W1003: Parent and household influences on calcium intake among preadolescents

(Multistate Research Project)

Status: Inactive/Terminating

W1003: Parent and household influences on calcium intake among preadolescents

Duration: 10/01/2002 to 09/30/2008

Administrative Advisor(s):

NIFA Reps:

Statement of Issues and Justification

"Calcium crisis affects American youth" was the headline for a December 10, 2001, news release from the National Institute of Child Health and Human Development. Data from the USDA's Continuing Survey of Food Intakes by Individuals for 1994-96 and 1998 (CSFII 1994-96 and 1998) estimated the mean calcium intake of girls aged 6-11 years to be 865 mg per day, whereas girls aged 12-19 years were consuming an average of 773 mg per day [1]. These averages are well below the 1300 mg Adequate Intake (AI) level for calcium set by the Institute of Medicine for girls and boys 9 through 18 years [2]. Usually boys consume more calcium than girls, however the average intakes for boys documented by the CSFII 1994-96 and 1998 surveys were 984 mg among 6-11 year olds and 1,145 among 12-19 year olds both well below the AI [1]. One of the major lines of evidence to establish the AI in this age group was calcium retention to meet peak bone mineral accretion. Obtaining sufficient calcium during adolescence helps ensure adequate mineralization of the skeleton to ensure bone health later in life. Research has suggested that peak bone density can occur as early as age 16 for the hip and the early mid-twenties for other bones [3]. Thus, during this time of maximum bone accretion, the youth of America are not consuming sufficient calcium to reach peak bone mass - potentially leaving themselves vulnerable to osteoporosis later in life. Osteoporosis has been described as a "pediatric disease that manifests itself in old age" [4]. Maintaining a high peak bone mass has been shown to not only prevent fracture in the postmenopausal years, but also during adolescence [5]. Adolescents are physiologically able to absorb and retain more calcium than children and young adults [6]. However, the extent to which this ability can be used to an adolescent's advantage is dependent on the level of calcium intake. Osteoporosis is the most readily identifiable health issue associated with inadequate calcium intake. Osteoporosis is responsible for more than 1.5 million fractures annually [7]. The health care costs associated with osteoporosis are significant and estimated at $13.8 billion per year for osteoporotic-related fractures alone. One in three women and one in eight men aged 50 years and older will experience an osteoporotic-related fracture in their lifetime [8]. An average of 24% of hip fracture patients aged 50 years and older die in the year following fracture and hip fracture is more likely than heart attack, stroke, and/or cancer to lead to functional impairment [9]. Osteoporosis is a major public health problem [10] that affects every gender, race and economic group though white females are at highest risk [11-13]. The National Osteoporosis Risk Assessment [14], a longitudinal observational study of 200,160 ambulatory postmenopausal women aged 50 years or older, found that Asian or Hispanic heritage was associated with a significantly increased likelihood of osteoporosis. On the other hand, African American heritage significantly decreased the likelihood. In addition to osteoporosis, research suggests there may be other negative health consequences associated with an inadequate calcium intake. Davies, et al. suggest that maintaining a high calcium intake while dieting (contrary to popular dieting notions) may help an individual lose or control their weight [15]. Research has also noted a relationship between calcium intake and blood pressure in adolescents. A study of 180 Hispanic and African American teenagers (14-16 years of age) whose diets were low in calcium, potassium, magnesium and several vitamins had higher blood pressure than those with more adequate diets. The comparison is made between the diets of these teens and the DASH trial that has highlighted the value of dairy products in controlling high blood pressure (dairy products provide calcium, magnesium, and potassium) [16]. Calcium intake depends, in large part, upon an intake of dairy foods and hence the Food Guide Pyramid [17] recommends that older children and teenagers, consume 3 servings/day from the milk, yogurt and cheese food group. However, data from the CSFII 1996 indicate that for the age group 12-19 the average number of dairy servings consumed by males was 1.7, and 1.6 for females [18]. This is approximately 50% of the recommendation. From a survey of 4,746 children aged 11-18 years [19], only 29.5% of the girls and 42.5% of the boys met the recommended intake for calcium (Healthy People 2010 target=75%). No socioeconomic (SES) group met the 2010 target, however there was a significant test for trend (p=.001) ranging from 37.6% among the high SES group to 22.3% among the low SES group. Data from the third National Health and Nutrition Examination Survey (NHANES III) support the observations that calcium intake is less than desirable [20]. NHANES III data used complete and reliable 24 hour recalls for 29,105 persons aged 2 months and older and estimated calcium intakes among two minority groups: non-Hispanic Blacks (n=8,391) and Mexican Americans (n=8,419), as well as non-Hispanic whites (n=10,533). Data indicate that for all age groups, including adolescence, males consumed higher amounts of calcium than their female age counterparts. In males, calcium intake peaked at adolescence and then declined in early adulthood. For females, the calcium intake peaked during childhood and began to decline in adolescence. For females, the average daily intake fell below the AI recommendation in all three ethnic groups beginning at the adolescent period [20]. Unfortunately, data from the NHANES III were considered "statistically unreliable" for Asians due to small sample size. This pattern of low calcium intake persists even though the National Dairy Council has, over the past decade, mounted a vigorous, aggressive media campaign to increase calcium intake. Multiple and diverse factors are working against achievement of adequate calcium nutrition in preadolescents and adolescents. It has been suggested that some of these factors include (1) displacement