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.

Racial divergence in adiposity during adolescence: The NHLBI Growth and Health Study.

BACKGROUND: Black women are particularly vulnerable to obesity, with a prevalence rate of >50%. The higher mortality and morbidity from cardiovascular disease, stroke, and diabetes have been attributed, in part, to their obesity. In recent years, a particular public health concern is the increasing secular trend in obesity with an even greater racial disparity, especially in girls and women. Between the early 1960s and late 1980s, the prevalence of obesity tripled in young black girls 6 to 11 years of age, while it doubled in white girls. Similarly, both overweight and obesity in adolescent girls 12 to 17 years of age also increased, with a greater increase again seen in adolescent black girls. This secular trend in obesity with a greater increase in black girls signals a potentially grave future chronic disease burden on black women, which is already higher than in white women. The increasing occurrence in children and adolescents of noninsulin-dependent diabetes, traditionally viewed as an adult-onset condition, may be a consequence of the currently high prevalence of obesity in American youth. Not surprisingly, this condition is seen more frequently among black youths. Prepubescent black girls are generally leaner than age-comparable white girls, but by 20 years of age, black women are considerably heavier than are white women. Thus, it is assumed that the racial disparity in adiposity evolves during adolescence. However, the specific age at which this occurs and underlying factors are yet to be identified because of the current paucity of longitudinal cohort data. OBJECTIVES: In 1985, the National Heart, Lung, and Blood Institute (NHLBI) initiated a 10-year longitudinal multicenter study (the NHLBI Growth and Health Study [NGHS]) to investigate the development of obesity in black and white girls during adolescence and its environmental, psychosocial, and cardiovascular disease risk factor correlates. The purpose of this report is to examine the natural history of adiposity and weight accretion during adolescence in a biracial cohort of girls to investigate the evolution of the racial divergence in adiposity and to examine the relationships between increases in adiposity and pubertal maturation, energy intake, and physical activity. PARTICIPANTS AND SETTING: A total of 2379 black (51%) and white (49%) girls, 9 to 10 years of age, were recruited from public and parochial schools in Richmond, California, and Cincinnati, Ohio, and from families enrolled in a large health maintenance organization in the Washington, DC area. Participant eligibility was limited to girls and their parents who declared themselves as being either black or white and who lived in racially concordant households. DESIGN AND STATISTICAL ANALYSIS: The NGHS is a multicenter prospective study of black and white girls with annual visits from 9 to 10 years of age through 18 to 19 years of age. The follow-up rate was 89% at the 10th annual visit. Skinfold measurements were obtained at the triceps, suprailiac, and subscapular sites with Holtain calipers. Sexual maturation was assessed by trained registered nurses. The onset of menarche was ascertained annually by questionnaire. All clinical assessments were conducted using a common protocol by centrally trained staff. Longitudinal regression (generalized estimating equations) models were used to examine the relationship between adiposity and race, age, pubertal maturation, daily energy intake, and physical activity. MAIN OUTCOME MEASURES: The main outcome measure was the sum of skinfolds (SSF) at the triceps, subscapular, and suprailiac sites as an index of adiposity for comparison between the 2 racial groups. Body mass index (BMI; weight in kilograms divided by height in meters, squared) distributions were examined by age and race. RESULTS: Racial differences in SSF, unadjusted for maturation, were evident at 10 years of age. For each chronological age, there was a higher proportion of black girls with more advanced pubertal maturation than white girls. The 15th percentiles for SSF were similar and remained thus throughout the study. The median for SSF for black girls, although similar to the median SSF of white girls at 9 years of age, became greater for black girls at 12 years of age (36 mm vs 32.5 mm) and at age 19 years the difference was 6 mm (49.5 mm vs 43.5 mm). In contrast, the difference in the 85th as well as the 95th percentile values for SSF were substantially higher in black girls at all ages (9 mm and 10 mm, or 18% and 15%, respectively, at age 9 years) and these racial differences widened with age (20 mm and 26 mm, or 25% and 24%, respectively, by age 19 years). The racial difference in the median BMI increased from 0.4 to 2.3 kg/m(2) between ages 9 and 19 years. Unlike SSF at the 15th percentile, the BMI for lean 9-year-old black girls was ~3% higher than whites. (ABSTRACT TRUNCATED)

Preference for thinness in Singapore--a newly industrialised society.

