The relationship between meal frequency and body mass index in black and white adolescent girls: more is less.

OBJECTIVE: To document meal frequency and its relationship to body mass index (BMI) in a longitudinal sample of black and white girls from ages 9-19 years. DESIGN: Ten-year longitudinal observational study. SUBJECTS: At baseline, 1209 Black girls (539 age nine years, 670 age 10 years) and 1,166 White girls (616 age nine years, 550 age 10 years) were enrolled in the National Heart, Lung and Blood Institute Growth and Health Study (NGHS). MEASUREMENTS: Three-day food diaries, measured height and weight and self-reported physical activity and television viewing were obtained at annual in-person visits. RESULTS: Over the course of the study, the percentage of girls eating 3+ meals on all 3 days was reduced by over half (15 vs 6%). Participants who ate 3+ meals on more days had lower BMI-for-age z-scores. Black girls, but not white girls, who ate 3+ meals on more days were less likely to meet criteria for overweight. CONCLUSION: Meal frequency was related to BMI and should be considered when developing guidelines to prevent childhood overweight.

The relative contributions of lean tissue mass and fat mass to bone density in young women.

Although obesity is associated with increased risk of many chronic diseases including cardiovascular disease, diabetes, hypertension, and cancer, there is little evidence to suggest that obesity increases risk of osteoporosis. In fact, both weight and body mass index (BMI) are positive predictors of bone mass in adults, suggesting that those who are overweight or obese may be at lower risk of osteoporosis. However, recent evidence suggests that in children and adolescents, obesity may be associated with lower rather than higher bone mass. To understand the relation of fat mass to bone mass, we examined data gathered from an ethnically diverse group of 921 young women, aged 20-25 years (317 African Americans, 154 Asians, 322 Caucasians, and 128 Latinas) to determine how fat mass (FM) as well as lean tissue mass (LTM) is associated with bone mass. Bone mass, FM, and LTM were measured using dual energy X-ray absorptiometry (GE Lunar Corp, Madison, WI). Bone mass was expressed as bone mineral density (BMD; g/cm2) and bone mineral apparent density (BMAD; g/cm3) for the spine and femoral neck, and as BMD and bone mineral content (BMC; g) for the whole body. Regression techniques were used to examine the following: (1) in separate equations, the associations of LTM and FM with each bone mass parameter; and (2) in the same equation, the independent contributions of LTM and FM to bone mass. LTM and FM were positively correlated with BMD at all skeletal sites. When the contributions of FM and LTM were examined simultaneously, both FM and LTM continued to be positively associated with bone mass parameters but the effect of FM was noted to be smaller than that of LTM. We conclude that in young women, LTM has a greater effect than fat mass on bone density per kg of tissue mass.

Exploring the relationship between timing of menarche and eating disorder symptoms in Black and White adolescent girls.

OBJECTIVE: This study examined the relationship between timing of sexual maturation and eating disorders symptoms in adolescent girls. METHOD: Data were collected over 10 years for a cohort of 1,213 Black girls and 1,166 White girls who were either 9 or 10 years old at study entry. Annually, girls' height and weight were measured and, biannually, girls completed self-report measures of eating disorders symptoms. RESULTS: Early-onset menarche is a risk factor for the development of body image and dieting concerns, but the effect of timing is due to the impact of early and late maturation on body weight. DISCUSSION: Findings underscore the importance of adiposity as a risk factor for poor mental health.

Ethnic issues in the epidemiology of childhood obesity.

