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.