of other women across the world.
In terms of health and longevity in the U.S., overall improvement in the incidence of heart disease and cancer has been small or non-existent despite tens of millions fewer Americans smoking (although the health of many of these formers smokers will certainly improve). In addition, nearly all countries, including many with higher smoking rates than the U.S., continue to see increases in average longevity while in recent years, improvement in U.S. average longevity has stalled.
Obesity and longevity
Much has been made of the obesity rates in the U.S., and the supposedly negative affect it is having on the health of Americans. To be sure, it is rather shocking to see the sharp increase in the rates of obesity in America (see graph below), which have more than doubled in a generation.
At the same time however, the obesity rates of most other countries, including those with higher average longevity than the U.S., have also been sharply increasing in recent years and outperforming the U.S. in both longevity and other factors of health. The correlation between obesity and longevity for these countries is nearly zero. (see graph below).
This does not indicate that obesity, especially severe obesity, has no effect on the health and healthcare of a population, just that thus far, the rate of obesity doesn't appear to be negatively affecting longevity in a significant way. It is possible that since obesity rates in the U.S., and especially other countries, have only started to increase substantially in recent years, effects on life expectancy (and disease) may show up farther down the road. One factor that appears to be affecting the U.S. more than other countries is the rapid rise and concentration of its more extremely or morbidly obese, which appears to have much more significant effects on longevity (and health, of course) than more moderate obesity, and seems to be more common in the U.S., compared to other countries (though it's difficult to find comparable data for other countries).
Extreme obesity may be an increasingly significant factor in the U.S. in the years ahead since its share of the obese has increased so sharply in recent years. Available research indicates that individuals with more extreme obesity have significantly lower lifespans, five or ten years or more. However, given that the number of extremely obese is still a relatively small percentage of the population, we cannot attribute the lower level of longevity the U.S. experiences compared to other countries to obesity. (That is not to say that the food many Americans eat, with obesity and becoming overweight as a by-product, does not have a noticeably negative affect on health, just that being “overweight” or “obese” does not in itself accurately indicate state of health. Many individuals termed “overweight” or “obese”, are in good health, likely due to an active lifestyle and good food choices.)
Alcohol and longevity
I did a similar comparison between longevity and alcohol consumption, (liters of pure alcohol per person per year, data from the World Health Organization). Despite the obvious dangers of alcohol, especially when consumed in high amounts, there is not a significantly correlative affect on overall life expectancy across countries, as the first graph below shows.
With more modest alcohol consumption, especially in the form of beer or wine, there is a much weaker correlation, though more research would be valuable. Indeed, in many countries, such as France, Spain, Portugal, Australia, New Zealand, South Korea, Greece and Slovenia, alcohol consumption is well above average, yet so is longevity. In the case of the U.S., given its rather average rates of alcohol consumption (and spirits), alcohol cannot rightly be called a significant explanatory factor for the U.S.' longevity and health underperformance.
Perhaps surprisingly, the available data showeither no correlative effect or a very weak one with these three variables - alcohol, smoking, and obesity. Next time I'll talk about some less obvious variables to potential health outcomes, but which might be more significant in explaining some of the under or overperformance of certain countries, including the U.S.