Mary K. Serdula

The relation of childhood BMI to adult adiposity: the Bogalusa Heart Study.

Objective. Although many studies have found that childhood levels of body mass index (BMI; kg/m2) are associated with adult levels, it has been reported that childhood BMI is not associated with adult adiposity. We further examined these longitudinal associations. Design. Cohort study based on examinations between 1973 and 1996. Setting. Bogalusa, Louisiana. Participants. Children (2610; ages 2-17 years old) who were followed to ages 18 to 37 years; the mean follow-up was 17.6 years. Main Outcome Measures. BMI-for-age and triceps skinfold thickness (SF) were measured in childhood. Subscapular and triceps SFs were measured among adults, and the mean SF was used as an adiposity index. Adult obesity was defined as a BMI ≥ 30 kg/m2 and adult overfat as a mean SF in the upper (gender-specific) quartile. Results. Childhood levels of both BMI and triceps SF were associated with adult levels of BMI and adiposity. The magnitude of these longitudinal associations increased with childhood age, but the BMI levels of even the youngest (ages 2-5 years) children were moderately associated (r = 0.33-0.41) with adult adiposity. Overweight (BMI-for-age ≥ 95th centile) 2- to 5-year-olds were >4 times as likely to become overfat adults (15 of 23 [65%]), as were children with a BMI < 50th centile (30 of 201 [15%]). Even after accounting for the triceps SF of children, BMI-for-age provided additional information on adult adiposity. Conclusions. Childhood BMI is associated with adult adiposity, but it is possible that the magnitude of this association depends on the relative fatness of children.

Racial and Ethnic Differences in Secular Trends for Childhood BMI, Weight, and Height

Objectives: The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican‐American children.

The association between fruit and vegetable intake and chronic disease risk factors.

Understanding the associations between fruit and vegetable intake and other health behaviors is important for properly interpreting the rapidly growing number of studies that link low intakes of fruits and vegetables to the risk of cancer and cardiovascular disease. To examine the association between fruit and vegetable intake and behavioral risk factors for chronic diseases, we analyzed data from a population-based behavioral risk factor survey. Data were collected in 1990 from 21,892 adults in 16 states by a random-digit-dial telephone survey. Respondents answered questions about behaviors related to chronic disease risk, including their frequency of intake of fruits and vegetables, using a six-item questionnaire. Consumption of fruits and vegetables was lowest among those who also reported that they were sedentary, heavy smokers, heavy drinkers, or had never had their blood cholesterol checked. Because fruit and vegetable intake covaries with several other chronic disease risk factors, it is important to account for possible confounding between fruit and vegetable intake and other behaviors in etiologic studies of the risk of cancer and cardiovascular disease.

Weight loss attempts in adults: goals, duration, and rate of weight loss.

OBJECTIVES Although attempted weight loss is common, little is known about the goals and durations of weight loss attempts and the rates of achieved weight loss in the general population. METHODS Data were collected by telephone in 1989 from adults aged 18 years and older in 39 states and the District of Columbia. Analyses were carried out separately for the 6758 men and 14,915 women who reported currently trying to lose weight. RESULTS Approximately 25% of the men respondents and 40% of the women respondents reported that they were currently trying to lose weight. Among men, a higher percentage of Hispanics (31%) than of Whites (25%) or Blacks (23%) reported trying to lose weight. Among women, however, there were no ethnic differences in prevalence. The average man wanted to lose 30 pounds and to weigh 178 pounds; the average woman wanted to lose 31 pounds and to weigh 133 pounds. Black women wanted to lose an average of 8 pounds more than did White women, but Black womens goal weight was 10 pounds heavier. The average rate of achieved weight loss was 1.4 pounds per week for men and 1.1 pounds per week for women; these averages, however, may reflect only the experience of those most successful at losing weight. CONCLUSIONS Attempted weight loss is a common behavior, regardless of age, gender, or ethnicity, and weight loss goals are substantial; however, obesity remains a major public health problem in the United States.