of milk as a fluid with soda, juices and sports drinks [21-23]; (2) the perception, particularly among females that milk and/or dairy products are fattening and therefore intake is restricted or eliminated; (3) milk intolerance; and (4) psychosocial developmental changes. At the same time, it is clear that some factors are also working to ensure at least a minimal intake of calcium such as consumption of milk by other family members, parental expectations that milk will be consumed regularly, and availability of calcium-rich foods in the home [24]. Familial factors play an important role in the calcium intake of youth [25], thus a clearer understanding of parental factors such as knowledge, attitudes, behaviors, and environment and their influence on calcium intake of preadolescents is needed. This project will examine these factors and how they relate to the child's intake of calcium-rich foods, knowledge, attitudes, and behaviors. A clearer understanding of familial factors and how they influence preadolescent calcium intake will enable intervention strategies to be more effective. Additionally little information is available on the role of dietary supplements and fortified foods, which are new to the food supply, and the contribution of these items to the calcium intake of children and adolescents. This project will examine these factors with special attention paid to gender and with a focus on the ethnic groups at highest risk for osteoporosis (Asians, Hispanics, and whites). Evidence suggests that dietary behavior is established in childhood [26,27]. Food habits and physical activity habits formed early in life have the potential to continue throughout adulthood [26,28]. The Child and Adolescent Trial for Cardiovascular Health (CATCH) demonstrated maintenance of health behaviors following a school-level intervention [29]. This cardiovascular program, targeting eating behaviors, physical activity, and smoking was introduced in the third grade and continued through the fifth grade, and then conducted a three-year follow-up. Students in the intervention schools had significantly lower total fat, saturated fat, and sodium intakes compared to students in the control schools three years following the program [29]. These results indicate that health behaviors that are initiated at a young age can be maintained through adolescence and young adulthood and possibly provide a protective effect later in life. There is no evidence to suggest that dietary behaviors related to calcium would differ from those related to dietary fat and sodium. Thus, research indicates that intervention at younger ages is effective. Building on information obtained from preadolescents and adolescents in the W191 Multistate Research Project (W191 project), this new proposal will focus on parental and household factors and their influence on calcium intake of preadolescent children (11-12 years old). This age group was selected to provide information helpful in preventing the decline in calcium consumption observed after this age. While information about influences on calcium intake has been gathered from children, parental viewpoints have not been examined. Factors to be addressed in this new proposal include availability of calcium-rich foods in the home, parental consumption of calcium-rich foods at home and away from home, actual or perceived lactose intolerance, belief that dairy products contribute to excess body weight, the presence of hectic day-to-day schedules, food preferences and dislikes, parental expectations regarding calcium-rich food consumption, parental knowledge regarding calcium needs of their child and what foods in what quantities meet calcium needs, attitudes toward use of supplements and calcium-rich foods, parenting skills, and the family eating environment. Industry has expressed concern about the lack of information about consumption of calcium supplements and calcium fortified food products. A consortium that includes organizations both within the federal research community (NIH, USDA, the Food and Drug Administration, and the Centers for Disease Control and Prevention) and outside it identified that the use of dietary supplements in children (infancy through adolescence) is increasing [30]. However, little is known about supplements for use by children. Further, this group noted that more information was needed concerning "Knowledge and attitudes of caregivers/parents and how they are developed need to be evaluated to determine the impact of such environmental factors on dietary supplement use by children". This proposal will address these concerns of stakeholders. A promising intervention program to improve calcium intake in preadolescents is currently being launched using the information gained from the W191 project with funding from the Initiative for Future Agriculture and Food Systems (IFAFS) of the USDA [31]. The intervention program is being directed to children through their schools and youth organization activities. The IFAFS research team wanted to include a family or parent component in the intervention plan, however due to the lack of information concerning the parents' perspective regarding their role in the calcium intake of their children, the research team did not include such a plan. This current proposal intends to fill this gap concerning parents, thus allowing intervention programs to achieve even better success. The W191 project and IFAFS project are multistate projects. The three ethnic groups most at risk for osteoporosis are accessible in participating states. In addition, multiple sites allow results to be generalized to the American population representing these ethnic groups. In summary, national data indicate that the average calcium intake among adolescents is less than desirable during a period when the greatest amount of bone accumulation is occurring. Although some programs have been initiated to redirect the trend in calcium intake, interventions that involve parents would likely enhance the outcomes of these newly developed programs. According to the Healthy People 2010 Objectives Report, 46% of persons age two years and older were at or above the calcium recommendations at baseline measurement and the target for 2010 is 75%. Therefore, the goal of this proposal will help improve the chances of our nation reaching the national objectives regarding calcium intake.

