Inter-relationships among childhood BMI, childhood height, and adult obesity: the Bogalusa Heart Study.

OBJECTIVE: Although the body mass index (BMI, mass index, kg/m2) is widely used as a surrogate measure of adiposity, it is moderately associated (r approximately 0.3) with height among children. We examined whether the resulting preferential classification of taller children as overweight is appropriate. DESIGN: Cross-sectional analyses of children (ages, 3-17 y) examined the relation of height to adiposity (as assessed by BMI and skinfold thicknesses) and fasting levels of insulin. Longitudinal analyses examined the relation of childhood height and weight-height indices to adult (mean age, 25 y) levels of adiposity and fasting insulin. SUBJECTS: Children (n=11,406) and adults (n=2911) who had participated in the Bogalusa Heart Study. MEASUREMENTS: We constructed three weight-height indices: BMI, W/H3, and W/Hp. The triceps and subscapular skinfolds, as well as fasting levels of insulin, were also measured. RESULTS: The classification of children as overweight (BMI-for-age > or =95th percentile) varied markedly by height, with a 10-fold difference in the prevalence of overweight across quintiles of height between the ages of 3 and 10 y. Childhood height, however, was also related to skinfold thicknesses and insulin levels, and all associations were modified in a similar manner by age. Furthermore, childhood height was related to adult adiposity, and of the three childhood weight-height indices, BMI showed the strongest associations with adult adiposity. CONCLUSIONS: Because BMI reflects the positive association between height and adiposity among children, it is a better weight-height index than is either W/H3 or W/Hp.

Relationship of childhood obesity to coronary heart disease risk factors in adulthood: the Bogalusa Heart Study.

BACKGROUND: Childhood obesity is related to adult levels of lipids, lipoproteins, blood pressure, and insulin and to morbidity from coronary heart disease (CHD). However, the importance of the age at which obesity develops in these associations remains uncertain. OBJECTIVE AND DESIGN: We assessed the longitudinal relationship of childhood body mass index (BMI, kg/m(2)) to adult levels of lipids, insulin, and blood pressure among 2617 participants. All participants were initially examined at ages 2 to 17 years and were reexamined at ages 18 to 37 years; the mean follow-up was 17 years. RESULTS: Of the overweight children (BMI >/=95th percentile), 77% remained obese (>/=30 kg/m(2)) as adults. Childhood overweight was related to adverse risk factor levels among adults, but associations were weak (r ~ 0.1-0.3) and were attributable to the strong persistence of weight status between childhood and adulthood. Although obese adults had adverse levels of lipids, insulin, and blood pressure, levels of these risk factors did not vary with childhood weight status or with the age (/=18 years) of obesity onset. CONCLUSIONS: Additional data are needed to assess the independent relationship of childhood weight status to CHD morbidity. Because normal-weight children who become obese adults have adverse risk factor levels and probably will be at increased risk for adult morbidity, our results emphasize the need for both primary and secondary prevention.

Use of nonprescription weight loss products: results from a multistate survey.

CONTEXT: Lifestyle changes to lose weight can be difficult; hence, both prescription and nonprescription diet products are appealing. Usage patterns of the nonprescription products phenylpropanolamine (PPA) and ephedra are of particular interest because of recent safety concerns. OBJECTIVE: To estimate the prevalence of overall and specific nonprescription weight loss product use by demographic characteristics, prescription diet pill use, diabetic status, and lifestyle choices. DESIGN AND SETTING: The Behavioral Risk Factor Surveillance System, a random-digit telephone survey conducted in 1998 in 5 states: Florida, Iowa, Michigan, West Virginia, and Wisconsin. PARTICIPANTS: Population-based sample of 14 679 noninstitutionalized adults 18 years or older. MAIN OUTCOME MEASURES: Prevalence of nonprescription weight loss product use in 1996-1998. RESULTS: Seven percent reported overall nonprescription weight loss product use, 2% reported PPA use, and 1% reported ephedra product use. Overall use was especially common among young obese women (28.4%). Moreover, 7.9% of normal-weight women reported use. There was no difference in nonprescription weight loss product use by daily consumption of fruits and vegetables; however, more users than nonusers reported being physically active (for those who exercised >/=30 minutes 5 times per week, odds ratio, 1.5; 95% confidence interval, 1.2-2.0). Among prescription weight loss product users, 33.8% also took nonprescription product. CONCLUSIONS: With increasing rates of obesity, nonprescription product use is likely to increase. Clinicians should know about their patients' use of both prescription and nonprescription weight loss products.

