Life expectancy in Mexico is decreasing because of the huge number of murders taking place throughout the country. Both men and women suffered declines in life expectancy, coupled with major rises in homicide rate.

Between 2005 and 2010, life expectancy in Mexican men dropped from 72-and-a-half years to just under 72 years. This falls in line with a big increase in the number of murders, which went from 9.5 murders every 100,000 deaths, to 22 every 100,000 deaths.

"Our results indicate that homicides can have a large impact on the average years of life of a population," said Hiram Beltrán-Sánchez, lead investigator on the study. "Violence in Mexico has spread throughout the entire country, so our findings suggest that homicides need to be addressed from a public health perspective to improve peoples' lives."

The study, published in Health Affairs, used data from the Mexican National Statistical Office and the Mexican Demographic Society to find the link. The researchers, from the University of California, analysed the causes of deaths in Mexico by age, sex and place of death, as well as life expectancy trends between the year 2000 and 2010.

Some areas of the country – including Chihuahua, Sinaloa and Durango – saw life expectancy decrease by up to three years, as the drug war took its toll predominantly on the male population.

Women saw small increases in their life expectancy's over the course of the study. However, when the researchers studied the north of the country alone, they too saw similar declines.

The average age of death in females dropped roughly six months in Chihuahua, and three months in other drug-afflicted areas. Women also saw their numbers for murders increase across the whole of the country.

The scientists also stress that the numbers used in the study were the bare minimum for total homicides. During the term of President Felipe Calderon – which lasted six years from 2006 – more than 26,000 people were reported missing. Those that are not found, are not reported as murders, and so could not be counted for this study.

Mexico's homicide rate is not one of the largest in Latin America. Honduras, for example, has a murder rate nearly four times that of Mexico.

The scientists now want to carry out similar investigations across more of these countries. Beltrán-Sánchez said: "The homicide rate in Mexico is lower than in other Latin American countries -- for example Honduras, Belize, El Salvador, Colombia and Brazil. One would expect homicides to have a greater impact in these countries. There is an urgent need to document the impact of homicides on the Latin American population."