Childhood obesity may be seen as a marker for high-risk dietary and physical inactivity practices. Recent increases in the prevalence of overweight and obesity among American children are not limited to one age, gender, or ethnic group, which suggests that unique behaviors of the members of various racial or ethnic subgroups of the population are unlikely to be the major contributing factors. Rather, it seems that environmental changes promoting increased energy intake and decreased energy output are occurring and have widespread impact on children from various backgrounds. Although no ethnic group is immune from the current shift in energy balance, differential rates of overweight seem to exist among ethnic groups. National probability samples of African-American, Hispanic, and white children in the United States provide clear evidence that white children are at lower risk for childhood overweight than are African-American or Hispanic children. Of concern is the lack of national data on the prevalence of overweight and obesity for Native-American and Asian-American groups. Also of concern is the aggregation of racial and ethnic subgroups, which may render prevalence rates meaningless. This possibility is clearly true with some surveys of weight status that combine diverse populations, such as Asians and Pacific Islanders, into one group. The high rates of obesity in African-American, Hispanic, and Native-American children are of concern. Although parental SES is associated inversely with childhood obesity among whites, higher SES does not seem to protect African-American and Hispanic children against obesity. In these groups, childhood obesity does not seem to be associated significantly with parental income and education. Health consequences of childhood obesity include a higher prevalence of type 2 diabetes and an increased risk for adverse levels of lipids, lipoproteins, and blood pressure. The effects of recently reported unprecedented levels of childhood overweight on subsequent risk for obesity in middle age are not known until future longitudinal data can be collected. It seems likely, however, that future health consequences of current early and severe childhood obesity will be staggering. Funding for adult follow-up of longitudinal studies of high-risk African American, Hispanic, and Native-American children is needed urgently to provide information on the long-term effects of childhood obesity. Halting the obesity epidemic is a formidable task, but the success in recent decades of drastically reducing childhood undernutrition offers hope and should spur similar action and leadership efforts. Promotion of efforts to reduce excess caloric intake with efforts to increase energy expenditure should receive paramount attention in the design of health programs. Given the relatively few published obesity-prevention and treatment studies that are designed to address specific cultural issues, it is important to promote the development of culturally appropriate intervention strategies that are shown to be effective among youth of diverse backgrounds. Although the dietary and activity goals will be similar, parental, family, and community messages and techniques grounded in cultural traditions and norms will be different for each ethnic group. This approach is crucial in the United States, a country with an increasingly diverse population.

Impact of timing of pubertal maturation on growth in black and white female adolescents: The National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVES: To evaluate the impact of early, mid-onset, and late maturation, as assessed by timing of menarche, on height, height velocity, weight, body mass index, and sum of skinfolds in a group of white and black girls. STUDY DESIGN: The Growth and Health Study recruited 9- and 10-year-old girls from Richmond, California, Cincinnati, Ohio, and Washington, DC. There were 616 white and 539 black participants recruited at age 9 and 550 white and 674 black participants recruited at age 10. Participants were seen annually for 10 visits. Longitudinal regression models were used to test for differences in each growth measure by timing of menarche across all ages and to determine whether these differences change with age. RESULTS: Mean age at menarche among white participants was 12.7 years, and among black participants, 12.0 years. According to race-specific 20th and 80th percentiles, early maturers were tallest at early ages and shortest after adult stature had been attained. Peak height velocity and post-menarche increment in stature were greatest in early maturers and least in late maturers. Weight was greatest in early and least in late maturers, as was body mass index. Sum of skinfolds was also greatest in early and least in late maturers. There was no impact of timing of maturation on two common measures of regional fat distribution. CONCLUSIONS: Girls who matured early were shorter in early adulthood, despite having greater peak height velocity and post-menarchal increment in height. Throughout puberty, early maturers had greater ponderosity and adiposity, although there was no association with regional distribution of fat.

Racial differences in the sums of skinfolds and percentage of body fat estimated from impedance in black and white girls, 9 to 19 years of age: the National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVES: This National Heart, Lung, and Blood Institute Growth and Health Study report assesses racial differences in fat patterning in black and white girls ages 9 to 19 years, comparing the sum of triceps and subscapular skinfolds (SSFs) and percentage of body fat (%BF) from impedance as two indices of adiposity. It is hypothesized that racial differences in fat patterning manifest during puberty. RESEARCH METHODS AND PROCEDURES: SSF and %BF were measured annually. Racial differences in SSF and %BF were evaluated by age. Associations between %BF and SSF were evaluated using the Pearson's correlations coefficient. Classification agreement was evaluated using the kappa-statistic. Effects of pubertal stage and race on classification agreement were examined using multivariate models. RESULTS: White girls had a greater mean %BF at 9 to 12 years of age; black girls had a greater %BF thereafter. Black girls had a greater mean SSF at every age. The correlation coefficient between SSF and %BF was 0.79, and there was good agreement between %BF and SSF in separating high (>85th percentile) from not high (kappa = 0.60 for whites and 0.66 for blacks). SSF associated more with %BF in prepuberty and early puberty than in late puberty. DISCUSSION: Despite good correlations between %BF and SSF, the two methods indicate different fat patterns in black and white girls.

