Experts say many could be treated at GP surgeries, urgent care centres or even stay at home rather than seek help for non-urgent complaints - putting further demands on already hard-pressed casualty staff.
But the study also uncovered evidence pressures in “overstretched” parts of the NHS could be driving patients to casualty units, with surveys suggesting half of arrivals had been told to attend by other health staff.
Rising demand, coupled with increasing staff shortages, has led to a significant worsening in A&E treatment times in recent years amid fears the coming winter could trigger a rapidly-escalating crisis.
Experts at Sheffield University looked at 1.3 million non-ambulance arrivals by patients at 19 casualty units in the region, which accounted for 75 per cent of total A&E attendances over 12 months.
Figures showed 23 per cent of adults and 31 per cent of children walking in for treatment did not need A&E care although there were significant variations across the region.
Around 30 per cent of adults with non-urgent problems could have been treated outside A&E instead of visiting Calderdale Royal Hospital in Halifax and Huddersfield Royal Infirmary but this fell to just 10 per cent of those travelling to Scarborough’s hospital, according to the analysis of non-ambulance arrivals at A&E units in Yorkshire in 2014.
Researchers found people had become “more demanding of the healthcare system, particularly amongst younger generations”.
Large numbers of patients were coming to emergency departments with non-urgent complaints which could be treated by GPs, walk-in centres, or by self-care at home.
“There seems an unwillingness or inability by patients to manage their own risk with increased concern that health problems are serious and a desire for rapid reassurance,” they said.
“These patients present an additional burden for emergency departments, taking resources away from patients who are sicker and require the specialist resources of an emergency department.”
But a survey of nearly 500 walk-in patients carried out last year for the study found half of arrivals had been advised to go to A&E by other health workers.
Some 35 per cent said GP practice staff had advised them to attend – three times as many as a similar poll in 1997.
Staff interviewed by researchers said patients were more demanding but regularly reported difficulties getting GP appointments, as well as accessing dental or mental healthcare.
Researchers said the findings could reflect a “system under great strain”.
They recommended better training for GPs to assess and treat children and co-locating GPs in A&E units, which is already becoming a key feature of care across the country.