Participation in the surveys is voluntary and participants have the right to withdraw from study at any time. Potential participants will be provided information about the study, measurements to be conducted and possible risks they may pose in written and oral formats. Those who decide to participate, will sign the informed consent form before examinations start. Depending on the requirements of national Ethics Committee, the informed consent may include separate points for questionnaires, physical measurements, biological sample collection, and DNA testing, or may provide general consent for all included measures. All PERSIAN Cohort activities will be carried out according to existing guidance in ethics as indicated in the Universal Declaration on Bioethics and Human Rights adopted by UNESCO (19/10/2005).

This project concerns the collection of personal information from the participants and biological samples including blood, urine, hair, nail, faeces, skin flora, deciduous teeth, milk, meconium, saliva, cord blood, and placenta. PERSIAN birth cohort will ensure standardized protocols are used and will collect biological samples. The collection of the biological samples is justified by the contribution of the research to be conducted on them to the improved understanding of an emerging risk of major public health interest, i.e., the role of early-life exposures in functional health in later life. The amount of biological samples to be collected is such as not to constitute any significant burden on the donors. Ethics approval will be sought from the local ethics committees prior to starting the fieldworks. The following procedures will be included in the research protocol to safeguard the privacy of study subjects:

• Reported study results will pertain to analyses of aggregate data. No individual’s name will be associated with any published or unpublished report of this study;
• Where personal information is used, including questionnaires and biological material it will be safety stored in secure facilities, and names will be replaced by unique study numbers, and stored separately. Primary databases and analysis files will be stored on computers with personal identifiers removed;
• Participants will be identified by a unique study number assigned by staff of the partner organizations. This unique identifier will link all basic data required for the study. The master key file linking the centre’s study numbers with personal identifiers will be maintained in each centre;
• All files containing personally identifiable information, including the master key file, will be stored in password protected computer files. Access to these files will be limited to authorized project personnel;
• Hard copy records or computer generated records containing personally identifiable information will be stored in locked cabinets in an office with limited access;
• All project personnel will be trained in the importance of confidentiality of individual records and required to sign a confidentiality agreement.
• During the project life-span information will be accessed and handled by members of the research teams only, unless specific permission has been given by the ethical committee.