Design and methods for evaluating an early childhood obesity prevention program in the childcare center setting

Centers must have met the following criteria to be included in the study: (1) > 30 children ages 2-to-5 currently enrolled; (2) Serve low income families who are a part of the USDA food program and SNAP eligible; (3) Reflect the ethnic distribution of the Miami-Dade County Public School System (63 percent Hispanic, 19 percent African American, 18 percent white); and (4) Center director agrees to participate and sign a letter of commitment. Centers were excluded if they did not meet these criteria.

Parents consented to have their child participate in the study. A total of 60% of children were Hispanic, with the most prevalent specific Hispanic ethnicity being ‘Other’ (31%), followed by Cuban (15%), and Mexican (10%). Other specific ethnicities represented were Haitian (15%), non-Hispanic Black (12%) and non-Hispanic White (2%). Table 1 shows demographic characteristics of each study arm. There were 1105 participating children with 726 in the intervention arm and 379 in the control arm.

The majority of caregivers were born outside of the US (71%). Languages other than English were preferred by 65% of the sample. Low levels of education were prevalent, with 37% completing less than a 12^th grade education, 25% completed high school/GED, and 38% completing education beyond high school (Table 2).

Treatment or intervention arm schools received a combination of (1) implementing a daily curricula for teachers/parents (the nutritional gatekeepers); (2) implementing a daily curricula for children; (3) technical assistance with meal and snack menu modifications such as including more fresh and less canned produce, no high fat milk, and less simple carbohydrate items; and (4) creation of a center policy for dietary requirements for meals and snacks, physical activity and screen time. Details of each of these components follows.

For childhood obesity prevention programs to achieve long-term success the nutritional gatekeeper (i.e. the person buying and supplying food for the children) must engage in healthy lifestyle behaviors and beliefs themselves. For young children the nutritional gatekeeper is most likely the parent or a primary caregiver and for those who attend childcare, the teachers and center staff also. Therefore, Curriculum Specialist (CS) utilized an integrated curriculum with teachers and parents at the child care centers. The teacher-focused curriculum consisted of 29 weekly technical assistance sessions delivered by HC2 curriculum specialists during weekly visits to the childcare centers. Additionally, HC2 program staff conducted joint parent-teacher meetings (providing a substitute so that teachers can attend during parent pickup times) that focused on an evidence-based nutrition and physical activity curriculum. CS taught parents and teachers about (1) Choosing healthy foods, with an emphasis on fruits and vegetables; (2) Making healthy food choices for infant and child development; (3) Preparing nutritious snacks; (4) Preparing new recipes; (5) Tasting new foods; (6) Learning about food safety and storage; (7) Planning meals; (8) Making grocery lists; (9) Shopping wisely for groceries; (10) Budgeting food dollars and food stamps; and, (11) Using food labels to choose best buys. Via role-modeling, parents and teachers were encouraged to implement change at the family/home and child care center level, not child level. Additionally, nutritional professionals served as role models for the teachers and parents and assisted them as nutritional gatekeepers and positive models for the children. Lessons on physical activity for the whole family were also included (Table 3).

Our framework was comprised of a variety of role modeling components from the USDA’s Project M.O.M [18, 21‐24]. These components were then adapted and merged into eight sessions that were appropriate for the parents/caregivers and teachers of pre-school aged children. All curriculum materials if not available in Spanish were translated and back translated into Spanish by a team of certified translators at the University of Miami.

Teachers received ongoing technical assistance to support the inclusion of healthy eating and physical fitness concepts in their weekly lessons, without the continued assistance of the CS, and so, during the second year of the study they could lead the lessons independently or without any CS assistance. Currently, in year two, booster trainings are being provided bimonthly in all centers to provide teachers with refresher overviews of all lesson plans.

Parents participated in monthly events such as dinners at the centers where they received the same nutrition and physical activity educational information that formed the content of the teacher curriculum. They also received monthly newsletters that contained information that was covered in that month’s school lessons and an overview of the center’s HC2 activities for that month.

