All but one of the top 10 countries are in Western Europe, North America and Australasia, with Japan the exception at ninth place, according to the ranking which comprises 91 per cent of the global population over the age of 60.
Norway tops the index, pushing last year's number one Sweden into second place in the second year the index has been released.
Unsurprisingly, African countries make up half of the lowest quarter of the index, although Venezuela, Turkey and Serbia are ranked 76th, 77th and 74th respectively.
"Specific policies need to be put in place to address the implications of ageing," said the report, published on the United Nations International Day of Older Persons.
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"Policies on income security in Mexico (30) have lifted it 26 places in the overall rankings since last year despite being less wealthy than Turkey (77)."
The index is based on 13 indicators grouped into four areas: income security; health status; capability, which includes employment and educational status; and the enabling environment, including issues such as physical safety.
This year's report focuses particularly on income security, namely pensions, which older people consistently identify as their top priority to fend off the risk of poverty.
With rising numbers of old people - two billion over the age of 60 by 2050, a similar number as children under 15 - HelpAge International chief Toby Porter said pensions were vital for all governments.
"Incomes are often too low to save for old age, which is why there's such a need for a basic social pension now," he said.
But it applauds an "explosion" of new tax-financed, non-contributory pensions over the past two decades, which provide regular income for the very poorest.
Across Latin America, countries have "dramatically extended coverage" of social pensions, helping push them up the global rankings.
The top 10 in the index are: Norway, Sweden, Switzerland, Canada, Germany, Netherlands, Iceland, United States, Japan and New Zealand.
The bottom 10 are: Iraq, Zambia, Uganda, Jordan, Pakistan, Tanzania, Malawi, West Bank and Gaza, Mozambique and Afghanistan.