Related, Current and Previous Work

Barriers to Adequate Calcium Intake: One factor that has been identified as reducing milk consumption is an increase in soft drink consumption [21,23,32]. Among 4,070 children ages 2-5, 6-11, and 12-17 participating in the CSFII 1994-96, intake of milk as a beverage was lowest among 12-17 year olds [23]. In contrast, the proportion of children consuming carbonated soft drinks increased significantly across the age strata. Carbonated soft drink consumption was significantly negatively correlated with both milk and juice consumption in all age groups. The researchers concluded that each ounce of carbonated soda consumed decreased the likelihood of achieving the recommended calcium intakes by 3% to 5% depending on the age group [23]. The reports published to date on soft drink consumption using national surveys include little information about Asian or Hispanic children. Data from the recent W191 project included 2 days of 24 hour recalls from 167 Asian, Hispanic, and white youth between 10 and 18 years old from 5 Western states. A significantly larger proportion of Hispanic children (67%) consumed 1 or more 12-ounce cans of soda per day compared to Asian children (29%) or white children (36%). In a multivariate model with calcium as the dependent variable, average milk consumption overwhelmed all other variables in predicting calcium intake. Female gender, Asian and Hispanic ethnicity, soda consumption, and water consumption were negatively associated with calcium consumption. This model confirms the importance of milk as a primary determinant of calcium intake for Asian, Hispanic, and white youth. Soda appears to displace milk among Hispanic children more than among Asian and white children. Dairy Products and Body Weight Concerns: Low intake of dairy foods was one of the major nutritional problems reported by 30,000 adolescents in the Minnesota Adolescent Health Survey (MAHS) [33,34]. Since dairy foods, especially fluid milk, represent a major food source of calcium, an inadequate intake of dairy foods can contribute to low calcium intake. The MAHS data also reported dieting and disordered eating among the female respondents, and to some extent among the male respondents. In addition, 31% and 58%, respectively, of the non-overweight boys and girls reported dissatisfaction with their current weight [33]. What the study did not indicate was whether or not weight dissatisfaction and dieting were contributing factors to low intakes of dairy foods, which would consequently serve as a barrier to adequate calcium intake. Some studies have suggested this may be the case [25,34-36]. However, the relationship between dieting and calcium intake is often reported only for female adolescents. Data are unavailable for males. In addition, consumption of diet soft drinks by preadolescents and adolescents may be a weight management strategy and also mediate inadequate calcium intake. Among the children completing 24-hour recalls in the W191 project, water consumption was significantly negatively associated with calcium intake; suggesting that energy-free beverages may be interfering with adequate calcium intakes. These are questions that need to be examined so that intervention messages for weight control and improved calcium intake do not become confusing to the public. Food at Home and Away From Home: From 1990-1995, the calcium density of food consumed by Americans declined. A contributing factor is the increase in the proportion of food eaten away from home. In 1977, 16% of all meals were eaten away from home compared to 27% in 1995. In addition, the amount of energy from foods eaten away from home almost doubled between 1977 and 1995, increasing from 18% to 34%. The nutrient density of calcium in foods consumed at home is estimated to be 425 mg per 1,000 kilocalories compared to 343 mg in foods consumed away from home [37]. The calcium density in weight (mg of calcium/100 g food) was significantly higher among white children completing 24-hour recalls in the W191 project compared to the Asian and Hispanic children. There were no significant differences between the groups in total energy consumption. A common food pattern among preadolescents and adolescents that may detract from adequate calcium intake is the popularity of fast foods. Fast foods can include foods from vending machines, self-service restaurants, convenience stores, and franchised food restaurants. It has been reported that adolescents eat approximately one-third of their meals away from home [38]. Preliminary data from 790 questionnaires collected in the W191 project indicated that about 47% of children between 11-18 years purchased food from school vending machines 1 to 4 times per week. Knowledge of Calcium Requirements: Inability to translate knowledge regarding the importance of calcium and bone health to specific dietary recommendations may also contribute to inadequate calcium intake. In detailed probe interviews with 75 well-educated white women (age range 25 to 50+), Terrio and Auld [39] found a surprisingly limited range of knowledge about osteoporosis. Most women had only superficial knowledge about steps they could take to reduce risk and only a third recognized the importance of calcium during growth or the amount of calcium needed daily. The lack of understanding about the importance of adequate calcium during childhood and adolescence, among this educated sample, suggests that women (mothers) may not be promoting a home environment that encourages adequate calcium intake for their children. Another study reported that while the majority of adolescents surveyed were familiar with the importance of calcium as a deterrent to osteoporosis, only 19% were aware of the recommended calcium intake, only 10% were aware of the calcium content of various dairy products, and only 45% knew about non-dairy sources of calcium [40]. This report helps to further illustrate that knowledge about the risk of low calcium intake, in and of itself, may be ineffective as a means of prompting increased intake. Focus group data from the W191 project confirmed that little was known about other food sources of calcium [24]. This is underscored by W-182 regional data that indicated adults are aware of recommendations but do not know how to operationalize recommendations [41]. One can only assume that this may be true for preadolescents and adolescents, too. Undoubtedly factors such as likes and dislikes, which were noted by participants in the W-182 regional survey data as the most important basis for food selection, play a role in such knowledge [42]. Supplements and Fortified Foods: According to the CSFII 1994, approximately one-third of the 423 adolescents (13-18 years) surveyed reported using supplements, with 16% using supplements on a daily basis [43]. Of the 143 adolescents who used supplements, only 14 