The National Childrens Study - Essay Example

BACKGROUND AND INTRODUCTION The National Children's Study (NCS) research plan proposes to analyze the dietary intakes of pregnant women and children utilizing a community food collection method to assess nutrient content, chemical contamination, and health outcomes. Substance toxins are widely used in the residential setting. Applications range from heavy metals in paints, compounds applied for pest control, to fertilizers used in lawn and garden maintenance (1,2). Diet is an important source of exposure to toxins (3). Therefore, the NCS will employ a food collection method to determine the extent of exposure to pregnant women and children. Historically, dietary monitoring methods have focused on collecting samples which duplicate the diet consumed during a monitoring period by the individual. Such an approach for residential-based exposure measurements and evaluating dietary intake is justified for the following reasons: it includes the contribution of residue contaminants added inadvertently during food preparation in the residence (i.e. bug spray, lead based paint, etc.), and it represents a reasonable measure of daily dietary intake of the individual during the monitoring period (4). Duplicate-diet collection is considered the "gold standard" for estimating dietary exposure to contaminants (5). Additionally, duplicate-diet collection can provide a more accurate picture of nutrient composition of an individual's dietary intake than food diary records. However, duplicate-diet methodology has also been shown to have certain shortcomings (6). For example, the variability in what people eat and the non-uniform distribution of chemical residues in foods over a period of time, duplicate-diet monitoring over a short time period (up to 4 days) provides data that adequately characterize exposure of the population as a whole, but not the individual being monitored. In addition, diet samples collected during short-term field studies may not be representative of long-term dietary intakes. Reports indicate that duplicate diet collections are burdensome and collection and analysis too costly. In addition, there is a social awkwardness of collecting, storing, and transporting additional portions of food, and some situations are simply not appropriate for duplicate diet food collections, such as a picnic) (7). Furthermore, the established indirect methods of assessing dietary intakes (market basket surveys) do not capture the important contributions of storage, preparation, and consumption in the residence, or handling by a child. As an alternative to the duplicate diet protocol, the community food item collection methodology was tested. Two focus groups were conducted to pilot test the study protocol. Focus group interviews are a way to obtain qualitative data (8). The group environment promoted purposeful interaction to generate feedback on the proposed research (9). This study aimed to investigate the feasibility of the community food item collection method as an alternative to the duplicate diet food collection as a valid way to measure the level of exposure to toxins in pregnant women and young children. Specific aims were to: 1) determine whether 60% of the subjects enrolled in the study would provide at least one food item; and 2) to estimate staff effort, cost, and resources necessary to recruit 50 mothers of children 15-24 months to the study. METHODS Study Design Mothers (n = 45) of toddlers 15 - 24 months old were enrolled in a prospective observational study testing the Community Food Collection Potential participants were screened by telephone to determine if eligibility requirements were met. Approximately 87% (n=53) of prospective subjects met eligibility criteria and were mailed consent forms. Overall, 45 mothers provided informed, written consent and were enrolled in the study, and 44 completed the study in its entirety. Eligible mothers were mailed a consent form, a child dietary habits survey, and a child food frequency questionnaire (FFQ). The Institutional Review Board of the University of Utah authorized the study protocol and informed, written consent was obtained from each subject. A list of foods to be included in the collection was developed by the research team. The criteria for selection were based on the potential for pesticide exposure and need for preparation and/or handling by the mothers. The list was further refined utilizing the following sources: Pesticide Data Program 2006 Report (10), previous research (3), the inventory of foods provided on the child FFQ, and the National Health and Nutrition Examination Survey 2003-2004 list of commonly consumed foods for children aged 1-2 years (11) . Once the consent, dietary habits survey and FFQ were returned, the first home visit was scheduled. During this home visit, child weight, height, and head circumference measurements were assessed, and the mothers completed a demographic survey. In addition, written and verbal instructions for food sample collection were provided. Five foods were selected from the food collection list based on what was normally consumed by the child as demonstrated by the FFQ. Mothers were instructed to collect three of the five foods. The mother was directed to use the same utensils to serve both the child's food and the duplicate portion. Participants were asked to store the collected food in the refrigerator no longer than 12 hours; at that point, they were to store the food in their freezer until pick-up by the staff. Labeled zip-lock bags were provided for food sample collection purposes. A token gift (coloring book and crayons) valuing five dollars was provided upon completion of the appointment. Participants