Oxford experts involved in study which finds Britons healthier than Americans, but more likely to doubt wellbeing
18% of British adults were likely to report their health as poor compared to 12% of adults in the US.
British adults in their 30s and 40s are healthier than their counterparts in the US - but are more likely to think their health is poor, a study has suggested.
The health of the US "acts as a warning" of what Britain could be like without the "safety net" of the NHS, researchers said, with differences potentially down to access to healthcare, diet and levels of poverty.
For the study, academics from the UCL Centre for Longitudinal Studies, University of Oxford, Syracuse University and University of North Carolina used data from the 1970 British Cohort Study and the National Longitudinal Study of Adolescent to Adult Health.
Analysis included 9,665 British people born in 1970 and 5,381 US adults.
It found adults in the US were more likely to have high cholesterol and high blood blood pressure, while four in 10 US adults were obese compared to 34.5% of Brits.
However, 18% of British adults were likely to report their health as poor compared to 12% of adults in the US.
Britons were also more likely to smoke every day, with 28% reporting cigarette use compared to 21% in the US cohort.
Dr Charis Bridger Staatz, of the UCL Centre for Longitudinal Studies, said: "Our new research shows that although British adults are more likely to believe that their health is poor, they tend to have better cardiovascular health than their US counterparts in midlife.
"While we were unable to directly investigate the causes of this, we can speculate that differences in levels of exercise, diets and poverty, and limited access to free healthcare may be driving worse physical health in the USA.
"Given political and social similarities between the US and Britain, the US acts as a warning of what the state of health could be like in Britain without the safety net of the NHS and a strong welfare system."
Professor George Ploubidis, of the UCL Centre for Longitudinal Studies, said the findings - published in the International Journal of Epidemiology - "should not distract" from levels of obesity and high blood pressure in Britain.
"In some ways, these findings could be seen to paint a positive picture for the nation, as the health of adults in Britain is better than that in the USA," he said.
"Nevertheless, this research should not distract us from the fact that more than a third of British adults are obese and a fifth have high blood pressure in midlife.
"The new Government's pledges to cut NHS waiting times will be severely tested if this and future generations continue to age in poor health."
Researchers also found that inequalities were typically wider in the US, with larger health differences between the poorest and wealthiest ends of society.
Dr Bridger Staatz said work to tackle health inequalities in Britain will be beneficial.
"Our findings reinforce previous research showing that health problems and inequalities in older age tend to have their origins earlier in life," she added.
"In both Britain and the US, public health policies tend to focus on improving health awareness and behaviours in childhood or older age.
"However, intervening in midlife offers a great opportunity to promote healthier ageing.
"In the wake of Lord Darzi's report into the state of the NHS, it is encouraging to hear the new prime minister prioritising a 10-year programme of reform for the health service.
"Long-term planning and investment in the NHS will likely help improve the health disparities we see in the UK and prevent the emergence of inequalities on the same scale as we see in the US. This will not only help to improve population health across life but create a happier and more prosperous society."