Associations Between the Milk Mothers Drink and the Milk Consumed by Their School-Aged Children

Family Economics and Nutrition Review, Wntr, 2001 by Rachel K. Johnson, Celeste V. Panely, Min Qi Wang

Evidence suggests that attainment of peak bone mass by early adulthood may be the most effective protection against osteoporotic fractures later in life (23). Throughout the developmental years, adequate calcium intake is essential to support bone growth (16). Substantial evidence exists linking higher calcium intakes with improved skeletal health in children (2,3,16,21,23,30). Data from the U.S. Department of Agriculture's (USDA) nationwide food consumption surveys reveal that most U.S. school-aged children have calcium intakes that are below recommended levels (4). Calcium intake is especially problematic for girls, with 59 percent ages 6-11 and 86 percent ages 12-18 not meeting recommendations (4).

Milk and dairy products are the primary source of calcium in children's diets (8). Johnson and colleagues found that in a large sample of school-aged children, on average, only those children who consumed milk at the noon meal met their daily requirement for calcium (15). Rising consumption of soft drinks has been shown to have a negative effect on calcium intake among children and adolescents by competing with milk as a preferred beverage (9). On the other hand, whole and 2% milk are leading sources of fat and saturated fat in the diets of U.S. children (33). USDA food consumption survey data indicate that for children in all age groups, mean total and saturated fat intakes exceed the recommended levels (4).

Because milk is an important contributor of both calcium and fat in the diets of children, it is important to identify the predictors of children's milk intake (both type and amount). The aim of this study was to identify predictors of U.S. school-aged children's milk intake. Familial aggregation studies show similarities in nutrient intake between parents (especially mothers) and their children (26). Hence, milk consumption patterns of mothers were included, along with sociodemographic variables, in the research model as possible predictors of children's milk intake.

Findings from this study will assist nutrition policymakers, school nutrition personnel, school administrators, nutrition educators, and parents in developing appropriate intervention strategies to address the problem of children's declining milk consumption.

Methods

Sample

The research sample was obtained from the 1994-95 USDA Continuing Survey of Food Intakes by Individuals (CSFII). The CSFII is a continuing component of the USDA Nationwide Food Consumption Survey. The surveys provide data on demographics as well as dietary intake for a nationally representative sample of noninstitutionalized persons residing in the United States. The 1994-95 survey included data on the food and nutrient intakes of 5,598 individuals. The response rate of the survey was 80 percent for Day 1 dietary intake data and 76 percent for Day 2 (4). These response rates are acceptable by research standards (7).

Trained interviewers used the multiple-pass 24-hour recall method to collect 2 days of dietary intake data from each respondent. The multiple-pass 24-hour recall method has been validated as an accurate measure of children's dietary intake (11). All children ages 5 to 17 years with 2 complete days of dietary intake data (N=1,303) and their mothers were included in this study.

Study Variables

The study investigated predictors of both the amount and type (skim, 1%, 2%, whole, or none) of milk consumed by U.S. school-aged children. The following sociodemographic variables were assessed as possible predictors: Child gender, age, and race; household income; geographic region; urbanization; and mother's age, education, and occupation. Participation in the USDA Food Stamp Program and participation in the USDA national school lunch and school breakfast programs were also included as possible predictors of a child's consumption of milk. Milk is required to be served in the national school lunch and school breakfast programs (5).

Mothers' milk consumption patterns (both type and amount) were included as potential predictors. A mother's nutrient intake has been shown to influence her child's nutrient intake (26). In addition, studies by Pelletier and colleagues indicated that among adult milk drinkers, consumption of lower fat versions of milk (1% and skim) was associated with increased average daily milk consumption (27). If the same is tree for children, promotion of 1% and skim milk in this population could have a positive influence on calcium intake.

The dependent variables in the analysis were "Child Milk Amount" and "Child Milk Type." Child Milk Amount was defined as the 2-day mean intake in grams of fluid milk consumed by the sample child. The 7,250 food codes in the CSFII database were searched, and all codes whose primary ingredient was fluid cows' milk were included. Items such as flavored milk, evaporated milk, dry reconstituted milk, eggnog, and milk shakes were included. However, items such as flavored drinks (e.g., Yoo-hoo[R]), canned meal replacements (e.g., Instant Breakfast[R]), and infant formulas were excluded.