A Randomized Controlled Trial of Short and Standard-Length Consent Forms for a Genetic Cohort Study: Is Longer Better?

Background Although the amount of detail in informed consent documents has increased over time and the documents have therefore become very long, there is little research on whether longer informed consent documents actually result in (1) better informed research subjects or (2) higher consent rates. We therefore conducted an add-on randomized controlled trial to the Takashima Study, a prospective Japanese population-based genetic cohort study, to test the hypothesis that a shorter informed consent form would satisfy both of the above goals. Methods Standard (10 459 words, 11 pages) and short (3602 words, 5 pages) consent forms in Japanese were developed and distributed using cluster-randomization to 293 potential cohort subjects living in 9 medico-social units and 288 subjects in 8 medico-social units, respectively. Results Few differences were found between the 2 groups with regard to outcome measures, including participants’ self-perceived understanding, recall of information, concerns, voluntariness, trust, satisfaction, sense of duty, and consent rates. Conclusions A short informed consent form was no less valid than a standard form with regard to fulfilling ethical requirements and securing the scientific validity of research.


Potential Benefits and Disadvantages to Study Participants
(1) Benefits The results of this study could benefit society in the future through various medical policies, health counseling and health initiatives. We will statistically analyze the information after it is made anonymous and combined and later publicly announce the results to society through academic conferences, academic journals and the Internet, using a format that retains participant privacy.
We will provide to all health-checkup attendees the results of the supplementary test items decided in consultation with Takashima City (ABI/PWV test for arteriosclerosis; urinary sodium, potassium and creatinine levels; and HbA1c levels). Participants in this study will also receive results on waist circumference, insulin levels, high-sensitivity CRP levels and BNP levels.
If any results from this study are judged in the future to be significant or beneficial for the medical care or treatment of an individual participant, we will provide all the information to him/her with an explanation and counseling. This also applies to genetic (DNA) testing results.
This study will analyze genes (DNA) and other biological materials. At this point in time, it is unknown what diseases or disorders they might be related to, and what meaning or consequences they will have. It can be expected to take years to determine whether or not the results from this study will be significant for individual medical care. Also, please note that we will not release the results of a participant who has died.
If, as a result of this study, any financial benefits should be generated in the future through patents or other means, you will not receive any proceeds because the rights for those financial benefits belong to the national government and/or research institutions.
(2) Disadvantages There will be no financial burden or cost to you for participating in this study.

(A) Physical disadvantages and risks
We ask that study participants allow us to draw 16-18 mL of blood for our research purposes in addition to the blood taken during the physical examination for the health-checkup program. The process of drawing blood may cause discomfort (such as pain or internal bleeding), rare complications (such as bacterial infections or nerve damage) and accidents (such as bent needles), but the likelihood of these events or an increase in the number of needle insertions is no greater than when your blood is taken in the healthcheckup program, since this process is conducted at one time.

(B) Social and informational disadvantages and risks
We strictly control information, materials and samples collected from you, the participant, as explained in "On Methods of Personal Information Protection" (the lower half of page 5). However, we cannot absolutely guarantee that no incidents will occur in which a malicious third party steals or leaks this controlled information. With genetic (DNA) test results in particular, there is the possibility of a malicious third party illicitly viewing the results to use against you (eg, in marriage, employment or health insurance contract negotiations). If this type of information theft or leak occurs, there is a possibility you will incur social disadvantages (eg, discrimination in job hunting or life insurance enrollment). The Shiga University of Medical Science is not responsible for personal information theft or leaks if the Takashima Study researchers are not clearly responsible. We ask for your understanding of this matter when participating in our study.
When analyzing your blood and identifying genetic (DNA) polymorphisms, we could identify potential illnesses specific to you and your family. For example, information from a blood test could reveal that you have a serious viral disease or a gene that often causes colon cancer. Having a gene (DNA) that indicates future illness increases the possibility that your relatives have the same gene (DNA) and the likelihood of future illness. If you want the individual results of the genetic analyses in the study, you and your relatives may experience mental stress from knowing the genetic (DNA) makeup and possible illnesses in your family. Therefore, when you first confirm your intent to cooperate with this study, please thoroughly consider the benefits and risks that come from knowledge before indicating whether or not you want genetic (DNA) results returned to you. For those who do not want the results in future years, we will return nothing as long as there are no new requests for the results of the analyses performed in this study.

Benefits to Study Participants
■ Results of this study will be publicly announced in specialized academic journals and other media to benefit society in ways such as the development of medical policies, using a format that retains participant privacy.
■ There are absolutely no financial benefits for individual study participants.
■ In addition to providing all health-checkup attendees with the results of supplementary test items determined in consultation with Takashima City, we will also provide study participants with information on waist circumference, insulin levels, high-sensitivity CRP levels, and BNP levels.
■ If results are judged to be significant to medical care or treatment of an individual participant, we will provide the information with an explanation and counseling. This also applies to genetic testing results. However, it may take years to determine whether or not the results are significant for individual medical care. We will not release the results of a participant who has died.

Risks and Possible Disadvantages from Participating in this Study
■ There will be no financial burden or cost to study participants.
■ We will control personal information to prevent external leaks. However, it is impossible to completely eliminate the likelihood that a malicious third party might breach this strictly guarded information, so there is a risk of information theft and leakage.
■ If theft or a leak of personal medical information does occur, you may incur social risks (eg, discrimination in applying for life insurance or job hunting).
The Shiga University of Medical Science and its individual researchers are not responsible for personal information theft or leaks if the researchers are not clearly at fault, so we ask for your understanding of this matter when participating in our study.
■ In the course of performing a blood test for this study, we may discover information in the future that could affect your health, such as a serious viral disease or a gene that often causes colon cancer. Having a gene that indicates future illness increases the possibility that your relatives will have the same gene.
■ Consequently, if you want the results of individual genetic analysis, you may experience mental stress from knowing the genetic makeup and possible illnesses in your family.