Weight Control Practices of U.S. Adolescents and Adults

Weight control is an important concern of adolescents and adults for reasons of both health and physical appearance. Although weight control may decrease the risk for chronic disease in adulthood, overemphasis on thinness in adolescence can lead to unhealthy weight-loss practices and may contribute to the development of eating disorders [1]. Although attempts at weight control are common in the U.S. population, little current information on the prevalence of weight control practices is available from population-based studies. Most previous surveys of weight control practices have been conducted among students attending a single high school or college or among persons enrolled in weight control programs. This report estimates the prevalence of various body weight perceptions and weight control practices among U.S. adolescents and adults. We examined data from two surveys: the Youth Risk Behavior Surveillance System, which collected data from a representative sample of U.S. high school students in 1990, and the Behavioral Risk Factor Surveillance System, which collected data from adults in 38 states and the District of Columbia in 1989. Methods Adolescents The national school-based Youth Risk Behavior Survey is used to monitor the prevalence of health risk behaviors among high school students [2, 3]. The 1990 national school-based Youth Risk Behavioral Survey used a self-administered, 75-item questionnaire given within one class period during the spring. Students from public and private schools were selected using a three-stage cluster design to obtain a sample of students in grades 9 through 12 that was representative of the 50 states, the District of Columbia, and the Virgin Islands. Schools with a high proportion of black and Hispanic students were oversampled. The response rate for schools was 74% (124 of 168 schools), and that for students was 87% (11 631 of 13 402 students). We excluded 164 students because of inadequate information on demographics or weight control practices. The final sample included was 11 467 students. Our analysis weighted all responses to compensate for the sampling design. Respondents were asked the following questions about weight perception and weight control practices: 1) Do you think of yourself as too thin (underweight), about the right weight, or too fat (overweight)? 2) Which of the following are you doing about your weight? Not trying to do anything about weight, trying to lose weight, trying to keep from gaining more weight, or trying to gain more weight? 3) During the past 7 days, how many meals did you skip to try to lose weight or to keep from gaining weight? None, 1 or 2 meals, 3 to 6 meals, 7 to 14 meals, 15 or more meals. 4) During the past 7 days, how many times did you take a diet pill, vomit on purpose, or exercise to try to lose weight or keep from gaining weight? Never done this; have done this but not in the past 7 days, 1 or 2 times, 3 to 6 times, 7 to 14 times, 15 or more times. For the purpose of analysis, we defined ever use of these specific weight control methods to include one or more times in the past 7 days or have done this but not in the past 7 days. Adults Data for the Behavioral Risk Factor Surveillance System were collected by state health departments in collaboration with the Centers for Disease Control. The primary purpose of this system was to provide state-specific estimates of behaviors that relate to the leading causes of death among U.S. adults. In each participating state, an independent probability sample of adult residents with telephones was selected using a multistage cluster sampling design based on the Waksberg method [4]. All states used an identical core questionnaire administered by trained interviewers. Interviews lasted approximately 25 minutes [5]. During the interview, all respondents were asked, Are you now trying to lose weight? Those who answered no were asked, Are you now trying to maintain your weight; that is, keep from gaining weight? After the questions on weight control practices, all respondents were asked, Do you now consider yourself to be overweight, underweight, or about average? Questions about self-reported weight and height were asked at the end of the interview [6]. During 1989, 38 states and the District of Columbia collected data. One state was excluded from analysis because information was not collected on weight control practices. We limited our analysis to the 64 311 persons who were not pregnant at the time of the interview. We excluded an additional 3 450 persons because of inadequate information on sociodemographic status, weight perception, weight control goals, or current weight and height. Our final sample included 60 861 participants. The median response rate for the states was 82%. We directly age-standardized all prevalence estimates using the age distribution of the total Behavioral Risk Factor Surveillance System sample as the referent population. We categorized