used a calcium supplement. Females versus males, adolescents living in the West versus other US regions, and adolescents living in smaller households versus larger households were more likely to use supplements. Adolescents taking supplements had higher mean dietary intakes of all micronutrients, including calcium [43]. The proportion of supplement users from CSFII is slightly higher than the 24% of adolescent males and 28% of adolescent females participating in NHANES III [44]. Over the past decade there has been an increase in calcium-fortified foods and beverages. The wider availability of fortified foods and beverages and supplements may cause increased calcium intake, especially in those individuals with low intake of dairy foods. Various calcium supplements are touted in printed and televised media. However, many of these are aimed at older women. The extent to which these messages are internalized by youth is unknown. To what extent parents encourage consumption of calcium supplements and calcium fortified foods and how this influences their child's calcium intake is unknown. Family Influences: The family can exert a strong influence over the consumption of dairy foods and other calcium-rich foods through the development of food preferences, modeling, making calcium-rich foods available, and expectations for consumption of calcium-rich foods at meals. Skinner et al (presentation American Dietetic Association) reported a strong relationship between food preferences of toddlers and their parents that tracks until eight years of age. Fisher et al [45] recently reported that maternal beverage choices determine the extent to which soda consumption replaces milk in daughters' diets. Mothers who drank more milk also drank fewer soft drinks and had daughters with similar beverage consumption patterns. In another study, modeling of milk use by a significant adult was associated with improved calcium intake for both males and females [46]. On the other hand, the W191 project found that parents can discourage milk consumption by not drinking milk themselves [47]. Recent research has shown the impact of parental expectations on adolescent food choices. Adolescents are more likely to eat breakfast, for example, because "My mom makes me" [48]. During focus groups among girls 11-12 and 16-17 years old conducted as part of the W191 project, fathers were infrequently mentioned by girls as an influence on milk consumption either through their encouragement to drink milk or because the father drank milk themselves. However, among boys the same ages, the father was frequently mentioned as a key influence to consuming milk, especially among the white and Asian boys. Novotny et al. [47] as part of the W191 project reported that parents and grandparents influence calcium intake by requiring consumption of milk and preparation of calcium-rich foods. The statement, "My dad forces me to drink milk, because he wants me to be big and strong" typifies this. Availability is a significant factor influencing food habits of adolescents. Lack of availability of healthy foods can make following healthy eating recommendations difficult [48]. Additionally, family meals can promote the consumption of healthy foods [49-51]. According to recent studies of preadolescents and adolescents, approximately 31% had eaten at least one meal a day with their family over the past week, with the average being 4.7 times per week [49] and dinner consumption with families was lower among 14 year olds than 9 year olds [51]. Older children and adolescents who eat dinner with their family consume greater quantities of several key nutrients including calcium [51,52]. Adolescents believe they would eat more healthful foods if they ate more often with their families [48,49]. Furthermore, adolescents are more confident they will eat healthful foods when they eat dinner with their family than in other situations such as fast food restaurants, the mall, alone, or with friends [49,50]. The challenge of this project will be to further identify and understand preadolescent motivators and barriers to the improved calcium consumption from a multi-perspective of ethnicity and gender. Preliminary data from the W-191 project indicate that some of these factors include: taste; food association; what is available at home; and the influence of 'Mom', and to a certain extent, 'Dad'. Adult data from the W-182 regional project indicated that factors related to food intake and selection were cost of food and time to prepare food [42]. Thus, it is important to keep in mind that factors that affect the adults in the household will undoubtedly affect what is available for the children in the family. This project, while related to some current Agricultural Experiment Station research projects, does not duplicate projects previously or currently funded by state experiment stations. A CRIS search completed 11/19/01 resulted in 321 records with 42 having information potentially pertinent to the W191 project and this current proposal. However, all of the projects focused on younger children or adults, athletes, or animal models. Many projects relied on national survey data rather than collecting hypothesis specific data. The only project directly related to this proposal was the current IFAFS project, Improving Bone Health in Adolescence Through Targeted Behavioral Intervention [31]. This IFAFS project, mentioned earlier, evolved from data collected in the W191 project. The information collected in this proposal will be used to move the current IFAFS project to the next level. One of the goals of this current proposal is to complement the IFAFS proposal by providing new information regarding parent and family influences on calcium intake in preadolescents thus allowing the investigators to secure funding for future interventions directed to parents and families from IFAFS, NRI, or other appropriate federal funding sources. The USDA and CREES strategic plans will be complemented by this project. The USDA's strategic goal to "Promote health by providing access to safe, affordable and nutritious food" and the REE's objective to "To optimize the health of consumers by improving the quality of diets, the quality of food, and the number of food choices" align with this project's overall goal. Through promoting a partnership with researchers and extension staff, this project reflects two outputs from the REE: "To annually reduce health risk factors through non-formal educational programs to improve dietary habits and physical exercise practices in which CSREES partners and cooperators play an active research, education, or extension role", and "To annually increase consumer awareness, understanding, and information on dietary guidance and appropriate nutrition practices in which CSREES partners and cooperators play an active research, education, or extension role."