Nutritional and health status of Tibetan children living at high altitudes.

BACKGROUND: Children living at high altitudes often have delayed growth, but whether growth retardation is related to altitude or to other factors is not known. METHODS: A multicultural health care team assessed 2078 Tibetan children 0 to 84 months of age for anthropometric and clinical signs of malnutrition. The children lived in 11 counties, which contained more than 50 diverse urban and nonurban (nomadic, agricultural, or periurban) communities in the Tibet Autonomous Region of China. The height and weight of the children were compared with those of U.S. children. Height and weight were expressed as z scores (the number of standard deviations from the median of the age- and sex-specific reference group). RESULTS: The mean z score for height fell from -0.5 to -1.6 in the first 12 months of life and generally ranged from -2.0 to -2.4 in older children. Overall, of 2078 children, 1067 (51 percent) had moderately or severely stunted growth, as defined by a z score of -2.0 or lower. Of the 1556 children 24 months of age or older, 871 (56 percent) had stunted growth, which was severe (z score, -3.0 or lower) in 380 (24 percent). Among the children in this age group, 787 of the 1313 nonurban children (60 percent) had stunting, as compared with 84 of the 243 urban children (35 percent). Stunting was associated with clinical conditions such as rickets, abdominal distention, hair depigmentation, and skin lesions and with a maternal history of hepatitis or goiter. Stunting was not associated with altitude, after adjustment for the type of community. CONCLUSIONS: In Tibetan children, severe stunting due to malnutrition occurs early in life, and morbidity is high.

Emotion-induced eating and sucrose intake in children: the NHLBI Growth and Health Study.

OBJECTIVE: Emotion-induced eating has been implicated as a risk factor for the development of obesity, yet no research has been done on emotion-induced eating in children. The National Heart, Lung, and Blood Institute Growth and Health Study (NGHS), a multicenter collaborative study of risk factors for obesity, developed an instrument for measuring emotion-induced eating in children and tested hypotheses regarding the association of emotion-induced eating with food intake and adiposity in preadolescent children. METHOD: Subjects were 1,213 black girls and 1,166 white girls who were 9 and 10 at study entry. Baseline data were utilized in this report. Girls were assessed by trained female health examiners who recorded height, weight, and indices of sexual maturation. Girls kept a 3-day food diary. Dietary data were coded and analyzed for total caloric and macro nutrient intake. A measure of emotion-induced eating was derived from seven questions about eating in response to emotions (Cronbach's alpha = .78). RESULTS: Black girls had significantly higher emotion-induced eating scores than white girls (10.8 vs. 9.7, p < .0001). For white girls, but not for black girls, emotion-induced eating was associated with increased intake of sucrose. In both races, a modest inverse association was found between body mass index and emotion-induced eating. DISCUSSION: Prospective studies are needed to explore further the role of emotion-induced eating and food intake and the role of emotion-induced eating in the development of obesity.

Influence of pre-adolescent diet on quantitative ultrasound measurements of the calcaneus in young adult women.

Nongenetic determinants of quantitative ultrasound (QUS) properties of the bone remain to be identified. The purpose of this study was to determine relationships between early adolescent diet and QUS bone measurements taken in young adulthood. Subjects were participants in the 10-year longitudinal National Heart, Lung, and Blood Institute Growth and Health Study (NGHS). QUS parameters measured at the calcaneus in a convenience subsample of 63 18- to 19-year-old black and white women were correlated with dietary data collected when the subjects were aged 9-11 years. We hypothesized that pre-adolescent intake of calcium, magnesium, vitamin C and protein, nutrients known to be associated with bone development, would be associated with QUS measurements in young women. Stepwise multiple regression analysis, controlling for race, height and weight, demonstrated that pre-adolescent intake of calcium and magnesium were positively related to QUS parameters (calcium with broadband ultrasound attenuation, and magnesium with speed of sound and bone velocity). Our findings suggest that pre-adolescent diet may be associated with bone properties as measured by ultrasound. Further investigations of this relationship may yield a deeper understanding of the impact of diet on skeletal development. The small size of the convenience sample used for the analysis precludes stronger inferences at this time.

