Year of Award


Document Type


Degree Type

Master of Science (MS)

Degree Name

Health and Human Performance (Community Health Option)

Department or School/College

Department of Health and Human Performance

Committee Chair

Blakely Brown

Commitee Members

Laura Dybdal, Vernon Grant , Kari Jo Harris


childhood obesity, siblings, physical activity


University of Montana


Seventy percent of children who are obese will grow up to be an overweight or obese adult, increasing their risk for mental, physical and health conditions including heart disease, diabetes, and joint problems (CDC, 2012). The sibling relationship consists of four major domains: 1) warmth and affection, 2) hostility and conflict, 3) rivalry, and 4) relative status/power (Furman, Buhrmester, 1985). These domains may be associated with sibling levels of physical activity (PA) and risk for obesity. Very few studies have assessed how sibling relationships affect one another’s PA and how these variables are related to the risk of childhood obesity. Purpose: The purpose of this study was to assess associations between amounts of sibling PA, sibling relationship domains (affection, hostility, rivalry and relative power/status) and body mass index (BMI) in sibling dyads, age 8-12 years old. Methods: Sibling dyads between 8 to 12 years old responded to questions about their relationships with one another and their amount of PA. Height and weight measures were collected on each child. The parents/guardians of the siblings provided demographic information for their age, gender, income, race, education level, and number of people supported by their yearly income. Data Analysis: Statistical analyses generated participant descriptive data and mean scores for sibling relationship domains, levels of sibling PA and BMI z-scores. Multiple linear regression models determined 1) how well sibling relationship domain scores and sibling PA scores predict sibling BMI z-scores, and, 2) how well parent demographic variables predict sibling BMI z-scores. Results: Thirty-two sibling dyads completed the study (n=64). The BMI-for age percentile classifications showed 1% (n=1) of the siblings were underweight, 60.9% (n=39) were normal weight, 14.1% (n=9) were overweight, and 23.4% (n=15) were obese. The BMI z-score mean was 0.62. Younger sibling PA scores (r2=0.026, p=0.19) were not significantly associated with older sibling BMI z-scores. Younger sibling affection (r2=0.026, p=0.88), rivalry (r2=0.026, p=0.24), hostility (r2=0.026, p=0.39), or relative status/power (r2=0.026, p=0.19) scores were not associated with older sibling BMI z-scores. Older sibling PA scores (r2=0.026, p=0.34) were not significantly associated with younger sibling BMI z-scores. Older sibling affection (r2=0.026, p=0.96), rivalry (r2=0.026, p=0.11), hostility (r2=0.026, p=0.97) or relative status/power (r2=0.026, p=0.42) scores were not significantly associated with younger sibling BMI z-scores. Parent/guardian age (r2=-0.32, p=0.61), race (r2=-0.32, p=0.16), yearly income (r2=-0.32, p=0.89), or education level (r2=-0.32, p=0.74) were not significantly associated with child participants BMI z-scores. Discussion and Future Directions: Siblings play an important role in each other’s lives while growing up. While these relationships may impact their risk of obesity our study found that the amount of sibling PA, affection, rivalry, hostility or relative status/power were not significantly associated with the siblings BMI z-score. Although this study did not yield significant results connecting sibling PA and SRQ scores to BMI z-scores, this topic does stimulate interest in the connections between sibling relationships and risk of childhood obesity and may inform the design of future childhood obesity interventions that target siblings and their families.



© Copyright 2016 Samantha Dalton