  1. Identify factors (knowledge, attitude, behavior, and environment) associated with total calcium intake among the parents of preadolescent children using qualitative methods.
  2. Identify parental factors (knowledge, attitudes, behavior, and environment) related to total calcium intake of their preadolescent children using qualitative methods.
  3. Quantify the salient parental and preadolescent factors (attitudes, knowledge, behaviors, and environment) that predict total calcium intake of the preadolescent using quantitative methods.
  4. Develop and test potential messages and dietary strategies among parents and preadolescents based on the salient factors related to preadolescent calcium intake.
  5. see W-191ObjectivesComment attachment


The proposed research project is an integrated project that involves agricultural experiment station researchers, and cooperative extension personnel. This provides an opportunity for cooperative extension personnel to be involved in the research project from its initiation, through data collection to the output. This plan will provide an opportunity for researchers to work closely with extension staff to ensure the applicability of the research to the programs that both researchers and extension staff are intending to impact. At the output phase, the research findings can be readily adapted to on-going extension education projects or, as with the previous project, they can be used to develop new extension programs and grant proposals. The proposed research is designed as a five-year project that will build on previous research and use both qualitative (open-ended interviews) and quantitative methodologies. The calcium motivator-barrier questionnaire for children and adolescents (MBQ-CA) and the calcium semi-quantitative food frequency questionnaire (FFQ) [53] developed and validated in the previous W-191 project will be used in this proposed project. New to this proposed project will be the development of a companion MBQ for the parents (MBQ-P) and an adaptation of a previously published supplement questionnaire to be completed by parents. Every state involved will contribute to each objective. This will allow the proposed project to reach the required sample size for each ethnic group and gender. For objectives 1 and 2, the study population will be composed of parents most responsible for food preparation of preadolescents (11-12 years) in the targeted macro ethnic groups. A convenience sample of parents will be recruited through ongoing engagement (extension) programs directed to youth, e.g., extension youth groups, faith-based groups, scouts, and after-school programs. Groups will be selected as being representative of a wide range of ethnic and socioeconomic groups. This representation will be possible, as each state will be involved with each objective. The "mixed" ethnic group category refers to individuals that identify themselves as being of multi-ethnicity, and at least part would be Asian or Hispanic. For objective 3, parent/child pairs (one preadolescent and parent, other children in household not included) will be recruited from the same venues, i.e., youth organizations, outlined above. For objective 4, the youth organizations assisting with the previous objectives will collectively participate in formative testing of nutrition communication strategies. See attached W-191-Table1. Phase I - Qualitative Data Collection (Objectives 1 and 2): Open-ended interviews are an effective research methodology to elicit qualitative data. This will allow the identification of parental knowledge, attitudes, and behaviors, and environmental factors affecting calcium intake, which is a unique feature of this project [54]. During the first year, one-on-one interviews will be conducted with a parent from each defined group (gender x ethnicity). This will provide a total sample of 180 participants with 20 per cell (Table 1). The number of parent interviews (each defined by gender and ethnicity of child) to be conducted by a given state will be reviewed and adjusted by the Technical Committee. The intent is to optimize the potential number of participants per cell and to distribute the work equitably among all participating stations. Qualitative techniques have been used in previous activities of the W191 project. However, to achieve standardization in the interviews between stations for this project, each interviewer will be trained in qualitative interviewer techniques and in the content format of the study protocol at a central location. Practice interviews will be conducted and monitored at each station. To enhance the responses of the interviewees and the quality of data, we will attempt to match the ethnicity between the interviewer and interviewee. Each interview will be conducted in a neutral location and audio-recorded. The tenets of the Social Learning (Cognitive) Theory [55,56] will be used to identify issues to be addressed in the interviews and structure the data analyses. Most of the influences on calcium intake noted above can be grouped into environmental factors (physical and social) and personal factors (expectations or expectancies). Interview discussions will explore such issues as: (a) availability of calcium-rich food and alternatives to these foods in the home; (b) modeling of