White, non-Hispanic females in the United States experienced a slight drop in life expectancy from 2013 to 2014, something that has rarely been seen in that demographic group,  a researcher with the Centers for Disease Control and prevention said Wednesday.

Drug overdoses, smoking, alcohol and suicides were cited by Elizabeth Arias, a demographer with the CDC's National Center for Health Statistics, as reasons for the decline. Arias told The Washington Post that another study to be published soon would show the relationship between the drop in life expectancy for white females – from 81.2 to 81.1 years – and the sharp increase in alcoholism-related diseases, prescription and illicit drug overdoses and suicide.

"The increase in death in this segment of the population was great enough to affect life expectancy at birth for the whole group," Arias told The New York Times. "That is very unusual."

The data was drawn from all deaths recorded in the United States in 2014.

The news came a few months after a report by a pair of Princeton economists revealed death rates for white men and women in the 45-54 age bracket had risen sharply between 1999 and 2013. The study showed a "marked increase" in mortality in the white middle-aged group with an epidemic of suicide as a leading cause.

The Princeton study also points to cheap and easily available heroin, the abuse of prescription opioids and  the effects of long-term alcohol abuse, as factors contributing to the group's increasing mortality rate.

While life expectancy in white females dropped, life expectancy for females in general remained unchanged at 81.2 years. For Hispanic females it rose from 83.8 to 84.0, and for black females it remain unchanged at 78.1 years.

A  look at the study shows good news for some groups:

  • Life expectancy at birth increased by 0.4 years for non-Hispanic black males and by 0.1 years for Hispanic males.  The life expectancy for white, non-Hispanic males remained the same at 76.5 years.
  • Hispanic males experienced the greatest increase in life expectancy at age 65 (0.3 years), followed by Hispanic females (0.2), and all other groups experienced a 0.1 year increase in life expectancy at age 65.
  • Between 2013 and 2014, life expectancy at birth for the total U.S. population (78.8 years), males (76.4), or females (81.2) did not change.

Life expectancy, as defined by the CDC, “represents the average number of years that a hypothetical group of infants would live at each attained age if the group was subject, throughout its lifetime, to the age-specific death rates prevailing for the actual population in a given year.”