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Participants were recruited from three WIC programs in southern Michigan. WIC is a federally funded program that provides nutrition consultation and other services to low-income pregnant/breastfeeding women and young children (< 5 years).
Procedure
Every woman coming to the collaborating WIC clinics during the data collection dates (June-July, 2007) was personally invited by trained recruiters to provide demographic information via a self-administered questionnaire. Then, women were invited to be screened except those who were obviously pregnant or older than 34 years. The screening survey addressed inclusion and exclusion criteria. Our enrollment process aimed for equal numbers of participants in two racial groups (African American and white) and three body mass index (BMI) categories (25.0-29.9 kg/m2, 30-34.9 kg/m2, and 35.0-39.9 kg/m2).
Inclusion criteria
Non-pregnant African American and white women between 18 and 34 years old who understood and spoke English and had a measured BMI between 25.0 and 39.9 kg/m2 were eligible for this study. Additional inclusion criteria included having a youngest child between 6 weeks and 3.5 years of age enrolled in one of our three collaborating WIC programs, not planning to become pregnant or change WIC clinics during the study, providing accurate contact information, and agreeing to provide updates for contact information and pregnancy status, willingness to accept randomized participation assignments, agreeing to participate in the project for 1.5 years, and willingness to have blood glucose tested via finger stick. Exclusion criteria. Women with fasting blood glucose greater than 126 mg/dl or random (non-fasting) blood glucose greater than 200 mg/dl, self-reported type 1 or 2 diabetes or an eating disorder, or inability to walk more than one block without resting or shortness of breath were excluded. Eligible participants provided their individual telephone and address and a telephone number of one back-up contact (relative, friend, or neighbor). The study procedure was approved by the Institute of Review Board at Michigan State University. Consent forms included demographic data for randomization.
Recruitment Strategies
We enhanced recruitment by emphasizing confidentiality and enlisting positive support from WIC personnel at the collaborating program sites. During recruitment, a DVD was used to help potential participants become familiar with the MIM study's materials and protocol, including requirements and incentives. Recruiters were Asian or white students and University staff who were trained to be culturally sensitive, speak clearly, and listen respectfully. They explained the study's purpose, requirements, confidentiality, flexible scheduling, benefits of participation (e.g., no-cost prevention of weight gain with strategies to mange stress), and incentives. They also emphasized that P-MIM was a collaborative effort between WIC and Michigan State University.
Retention Strategies
During recruitment, we obtained two working phone numbers from each participant. Also, they were asked to provide the best time to reach for a 45-55 minute interview. Trained interviewers used a flexible schedule including nights/weekends, provided toll-free numbers for return calls, made repeated calls over a 4-week period if necessary to reach participants, and called the same assigned participants for interview throughout the project. A computerized tracking system kept confidential records of participants' responses and each attempted phone contact. We mailed easy-to-read reminders before and sent thank-you letters after each phone interview. The MIM logo, developed with input from WIC partners and the target audience, was used on all correspondence mailed materials for this study. To further maintain contact, we mailed birthday and holiday greeting cards to participants.
We provided a $5.00 incentive when participants contacted us via phone or a postcard with a change of address, phone number, or pregnancy status. We also provided incentives that reimbursed participants for their time and cell phone costs, e.g., $40 for completing a telephone interview and returning to the WIC clinic where they had been recruited to have their body weight measured. At the final data collection, a bonus incentive was provided: $10 for a completion of the final data collection and $20 if interviews were complete for all three time points of data collection.
Stratified Randomization
Following the baseline telephone interview, participants were randomly assigned to an intervention (diet, physical activity, stress management, usual WIC care, n = 64) or a control group (usual WIC care and an option of receiving IDVD at the end of the study, n = 65) equalized for racial representation and three BMI categories.
Intervention
This 10-week pilot intervention was developed following a community-based participatory research model. Its theory-based culturally sensitive educational messages were delivered via a series of five chapters in an IDVD (10-15 minutes/chapter) that were reinforced by five PSGTs (30 minutes/per session). The IDVD featured peers (overweight and obese WIC mothers) and the PSGTs were led by educators from three collaborating WIC programs in Michigan. The five chapter topics in the IDVD were stress management and avoiding eating foods for comfort, ways to be physically active with young children, grocery shopping and food label reading, meal planning, and food preparation. Each chapter included an interactive information presentation (1-2 minutes), culturally sensitive narratives (7-10 minutes), a section on setting personal goals (2-3 minutes), and three quiz questions (~20 seconds) to verify attention to the content.
A package of intervention materials with the MIM logo was sent via certified mail (signature required) to intervention participants' homes. The intervention package included one five-chapter IDVD, five weekly worksheets, five quizzes, five pamphlets, two postcards for reporting changes of address or phone number, and one postcard for pregnancy status notification.
Viewing IDVD at home
Intervention participants were asked to view a designated chapter in the IDVD every other week (10-15 minutes/chapter) for 10 weeks and to refrain from sharing the IDVD with other WIC mothers during the study. After viewing a designated chapter, they answered three quiz questions and wrote one or two short- and long-term goals on their weekly worksheets, and monitored their progress for seven days by circling whether their progress that day was 'not so great," "so so," or "great." Weekly worksheet and quiz questions were mailed to the study office.