calcium intake in and outside the home; (c) misconceptions, e.g., lactose intolerance and weight; (d) family expectations in and outside the home; (e) action-related behaviors related to calcium intake, e.g., regularly purchasing milk; (f) attitudes toward calcium supplements and fortified foods for the parent and the child; (g) parenting skills; and (i) the family eating environment. The interview audiotapes will be transcribed and reviewed for accuracy using the interviewer's notes prior to analyses. Reliability is generally established for interviews by establishing consistency between interviewers [54]. The information from these interviews will be used to guide the design and content of the MBQ-P that will be used in Phase II. This same approach was previously successful in developing the MBQ-CA. Prior to the open-ended interviews, the supplement questionnaires used by the NHANES III and CSFII will be adapted for use in this proposal to acquire information about preadolescents' use of calcium supplements and calcium-fortified foods from their parents. Immediately after the open-ended interview, the interviewee will be asked to complete the supplement/fortification questionnaire. Visual prompts of these dietary sources will be shown to the parent. If the parent notes that his/her child takes something not displayed, the parent will be given a self-addressed stamped envelope to complete the information at home and send it back. Phase II - Quantitative Data Collection - Parent and Child MBQ and Food Frequency Questionnaire (Objective 3): Based on analyses of data from the parent interviews, a parental questionnaire will be developed, tested, and validated to gather quantitative data on the salient factors related to calcium intake in parents and their preadolescents (MBQ-P) using methods developed in the W191 project. The MBQ-CA developed and validated for youth from the previous efforts of the W191 project will be used with the children. Fourteen scales and sub-scales associated with calcium intake are identified on the MBQ-CA. Examples include major scales such as taste, family influence, eating occasion, eating location, and health. Some sub-scales are weight concerns, food associations, and calcium availability at home. In addition, the calcium FFQ that was developed and calibrated from the efforts of the W191 project will be used to assess calcium intake in the parents and children. The FFQ was calibrated for preadolescents and adolescents from three ethnic groups (Asian, Hispanic, and white). Although the instrument was developed for youth, few instruments exist that measure exclusively calcium, thus limiting our choices of validated instruments for adults. In addition, the comparison of calcium intake between parent and child will be less biased if the same instrument is used for each pair. The FFQ may be amended based on the information concerning use of calcium supplements and fortified foods gathered from the supplement/ fortification questionnaire in Phase I. Sampling techniques, as utilized with the Phase I interviews, will be employed to provide ethnic and socioeconomic representation within a targeted 180 survey pairs per state. The number of parent/child pairs will be approximately 1600 total with 200 from each gender/ethnic group (See Table 1). The sample size per state is larger than the necessary sample size outlined in Table 1, thus allowing margin for error for incomplete questionnaires. Phase III - Formative Evaluation - Parent and Child Nutrition strategies (Objective 4): Based on the analyses of data from the parent interviews, and preliminary data from the MBQ-P and the MBQ-CA, key communication strategies will be developed [57] with the assistance of Extension personnel. Some of the potentially critical topics may be: 1) how do you tell someone how much calcium to eat?; 2) how to obtain adequate calcium on a limited budget?; 3) supplements versus food as calcium sources; 4) guidelines to avoid lactose intolerance; 5) substitution ideas for the replacement of non-calcium foods with calcium-containing foods; and 6) addressing misconceptions about the taste of calcium-rich foods. Formative evaluation of nutrition strategies and delivery methods will be in concert with extension personnel. This will allow extension personnel to be actively involved with program development while delivering programs to the community. Formative evaluation will test feasibility of implementation [57]. The formative evaluation will include assessment comprehension, relevance, desirability, and attractiveness. The goal of Phase III is to develop at least five credible and usable nutrition strategies that can become components of a larger intervention to improve calcium intakes among parents and preadolescents. To assemble a major, successful health communication program, the components need to be tested with audiences [57]. Each state will participate in testing at least one communication strategy during the course of data collection, thus allowing feedback from two states for each communication strategy. It may be necessary to divide the strategies based on availability of individuals to deliver the information in languages other than English. Since the intervention strategies will be delivered through the youth organizations involved