Twenty lesson plans were developed to promote nutrition and physical activity and were supplemented with the OrganWise Guys (OWG). The lesson plans focused on core principles of healthy living (high fiber, low fat, lots of water, exercise) and eating (nutrient-dense foods), nutritious dietary offerings in USDA meals that model classroom-based and parent nutrition education programming via the USDA feeding and nutrition education programs and has been shown to have positive health outcomes among primary school children [19, 20].

This classroom-based curriculum consists of 20 weekly sessions that were provided to the teachers by project curriculum specialists (CS) during weekly visits. The teachers then taught the curriculum to the children. The CS would address menu changes and target the cognitive, cultural, and environmental barriers to a low fat, high fiber diet that include more fruits and vegetables. These weekly visits are designed to assist center staff in problem-solving ways to ensure implementation. In addition, the curriculum was translated and subsequently implemented in Spanish where applicable.

All center modifications were revenue neutral (do not have an additional cost). The meals, snacks and beverages were provided by caterers who were given technical assistance by the HC2 nutritionist to ensure that the meals followed the policy guidelines yet still met USDA nutrition requirements. Center administrators were given monthly technical assistance by both the project nutritionist and staff on menu development and curriculum enhancements that would include the integration of the nutritional gatekeeper curriculum [3, 25‐27] critical for intervention maintenance and effective mediators of change.

Menus in intervention centers were modified to include low-fat (1%) or skim milk, water, less juice. Low fat or skim milk was promoted only at lunch, and water was promoted as the primary beverage for staff and children, especially after physical activity.

Menus in intervention centers were modified to include more fresh fruit (or canned fruit in water or 100% juice), fresh vegetables (or low-sodium canned vegetables), and fewer simple carbohydrate snacks (cookies, crackers, etc.). The centers also were encouraged to incorporate fresh fruits and vegetables for snack and meal time as often as possible. In addition, we provided food tastings to the children to expose them to new fruits and vegetables that they may have never tried before (e.g. kiwi, blackberries, rhubarb, edamame, and cauliflower).

Physical activity was promoted for at least 60 minutes per day. Lesson plans offered structured physical activities in the classrooms and included music and movement CDs with songs and exercises. Teachers were also provided with rainy day activities that could be used in the classroom and equipment that can be purchased inexpensively at local stores (jump ropes, hula-hoops, balls, etc.) but were encouraged to conduct physical activities outside and incorporate free play as much as possible.

The reduction of screen time was addressed by limiting television viewing, watching movies, and playing computer games to 30 minutes or less each day. The amount of time screens was documented.

Those schools randomized to the control arm received a safety curriculum and some child care center locations received an attention control consisting of one visit from the Injury Free Mobile which provided parents and teachers with home, car and child seat safety information. The control group received all the same pre-post measures (see below) as the intervention arms. They also received the same incentives as the intervention arms to foster involvement and ensure retention/reduce loss to follow up.

Height (by stadiometer), weight (by digital scale) and waist circumference measurements were collected at the beginning and the end of year one and two school year. Children’s shoes and any heavy outer clothing prior to measurement. BMI is converted to an age and sex- adjusted percentile and z-score [28]. According to the CDC, the following percentile categories will be used to define weight groups; underweight (< 5^th percentile), normal weight (≥ 5^th to < 85^th percentile), at risk for overweight (≥ 85^th to < 95^th percentile ) and overweight (≥ 95^th percentile) [29].

The Healthy Kids Checklist[30‐32] was administered to measure nutrition behaviors and physical activity patterns at home of both parent and child. It also evaluates parental role modeling of healthy lifestyle practices. The parent serves as a reporter for a child’s lifestyle (physical activity, sleep duration, television viewing, and presence of a television in the child’s bedroom) and eating behaviors.

