In order to draw generalizable conclusions, it is important that cohort studies represent the population of interest faithfully. Against this backdrop it has been noted that not all individuals are equally willing to participate in biobank related studies. Factors associated with willingness to participate in biobank studies have not been well addressed to date.
In order to fill the knowledge-gap a study led by Janet E. Olson of the Mayo Clinic sought to determine the factors associated with participation in the Mayo Clinic Biobank (MCB) as well as associated follow-up studies. The results were published in the journal Frontiers in Public Health.
In April 2009 MCB began recruiting participants. Patients were approached following booking clinical appointments in Rochester, Minnesota. The minimal requirements were aged at least 18, current residents of the United States, and able to provide informed consent. Selection was biased towards primary care appointments. Recruitment was expanded to the other Mayo Clinic sites in Jacksonville, Florida in June, 2012 and La Crosse, Wisconsin in August, 2013. By December, 2015 the 50,000-participant target had been met. Compensation of USD $20 was provided. Additional patients that want to volunteer can still enrol.
Under the terms of consent Mayo Clinic is provisioned to request participation in up to two additional studies per year. Forty such studies have been conducted to date. Remuneration ranged from $0 for studies with only questionnaires, $10 for new samples to upwards of $800 for studies with greater participant burden. Compensation was mentioned at the time of the study invitation and distributed after all study requirements were complete.
Of the 251,102 eligible patients, 48,312 (19%) participated, 23,944 (10%) refused, and 178,846 (71%) did not respond within 90 days of the written request. When invited for a follow-up study, 71% of participants agreed to at least one additional study and 30% participated in more than one study.
Of the participants in MCB 93% were white, 60% were female, and 34% had some college education. The Rochester site recruited 77% of the MCB. The average age of participants was 60 years. The highest rate of consent was among 70–89 years of age with 26% consenting across the three sites.
Patients who self-reported their race as white were most likely to consent at all sites (20% overall) with American Indian/Alaskan Native patients consenting at the next highest level of 13% overall. Patients who self-reported as Asian or Black/African American consented at the lowest rates at 10 and 7%, respectively. Patient consent rates fluctuated depending on the time of year. Participation was lowest when invites were sent in November and December and highest in March, April, and October.
“In conclusion, we describe factors related to participation in the Mayo Clinic Biobank as well in studies embedded within it. We found that consent rates among younger and non-white patients were lower than in older, white patients. However, we also found that participation rates among those already enrolled in the biobank were much higher than those seen in new recruitment efforts, external to an existing biobank,” stated the authors.