respondents according to three categories of body mass index based on the National Health and Examination Survey (NHANES) II reference sample for persons 20 to 29 years old (< 85th percentile, 85th to < 95th percentile, and 95th percentile) [7]. Results Adolescents Among All Students The Youth Risk Behavior Survey found substantial differences in weight perception between male and female students. Female students were more than twice as likely as male students to consider themselves to be too fat (34% and 15%, respectively) and were less than half as likely to consider themselves to be too thin (7% and 16%, respectively). Among female students, 37% of both whites and Hispanics considered themselves to be too fat compared with 25% among blacks. Among male students, whites and Hispanics were also more likely than blacks to consider themselves to be overweight (16%, 15%, and 8%, respectively). Among female students, 44% reported that they were trying to lose weight, 26% were trying to keep from gaining weight, 7% were trying to gain weight, and 23% were not trying to do anything about their weight (Table 1). Among male students, 15% reported that they were trying to lose weight, 15% were trying to keep from gaining weight, 26% were trying to gain weight, and 44% were not trying to do anything about their weight. Among both male and female students, attempts to lose weight were unrelated to grade level and were most strongly associated with weight perception, although less so among blacks. The students reported using the following methods to lose or maintain weight in the 7 days preceding the survey: exercising (51% of female students and 30% of male students), skipping meals (49% and 18%, respectively), using diet pills (4% and 2%, respectively), and vomiting (3% and 1%, respectively). In general, the percentage of students who reported ever having used these methods was much higher: exercising (80% and 44%, respectively), using diet pills (21% and 5%, respectively), and vomiting (14% and 4%, respectively). Table 1. Prevalence of Current Weight Control Practices among High School Students, by Selected Characteristics from the Youth Risk Behavior Survey, 1990 Among Students Trying To Lose Weight Among both sexes, exercise and skipping meals were much more frequently used to lose weight than were either diet pills or vomiting (Table 2). Exercising once a day or more as a means of weight control was more frequent among male students (29% of male students compared with 19% of female students), whereas skipping meals at least daily was more common among female students (17% of female students compared with 11% of male students). Table 2. Prevalence and Reported Frequency of Specific Weight Control Practices among High School Students Reported in the Past 7 Days among Those Who Are Currently Trying to Lose Weight by Selected Characteristics from the Youth Risk Behavior Survey, 1991* Compared with female students trying to lose weight, male students were slightly more likely to use exercise and less likely to skip meals. Among female students trying to lose weight, use of exercise in the previous week was somewhat higher among those in their first 2 years of high school (see Table 2). Use of other methods did not vary consistently by grade level. White students were most likely and black students were least likely to use exercise for weight control. Among male students who were trying to lose weight, use of diet pills and exercise increased with increasing grade level; however, use of other methods did not vary consistently by grade. Compared with white students, black students were somewhat less likely to report exercise as a means of weight control. Adults Women were more likely than men to consider themselves to be overweight (38% compared with 28%). White, black, and Hispanic women were equally likely to consider themselves overweight. Among men, whites and Hispanics were somewhat more likely than blacks to consider themselves overweight (29%, 28%, and 23%, respectively). Among women, 38% reported that they were trying to lose weight at the time of the survey, 28% were trying to maintain weight, and 33% were doing neither. Among men, 24% reported that they were trying to lose weight, 28% were trying to maintain weight, and 48% were doing neither. Among both sexes, the prevalence of attempts at weight loss was similar among all participants up to 59 years old but decreased substantially at older ages (Table 3). Among women, the prevalence of attempts at weight loss was similar across ethnic and education groups. Among men, Hispanics and the more educated were more likely to report trying to lose weight. Among both sexes, the practice of trying to lose weight was strongly associated with body mass index and weight perception. Table 3. Prevalence of Current Weight Control Practices among Adults by Selected Characteristics from the Behavioral Risk Factor Surveillance System, 1989* Discussion Attempts at weight control are very prevalent among bo

