The participation of children in medical research raises many ethical issues, in particular regarding assent. However, little is known about children's own views on participation. This study presents results from interviews with children 10–12 years old with and without experience in a large-scale longitudinal screening study. We identified five themes: (1) knowledge about research, (2) a sense of altruism, (3) shared decision-making and right to dissent, (4) notions of integrity, privacy, and access, and (5) understanding of disease risk and personal responsibilities. We conclude that the children feel positive towards medical research, and want to take an active part in decisions and have their integrity respected. However, the study also indicates that children who had participated in longitudinal screening had a limited understanding, suggesting the vital importance of providing information appropriate to their age and maturity. This information should be provided out of respect for the children as persons, but also to promote their willingness to continue participating in longitudinal studies.                 

Objective: The objective of this study was to investigate the importance of trust in researchers and other reasons that participating parents, former participants, and non-participants had for participating, or not participating, in a longitudinal cohort study on prediction and development of diabetes in children. Study design: A questionnaire addressing each of these groups, where respondents graded the importance of a set of listed reasons for participating/not participating, was randomly distributed to 2500 families in the All Babies in Southeast Sweden (ABIS) study region with children born between 1997 and 1999. Results: Lack of trust was not a central factor to a great majority of respondents who decided not to participate in the ABIS study or who later decided to opt out. Practical matters, like blood sampling and lack of time, were important factors to many more. Yet, four fifths of those who still participate in the ABIS study stated trust in the researchers to be an important factor to their initial decision to participate. Conclusions: Trust in researchers may be a necessary prerequisite in order for people to be willing to participate in research, but practical matters such as time that has to be spent or pain involved in collecting blood were more important factors than lack of trust in explaining opt out in relation to the ABIS study.

Based on extensive questionnaire data, this paper focuses on parents views about childrens right to decide about participation in research. The data originates from 4000 families participating in a longitudinal prospective screening as 1997. Although current regulations and recommendations underline that children should have influence over their participation, many parents in this study disagree. Most (66%) were positive providing information to the child about relevant aspects of the study. However, responding parents were split about whether or not children should at some point be allowed decisional authority when participating in research: 41.6% of the parents reported being against or unsure. Those who responded positively believed that children should be allowed to decide about blood-sampling procedures (70%), but to a less extent about participation (48.5%), analyses of samples (19.7%) and biological bank storage (15.4%). That as many as possible should remain in the study, and that children do not have the competence to understand the consequences for research was strongly stressed by respondents who do not think children should have a right to decide. When asked what interests they consider most important in paediatric research, child autonomy and decision-making was ranked lowest. We discuss the implications of these findings.

Based on extensive clinical questionnaire data, this paper explores the relation between research subjects' self-assessed understanding and actual knowledge of a largescale predictive screening study, and its implications for the proper handling of information and consent routines in longitudinal studies. The intitial data show that low self-assessed understanding among participants was correlated with limited knowledge, concern over participation and collected samples, less satisfaction with information, and feeling passive or negative towards the study. Among those reporting high understanding, a non-negligible number displayed a lack of knowledge regarding central aspects of the study. Regarding high assessed understanding, the multivariate analysis identified the main predictor variables to be knowledge, having a positive attitude towards participation and the study itself, being satisfied with information, having a stable psychosocial background and feeling calm regarding the handling of samples. These findings indicate that to evaluate participants' understanding through self-assessment may not be reliable method. Self-assessed understanding may rather be a good indicator of general attitudes than a tool for analysing content. The data also show that actual understanding varies considerably among participants, suggesting that more effort needs to be put into adjusting the information to the needs of different subgroups. It is argued that when doing this, researchers in longitudinal studies must be careful not to exhaust participants with excessive information that they do not want and that may cause them to drop out. The ethical relevance of obtaining repeated consents in longitudinal research is discussed.

Data from the 5-6 year control questionnaire of the ABIS study, a Swedish prospective screening of children for Type 1 diabetes, indicates a genuine trust in the researchers - very few participating families expressed concern about their participation. Nevertheless, a majority do not want their research data to be used beyond the agreement of the original consent. They want to be asked for renewed consent in such cases. A vast majority also want potential high-risk information about their child to be communicated to them. Most participating families want this regardless of whether any preventive treatment is available. Although potential benefits for their child is a motivation for participation for a majority of the respondents, they also claim to be motivated by altruistic reasons. These results are compared to results from two similar studies in the UK.

The 'right not to know' one's genetic status has been increasingly more recognised in ethical and legal instruments. Yet empirical research is limited, leaving discussion on a theoretical level. There are also divergent ideas as to what extent it should be respected. In this study, we explored the clinical preconditions for disclosure of increased risk of getting diabetes in children. We included questions in the clinical 5-year questionnaire of a predictive screening for the risk of type 1 diabetes (T1DM), asking the respondents (n=7206) whether they wished to be informed of their children's potential risk status. The group of 2% of the respondents who did not want to know about risk status proved to be significantly associated to concern with natural history data (OR 4.03), lack of knowledge (OR 3.17), pressure to participate (OR 2.99) and the child's disease development (OR 2.18). We discuss whether parents'/participants' 'no' to high-risk information may call for a more nuanced response such as information and support, rather than simply respect their wish not to know. We furthermore argue that it is ethically questionable whether the parents' expressed wish not to know should prima facie override the potential benefits for their child. We conclude that this constitutes sufficient reason not to promote a default solution where people's expressed wishes not to know are taken at face value.

Empirical findings from a Swedish longitudinal screening study show that many of the research subjects had a limited understanding of the study. Nevertheless they were satisfied with the understanding they had and found it sufficient for informed continued participation. Were they wrong? In this paper, it is argued that the kind of understanding that is morally required depends partly on the kind of understanding on which the research subjects want to base their decisions, and partly on what kind of knowledge they lack. Researchers must ensure that the information process is not flawed and that participants receive the information they want. To achieve this, new information efforts may be needed. Researchers must also ensure that research subjects have knowledge about aspects of importance to them. Lack of understanding may, however, be the result of conscious choices by research subjects to disregard some of the information because it is not important to them. Such choices should normally be respected.

This empirical study explores participants' perceptions of information and understanding of their children's and their own involvement in a longitudinal screening, the ABIS Study. ABIS (All Babies In Southeast Sweden) is a multicentre, longitudinal research screening for Type 1 diabetes and multifactorial diseases involving 17 005 children and their families. For this study, a random selection of mothers was made, using perinatal questionnaire serial numbers from the ABIS study. In total, 293 of these mothers completed an anonymous questionnaire (response rate 73.3%). Our findings from the questionnaire indicate a marked difference between the reported satisfaction with and understanding of the information provided on the one hand and the significant lack of knowledge of some of the aims and methods of the ABIS screening on the other, namely concerning high-risk identification of involved children, potential prevention and future questionnaires. Two questions evoked by our results are: (1) what information is required for participants in longitudinal studies involving children? and (2) how do we ensure and sustain understanding, and thus in a prolonging, informed consent in these studies? This study underlines the importance of an increased understanding of the ethical issues that longitudinal research on children raise and the need to discuss how information and informed consent strategies should be analysed and designed in longitudinal studies.