Use of prescription weight loss pills among U.S. adults in 1996-1998.

BACKGROUND: Pharmacotherapy is recommended for the treatment of obese persons with a body mass index of 30 kg/m(2) or higher or a body mass index of at least 27 kg/m(2) plus an obesity-related comorbid condition. OBJECTIVE: To estimate the prevalence of use of prescription weight loss pills in the United States in 1996-1998. DESIGN: 1998 Behavioral Risk Factor Surveillance System, a nationally representative telephone survey. SETTING: United States. PARTICIPANTS: 139 779 adults 18 years of age and older. MEASUREMENTS: Self-reported pill use for 1996-1998, body mass index (current and before pill use), age, sex, and race or ethnicity. RESULTS: The 2-year prevalence of pill use was 2.5% (95% CI, 2.1% to 2.9%), or 4.6 million U.S. adults. Use was higher in women than in men (4.0% vs. 0.9%, respectively) and highest among Hispanic respondents (3.2%). Of pill users, 25% were not overweight (body mass index < 27 kg/m(2) before using pills. CONCLUSIONS: Nearly 5 million U.S. adults used prescription weight loss pills in 1996-1998. However, one quarter of users were not overweight, suggesting that weight loss pills may be inappropriately used, especially among women, white persons, and Hispanic persons.

Development of a modified picture-sort food frequency questionnaire administered to low-income, overweight, African-American adolescent girls.

There is essentially no ideal method of dietary assessment. Physiologic methods (i.e., doubly labeled water) probably come closest, but high cost, participant burden, and limited information limit their use. Furthermore, most dietary assessment methods have been designed for and tested in white adults. Very few have been designed for and tested in African-American adolescents. This study examined validity and reliability of a modified picture-sort food frequency questionnaire (FFQ) administered to 22 low-income, overweight, African-American adolescent girls, aged 11 to 17 years. The FFQ was administered to subjects twice during a 2-week period, and evaluated using the mean values of three 24-hour recalls. The natural log-transformed energy-adjusted, deattenuated correlation coefficients between the second FFQ and the mean from 3 recalls exceeded 0.50 for most nutrients, ranging from 0.32 (protein) to 0.87 (saturated fat). The energy and nutrient values from the first FFQ were greater than those from the second FFQ. Most correlation coefficients for the test-retest reliability of the FFQ were not significant. We conclude that although larger samples are needed to generalize results, the picture-sort dietary assessment method appears to be promising and merits further research.

Iron deficiency anemia: higher prevalence in Mexican American than in non-Hispanic white females in the third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: Mexican American females have a higher prevalence of iron deficiency than do non-Hispanic white females. OBJECTIVE: The objective was to estimate the prevalence of iron deficiency anemia and examine potential reasons for this difference between Mexican American (n = 1194) and non-Hispanic white (n = 1183) females aged 12-39 y. DESIGN: We used data from the third National Health and Nutrition Examination Survey (1988-1994). Iron deficiency anemia was defined as abnormal results from >/=2 of 3 tests (erythrocyte protoporphyrin, transferrin saturation, and serum ferritin) and a low hemoglobin concentration. We used multiple logistic regression to adjust for factors that were more prevalent in Mexican American females and significantly associated with iron deficiency anemia. RESULTS: The prevalence of iron deficiency anemia was 6.2 +/- 0.8% (f1.gif" BORDER="0"> +/- SE) in Mexican American females and 2.3 +/- 0.4% in non-Hispanic white females. Mean dietary iron intake, mean serum vitamin C concentrations, and the proportion of females using oral contraceptives were similar in the 2 groups. Age <20 y and education were not associated with iron deficiency anemia. After adjustment for poverty level, parity, and iron supplement use, the prevalence of iron deficiency anemia was 2.3 times higher in Mexican American than in non-Hispanic white females (95% CI: 1.4, 3.9). In those with a poverty income ratio (based on household income) >3.0, however, the prevalence of iron deficiency anemia was 2.6 +/- 0.9% in Mexican American and 1.9 +/- 0.6% in non-Hispanic white females (NS). CONCLUSION: Although much of the ethnic disparity in iron deficiency anemia remains unexplained, factors associated with household income may be involved.

