Intrafamilial correlates of overweight and obesity

Nutrition Research Newsletter, Feb, 2005

The prevalence of childhood overweight and risk for overweight has reached epidemic proportions. Approximately 10% of annual health costs are due to overweight. Overweight in childhood is associated with increased risk and earlier onset for chronic diseases such as diabetes mellitus and cardiovascular diseases. Obesity has a profound negative affect on both the physiological and psychological health of children, adolescents, and adults, at great cost to society. Overweight is more prevalent in African American and Native American families than in whites. More national data on overweight in Native American and African-American children are needed. Television viewing contributes to overweight by replacing physical activity and increasing consumption of high-energy foods. Increased levels of physical activity in children not only promote lower body fat and may help prevent early development of chronic diseases, but also improve mental health.

Oklahoma's population is 7.8% African Americans and 7.8% Native Americans. More than 56% of Oklahoma adults had BMIs >25 in 2000. Native Americans had the highest rate of BMI >30, at 28%, followed by African Americans with a rate of 26%. High levels of cardiovascular disease and diabetes exist in Native American and African American ethnic groups, especially in Oklahoma. The objective of this study was to assess the prevalence of overweight in African American and Native American families and also to examine correlates of childhood obesity in families. Ethnic groups were compared because overweight and diabetes are more prevalent in Native Americans than in African Americans in Oklahoma.

A convenience sample of 84 three-generation families was recruited from 10 sites in rural Oklahoma. Families were recruited through community contacts at health, senior, community, and tribal centers. A questionnaire for data collection was administered to each subject. The questionnaire consisted of 32 questions on socioeconomic, health, diet, and physical activity information. The questionnaire included a 3-day, 24-hour food recall, a 1-month food frequency questionnaire, anthropometric measurements, and family contact information. Forty-four families were Native American and 40 were African American. A diverse sample was obtained with 11 of 44 Native American tribes in Oklahoma represented. Each family was given an $85-incentive after all data were collected. Triceps skinfold measurements were taken, and weight and body composition were measured. According to National Institutes of Health guidelines for adults, a BMI of > 25 or <30 was defined as overweight, while a BMI of 30 or above was defined as obese. According to National Institutes of Health guidelines for children, a BMI at or above the 85th and below the 95th percentile was defined as at risk for overweight, while a BMI at or above the 95th percentile was defined as overweight. Activity levels were self-reported and choices ranged from one (no regular exercise program) to six (more than 3 hr weekly or 30 min daily of vigorous physical activity). The subjects estimated daily television hours, and this value was multiplied by seven to obtain weekly hours to compare these data with current recommendations. Three days of 24-hour recalls were self-reported.

Mean percent body fat of Native American parents was significantly greater than that of African American parents. Mean percent body fat and waist circumference were significantly higher in Native American children than in African American children. Children reported higher activity levels than parents or grandparents but averaged only 10 min daily of activity, while watching 16 to 21 hours of television weekly. Diets were high in fat, but within acceptable ranges for carbohydrate and protein. African American subjects had significantly higher-fat diets than Native American subjects. In this sample, approximately 90% of all parents and grandparents were overweight or obese. Native American and African American adults in this sample appear to have much higher rates of overweight and obesity compared with white adults. In this sample, 42% of African American and 61% of Native American children were overweight or at risk for overweight. These findings demonstrate the extent of the overweight problem in Oklahoma.

The activity level for all subjects in this study is quite low. None met the US minimum recommendation of 30 min/ day for physical activity. Daily television watching hours were generally excessive for children: 90.9% of Native American and 95% of African American children reported watching 4 hr or more daily. Children, parents, and grandparents in both ethnic groups exhibited sedentary lifestyles. This study showed a significant correlation between children and parents for television hours, indicating the possibility of a causal relationship. A significant relationship also existed between child BMI z scores and grandparent television hours. Child television hours and activity level of parents and grandparents were significantly associated. These significant associations indicate that sedentary caretakers facilitate children watching more hours of television and being less active.

D Polley, M Spicer, A Knight, B Hartley. Intrafamilial correlates of overweight and obesity in African-American and Native-American grandparents, parents, and children in rural Oklahoma. JADA 105(2): 262-265 (February 2005) [Correspondence to: Diana C. Polley, PhD, RD, Postdoctoral Research Associate, Langston University, 1412 Woodbury Circle, Edmond, Oklahoma, 73034. Email: dcpolley@yahoo.com]