Health Desk- Dec 10, 2016: Life expectancy has declined in the United States for the first time in 20 years.
US National Center for Health Statistics showed a drop for men from 76.5 years in 2014 to 76.3 in 2015 and for women from 81.3 to 81.2 years.
Rises in deaths from heart disease and dementia and accidental infant deaths are mentioned as the primary cause of such decline, the BBC has reported.
Life expectancy continued to improve steadily since the World War Two, rising from little over 68 years in 1950.
Life expectancy last fell in 1993 at the peak of HIV/AIDS crisis. It also fell in 1980, after a sever outbreak of flu, the report said.
The report is based mainly on 2015 death certificates.
"This is unusual," lead author Jiaquan Xu, an epidemiologist at the NCHS, said.
"2015 is kind of different from every year. It looks like much more death than we have seen in the last few years."
Overall life expectancy for men and women is now 78.8 years, a decrease of 0.1 year from 2014.
According to the scientists, a decline of 0.1 years in life expectancy means people are dying, on average, a little over a month earlier - or two months earlier for men.
To compare it with the two other declines in the past 30 years, the drop from 1992 to 1993 was 0.3 years, and the drop from 1979 to 1980 was 0.2%, according to the BBC report.
What's also worrying some experts is that the trend had been largely flat for the preceding three years, rather than steady increase which has prevailed since the 1970s.
A mixture of factors is identified for such change. Death rates have risen for eight out of 10 of the leading causes of death: heart disease (0.9% rise), chronic lower respiratory diseases (2.7% rise), unintentional injuries (6.7% rise), stroke (3% rise), Alzheimer's disease (15.7% rise), diabetes (1.9% rise), kidney disease (1.5% rise) and suicide (2.3% rise).
With more than four times as many deaths as each of the others, heart disease is the biggest killer. So, even the relatively small 0.9% rise in the heart disease death rate is a major contributor.
An 11.3% increase in the rate of death for babies due to unintentional injuries and Alzheimer's disease are two of the other biggest causes deaths. "Most of them died from accidental suffocation and strangulation in bed," Jiaquan Xu said about the infant deaths.
Experts point to obesity levels, an ageing population and economic struggles as wider factors.