Obesity in women from developing countries.

OBJECTIVES: The key objective was to estimate obesity (>/=30 kg/m2) in women 15-49 y from developing countries. A second objective was to study how obesity varies by educational level and by residence in urban and rural areas. A third objective was to investigate how national incomes shape the relationship between obesity and eduction or residence. DESIGN: The analyses use cross-sectional data from nationally representative surveys from developing countries carried out in the last decade. Most of the surveys were Demographic Health Surveys (DHS). Data from a survey from the USA are used for comparison. SETTING: The 39 surveys used come from 38 developing countries and the USA. SUBJECTS: A total of 147,938 non-pregnant women 15-49 y were included in the analyses. RESULTS: The percentage of obese women was 0.1% in South Asia, 2.5% in Sub-Saharan Africa, 9. 6% in Latin America and the Caribbean, 15.4% in Central Eastern Europe/Commonwealth of Independent States (CEE/CIS), 17.2% in the Middle East and North Africa, and 20.7% in the USA. Levels of obesity in countries increased sharply until a gross national product of US$1500 per capita (1992 values) was reached and changed little thereafter. In very poor countries, such as in Sub-Saharan Africa, obesity levels were greatly concentrated among urban and higher educated women. In more developed countries, such as those in Latin America and the CEE/CIS regions, obesity levels were more equally distributed in the general population. CONCLUSIONS: Based on the analyses presented and on a review of the literature, it is concluded that obesity among women is a serious problem in Latin America and the Caribbean, the Middle East and North Africa, and the CEE/CIS region. Obesity is less of a concern in Sub-Saharan Africa, China and South Asia. Obesity levels increased over time in most of the limited number of countries with data, but at varying rates. Rising national incomes in developing countries and increased 'Westernization' will most likely lead to increased levels of obesity in the future. SPONSORSHIP: Financial support was provided by the Food and Nutrition Program of the Pan American Health Organization and by the World Bank.

Secular trends in height among children during 2 decades: The Bogalusa Heart Study.

OBJECTIVE: To examine trends in height among 5- to 17-year-old children between 1973 and 1992. DESIGN: A panel design consisting of 7 cross-sectional surveys. PARTICIPANTS: All schoolchildren residing in Bogalusa, La, were eligible. A total of 24 070 examinations were performed. RESULTS: During the study period, the mean height of schoolchildren increased by 0.70 cm per decade independently of race, sex, and age. Trends were most pronounced among preadolescents, blacks, and boys, with 9- to 12-year-old black boys showing a height increase of 1.8 cm per decade. We observed a decrease in the number of relatively short children (<10th percentile of height) and an increase in the number of tall children (>90th percentile of height). Because a secular trend was not seen among the 15- to 17-year-old children, our findings likely reflect an acceleration of maturation. CONCLUSIONS: It has generally been assumed that secular increases in height among schoolchildren in the United States ceased by the mid-1900s. Our findings, which may be due to various environmental factors, demonstrate that care must be taken when using nonconcurrent reference data to assess the growth of children. Additional study is needed to determine if these secular trends are continuing and to examine possible explanations and consequences of these trends.

