Life expectancy at birth for white, non-Hispanic females in the United States declined slightly from 2013 to 2014, a change that could be a statistical blip but still represents a rare drop for a major demographic group, according to new data from the Centers for Disease Control and Prevention.

This unusual down-tick in life expectancy – from 81.2 to 81.1 years – is consistent with other research showing that drug overdoses, suicides and diseases related to smoking and heavy drinking are killing unprecedented numbers of white Americans, particularly women in mid-life.

“Taken by itself, it could just be a random fluctuation from one year to the next,” said Elizabeth Arias, a demographer with the CDC’s National Center for Health Statistics. But the data, which was released Wednesday, also showed that Americans collectively have lost momentum when it comes to greater longevity. Life expectancy at birth has remained virtually stagnant for the nation since 2010.

Arias said another study by her agency, to be published soon, will document the sharp increase in suicides, alcoholism-related diseases and overdoses.

“Despite the positive influences of declines in heart disease and cancer and stroke, increases in other causes like suicide, chronic liver disease and unintentional poisonings were so large that they had a negative effect on life expectancy,” she said.

Amid the bleak news for whites have been the improving numbers for African Americans and Hispanics, the new study indicates. Hispanic life expectancy rose from 81.6 to 81.8 years between 2013 and 2014; gains were seen for both males and females. Life expectancy for blacks rose from 75.1 to 75.2 years, driven by a particularly large jump among black males, from 71.8 to 72.2 years.

“The gap between the white and black populations is quickly closing, and it’s mainly because the black population is experiencing a great drop in mortality,” said Arias, who authored the accompanying brief.

A report last November by Princeton economists Anne Case and Angus Deaton pointed out that death rates for white men and women in the 45-54 age bracket had risen strikingly between 1999 and 2013. The Post’s subsequent analysis of death records, published earlier this month, found the most pronounced increase in mortality has been among white women ages 25 to 54 in small cities, small towns and the most rural parts of the country.

Urban Institute researcher Laudy Aron, who has written extensively on the “health disadvantage” of Americans compared to citizens of other affluent countries, said the new CDC data is “more confirming evidence of this larger phenomenon.”

“We continue to deviate from what these other high-income countries are doing, especially among women,” Aron said. “Equally important will be what happens next year and the year after, and seeing if we are on some kind of new trend line.”

Life expectancy is not a prediction for any given person; it’s a statistical construct. As the new report puts it, “Life expectancy 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.”