PSGTs
Intervention participants were asked to call in to a scheduled PSGT the week after they viewed a designated chapter in the IDVD. A moderator and assistant moderator were on-line as participants called in to PSGTs. The moderator opened the group with an "ice-breaker" activity and introduced ground rules and specific subtopics that were consistent with contents presented in the previous week of IDVD at the beginning of each session. Participants were asked to share their personal goals, report problems with application, and encourage each other to make positive lifestyle behavioral changes. The moderator assisted in problem solving, identified barriers in behavior changes, and assessed participants' ability to apply learned cognitive skills to daily life. The assistant moderator took notes and kept track of who was online. The session closed with participants' reviews of lessons learned and possible new strategies for behavioral changes. The moderator also reminded participants of the following week's topics in the IDVD and procedures.
Usual WIC care
Regardless of her group assignment, each participant received WIC nutrition education for approximately 20 minutes every six months during the re-certification appointment for her young child(ren).
Measures
Survey data were collected by telephone interview and body weight was measured at collaborating WIC clinics at three time points: baseline, two-month post intervention (six-month follow up), and eight-month post intervention (one-year follow up).
Fat, fruit, and vegetable intake
The National Cancer Institute (NCI) 15-item Fat Screener and algorithm with established predictive validity was used to generate a fat intake score, with a higher score indicating a higher percent of calories from fat [15, 16]. The NCI fruit and vegetable Short Assessment Form and algorithm with established predictive validity (19 items) were used to generate a score, with a higher score indicating a higher fruit and vegetable intake [17, 18].
Physical activity
The Godin Leisure Time Exercise Questionnaire with established validity and reliability was used to measure moderate physical activity (6 items) [15]. Participants were asked how frequently and for how long they participated in moderate physical activity in the last seven days (i.e., walking, jogging, biking, aerobic exercise, dancing, and playing active activities with children). We multiplied METs (metabolic equivalent hours per week) for each activity [16] and summed six activities to a single score with a higher score indicating more physical activity.
Perceived stress
The Perceived Stress Scale (9 items) with established validity and reliability was used to measure stress. Responses to each item were rated on a 4-point scale ranging from 1 (rarely or never) to 5 (usually or always) [17]. Nine items were summed to create a score with a higher score indicating less stress.
Affect
The 18-item Positive Affect and Negative Affect Scale (PANAS) with established validity and reliability was used to measure affect, a prevalent and relevant outcome of stress [18, 19]. Participants responded to a list of words that describe different feelings and emotions, e.g., happy, interested, strong (positive affect), stress, upset, and guilty (negative affect). Responses to each item were rated on a 5-point scale ranging from 1 (very slightly or not at all) to 5 (extremely) [20]. Eleven negative affect items were summed to create a score with a higher score indicating experience of less negative affect. Similarly, seven positive affect items were summed to create a score with a higher score indicating stronger positive affect.
Depression
The Center for Epidemiologic Studies Depression Scale (CES-D) with established validity and reliability was used to measure depression (20 items). Responses to each item were rated on a 4-point scale ranging from 0 (rarely or none of the time) to 3 (most or all of the time) [21]. Twenty items were summed to create a score with a higher score indicating more depression.
Height and weight
Height without shoes was measured to the nearest 0.1 cm using a wall-mounted stadiometer. Weight was measured to the nearest 0.1 kg on an electronic scale with the participants wearing light clothing and no shoes. These two measurements were done at the collaborating WIC clinics. BMI was calculated from weight (kg)/height (m2). Baseline height and weight were measured by trained recruiters and follow up body weight was measured by trained WIC staff members.
Qualitative evaluation
Procedures were evaluated via recruiters' log notes, focus groups with P-MIM intervention participants, and focus groups with WIC personnel. Of the 28 intervention participants who had completed phone interviews (two-month post intervention) and were invited to attend focus group discussions, 12 participants attended one of three focus groups. In addition, five focus groups were conducted with a total of 25 WIC personnel. A trained moderator used a semi-structured interview guide to lead the group discussions. A trained research assistant audio-taped the proceedings and took notes. At the end of each focus group discussion, the moderator verified the data collected by summarizing main points from the discussion and asking participants if any key ideas were missed. The group discussion took place in collaborating County Health Department meeting rooms. Participants signed consent forms before participation and the procedure was approved by Michigan State University Institute of Review Board.
Data Analysis
Quantitative data analysis
Women who became pregnant (n = 5 at six-month follow up, n = 6 between six-month and one-year follow up) during the trial were excluded from analysis because of violation of inclusion criteria. T-test and Mann-Whitney tests were used to analyze continuous variables and chi-square was used for analysis of categorical variables. Forward stepwise multiple logistic regression was performed to identify predictors of early and late dropout and overall retention, all via NCSS software [22]. We defined dropouts as participants who did not complete either telephone interview or a body weight measure at one-year follow up. Qualitative data analysis. Common themes were identified from recruiters' log notes. Research assistants transcribed focus group audiotapes and incorporated the moderator's field notes. Two research assistants coded data independently to identify common themes with 96% inter-rater agreement.
