After years of consideration, the World Medical Association is close to agreement on a revised version of the historic Declaration of Helsinki - the document that lays down ethical guidelines for research on humans.

Speaking at a conference in Helsinki today, Dr Delon Human, Secretary General of the WMA, said the association hoped to be able to adopt a revised Declaration at its annual General Assembly in Edinburgh in October or at next year's Assembly in New Delhi.

Addressing a meeting organised by the World Association of Medical Law and the Finnish Medical Association, Dr Human said the WMA had consulted widely outside the medical profession on how the Declaration might be revised. He said revisions were necessary because research had changed dramatically since the first version of the document in 1964. At that time a distinction could be made between therapeutic and non-therapeutic research. But it had now become clear that this confused rather than clarified the situation.

Dr Human said the WMA was now attempting to highlight the fact that where research was combined with medical care, additional measures should be taken to ensure the safety of human participants in research.

Another sensitive issue concerned the use of control groups. The current Declaration stated that "In any medical study, every patient - including those in the control group, if any - should be assured of the best proven diagnostic and therapeutic method. This does not exclude the use of inert placebo in studies where no proven diagnostic or therapeutic method exists".

But Dr Human said some ethicists argued that this provision ruled out the developments of all new treatments except those for diseases for which there were no proven therapeutic methods. Others disagreed with this literal interpretation.

Serious concern had been raised by a number of individuals and groups about the change of "best proven diagnostic and therapeutic method" to "proven available prophylactic, diagnostic and therapeutic method". Many people had interpreted the change as a watering down of the standard set in the current Declaration.

Recalling that the WMA came into being because of the lack of research ethics, Dr Human said: "The Second World War facilitated research of the most inhumane, horrific kind. During this war, physicians and others were involved in subjecting patients to research that could only be described as a brutal violation of any sort of human right and dignity".

It was in response to these atrocities that the WMA was established and it was on the basis of the Nuremberg Code that the Declaration of Helsinki was later approved to formulate ethical guidelines to protect patients and set standards for the profession.

Dr Human said one of the objectives of a revised Declaration was to make quite sure that the patient was protected in a changing global research environment.