BACKGROUND/AIMS: A cultural preference for thinness has been implicated in the development of eating disorders in Western, post-industrialised societies. In transitional societies like Singapore, a shift in expectations of ideal body size (toward thinness) may lead to an increase in eating disorders. This study investigated perceptions about body size and shape in over 200 youths living in Singapore, and the influences of adiposity, gender, Westernization and parents' education. METHODS: A self-administered questionnaire was used to gather social and cultural information from 137 males and 143 females, aged 17-22 years. It included questions relating to eating behaviour and body satisfaction from which a "preference for thinness score" was derived. Westernization was indicated by language spoken at home. Adiposity was measured by triceps skinfold and body mass index. Multiple linear regression analysis was used to assess the associations of adiposity, mother's education, father's education, and language spoken at home with the preference for thinness score. RESULTS: Dissatisfaction with body size and shape increased with tertile of adiposity among females, and thoughts about dieting and becoming thinner were present even among underweight girls. Unlike the females, the highest proportion of males satisfied with their body size and shape, was associated with the middle tertile of BMI. Speaking English at home, but not parents' education, was positively associated with body dissatisfaction after controlling for BMI. CONCLUSION: Chinese Singaporean female youths have a preference for thinness as an ideal body size. The epidemiology of eating disorders in Singapore and other newly industrialised societies warrants further investigation.

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.

Lipoprotein and apolipoprotein differences in black and white girls. The National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVE: To define racial differences in lipoprotein and apolipoprotein levels in girls aged 9 to 10 years. DESIGN: Baseline analysis of a prospective cohort study. SETTING: Three clinical sites. SUBJECTS: A total of 1871 black and white girls, aged 9 to 10 years, with complete maturation data (pubic hair and areolar development and menarche) and an 8-hour fast before blood draw. MAIN OUTCOME MEASURES: Anthropometric measures and serum lipid, lipoprotein, and apolipoprotein levels. RESULTS: All analyses were adjusted for maturational differences between blacks and whites (areolar or pubic hair development and menarche). The mean body mass index was marginally higher in black girls than in white girls (18.9 vs 18.3 kg/m2; P = .002), while the sum of skinfolds (34.5 vs 34.8 mm; P = .77) was equivalent. However, both body mass measures were skewed higher at the upper percentiles in black girls. The low-density lipoprotein cholesterol level was similar between black and white girls. Mean triglyceride values were higher in white girls than in black girls (0.92 vs 0.79 mmol/L [81 vs 70 mg/dL]; P < .001); however, these differences were most pronounced in the upper percentiles. Conversely, mean high-density lipoprotein cholesterol and apolipoprotein A-I levels were higher in black girls than in white girls (1.44 vs 1.37 mmol/L [56 vs 39 mg/dL] and 147 vs 138 mg/dL, respectively; both P < .001); and again the differences were most evident at the upper end of the distributions. CONCLUSIONS: Racial differences in the mean levels of triglycerides, high-density lipoprotein cholesterol, and body mass in girls in the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS) at age 9 to 10 years were predominantly the result of differences observed at the upper end of the distributions. The reported black-white differences for mean high-density and low-density lipoprotein cholesterol and triglyceride levels in adult women are comparable to NGHS results. Distributional characteristics of these risk factors as well as trends in lipids, lipoproteins, and apolipoproteins, will be evaluated in an ongoing longitudinal assessment that covers the full maturational period.

Race, socioeconomic status, and obesity in 9- to 10-year-old girls: the NHLBI Growth and Health Study.

The purpose of this investigation was to determine whether measures of socioeconomic status (SES) are inversely associated with obesity in 9- to 10-year-old black and white girls and their parents. Subjects were participants in the Growth and Health Study (NGHS) of the National Heart, Lung, and Blood Institute. Extensive SES, anthropometric, and dietary data were collected at baseline on 2379 NGHS participants. The prevalence of obesity was examined in the NGHS girls and parents in relation to SES and selected environmental factors. Less obesity was observed at higher levels of household income and parental education in white girls but not in black girls. Among the mothers of the NGHS participants who were seen, lower prevalence of obesity was observed with higher levels of income and education for white mothers, but no consistent patterns were seen in black mothers. Univariate logistic models indicated that the prevalence of obesity was significantly and inversely associated with parental income and education and number of parents in the household in white girls whereas caloric intake and TV viewing were significantly and positively associated with obesity. Among black girls, only TV viewing was significantly and positively associated with the prevalence of obesity. Multivariate logistic regression models revealed that lower parental educational attainment, one-parent household, and increased caloric intake were significantly associated with the prevalence of obesity in white girls; for black girls, only increased hours of TV viewing were significant in these models. It is concluded that socioeconomic status, as measured by education and income, was related to the prevalence of obesity in girls, with racial variation in these associations. A lower prevalence of obesity was seen at higher levels of socioeconomic status in white girls, whereas no clear relationship was detected in black girls. These findings raise new questions regarding the correlates of obesity in black girls.

