Energy use in clinical research premises and trial-related air travel have been identified as the biggest culprits, in an article published in the March 31 issue of the British Medical Journal .
The situation is only set to intensify as the trend towards outsourcing various elements of clinical trials to far flung destinations all over the world continues to gain momentum.
During a one year audit period of a sample clinical trial, the total emission of greenhouse gasses related to the trial was 126 tonnes of carbon dioxide equivalents (CDEs) - an amount that corresponds to that produced by 32 people in one year on the basis of global per capita estimates, said the researchers.
For the entire five-year duration of the sample trial, about 630 tonnes of CDEs were produced - an amount that is equivalent to 525 round trips flights from London to New York for one passenger, the researchers said.
Specifically, the trial coordination centre accounted for the largest proportion of emissions, generating 50 tonnes (39 per cent), with 45 out of the 50 tonnes coming from electricity usage and the remainder from office waste disposal.
The distribution of drugs and documents was the next biggest contributor, with 35 tonnes (28 per cent) and the majority of this stemmed from the airfreight of treatment packs and documents to hospitals.
This was followed closely by trial-related travel, responsible for 29 tonnes (23 per cent) of emissions, with most coming from air travel, as well as hotel stays for site visits, on-site data verification and meetings.
Furthermore, each individual clinical trial employee was found by the researchers to generate 14 tonnes of CDEs each year, compared with the substantially-lower average of 4-6 tonnes for employees in other service industries.
The research was conducted during August 2003 and July 2004 by the Sustainable Trials Study Group, which was convened by the London School of Hygiene and Tropical Medicine to find ways of reducing greenhouse gas emissions from clinical trials.
For the purpose, a 'carbon audit' was conducted on a multicentre international trial being run by the Medical Research Council (MRC), called CRASH.
The CRASH trial involved 10,008 participants at sites in 49 countries over five years and was investigating the effect of corticosteroids on death and disability in adults with head injury.
The trial was coordinated from London; involved a drug made by Pfizer in the US; a placebo made in France; packaging of both study drugs was done in Wales, from where treatment packs were sent to London for distribution to hospitals around the world.
Commenting on the results, the researchers said: "Clinical trials are energy intensive and produce substantial greenhouse gas emissions."
"Our audit provides insights into how to reduce the carbon intensity of clinical trials."
Suggestions given include using renewable energy sources as well as more efficient energy consumption at clinical trial sites, in addition to reducing the number of staff employed, in order to cut emissions.
Other suggestions posed by the researchers were to simplify trial designs to minimise superfluous data collection, coupled with increasing the use of remote electronic data capture; reduce bureaucracy associated with ethics committee- and-regulatory applications; as well as the increased use of teleconferencing and videoconferencing where possible to slash unnecessary travel.
They also made an interesting parting comment: "Trial results should be made publicly available, as the environmental consequences affect us all."