Sociodemographic factors and obesity in preadolescent black and white girls: NHLBI's Growth and Health Study.

The association of sociodemographic and family composition data with obesity was studied in 1213 black and 1166 white girls, ages 9 and 10, enrolled in the National Heart, Lung, and Blood Institute's Growth and Health Study. Obesity was defined as body mass index at or greater than age- and sex-specific 85th percentile as outlined in the Second National Health and Nutrition Examination Survey. The prevalence of obesity was higher for pubertal girls than for prepubertal girls and for girls with older mothers/female guardians. As odds ratio of 1.14 was observed for each 5-year increase in maternal age. Obesity was less common for girls with more siblings; the odds for obesity decreased by 14% for each additional sibling in the household. In blacks, the prevalence of obesity was not related to parental employment or to parental education. In whites, the odds of obesity were higher for girls with no employed parent/guardian in the household and for girls with parents or guardians with lower levels of educational attainment. Examining the associations between sociodemographic factors and risk of childhood obesity provides important clues for understanding racial differences in obesity, a major risk factor for coronary heart disease.

A longitudinal study of the dietary practices of black and white girls 9 and 10 years old at enrollment: the NHLBI Growth and Health Study.

PURPOSE: To determine whether there are racial differences in the frequency with which black and white girls engaged in eating practices commonly targeted for modification in weight reduction programs. METHODS: This is part of the NHLBI Growth and Health Study, a longitudinal study of preadolescent girls designed to examine the factors associated with development of obesity, and its later effects on cardiovascular risk factors. Black and white girls ages 9-10 years at entry (n = 2,379) were recruited at three clinical sites. Racial differences were examined in 11 "weight-related" eating practices such as eating with TV, eating while doing homework, and skipping meals. Multiple logistic regression analyses were then conducted for each of the dependent variables. RESULTS: Black girls were more than twice as likely as white girls to frequently engage in the targeted weight-related eating practices. The odds of a study girl frequently engaging in most of these eating practices decreased with an increase in parents' income and education level. However, even when controlling for socioeconomic and demographic effects, black girls remained more likely to engage in these eating practices than white girls. For most of the behaviors, girls who frequently practiced a behavior had higher energy intakes compared to those who practiced it infrequently. CONCLUSIONS: The finding that black girls at an early age more frequently engage in eating practices associated with weight gain may have significant implications for obesity development. For both young black and white girls, early education efforts may be necessary in helping develop good eating habits. Since it appears that black girls have a higher risk of developing adverse weight-related eating practices, culturally appropriate education materials may be required.

The effects of race, household income, and parental education on nutrient intakes of 9- and 10-year-old girls. NHLBI Growth and Health Study.

Nutrient intakes of 2149 black and white, 9- and 10-year-old girls varied by race, household income, and parental education. Of the three variables, higher education was most consistently associated with more desirable levels of nutrient intakes, that is, lower percentage of dietary fat and higher levels of vitamin C, calcium, and potassium. Higher income was related to higher intakes of vitamin C, but lower intakes of calcium and iron. Higher income was associated with lower percentage of dietary fat. After adjustment for income and education, race was associated with intakes of calcium, vitamin C, and to a lesser extent, percentages of kilocalories from total fat and polyunsaturated fat, and potassium. Black girls had a significantly lower intake of calcium (720 versus 889 mg) and a higher intake of vitamin C (91 versus 83 mg). Proportions of the cohort with inadequate or excessive intakes of micronutrients and macronutrients were also estimated. A high proportion of girls exceeded the recommended intake level of 30% of kilocalories from total fat (90% of black girls; 84% of white girls) and 10% of kilocalories from saturated fat (92 and 93%, respectively). Low intakes of calcium (40% of black girls and and 20% og white girls) and zinc (36 and 38%, respectively) commonly were found for girls of both names.

