This survey was carried out at the Institute for Maternal and Child Health IRCCS Burlo Garofolo of Trieste (Italy), a third level hospital and one of the three pediatric research institute recognized by the Italian Ministry of Health.
The mothers of healthy term newborns contacted or enrolled in the Phime cohort study (Public health impact of long-term, low-level mixed element exposure in susceptible population strata, 6th Framework Program) were asked to participate in this survey. The protocol of the Phime study was approved February 5, 2007 by the Bioethics Committee of the Institute for Maternal and child Health IRCCS Burlo Garofolo. An amendment, including a prolonged follow up (up to 7 years of child’s life) and the possibility to re-contact parents in order to carry out studies related with the Phime (such as the present), was approved April 12, 2009. Subsequently, women were contacted during the follow-up visits to give their consent to fill-in the questionnaires about motivations. The informed consents for both the Phime and the motivations studies were written and obtained face to face by two trained researchers.
The Phime study assessed the association between low-level prenatal mercury exposure through maternal fish consumption and child neurodevelopment . The first results of the study are published elsewhere . The participation to the Phime study was very demanding for families. All the women living in the area of Trieste, ≥18 years of age and Italian speaking were contacted during pregnancy. After enrollment, at 20th-22nd week of pregnancy (morphological ultrasound screening), a blood sample was collected, a hair sample was cut from the occipital area of the scalp and a brief questionnaire about food habits, socio-demographic information and health status was filled in; at 30th-32nd week of pregnancy (biometric ultrasound screening) the Raven’s standard progressive matrices test of intellectual efficiency and general intelligence was administrated to mothers and a urine sample was collected; at delivery a cord blood sample, a piece of cord tissue and, when possible, a sample of the first urine of the newborn were collected; within the first month of life, a more extensive questionnaire, including detailed food frequency questions and the evaluation of environmental exposures, was filled in by mothers; a 24 hour breast milk collection was carried out one month after birth; in the second year of life, the child postnatal dietary exposure, including types and amounts of food consumed, was recorded by parents through a one week diary; at 18 months after birth, a home visit was carried out to evaluate the familiar environment using the HOME (Home Observation for Measurement of the Environment) questionnaire; finally, to evaluate the child neurocognitive abilities at 18 and at 40 months of life the Bayley Scales of Infant and Toddler Development, Third edition (BSID III) was administered during an ad hoc hospital visit.
The Phime study started the enrolment of women during pregnancy in April 2007; the 18 months follow up started in January 2009.
To evaluate the reasons that led women contacted for the enrollment in the Phime cohort study to give or not their consent to participate, two different questionnaires were administered:
1) Women who give their consent: after the evaluation of child neurocognitive abilities at 18 months of life (BSID III), mothers were asked to fill in an anonymous questionnaire about motivation to participate, consisting of multiple choice questions investigating four areas: 1) the reasons influencing the participation to the Phime study; 2) the possible reasons affecting the choice to participate to further studies or to refuse the participation; 3) the appropriateness of the enrollment place; 4) the involvement during pregnancy in other studies other than Phime. Socio demographic information (women age, years of education, marital status, working situation) were also collected. This questionnaire was not part of the Phime study and was developed ad hoc. After receiving the approval of the Bioethical committee in April 2009, it was proposed to all mothers enrolled in the Phime study and in follow up at 18 months. A simplified version of the questionnaire is available as Additional file 1.
2) Women who refused to participate or withdraw their consent: these questionnaires were part of the Phime study and they were administered to women at the time of refusal or withdrawal. They include multiple choice questions about the reasons which influenced the refusal or the withdrawal and about socio demographic characteristics.
The responses to the questionnaires were entered into a database using EPIDATA (http://www.epidata.dk).
A descriptive analysis was carried out; categorical data are presented as absolute frequencies and percentages; continuous data as medians and interquartile ranges (IQR). To compare the main socio-demographic variables available in questionnaires (women age at delivery and level of education) among groups, the Kruskal-Wallis test and the Fisher exact test were used respectively. To evaluate the potential influence of socio-demographic characteristics (women age, education, marital status, working situation) on the willingness to participate to further research in women who filled in the questionnaire on motivation to participate, a multiple logistic regression analysis was carried out.