in Phases I and II, the delivery channel is predetermined, i.e., youth organizations. However, the critical messages will determine audience segmentation, i.e., parents or parents and children together, or a combination of both. Once the audience segmentation has been determined, then the method of delivery and prototype material formats can be determined and tested. Some examples of different methods of delivery and materials include informational magnets, interactive sessions, or brochures. Data Analyses Phase I (Objectives 1 &2). All qualitative analyses will be systematic and verifiable. Interview transcriptions will be organized according to the ethnic/gender groups, to allow for easier interpretation of expected themes and issues, yet allow for the recognition of unexpected themes/issues. Analyses will follow a Grounded Theory approach to data reduction and integration [58]. Both a priori theme analysis (manifest content analysis) and emerging themes analysis (latent content analysis, constant comparative analysis) will be used to analyze the interview data. The first step of data reduction will be to identify salient themes, recurring ideas or language, and patterns of beliefs [59]. The second step of analysis will be to characterize each category's properties, comparable to Lincoln's and Guba's [60] content comparative method in which concepts or incidents (single piece of information that can stand alone) are compared with previous incidents in the same or different categories. A level of agreement between reviewers on categories and common themes equal to or greater than 75% will be used to establish reliability. This process will be repeated for each of the ethnic groups. Finally, there will be an integration of categories across the interviews to identify overall themes and relationships, which will be verified against the original data [58,60]. Phase II (Objective 3). The MBQ-P and the FFQ will be field-tested for reliability with a small sample of 100 subjects (25 from each of the 4 targeted ethnic groups) completing the questionnaire twice one week apart. A principal components analysis will be done to identify predetermined common scales such as those identified with the MBQ-CA. Reliability will be determined by test/retest correlations and paired t-tests between the scales versus individual questions in the MBQ-P and total calcium from the FFQ. These same techniques were used previously in developing the MBQ-CA in the W191 project. Half of the parents will complete 2 days of food records during the same week. Calibration of the FFQ for adults will be determined by correlations and paired t-tests between the 2nd FFQ and the mean calcium from the food records. Questionnaires from both the parent and child, i.e., the MBQ-P, the MBQ-CA and the FFQs, will be sent to one location for scanning, cleaning and checking for accuracy. The common scales identified in the parent field test will be verified prior to analysis. The child's calcium intake will be correlated to the parent's calcium intake using a Pearson's correlation coefficient. Multiple regression analysis will be used to predict the child's calcium intake from relevant scales identified using parent and child questionnaires. Interactions among parent and child scales will be tested when used in the same model. Univariate analysis of individual scales will be used to identify the most salient factors as being positively associated with the child's calcium intake or negatively associated with the child's intake in separate models. For example, a scale of 'parents' expectations' may positively influence a child's calcium intake; whereas an environmental factor, such as frequent dining outside of the home may negatively influence a child's calcium intake. Gender and ethnicity will be co-variates in each model. The Social Cognitive Theory would predict that at least one personal factor (taste, health motivation, knowledge) and at least one environmental factor (Social: peers, parent's expectations; Physical: availability, eating location) would simultaneously make a significant contribution to the behavior (intake of calcium). The models will be repeated with frequency of intake of calcium-rich foods as the dependent variable. Phase III (Objective 4). Field testing forms outlined in the Making Health Communication Programs Work [57] will be adapted for the formative evaluation. The testing forms include sample questions and responses with regard to comprehension, appeal (likes/dislikes), and review of main messages. The key issues to be addressed include: reaction to the message concepts, understanding of the message, ability to recall the message, acceptance of the message's importance, and agreement with the value of the message. When applicable, a pre- and post-test will be used to measure change in knowledge or behavior. Based on responses from the target audience, necessary changes to the nutrition strategy will be made. Some of the forms are developed for paper and pencil format and some are developed for interview format. Both will be used. In addition, the amount of time involved, number in attendance, and the ease of delivery will be measured. Finally, ways to promote the message, distribute materials, and track the progress of target audiences will be determined.