Energy intake and physical activity in relation to indexes of body fat: the National Heart, Lung, and Blood Institute Growth and Health Study.

The relationship between energy intake, physical activity, and body fat was investigated in the baseline visit of 2379 black and white girls aged 9-10 y enrolled in the National Heart, Lung, and Blood Institute Growth and Health Study. Three-day food records, three-day physical activity diaries, physical-activity-patterns questionnaires, and an assessment of the number of hours of television and video watched were obtained. Multivariate-regression analyses showed that age, the number of hours of television and video watched, the percent of energy from saturated fatty acids, and the activity-patterns score best explained the variation in body mass index and sum of three skin-fold-thickness measurements for black girls. The best model for white girls included age, the number of hours of television and video watched, and the percent of energy from total fat. These results indicate that body fatness is related to energy intake and expenditure in both black and white girls. Longitudinal studies will help assess the value of these variables in predicting changes in body fat.

Comparative advantage of 3-day food records over 24-hour recall and 5-day food frequency validated by observation of 9- and 10-year-old girls.

OBJECTIVE: The validity of the 24-hour recall, 3-day food record, and 5-day food frequency was assessed to decide on a dietary assessment method for the National Heart, Lung, and Blood Institute (NHLBI) Growth and Health Study. DESIGN: All subjects were assigned to one of three dietary assessment methods. Unobtrusive observers recorded types and amounts of foods eaten during lunch, and these were compared with the foods reported by the girls in the study. SETTING: School lunchrooms in California and Ohio. SUBJECTS: 58 girls, aged 9 and 10 years. MAIN OUTCOME MEASURES: Reporting errors for dietary assessment methods. STATISTICAL ANALYSES PERFORMED: Descriptive statistics, matched pair t tests, and Spearman correlation coefficients. RESULTS: Comparison of the intakes of energy and selected macronutrients showed different ranges of, and median percentage absolute errors for, each dietary assessment method. Percentage absolute errors ranged between 20 and 33 for the 5-day food frequency method; 19 and 39 for the 24-hour recall; and 12 and 22 for the 3-day food record. The proportion of missing foods (ie, observed food items not reported) and phantom foods (ie, reported food items not observed) by each method were 46% and 40%, respectively, for the 5-day food frequency; 30% and 33%, respectively, for the 24-hour recall; and 25% and 10%, respectively, for the 3-day food record. APPLICATIONS/CONCLUSIONS: Errors in food reporting and quantification can vary with the type of dietary methodology. Agreement between observed and reported intakes from 3-day food records made it the best overall choice. On this basis, it was selected as the method of assessment for the NHLBI Growth and Health Study.

Income and racial patterns of dietary vitamin C intake among black and white girls.

The authors examined the influence of income and race on mean dietary vitamin C intake and the risk of dietary vitamin C intake at levels below the recommended dietary allowance (RDA). They performed a cross-sectional analysis of 2,032 black and white 9- and 10-year-old females, from a wide range of income groups, who participated in the National Heart, Lung, and Blood Institute Growth and Health Study. Mean intake of vitamin C, exclusive of vitamin supplements and determined by 3-day diet records, exceeded the RDA of 45 milligrams per day for that age group in all racial and income categories. The investigators found that annual household income was directly associated with mean dietary vitamin C intake (P < 0.0001) and that blacks had higher mean dietary vitamin C intakes than whites (P < 0.01). Among both blacks and whites, household income and risk of below-RDA vitamin C intake were inversely correlated, but this trend was statistically significant for blacks only (P < 0.05). Except for the lowest level income group (less than $10,000 per year), black girls from households with incomes less than $30,000 per year were at increased risk for below-RDA vitamin C intake (relative risk = 1.93 in the $10,000-$19,999 per year group and 1.63 in the $20,000-29,999 per year group, P < 0.05), compared with black girls in the highest income category. One-quarter of white girls overall and more than 30 percent of white girls in the lowest two income groups had below-RDA vitamin C intakes. If the findings are generalizable,they underscore the importance of public health programs to address the adequacy of dietary vitamin C intake among preadolescent black and white females.