Child nutritional behaviors are assessed with two measures. Healthy Kids Checklist[30‐32], which includes 8 determinants: fat, fiber, fruit/vegetable intake, calcium/dairy intake, sweetened beverages, eating in restaurants, breakfast skipping, energy density. This measured (by parent proxy) child nutritional behaviors at home and the Food Frequency Questionnaire (FFQ) [33] measures nutritional behaviors at school. The FFQ has been adapted from the Willett Semiquantitative Food Frequency Questionnaire [34] to measure monthly changes in food items served to the children by the childcare centers. Additionally, center directors provided a copy of the invoice of food ordered for the month accompanying the questionnaire.

The following two instruments assessed adult nutritional behaviors; (1) the Food Behavior Checklist[30] is a short, culturally neutral, valid and reliable indicator of fruit and vegetable consumption. The 16-item checklist includes 7 fruit/vegetable, 2 milk/dairy, 1 food security, 3 diet quality and 3 fat/cholesterol items. Convergent validity was reported for 10 selected nutrients and the Healthy Eating Index for the 16-item tool [30, 31]; and (2) the Fruit and Vegetable Inventory[32], an instrument that contains 13 psychosocial items shown to be related to fruit and vegetable intake. The six constructs are perceived control, self-efficacy for eating healthier, readiness to eat more fruit, readiness to eat more vegetables, and perceived diet quality.

Adult health literacy is measured using the Pediatric Health Literacy Activities Test[35] a 10-item instrument validated in English and Spanish among caregivers of young children. It correlates well with lengthier measures of literacy and numeracy. It includes items related to growth and nutrition (e.g., infant formula mixing, nutrition labels), as well as general health items.

A modified (only the 4 items relating to physical activity were administered) version of the CATCH Physical Activity Self Efficacy Questionnaire[36] measures parent’s self-efficacy to be physically active.

Baseline characteristics for children, parents and childcare providers were collected and included infant feeding history (breastfeeding exclusivity and duration, onset of solid foods, age of weaning from bottle), and parent perception of child weight status, acculturation level, and level of food insecurity in the household.

Time spent in daily physical activity, classroom schedules and lesson plans, and foods and drinks (items, amounts) and monthly behavior observations are recorded by study staff for each classroom.

To track the amount of dinners parents attend, activities parents complete, and number of newsletters that are received/read, parents are given an annual survey that includes a satisfaction component inviting parents to give feedback and to rate the helpfulness of each activity.

Process data is collected to determine the feasibility of implementing HC2 on a larger scale and to determine the sustainability of the project. The CS complete a weekly process worksheet for each center by interviewing teachers. This information will help answer the larger feasibility questions of: 1) What are the range of common and uncommon barriers to implementing an intervention like HC2? 2) What is the range of creative solutions to overcoming these barriers? 3) What are the unique assets of child-care centers that enable them to adapt such an intervention? 4) What key community assets may be necessary to bring an intervention like HC2 “to scale” across the entire county?

Our univariate analysis consists of simple descriptive measures such as percentages, medians, ranges, variances, and standard deviations to describe all study participants and sites. Bivariate analysis is used to explore possible confounding variables such as age, gender and ethnicity via simple contingency table analysis and ANOVA. Pearson product moment correlation coefficient matrixes investigate the relationships (either positive or negative) in the percent change in BMI and all predictor variables. We pool data within-cells to account for our randomized group study design that essentially blocks at the center level (PROC DISCRIM procedure in the SAS statistical package). Multivariate . Repeated measures linear regression models are used to determine patterns of progression or improvement in BMI percentile over time, as well as to identify demographic and family characteristics associated with BMI outcomes. Repeated measures analysis of covariance (ANCOVA) determines the relationships between BMI and our environmental and family modification (via the theoretical constructs) covariates. ANCOVA is used to increase power in a one-way or two-way ANOVA by adding a second or third variable as a covariate. ANCOVA was an attractive higher level method of analysis for our design because it is capable of removing the obscuring effects of pre-existing individual differences among subjects while also allowing for compensation for systematic biases among our samples. Cost Analysis. Resource use and cost data for the intervention are being collected across all intervention centers. Key statistics from the cost evaluation will include total annual economic cost for the intervention and weekly economic cost per child.