document: The Social Market Foundation, a left of centre think tank, studied policies in Australia and the US that are similar to the UK's pension reforms.
  It found a significant proportion of people withdraw funds at an unsustainable rate.
  In the UK, thousands have cashed in their pension pots since April.
  The new rules, which came into force in April, allow pension savers to cash in their pension pots from the age of 55.
  This is one of a number of options for savers. In doing so, they pay no tax on the first 25% of these funds, but pay the normal rate of tax on the rest.
  Figures from HM Revenue and Customs (HMRC) found that 146,000 people cashed-in pension pots in the six months since April, withdrawing a total of Â£2.7bn.
  Separate data, recorded slightly differently, from the Association of British Insurers suggested that Â£2.5bn was withdrawn over the same period in 166,700 cash lump sum payments, with an average withdrawal of just under Â£15,000.
  Research by financial firms indicates that the funds are being used to pay off debt, upgrade the car or go on holiday.
  The Social Market Foundation warned that evidence from overseas revealed a danger of pensioners spending money too quickly.
  It said four out of 10 Australians with pension savings spent them all by the age of 75, while Americans typically withdrew at an unsustainable rate of 8% a year.
  The think tank is urging the government to give older people a mid-retirement financial health check, to assess how fast they are using up their money.
  Early withdrawal of funds provides a tax income boost for the Treasury - it is expected to take double the amount it predicted during the first year of reforms.
  However, if pensioners use up savings, the eventual effect is an increased reliance on benefits and the state - a long-term cost to the Treasury.
  Providers suggest that people are taking relatively safe approach to retirement savings.
  "It is clear that people are taking a sensible approach and considering how they will pay for their retirement," said Yvonne Braun, of the ABI.
  "However, the figures also show that ensuring people save enough for retirement remains our key challenge. With life expectancy increasing and final-salary pension provision declining, we must now turn our attention to helping customers grow bigger pots."
  Tom McPhail, head of retirement policy at Hargreaves Lansdown, said: "For most retiring investors, a mix and match strategy will work best, using a combination of state pension, annuity purchase and drawdown."
summary: Individuals could be at risk of running short of retirement funds after cashing in their pension pots, analysis of overseas schemes suggests.