(CNN)A troubling gap in life expectancy among the rich and poor has emerged in the United Kingdom, and researchers say it also has been seen in the United States.
The life expectancy gap between the most affluent and most deprived girls and women in the UK rose from a difference of 6.1 years in 2001 to 7.9 in 2016, according to a study published in the journal Lancet Public Health on Thursday.
The life expectancy gap between the most affluent and most deprived boys and men in the UK climbed from a difference of nine years to 9.7 years, according to the study.
"The finding is that in every age group and from every disease, there is a contribution towards inequality, which really means ... the poor are suffering across the board," said Majid Ezzati, a professor of global environmental health at the Imperial College London in the UK, who was senior author of the study.
"Overall, access to health care and use of health care is worse by the poor, even in a country that has a national health system, although probably not nearly as bad as the situation in the US," he said. "So there's some combination of social, economic behaviors and health care."
A decade ago, a similar study also led by Ezzati found a steady increase in life expectancy inequalities across US countries between 1983 and 1999, resulting from disparities among the poor. That study was published in the journal PLOS Medicine.
In general, the global life expectancy at birth in 2016 was 72 years, according to the World Health Organization. The global average life expectancy rose by 5.5 years between 2000 and 2016, the fastest increase since the 1960s, WHO said.
Life expectancy on the rise 01:22
The new study involved health data from the Office for National Statistics on population and deaths in England. The researchers analyzed the data, which included 7.65 million deaths between 2001 and 2016, taking a close look at where each death occurred and disparities by community, noting which communities were the most affluent and which were the most deprived.
The researchers found that life expectancy at birth in 2016 was consistently lower in more deprived communities. Among women, life expectancy ranged from 78.8 years in the most deprived areas to 86.7 years in the most affluent areas, and among men, it ranged from 74 to 83.8, the researchers found.
Additionally, although life expectancy increased in most communities from 2001 to 2016, gains were larger in the affluent groups, the researchers found.
"We know that inequality in life expectancy and longevity exists, and we knew that they were going up. But we hadn't really noted that they were going up partly because the poor are losing life, rather than gaining," Ezzati said.
"For the poorest communities, life expectancy actually for the past six or seven years has started to go down -- go down slowly but nonetheless go down," he said.
More research is needed to determine the exact contribution of factors driving such inequalities, but the researchers noted in the study that the largest contributors to life expectancy inequalities were deaths in children younger than 5, mostly neonatal deaths; respiratory diseases; heart disease; lung and digestive cancers; and dementias in older adults.
The study has some limitations, including that the data were grouped based on community trends, and so the findings should not be attributed solely to changes in health status of individuals.
"There is an extensive body of research on inequalities in health, which points primarily to the conditions within which people live and work, with the most deprived experiencing precarious income, employment, housing and now even food supply in the UK," said Martin McKee, professor of European public health at the London School of Hygiene and Tropical Medicine, who was not involved in the study but has conducted separate life expectancy research.
As for the new study, "this is the most comprehensive study to date of how this varies by levels of deprivation," McKee said.
"The overall findings are consistent with these previous studies, but it adds an important new dimension. It confirms that women in particular in the most deprived areas have really been suffering over the last eight years or so," he said. "The finding that life expectancy is actually declining for some groups should be taken extremely seriously as, historically, this has always been an indicator of deep seated problems in society."
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John Newton, director of Health Improvement at Public Health England, wrote an editorial that accompanied the new study in Lancet Public Health.
"As a society, we need to register an appropriate level of shame about these results and adopt a corresponding level of urgency and diligence in seeking to address them," Newton wrote.
"It seems clear that a substantial portion of the population is being left behind in terms of their health outcomes," he wrote. "There is a lot to do if we are to see these numbers improve. Evidence already exists to support many of the population-wide interventions needed. New technologies offer new opportunities to engage the public in improving their health but we must make sure that future efficiency in health improvement is not achieved at the cost of equity."
