Development of a Diet Quality Index for Preschool Children and Its Application in Examining Dietary Trends in the United States

Year: 2002

Research Center: Department of Nutrition at the University of California, Davis

Investigator: Kranz, Sibylle, and Anna Maria Siega-Riz

Institution: Pennsylvania State University

Project Contact:
Sibylle Kranz, Assistant Professor
The Pennsylvania State University
Department of Nutritional Sciences
252 Henderson South Building
University Park, PA 16802
Phone: 814-865-2138


The prevalence of childhood obesity has increased significantly in the past three decades. Obesity carries a number of negative medical consequences, including cardiovascular problems and diabetes. In addition, the dietary intake behavior of adults is strongly associated with their dietary intake behavior as children. The authors designed a tool to assess total diet quality in American preschoolers: the children’s diet quality index (C-DQI). The C-DQI can be used to measure the effectiveness of child nutrition programs in improving overall diet quality in children and to help target child nutrition programs to population groups at greatest risk of poor diet quality.

The authors used dietary and sociodemographic data for over 5,000 children ages 2-5 from the 1994-96 and 1998 Continuing Survey of Food Intake in Individuals (CSFII). They designed the index using information on common nutritional problems in the preschool population and dietary intake recommendations by such organizations as the American Academy of Pediatrics, American Dietetic Association, and the National Academy of Sciences. The authors selected eight components of the index that incorporate information on the recommended consumption levels of added sugar, total fat, saturated fat, fruit, vegetables, grains, fruit juice, and iron.

The study found that the C-DQI values range from 16 to 70 points within the population, with an average of 46 out of 70 points. The authors tested the index’s ability to distinguish between different levels of diet quality and found that better diet quality (a more healthful diet) within each of the components of the index is significantly associated with a higher overall C-DQI score. The analysis indicates that overall diet quality is better for boys than for girls and for children living in metropolitan areas than for those living in nonmetropolitan areas. Diet quality in low-income households is better for Hispanic children than for non-Hispanic Black or White children and for children who attend day care or preschool than for children who do not attend. Average diet quality declines as children get older.

The authors also examined the trend in children’s diet quality over time by comparing C-DQI total and component scores among respondents to the National Food Consumption Survey 1977-79, the CSFII 1989-91, and the CSFII 1994-96, 1998. They found that overall diet quality improved somewhat during the study period, but that an increase in consumption of added sugar, excess juice, and excess dairy and a decrease in iron consumption caused declines in some components of diet quality. Fat consumption, as measured in grams per day, remained stable between 1977 and the mid- to late 1990s, while fat consumption as a percentage of total calories dropped 4 percent. The average number of fruit servings consumed almost doubled between the early 1990s and the mid- to late 1990s, with most of the rise attributable to an increase in fruit juice consumption. The authors noted that the intake of fat and saturated fat has not decreased since 1977, despite public health messages about the importance of reducing fat consumption.

The study results indicate that children’s diet quality is influenced by sociodemographic characteristics of children and their families. Thus, public health messages could be targeted specifically to population groups at greatest risk for poor diet quality. Federal programs designed to enhance children’s diet quality, such as the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) and Head Start, target children at high risk for poor diet quality. The C-DQI could be used to measure the impact of Federal programs, such as WIC, on overall diet quality and on the level of diet quality in the individual components of the index. Using the C-DQI as an outcome measure could help to inform policymakers in the design and implementation of nutrition programs that will most effectively improve children’s overall diet quality.