Validity and reliability of a modified qualitative dietary fat index in low-income, overweight, African American adolescent girls.

This study evaluated the validity and reliability of a modified qualitative dietary fat index questionnaire (QFQ) in an adolescent minority population. The QFQ was administered to study participants twice over a 2-week period, and data were compared with mean values from three 24-hour recalls. Fifty-seven low-income, overweight, African American adolescent girls, aged 11 to 17 years, were recruited from 7 public housing developments in Atlanta, Georgia. To determine validity, the total QFQ score was compared with the mean values of total fat, percentage of energy from fat, and total energy from three 24-hour recalls within 2 weeks of first administration of the QFQ. Reliability was tested in a subsample (n = 22) by comparing total QFQ scores administered 2 weeks apart. Total fat was significantly correlated (r = 0.31, P < .05) with the QFQ score. Total energy (r = 20.23) and percentage of energy from fat (r = -0.23) were not significantly correlated with the QFQ score. The test-retest QFQ scores were significantly correlated (r = 0.54, P < .01). The data suggest that additional modifications are needed to make the QFQ more appropriate for low-income, over-weight, African American adolescent girls.

Blood lead concentration and children's anthropometric dimensions in the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994.

OBJECTIVE: To assess the association between lead exposure and children's physical growth. DESIGN: Cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey, 1988-1994. PARTICIPANTS: A total of 4391 non-Hispanic white, non-Hispanic black, and Mexican-American children age 1 to 7 years. MEASUREMENTS AND RESULTS: We investigated the association between blood lead concentration and stature, head circumference, weight, and body mass index with multiple regression analysis adjusting for sex, ethnic group, iron status, dietary intake, medical history, sociodemographic factors, and household characteristics. Blood lead concentration was significantly negatively associated with stature and head circumference. Regression models predicted reductions of 1. 57 cm in stature and 0.52 cm in head circumference for each 0.48 micromol/L (10 micrograms/dL) increase in blood lead concentration. We did not find significant associations between blood lead concentration and weight or body mass index. CONCLUSIONS: The significant negative associations between blood lead concentration and stature and head circumference among children age 1 through 7 years, similar in magnitude to those reported for the Second National Health and Nutrition Examination Survey, 1976-1980, suggest that although mean blood lead concentrations of children have been declining in the United States for 2 decades, lead exposure may continue to affect the growth of some children.

Obesity in Latin American women and children.

National surveys conducted since 1982 were used to assess maternal and child obesity in Latin American and Caribbean countries and in U. S. residents of Mexican descent. Obesity in women, a body mass index (BMI) >/=30 kg/m2, was 3% in Haiti, 8-10% in eight Latin American countries and 29% in Mexican Americans. Median BMI for Latin American women were near or above the 50th percentile of the general U.S. population; values exceeded the 75th percentile in the case of Mexican Americans. The prevalence of overweight (>1 SD above mean weight-for-height) in children 1-5 y of age ranged from 6% in Haiti to 24% in Peru among 13 countries. Overweight occurred in 24% of Mexican-American children. Prevalences of overweight in children and of obesity in women were greater in urban areas and in households of higher socioeconomic status. Overweight in children increased with higher maternal education; however, in some countries, obesity in women decreased with higher education. No general pattern of change over time was observed in eight countries in overweight in children. Obesity in women increased in the three countries with such data and in Mexican-American women and children. There was a tendency for greater national incomes to be associated with greater obesity levels in women and with lower levels of stunting in children. Levels of obesity in the region indicate a public health concern, particularly among women, considering that studies have identified mortality and morbidity risks associated with obesity in adults.

A conceptual model of the food and nutrition system.

