(credit: Gerald Lau/Flickr)

A plague of drug violence in Mexico stands to undo gains in life expectancy from the last century, according to new research published in Health Affairs.

Life expectancy crept upward during most of the 20^th century, largely thanks to improved access to health care and quality of life. But from 2005 to 2010, the trend reversed for men and slowed for women as the number of homicides spiked.

In that time frame, the country’s homicide rate more than doubled, from 9.5 deaths in 100,000 people during 2005 to 22 in 100,000 by 2010. That cropped life expectancy of men in all 31 Mexican states and the Federal District. Across the country, average life spans dropped from 72.5 years to about 72 years in the time frame. But areas more hard-hit by drug violence saw larger drops in life expectancy. In the northern states of Chihuahua, Sinaloa, and Durango, for instance, life expectancy fell by up to three years. For women country-wide, the upward trend in life expectancy merely slowed from 2005 to 2010. But drug violence in the northern states stunted life expectancy for women by several months.