Evaluation of a brief telephone questionnaire to estimate fruit and vegetable consumption in diverse study populations

We evaluated use of a six-item telephone questionnaire to estimate fruit and vegetable intakes in five diverse populations. Researchers administered the telephone questionnaire to persons who had previously undergone more extensive dietary assessment. The study populations included 553 middle-aged and older adults in Beaver Dam, WI; 252 middle-aged and older women throughout Wisconsin; 150 parents of school children in Augusta, GA; 73 low-income, Hispanic mothers in Chicago, IL; and 51 older adults in Arizona. Spearman correlation coefficients between total fruit and vegetable intakes measured by the brief telephone survey and by more extensive food frequency questionnaires were 0.47 (Augusta), 0.48 (Arizona), 0.56 (Wisconsin), and 0.57 (Beaver Dam). Correlation between intakes measured by the brief telephone survey and by multiple diet records or recalls were 0.29 (Arizona), 0.46 (Chicago), and 0.54 (Beaver Dam). With the exception of Arizona, mean daily fruit and vegetable intakes measured by the telephone survey were similar to intakes estimated by multiple diet records or recalls and lower than those estimated by extensive food frequency questionnaires. Although caution may be needed in interpreting dietary reports from some ethnic subgroups, this brief telephone questionnaire may be useful for surveillance of fruit and vegetable intake in the United States. (Epidemiology 1993;4:455–463)

Walking trends among U.S. adults: the Behavioral Risk Factor Surveillance System, 1987-2000.

OBJECTIVE To examine trends in walking among adults in 31 states. METHODS Trends by sociodemographic strata were analyzed from respondents who participated in the Behavioral Risk Factor Surveillance System (BRFSS). RESULTS The prevalence of walking among men increased 3.8% (95% confidence interval [CI]=2.4-5.2), from 26.2% (95% CI=25.1-25.3) in 1987 to 30.1% (95% CI=29.4-30.8) in 2000. In women, walking increased 6.6% (95% CI=5.4-7.8), from 40.4% (95% CI=-39.4-41.1) to 46.9% (95% CI=46.2-47.6) during the same time period. However, the prevalence of walking three times a week for 30 minutes duration remained constant across all years. The largest increases occurred in minority subpopulations: 8.7% (95% CI=3.2-14.2) in Hispanic women, 8.5% (95% CI=4.4-12.6) non-Hispanic black women, and 7.0% (95% CI=2.3-11.7) in non-Hispanic black men. Walking was the most frequently reported activity among adults who met the national recommendations for regular physical activity (defined as five or more times a week for > or =30 minutes per session). CONCLUSIONS Given the acceptability of walking across all sociodemographic subgroups, efforts to increase the frequency of walking could markedly increase the percentage of U.S. adults who engage in regular physical activity, a national priority identified in the Healthy People 2010 objectives for the nation.

The validity of self-reports of past body weights by U.S. adults.

Past weight or patterns of weight change may be more important to chronic disease risk than current weight. Self-reports, however, are often the only source of information about past body weight. To date, very few studies have examined factors affecting the validity of self-reported past body weight. We examined the validity of self-reported past body weights of 1,931 U.S. adults who were participants in the First National Health and Nutrition Examination Survey (1971–1975) and were interviewed again in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (1982–1984). We compared the body weight measured during the initial examination (1971–1975) with the recalled 1971–1975 body weight reported during the follow-up interview (1982–1984). Recalled past weight was strongly correlated with previously measured weight (r = 0.73 for men, and r = 0.74 for women). Men overestimated their past body weight, whereas women underestimated their past weight. Although 39% of men and 41% of women estimated their past weight within 5 pounds, approximately 17% of women and 10% of men underestimated their past weight more than 15 pounds. Accuracy of reporting was influenced by sex, race, current body mass index, and the amount of weight gained over the 10 years following the initial examination. These factors should be considered when using recalled weight in epidemiologic studies.

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∼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/H 3, and W/H p. 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 ⩾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/H 3 or W/H p.

Trends in Fruit and Vegetable Consumption Among Adults in the United States: Behavioral Risk Factor Surveillance System, 1994–2000

OBJECTIVES We examined trends in fruit and vegetable consumption in the United States. METHODS A 6-item food frequency questionnaire was used to assess consumption among 434 121 adults in 49 states and the District of Columbia who were sampled in random-digit-dialed telephone surveys administered in 1994, 1996, 1998, and 2000. RESULTS Although the geometric mean frequency of fruit and vegetable consumption declined slightly, the proportion of respondents consuming fruits and vegetables 5 or more times per day did not change. With the exception of the group aged 18 to 24 years, which experienced a 3-percentage-point increase, little change was seen among sociodemographic subgroups. CONCLUSIONS Frequency of fruit and vegetable consumption changed little from 1994 to 2000. If increases are to be achieved, additional efforts and new strategies will be needed.