Childhood obesity's relationship to time spent in sedentary behavior

Military Medicine, Jul 2003 by Arluk, Shaye L, Branch, J David, Swain, David P, Dowling, Elizabeth A

Objective: The purpose of this study was to evaluate various types of sedentary behavior children participate in and to look for an association to childhood obesity. Methods: Questionnaires were used to gather data on physical and sedentary activity, dietary intake, demographics, and anthropometrics of 9- to 12-year-old military dependents and their parents. Results: Using body mass index (BMI), 39.8% of children were obese. A significant relationship was found between childhood obesity and computer usage, television watching, total hours in sedentary behavior, and maternal BMI. An indirect significant relationship with childhood obesity was also shown if a parent was home when the child got home from school and if a father participated in exercise with their child. Caloric intake, total time in physical activity, demographic variables, and father's BMI showed no significant relationship with children's BMI. Conclusion: Interventions should be designed targeting total time spent on the computer, total time watching television, and maternal obesity in child obesity programs.

Introduction

According to the 1999 National Health and Nutrition Examination Survey, approximately 13% of children age 6 to 11 years old and 14% of children age 12 to 19 years old are overweight (body mass index [BMI] values greater than the 95th percentile).1 The prevalence of overweight children has more than doubled since the first nutrition examination survey, which was conducted over 30 years ago. Numerous studies have investigated the detrimental effects of childhood obesity as well as other factors associated with childhood obesity such as heredity, dietary intake, exercise fitness level, and social environment.2-8 The role of physical inactivity in childhood obesity has received specific attention with television viewing time9,10 and decreased physical fitness level11 reported to be strongly correlated with childhood obesity.

Although research has investigated the association between television viewing time and childhood obesity, the inactive time of Americans today can be related to more than just time spent in front of the television. With the boom of the technology age, it has been observed that American adults' sedentary time has increased dramatically. Has technology done the same to our children? Children today have many activities they participate in that require little energy expenditure. Computers, the Internet, real-life video games, and chat lines are all media that could also contribute to the rise in childhood obesity over the last 20 years. The effect of total time spent in sedentary activity on childhood obesity has been sparsely covered in the literature. The children of U.S. Navy personnel are a seldom-studied population for which there is a high prevalence of childhood obesity as observed by dietitians and pediatricians in the outpatient clinics. Therefore, the purpose of the present study was to examine the relationship between sedentary behaviors and childhood obesity in U.S. Navy dependents.

Methods

Sample

A cross-sectional convenience sample of 101 children, ages 9 to 12 years, from Navy families in the Hampton Roads, Virginia area were used for this study. Children received survey packets with three questionnaires when they checked into the pediatric clinics at the Naval Medical Center Portsmouth and Boone Pediatric Clinic in September 2000. Five hundred surveys were made available to the clinics, resulting in a return rate of 20.2%. However, later questioning of the house staff revealed 150 surveys were never handed out, changing the response rate to 29%. Inclusion criteria were subjects who completed all three questionnaires and had no documented endocrine or metabolic disorder that could precipitate obesity. Before beginning the research, permission was obtained from the Human Subject/Institutional Review Board at Old Dominion University as well as the Internal Review Board at the Naval Medical Center Portsmouth. The cover letter to the survey packet stated that parent and child consent to use the information was acknowledged by return of the surveys to the clinics.

Measures

Every day for 1 month, parents of children attending the Pediatric or Nutrition Clinic at the Naval Medical Center Portsmouth or Boone Clinic in Virginia Beach were handed a survey package upon check-in. The children's survey was a 17-item questionnaire, designed from a previous validated instrument,12 entitled Adolescent Lifestyle Questionnaire. The questionnaire determined factors related to time spent in vigorous and moderate level activity as well as time spent in sedentary activity. In addition, the last seven questions of the questionnaire included a modified 24-hour recall. Also included in the survey packet was a weekly food frequency questionnaire with standardized instructions for completion. A parent questionnaire was also included for the parent or legal guardian who spends the most time with the child to complete. The parent survey was used to verify the children's results on dietary intake and exercise as well as to obtain familial adiposity patterns.