Impact on mortality and cancer incidence rates of using random invitation from population registers for recruitment to trials

2011

Impact of Random Invitations on Mortality and Cancer Rates in Trials

Sample size: 202638 publication 10 minutes Evidence: moderate

Author Information

Author(s): Matthew Burnell, Aleksandra Gentry-Maharaj, Andy Ryan, Sophia Apostolidou, Mariam Habib, Jatinderpal Kalsi, Steven Skates, Mahesh Parmar, Mourad W Seif, Nazar N Amso, Keith Godfrey, David Oram, Jonathan Herod, Karin Williamson, Howard Jenkins, Tim Mould, Robert Woolas, John Murdoch, Stephen Dobbs, Simon Leeson, Derek Cruickshank, Stuart Campbell, Lesley Fallowfield, Ian Jacobs, Usha Menon

Primary Institution: UCL EGA Institute for Women's Health

Hypothesis

The healthy volunteer effect in trials is related to socioeconomic status.

Conclusion

Inviting women from population registers for screening trials does not eliminate the healthy volunteer effect on mortality, although its impact on cancer incidence is smaller.

Supporting Evidence

The study involved 202,638 women, making it one of the largest trials of its kind.
Mortality rates were significantly lower than expected, indicating a healthy volunteer effect.
Socioeconomic status was linked to both mortality and cancer incidence rates.
Participants who joined the trial were less deprived than those invited.

Takeaway

When researchers invite people randomly to join health studies, the ones who show up are often healthier than the average person, which can skew results.

Methodology

The study analyzed mortality and cancer incidence data from 202,638 postmenopausal women recruited between 2001 and 2005, comparing observed rates to expected rates based on national statistics.