Measurement of Progress and Results


  • The qualitative and quantitative data that are collected through interviews and questionnaires will provide direction for strategies to improve calcium intake in preadolescents to prevent the observed decline in calcium intake that has been documented over the past decade, and from preadolescents to adolescents.

Outcomes or Projected Impacts

  • This project will provide important information about the influence of parents on calcium nutriture in a vulnerable population group - preadolescents. Insights will be gained on the degree to which parents can improve their child's intake of calcium. In addition, data on the potential positive effect of calcium fortified drinks and supplements on calcium intake will be collected. Data on calcium-fortified food use for this age group is non-existent and this project will fill an important knowledge gap.
  • Data obtained in this project will lend itself to future strategies aimed at improving calcium nutriture and consequently reducing osteoporosis risk for the three ethnic groups at greatest risk for osteoporosis: Asians, Hispanics, and whites. The information from mixed households will represent data not previously collected or reported. The involvement of extension personnel in this integrated project enhances the likelihood of the development and implementation of appropriate educational strategies that can be used nationwide.


(2002): see attached W-191chart

(2003): see attached W-191chart

(2004): see attached W-191chart

(2005): see attached W-191chart

(2006): see attached W-191chart

(0):ached W-191chart

Projected Participation

View Appendix E: Participation

Outreach Plan

This study will yield a tremendous amount of detailed quantitative and qualitative information related to consumption of calcium-rich foods. Two outputs from this proposed project are unknown at this time: 1) information about parents' influence on preadolescents' calcium intake, and 2) information about consumption of calcium-fortified food products and calcium supplements. Therefore, publications in peer-reviewed journals will be a natural extension of this project. The educational modules will be publicized in an educator venue, specifically to reach educators serving Asian, Hispanic, and white populations. As a result of extension staff actively involved in this proposal, the dissemination of the educational materials will be enhanced through the existing extension systems.


(a) In addition to the scientists identified as participants, the project will have a consulting statistician. (b) The participants will meet once a year. At that time, the following year's meeting time and place will be decided. (c) Officers: A chairperson and secretary will be elected at the first meeting. Each will serve a one-year term; new officers will be elected annually. Sub-committees will be formed as needed. (d) Publication of Data: The research project shall establish its policies and guidelines for use of data and dissemination of findings from this project at the first meeting. The W-191 research project scientists, most of whom are on this proposal, have established a publication protocol. For the W-191 project each station contributed equally to the project, therefore all members are listed on each publication. Sub-committees of two to four who actually write the manuscripts are listed first and the rest of the participants follow in alphabetical order. Tentative publication topics from this proposed research are tied to each of the working hypotheses already listed. In addition, it is envisioned that other relevant topics might emerge as the data analyses for each phase of the project are completed. (e) Human Subjects Review: After approval of the regional project, each state's project leader will initiate a contributing project at his/her station and will follow that institution's protocols for obtaining clearance for research involving human subjects.

Literature Cited

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