The food system is a widely used concept, but few systematic frameworks model the full scope and structure of the food and nutrition system. Bibliographic searches, a modified Delphi technique, focus groups and interviews with experts on the topic were conducted to identify existing models of agriculture, food, nutrition, health and environmental systems. These models were examined, classified and synthesized into an integrated conceptual model of the food and nutrition system. Few existing models broadly described the system and most focused on one disciplinary perspective or one segment of the system. Four major types of models were identified: food chains, food cycles, food webs and food contexts. The integrated model developed here included three subsystems (producer, consumer, nutrition) and nine stages (production, processing, distribution, acquisition, preparation, consumption, digestion, transport, metabolism). The integrated model considers the processes and transformations that occur within the system and relationships between the system and other systems in the biophysical and social environments. The integrated conceptual model of the food and nutrition system presents food and nutrition activities as part of a larger context and identifies linkages among the many disciplines that deal with the food and nutrition system.

Effect of hemolysis on serum retinol as assessed by direct fluorometry.

To assess the effect of hemolysis on serum retinol concentrations determined by direct fluorometry, we assayed 196 blood samples from children 6-72-mo of age with various grades of hemolysis for serum retinol by both fluorescence and HPLC. Mean serum retinol concentrations determined by HPLC did not differ significantly according to hemolysis grade; however, fluorometric values did. Additionally, serum retinol concentrations obtained from HPLC and those obtained from direct fluorometry were significantly different in samples with severe hemolysis. Multivariate-regression analysis showed that hemolysis grade was a significant predictor of the difference in mean serum retinol values determined by the two methods. Although severe hemolysis interfered with determinations of serum retinol by direct fluorometry, this method is still a viable choice for field studies of vitamin A status.

Acculturation, socioeconomic status, and obesity in Mexican Americans, Cuban Americans, and Puerto Ricans.

OBJECTIVES: This study examined the relationship between acculturation and obesity in United States (US) Hispanics, controlling for socioeconomic status (SES). METHODS: The sample included 3141 Mexican American, 828 Cuban American, and 1211 Puerto Rican adults 18-74 y of age in the 1982-84 Hispanic Health and Nutrition Examination Survey (HHANES). Acculturation was measured by language preference and generation; SES by income and education; and obesity by body mass index (BMI). RESULTS: Mean and standard deviations of BMI (kg/m2) were 25.9 +/- 4.4, 26.0 +/- 4.2, and 25.5 +/- 4.3 in men of Mexican American, Cuban American, and Puerto Rican origin, respectively. For women, the corresponding values were 26.6 +/- 5.8, 25.9 +/- 5.0, and 26.2 +/- 5.9. Linear regression models of BMI which included acculturation, income, education, and other covariates were carried out. Income and education were not associated consistently with BMI. Acculturation, but only among Mexican Americans, was associated with BMI. Specifically, greater preference for English was associated with reduced BMI among women (P < 0.01). Also, men and women of the second (P < 0.001 in both sexes) and third (P < 0.01 in men P < 0.001 in women) generation had greater BMIs. Relative to the first generation, the increase in BMI units was 1.15 +/- 0.34 in men and 1.76 +/- 0.39 in women in the second generation and 0.83 +/- 0.31 in men and 1.83 +/- 0.37 in women of the third generation. CONCLUSIONS: BMI was not associated with SES, an unexpected finding since the relationship is generally negative in women from developed countries. The relationship between BMI and acculturation was weak and conditional. BMI in Mexican Americans appeared to be somewhat more sensitive to the process of acculturation than among Cubans or Puerto Ricans.

Reversibility of stunting: epidemiological findings in children from developing countries.

The growth literature from developing countries is reviewed to assess the extent to which stunting, a phenomenon of early childhood, can be reversed in later childhood and adolescence. The potential for catch-up growth increases as maturation is delayed and the growth period is prolonged. However, maturational delays in developing countries are usually less than two years, only enough to compensate for a small fraction of the growth retardation of early childhood. Follow-up studies find that subjects who remain in the setting in which they became stunted experience little or no catch-up in growth later in life. Improvements in living conditions, as through food supplementation or through adoption, trigger catch-up growth but do so more effectively in the very young. One study cautions that in older adopted subjects, accelerated growth may accelerate maturation, shorten the growth period and lead to short adult stature.