Dietary vitamin C and serum lipids in black and white girls.

We examined the cross-sectional relation of dietary vitamin C intake to serum lipids in 1,825 preadolescent black and white girls. Dietary vitamin C intake exclusive of supplement use, determined by 3-day diet record, appeared unrelated to total serum cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and triglyceride levels. Because other investigators have demonstrated an inverse association between vitamin C and total serum cholesterol in individuals with elevated total serum cholesterol levels, we analyzed the subgroup of 285 girls (142 blacks and 143 whites) with total serum cholesterol levels > or = 200 mg per dl. Multivariate analyses of this subgroup, which adjusted for saturated fat, polyunsaturated fat, monounsaturated fat, cholesterol, fiber, and energy intake and for body mass index, demonstrated negative association between vitamin C intake and total serum cholesterol. In girls with total serum cholesterol levels > or = 200 mg per dl, each 100 mg per day increase in dietary vitamin C intake (ranges 13-373 and 14-242 mg per day for blacks and whites, respectively) was associated with a total serum cholesterol decrease of 4 mg per dl (95% confidence limits = -10.34, 2.77) in blacks and 13 mg per dl (95% confidence limits = -22.99, -2.68) in whites. If the observed association is causal and generalizable, our results suggest that increased vitamin C intake could play an important role in the cholesterol homeostasis of females with elevated total cholesterol levels.

Early growth predicts timing of puberty in boys: results of a 14-year nutrition and growth study.

Diet and growth were studied prospectively in 78 boys ages 6 months to 14 years. All boys were well nourished and not grossly obese. Pubertal development was evaluated at age 14 years, and the results correlated with diet and early growth. No nutrients were significantly correlated with the stage of pubertal development. Boys with more advanced pubic hair development (Tanner greater than 3) and longer penile length (greater than or equal to 10 cm) had been significantly heavier at ages 6 months, 2 years, and 4 years (all P less than 0.025). Muscle mass, as estimated by the cross-sectional muscle area of the upper arm, had been significantly greater in the early maturers at the same ages (P less than 0.025 in seven of nine comparisons). Although the more sexually mature boys also had been taller and had had larger skinfolds at virtually all measurements from age 6 months to 4 years, the differences were less pronounced. In this adequately nourished male population, body size in the first years of life was significantly correlated with the timing of puberty.

Obesity prognosis: a longitudinal study of children from the age of 6 months to 9 years.

The development of body fatness and leanness is examined in an ongoing prospective nutrition and growth study. Individual skinfold thicknesses, relative weights, weight gains, activity levels, and caloric intakes were examined at seven ages between 6 months and 9 years. Changes in body fatness in this group of children provide evidence that the obese infant usually does not become the obese child. Weight gain in infancy is also a poor predictor of 9-year old obesity. Changes from obese to non-obese or lean are often not linear. There is evidence that impending or actual obesity begins at ages 6 to 9 years with some predictability provided as early as age 2 years for girls, age 3 years for boys.

Body composition and physical activity in 8-year-old children.

Body measurements and determinations were made of normal children age 8 3/4 yr. Anthropometric indices most highly correlated with percentage fat as determined by body density were the sum of four skinfolds, relative weight, and triceps skinfold thickness. Girls had a significantly higher percentage of fat than boys. Percentage fat at this age was compared to longitudinal activity scores (based on 1-day activity records) obtained from 6 months to the current age. There was no significant correlation of activity with fatness in girls. In boys, activity at 3 and 4 yr had a significant negative correlation with fatness at age 8; activity at age 8 was not correlated. Relative-leanness-fatness was better related to past than current activity. Comparison of longitudinal activity scores revealed a continuity of activity patterns for short intervals (e.g., 1 yr), but over longer periods (e.g., 4 or more yr) the effect diminished.