Not having health insurance can kill you:  so says this study, slated for publication in the December issue of the American Journal of Public Health.  The authors found that, after controlling for obesity, exercise, gender, race, tobacco and alcohol use, and the like, deaths among uninsured Americans were 40 percent higher than among their counterparts with private health insurance.

That makes uninsurance a leading killer in the US, responsible for more deaths more than both kidney disease and traffic accidents.  (Traffic deaths, by the way, are on the decline:  increases in gas prices led to declines in driving and vehicle speed, which in turn lowered US traffic fatality rates by a whopping 17 percent between 2005 and 2008.)

Curiously, the estimated death rate from uninsurance has soared over the last couple of decades.  A 1993 study, using data from the 1970s and 1980s, found a much lower death rate from uninsurance.  And as recently as 2002, the National Institutes of Medicine reported that lack of health insurance was responsible for just 18,000 deaths per year in the US.  But this new study, using very similar methods as earlier efforts, pegs the figure 45,000 annual deaths—suggesting that going without health insurance has become far riskier than it used to be. Whether the rising risk from uninsurance results from changes in the health care system—say, that doctors and hospitals are now refusing care to the uninsured, or that medical care has gotten better at keeping us healthy—remains unclear.

Regardless of the underlying dynamics, the study certainly gives ammunition to those who are fighting to improve access to medical insurance in the US— and plenty of fodder for epidemiologists trying to figure out why US life expectancy remains among the lowest in the developed world.