Data for this study are from the third wave (2005–2008) of the ADA study which was specifically designed to assess the associations of asthma and asthma care with child and parental psychiatric disorders among Puerto Rican children 4 to 17 years of age.23,24
We were however, able to collect some limited information on obesity and physical activity in this third wave. Wave one and two did not include these questions; thus, the analyses presented here involve cross-sectional data from wave three. Wave one was conducted from 1999–2000, and wave two was a one-year follow-up from 2000–2001. Details regarding the sampling design and procedures have been previously described for wave one and two.23,24
Therefore, the sample and measures are described briefly, with particular focus paid to describing wave three of the study, which has not been previously reported.
Youth between the ages of 4 and 17 years living on the island of Puerto Rico comprised an island-wide household probability sample stratified by four dimensions: urban versus rural areas, Puerto Rico’s health reform areas, child’s age, and gender. A total of 2,102 children from the community were deemed eligible. At wave one, 1,886 children and their caregivers were interviewed for a response rate of 90.1%. A total of 1,789 caregiver-youth dyads from wave one were interviewed at wave two, for a 94.9% retention rate at one-year follow-up.
For wave three, we used direct mail to recruit participants from wave two. The goal for the ADA study was to obtain a representative community sample including youth and young adults stratified into four groups (asthma and anxiety/depression; asthma no anxiety/depression; anxiety/depression no asthma; neither asthma nor anxiety/depression). Using simple random selection, 825 households were contacted, from which 656 youth and young adults, 10 to 25 years old, were interviewed for a response rate of 79.5%. Because the current study focuses only on youth and not young adults (because some of the youth in wave 1 were young adults by wave three), we included caregiver-youth dyads with male and female youth between 10 and 19 years old (n=436) at the time of wave three data collection.23,24
Blinded interviewers conducted interviews in the families’ homes and different interviewers were used for the youth/young adult and caregiver interviews. The adult informant was the participant’s biological mother for ~89% of the interviews. All interviews were audiotaped, and 15% were randomly reviewed for quality control. The study protocol was approved by the institutional review boards (IRBs) of the University of Puerto Rico, Medical Sciences Campus and the University of California Los Angeles. Caregiver consent and child assent were obtained for youth under the age of eighteen years. Consent was obtained for participants eighteen years and older. In order for a youth/young adult to participate, caregivers were also required to participate in the study to provide information about themselves and their progeny.
The survey collected demographic information, BMI, and physical activity level, among other measures.23,24,27–29
Parent-reported demographic variables included parental education, marital status, work status, household income, household composition, perception of poverty, and child’s age and sex.31
BMI was based on child height and weight information obtained from parental report for youth below age 17 years. Youth 17 to 19 years old provided information on their own weight and height. For youth under the age of 20, the 85th
percentile for age- and gender-specific BMI levels using CDC growth chart norms was used as the cutpoint for child classification as overweight and the 95th
percentile for classification as obese.27
All youth weight below the 85th
percentile was termed, “desirable weight.” Weight status was interpreted for caregivers (≥ 20 years) using CDC-defined standard weight status categories (i.e., desirable weight, overweight, obese).27,28
We used a measure of youth compliance to the federal recommendation of at least 60 minutes of MVPA daily.18
A two-item PACE+ Adolescent Physical Activity Measure assessed the number of days youth had accumulated at least 60 minutes of MVPA per day during the past seven days and for a typical week.29
Information regarding MVPA was obtained by parental report for children younger than 17 years old, while youth 17 to 19 years old provided their own information. We report a composite average of the two items, yielding a score of the number of days per week during which the youth accumulated 60 minutes of MVPA.29
Five or more days per week met the federal guideline for youth.29
Analyses were weighted to account for the complex sampling design, to correct for differential nonresponse, and to represent the general population of youth in Puerto Rico using 2008 U.S. Census data. The estimation of design weights used to make our sample representative of youth in Puerto Rico was accomplished in two stages. We estimated the subjects’ probability of selection during the third wave and made an additional adjustment for the response rate. The probability of selection took into account that for wave three we selected a different number of subjects from four strata of different sizes. The inverse of this final probability was used to estimate the initial design weights. The design weight estimated during this first stage made our sample representative of the youth population in Puerto Rico in the year 2000 using 2000 U.S. Census Data. In the second stage we made an additional adjustment to our design weights by post-stratifying the data to the population of youth in Puerto Rico as documented in 2008 U.S. Census data. The results were estimated with SUDAAN 10 software to adjust standard errors for multistage sampling, with youth-caretaker dyads nested within households and households nested within primary sampling units.30
Chi-square tests and logistic regression models were used to examine associations among youth overweight/obesity with physical activity, socioeconomic status (SES), parent marital status and parent body mass index (BMI).