The research team analysed data from NHS Blood & Transplant for all four UK countries for the period 1990 to 2009, and compared data on registration and donation from other European countries.

They looked at rates of donation for kidney, liver, heart, lung and cornea per million of the population to see if there were any differences among the four countries and if these were related to organ type.

Wales consistently outperformed its UK neighbours, both in terms of the percentage of the population registered and its organ donation rate, which has been higher than the UK average for most of the past 20 years.

England, which has the third highest number of the population registered, only managed a higher than average organ donation rate for three of the past 20 years.

Yet Northern Ireland, where donor registration is the lowest of the four countries, outperformed England and Scotland in the rate of organ donation.

While rates of organ donation have remained fairly steady in England over the past two decades, they have fallen in Scotland.

The analysis also revealed significant differences among the countries in the type of organs donated, including liver donations. And England had significantly fewer heart donations than both Wales and Northern Ireland.

The rate of heart donations has also fallen over the past 20 years for Wales, Scotland and England, the findings showed.

The rate of lung donation has risen since 1990, with Northern Ireland being the greatest contributor over most of this period.

But the authors point out that heart and lung donations have been few in all four countries compared with other organs, possibly because the number of living donors, on which most heart and lung transplants depend, has been steadily falling.

While differences in kidney and cornea donations evened out over time, in Northern Ireland cornea donations have been significantly lower across the entire period.

Culture and tradition may explain some of this difference, suggest the authors, as well as the fact that there is no eye bank or eye retrieval centre in Northern Ireland.

A system of presumed consent, unless otherwise specified, has been mooted as a way of boosting organ donation rates in the UK, where supply is failing to meet increasing demand.

But the authors warn that where legislation to this effect has been introduced in other European countries, the results have been mixed.

"Comparison of EU nations, and particularly Spain, indicates that improvement of organ donation rates is unlikely to be achieved by introducing new legislation alone," they write.

Note: If no author is given, the source is cited instead.

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• Health Policy

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• Organ transplant
• Transplant rejection
• Kidney transplantation
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• Liver transplantation