POOR adults in Britain today are in worse health than those born in 1920, according to a study which warns of widening inequalities and a looming crisis for the NHS as baby boomers age.

Research carried out at University College London compared the health in adulthood of 16 birth cohorts, ranging from those born between 1920-1922 up to those born between 1968-1970.

It found a wider gap between rich and poor among later generations despite the arrival of free healthcare.

Lifestyle factors such as higher smoking rates among poorer people born later in the century, alongside a decline in social housing provision, were also blamed.

Dr Stephen Jivraj, who led the study, said it was also likely that the difference was down to working-class Brits who were born in 1920 having benefitted from their working lives coinciding with an era of high employment in traditional industrial occupations compared to later generations entering the workforce in the 1980s.

He added that the growth in health inequalities also runs parallel to rising income inequality in Britain during the 20th century.

Dr Jivraj, an associate professor in UCL's department of public health and epidemiology, said: "If you look at the period and what happened to people during their working lives for people born in these cohorts, income inequality is one of the major things that has changed over the period.

"It is much greater for these people born in the later 20th century than for those in the earlier part of the century.

"That has really driven poorer health among the poorest in society for many reasons including support for public services.

"I think it's tied to de-industrialisation - people who would have been the poorest in society who were born in the 1920s would generally have found it easier to find good quality work than they would have done if they had been born in the late 1960s.

"They are two things that I can't directly attribute to this difference in rich and poor, but they certainly tally.

"So on the one hand, you have something that doesn't seem to tally - why hasn't the creation of the NHS meant narrowing of health inequalities because it means free healthcare for everybody? But there's a lot of other factors at play that increase inequalities in health."

The findings are based on data gathered over the decades, up to 2011, from 200,000 working age adults from Scotland, England and Wales in successive household surveys where people were asked to comment on their own health.

The results compared the responses of the various birth cohorts at ages 30-59 and split up by household income, rather than other socioeconomic measures such as education or the deprivation status of their postcode.

The study, published today in the BMJ's Journal of Epidemiology & Community Health, is one of the first to examine health inequalities in this way.

Prof Jivraj found evidence of deteriorating health in the poorest third of the population, while wealthiest third had improved.

One in four (26%) men born in 1920-22 who were living in the poorest third of British households when they responded to the survey as adults said they had a life-limiting illness. That compared to 16% in the richest households.

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For men born in 1968-70, more than a third (35%) of those living in the poorest households reported a life-limiting illness compared with only around one in 10 (11%) of those living in the richest households.

For women, in the poorest third, 23% of those born between 1920-22 reported a life-limiting illness as adults compared to 32% of those born between 1968-1970.

For women in the richest third, however, there was little change in adulthood illness - from 13% to 12% - for those born in the early '20s compared to those born at the end of 1960s.

The paper states: "There is a suggestion that increased income inequality is responsible for increases in poor health in Britain in the latter quarter of of the 20th Century.

"This could be due to the increased marginalisation of the poorest in society who have not shared equally in postwar economic growth."

It added that lifestyle may also be at play.

"Other factors strongly related to income might explain differences in the health of people born after 1945 compared with those born before, including smoking which has increased in the poorest in society, and housing tenure, which has become increasingly polarised by social class and likely to become even more so in future through housing inheritance."

The findings come amid concern over impact of austerity on life expectancy in the UK, which has stalled and even fallen in some parts of Scotland for the first time in decades.

However, Prof Jivraj said the research comparing health outcomes for those born in 1920 to those born in 1970 points to a longer term decline in health for the poorest Brits.

"It would appear that we were looking after people better in those generations than we are today," he said.

"I think poorer people in society today are getting a much rawer deal that in the past in terms of housing provision, social security payments - I think things are tighter for those people than they were in the past."

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He added that the findings raise serious implications for the NHS and social care.

He said: "What this is saying is that someone who was born in 1970, who is in the poorest section of society now, the probability of them being ill at a given age is greater compared to previous generations.

"The consequence of that is greater demands placed on health and social care in the future, at earlier ages, which is really problematic for health ans social care sectors across the UK.

"We already have an ageing population, which means more older people as a share of the overall population, who will require health and social care.

"But if poorer people are also getting ill earlier in life - people who won't have private health cover, or resources to pay for it themselves - it makes an even more pressing case for us to tackle this."