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.

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.

Issues in the evaluation of nutrition interventions.

Malnutrition in developing countries is essentially a problem of poverty and low food consumption. Thus, its alleviation rests in integrating nutrition interventions with socio-economic development measures. With this orientation, evaluation is becoming increasingly necessary. However, the methodology available for assessing nutritional status places unreasonable demands on the human and financial resources of any programme. There is also a serious lack of knowledge of the effect of malnutrition on the physical capacity and mental functioning and on the relationship between malnutrition and income. Evaluation may, with advantage, be built into the framework of the intervention project design, and be introduced at the appropriate time when impact is likely to be detectable. Of concern are such operational aspects as the relation of evaluators to operation staff, the involvement of project participants and the management of evaluation ata. In addition, the political and ethical implications of evaluating nutrition interventions need to be kept in focus in order to maximize the value of evaluation efforts.

PIP: Evaluation of a nutrition intervention is essentially an inquiry into the relationship between the intervention and the impact it is expected to have. For the purposes of this discussion, 2 aspects of evaluation should be kept in mind: that of inputs or treatments (process evaluation) and that of outputs or outcomes (impact evaluation). Process evaluation provides information about the project operation and is concerned with the adherence of the project to its design and stated guidelines of operation. Impact evaluation determines how well the treatment achieved its objectives. It is concerned with the situation change resulting from the project in relation to its objective and anticipated outcome. The most crucial issue of concern is the scarcity of adequate evaluations of nutrition intervention. Basically, the main issues of concern in planning and implementing an evaluation deal with technical expertise, cost, implementation, and implications. In the area of technical expertise, the primary concern is uncertainty about the measurement of parameters that reflect nutritional status adequately. The most readily available data on food supply (at the country level) and on food consumption (at the community or household levels) are of limited value, for they give an average consumption of a population group which cannot be disaggregated to the level of the individual. Variations in sensitivity and selectivity make it necessary to use several types of measurements in any assessment of nutritonal status. Most project planners are reluctant to allocate substantial proportions of their budgets to evaluation. The financial resources needed for evaluation should be considered on their own rather than as a fixed proportion of the budget. The timing of evaluation is critically important as is its relation to the operation of the intervention program. Where evaluation is introduced after a project begins, it is essential that enough time be allowed to show some effect. Where evaluation is designed as part of the intervention from the start, it becomes a natural stage of development and there is less danger of premature commitment on a single form of action. The political implications of evaluating nutrition intervention programs are frequently so deceptive that the evaluator overlooks their impact on his or her work. Nutritional status is a reflection of the socioeconomic conditions of that individual or community. The dilemmas relating to ethnic implications of nutriton evaluation can largely be resolved by involving the participants of any nutrition intervention in the planning, implementation, and evaluation stages.

Nutrition and rural development.

This paper summarizes the conceptual and methodological work carried out by a team of FAO staff and consultants in a continuing effort to introduce nutritional considerations into the planning and execution of agricultural programmes and projects. Guidelines were prepared on the basis of experience acquired to various case-studies and are currently being applied in field projects.

Multivariate analysis of diet and serum lipids in normal men.

The relationships among intake of dietary fiber, fat, and serum lipids were examined in a population of 200 normal men. Univariate analyses indicated that men with lower serum cholesterol and triglyceride concentrations were consuming significantly more dietary fiber and proportionately fewer fat calories. However, higher fiber consumption was also associated with differences in relative body weight, fat intake, and cigarette smoking; the relationship of dietary fiber intake to serum lipids was largely mediated by those coexisting differences in other environmental variables. In contrast, the percentage of total calories consumed as fat was independently positively related to both serum cholesterol and triglyceride levels.