Longitudinal validity of the FNPA screening tool to predict changes in weight status in children
The increasing prevalence of overweight and obesity and the accompanying comorbidities among children and adolescents in recent decades is cause for public health concern. Many factors influence weight status and obesity risk, but little research has examined the influence of the home environment on weight status across different age groups, particularly in longitudinal designs. The Family Nutrition and Physical Activity (FNPA) screening tool is a validated measure of the home environment, but further testing of the tool is needed. The purposes of this dissertation were to 1) compare various versions of the FNPA to evaluate user perceptions and test reliability, 2) to determine the efficacy of the FNPA and influence of socio-demographic variables on weight status in children and adolescents and, 3) to examine the influences of home environment and economic factors on long-term growth trajectories among youth.
The first study provided support for the continued use of the subjective (Almost Never/Sometimes/Often/Almost Always) response scale based on superior test-retest reliability and inter-item reliability when compared to a proposed objective (days per week) response scale. Parent users provided feedback as to re-wording of many FNPA items. The second study evaluated the utility of this revised FNPA in 1st grade students and 10th grade students and showed that 1st grade children with FNPA scores in the lowest tertile were significantly more likely to be overweight/obese than 1st grade children with FNPA scores in the highest tertile. This relationship was not present in 10th grade students, although school-level socioeconomic status (SES) did influence weight in older youth. The third study demonstrated that parent weight status, race, family income, and school SES influence growth trajectories from 1st to 10th grade. A unique finding of this study was that change in FNPA score from 1st to 10th grade was a significant predictor of BMI percentile and BMI50, an alternative measure of weight status, in 10th grade.
This dissertation adds to the existing literature regarding factors that influence obesity risk during childhood and adolescence. The results provide further support for the continued use of the FNPA, utilizing the subjective response scale. Additionally, these studies highlight the influence parent weight status, race, family income, and school-level SES on weight status throughout childhood. Future research is needed to examine the FNPA in additional populations and to further examine the influence of these family- and community-level factors of obesity risk.