Study's authors surprised by poor performance after they find only Malta has more deaths of children under five

Children in the UK are more likely to die before they reach their fifth birthday than in any other western European country except Malta.

Almost five in every 1,000 children born in the UK die before the age of five, a rate the authors of the global study said was surprising for a country with free, universal healthcare. Researchers at the Institute of Health Metrics and Evaluation (IHME) in Seattle said that 3,000 children in the UK died before their first birthday in 2012.

Experts said poverty and deprivation in the UK, together with cuts in welfare, were directly linked to the deaths of the youngest children. Babies who die under age of one tend to be from deprived households, have a low birthweight and have parents who smoked. Between ages of one and five, deaths are mostly linked to injuries, accidents and serious diseases such as cancer.

The death rate in the US, which has even greater health inequalities, is worse, at 6.6 child deaths per 1,000 births, but the UK rate of 4.9 is double that of the best in Europe, Iceland, which has 2.4 deaths per 1,000. Sweden, Finland and Norway are also towards the top of the league.

"We were surprised by these findings because the UK has made so many significant advances in public health over the years," said Dr Christopher Murray, IHME director and the study's senior author. "The higher than expected child death rates in the UK are a reminder to all of us that, even as we are seeing child mortality decline worldwide, countries need to examine what they are doing to make sure more children grow into adulthood."

Dr Ingrid Wolfe – of the Royal College of Paediatrics and Child Health and the author of a separate report published this week on child deaths in the UK – said: "In 2008 during the election, David Cameron said he would make the UK the best place in the world to grow up. The evidence categorically suggests otherwise.

"There is a mismatch between the rhetoric of government and the policies they have put into place, particularly with regard to welfare and children."

The figures are published online by the Lancet medical journal, whose editor, Dr Richard Horton, said politicians need to take child health more seriously.

"The reasons for this are likely to be complex, but undoubtedly include the poor organisation of children's health services in the UK. Until our politicians begin to take the health of children – the health of the next generation of British citizens – more seriously, newborns and older children will continue to suffer and die needlessly."

Child deaths are high in the UK compared with the rest of western Europe in the first six days of life, between one month and a year and between the age of one and four. Outside Europe, the UK has a higher under-fives death rate than Australia, Israel, Japan and South Korea.

In their report, Wolfe and colleagues from the National Children's Bureau called call for an end to the welfare cap in the UK. "We are asking the government to spell out how they are going to meet the child poverty targets," she said. "We want the Office for Budget Responsibility to do an assessment of the impact on children."

Children between ages of one and four die of injuries and accidents more often in poorer than richer communities, where road traffic may be heavier and there are fewer safe places to play. Childhood diseases such as cancer may be missed, because of an "old-fashioned" NHS system which keeps paediatricians in hospitals, when they should be working alongside GPs in the community, said Horton.

Dan Poulter, the health minister, said: "As a result of our investment in children we have seen a 23% rise in the number of health visitors to give each and every child the very best start in life, and we have invested £54m in mental health support for young people. We are also investing more in training so that GPs have stronger integrated skills to care for children and young people with specialist long term conditions in the community. We recognise that more needs to be done, but it is our ambition to make health inequalities a thing of the past."

The welfare cap, said the Department of Health, was a matter for the Treasury, which said it "will, for the first time, bring over £115bn of welfare under control, helping to put the public finances on a more sustainable footing and deliver the government's long term economic plan".

Labour said it broadly supported the welfare cap although it needed to be set at a regional level to make it more fair. Child deaths, said shadow public health minister Luciana Berger, were a tragedy not befitting a civilised country.