contacted research staff upon completion of the food collection to schedule the second home visit. At this appointment a quality assurance interview was conducted with the participants. Additionally, mothers completed the participant evaluation form and a child and environmental health survey. A $25 grocery card was provided to the participants as compensation for their time and food they supplied to the study. The collected specimens were placed in a styrofoam box with dry ice (frozen samples) or a cooler with blue ice packs (refrigerated samples) for transportation. Research staff delivered the foods to the University of Utah campus. A portable balance scale was used to weigh the food samples to the nearest gram prior to storing in a -20 C freezer. Subjects Mothers of children 15-24 months were recruited to participate in the study via fliers posted at several locations in Salt Lake City and Salt Lake County: Special Supplemental Nutrition Program for Women, Infants, and Children clinics; University of Utah Hospital and clinics; day care centers; and private pediatric offices. Eligibility criteria included: non-Hispanic white and Hispanic ethnicities; mother fluent in English; mother primarily responsible for food preparation in the home; and age-appropriate intakes of solid foods for the child. In addition, mothers were recruited for the two focus groups. These women met the same qualifications as the study participants. Anthropometric Data Trained personnel assessed child length, weight, and head circumference. Length was evaluated with an infantometer (Seca 416; Mobile Mechanical Length Board, Snoqualmie, WA). Weight measurements were determined with a calibrated digital scale (model BWB-800S; Tanita, Arlington Heights, IL). Head circumferences were ascertained with a head circumference measuring tape (model PE-CIRC; Perspective Enterprises, Portage, MI). Height, weight, and head circumference were measured according to the protocol outlined in training modules provided by the U.S. Health and Human Services Maternal and Child Health Bureau (11). Height, weight, and head circumference was measured twice to the nearest 0.01 cm, 0.01 kg, and 0.01 cm respectively. Anthropometric data were evaluated using the CDC 2000 growth charts for boys and girls birth to 36 months. Children were rated as underweight below the 5th percentile, between the 5th and the 95th percentile was classified as normal weight, and children above the 95th percentile were categorized as overweight (12). Data Collection Measures Data were extracted from information provided by the moms and study personnel from several questionnaires and surveys, as displayed in Appendix I. The Harvard Service Food Frequency Questionnaire. This form consisted of a list of approximately 100 foods specific to children to collect information on total diet. The reference period was for the past month (13). Child Dietary Habits. This 3-item survey was developed from the National Children's Study, Summary of Proposed Dietary Data Collection for Expert Review (January 20, 2006, unpublished data). This form assessed child intake habits that could have an impact on dietary exposure to contaminants from sources including the consumption of commercial baby foods, organic foods, and water. Maternal and Child History Questionnaire. This 17-item questionnaire was adapted from an instrument used in a published study of low-income mothers of young children (7). The form contained information relevant to the mother (age, ethnicity, household income, household size, residence location, employment status, educational level, occupation) and child (ethnicity). Child and Environmental Health Survey. This survey was designed to assess children's exposures to environmental contaminants. Participants were asked to record frequency of pesticide usage, application locations, an inventory of pesticide product names, child care attendance, and hand-washing behaviors of the child. In addition, the survey evaluated food handling behaviors that may impact dietary exposure to contaminants (14). Quality Assurance Checklist. Participants level of compliance with the food collection protocol was assessed with this 6-item form. The survey contained questions about food collection, food storage location, and any addition of prescription medicine to the food sample. Also, participants were asked if the collected food items came in contact with utensils or their hands (15). Participant Evaluation Form. This form included 13 items on a five-point scale (one=strongly disagree to five=strongly agree), as well as open-ended questions. Participants were asked to rank the burden of the community-based food collection, the understandability of testing instructions, and the time involved for participating in the study. Home Visit Logs. These forms were completed by the study personnel. The home visit logs examined how many reminder phone calls were necessary to obtain the food samples, the time and mileage requirements for the home visits, the number of food samples collected at the home visit, the thoroughness of the description of the food, and completion of the surveys, and if there were any obstacles to the food sample collection process. Feasibility Documentation Form. This 30-item form included questions pertaining to the study organization. Staff were asked to assess training and food transport. Also, the questionnaire summarized the average reminder calls, time to drive and miles driven roundtrip per visit, and time to complete each home visit. Data Analysis Statistical analyses were conducted with the Statistical Package for the Social Sciences (version 14.0, 2005, SPSS Inc, Chicago, IL) with a significance level of p Read More