The distribution of body fat from childhood to adulthood in a longitudinal study population.

Body fat distribution, its continuity from childhood (4-6 years) to 30 years of age, and its link to that of parents is described in a longitudinal study population. A computer-assisted image analysis technique was used to measure body fat distribution (as measured by waist and hip diameters) from somatotype photographs. Pearson correlation coefficients were used to assess the association between the waist/hip diameter ratio (WHDR) and the body mass index (BMI) at all ages and between the WHDR of parents and offspring. Both Pearson correlation coefficients and the Foulkes-Davis tracking index were used to assess tracking of the WHDR from childhood to age 30 years. Stepwise regression analyses were performed to determine the predictability of the WHDR at age 30 years from WHDRs in childhood and adolescence. Among both sexes the WHDR decreased and BMIs increased with age from childhood to 18 years, then both increased from age 18 to 30 years. The correlation between the WHDR and BMI was significant only at 30 years for males (r = 0.37; p < 0.05) and during all stages of adolescence in females (p < 0.05). Age-to-age correlations were high for both sexes (p < 0.0001), and remained significant over a span of up to 25 years. Using the Foulkes-Davis tracking index, tracking from the year of peak height velocity to 30 years (a span of approximately 20 years) was strong for both sexes. Parent and child WHDRs were correlated and differed by sex. Father-son correlations were not significant in childhood, but reached significance in early adolescence (2 years before the year of peak velocity) and remained significant to 30 years (p < 0.05). Mother-daughter correlations were significant at all ages (p < 0.05). The level of the WHDR at the peak of the pubertal growth spurt (year of peak height velocity) predicted up to 58% of the variance in males and 51% of the variance in females of the WHDR at 30 years. We conclude that the adult WHDR (a proxy for the waist/hip ratio) becomes evident by the year of the pubertal growth spurt in height.

Body mass index from childhood to middle age: a 50-y follow-up.

The tracking of body mass index (BMI) over a 50-y period in a longitudinal study was examined by using both correlation coefficients and the Foulkes-Davis tracking index. Over the long term, BMIs before maturity were poor predictors of middle-aged BMI status in females but were good predictors in males. The correlation between females' BMI in childhood and their BMIs at two points during middle age (40 and 50 y) was zero; in males it was r = 0.36 and 0.41, respectively. Between-age correlations were high (P less than 0.0001) for both sexes, reflecting stability in BMI over the shorter term (less than or equal to 10 y). The tracking of BMI (with the Foulkes-Davis tracking index) from childhood to middle age was better for males than for females (P less than 0.1). Linear-regression analysis was also used to assess the predictability of relative body size in middle age from earlier measures; BMI in childhood accounted for 0% of the variance in females and 17% in males. We conclude that the prediction of ponderosity in middle age from BMIs early in life is more reliable for males than for females.

Modelling adolescent blood pressure patterns and their prediction of adult pressures.

Tracking of blood pressure in adolescent boys is investigated using a mathematical model that corresponds to progression along a constant percentile. A more general analysis, based on the method of principal components, is also proposed that determines various alternative tracks or patterns that are most prevalent in the longitudinal blood pressure data. The degree of tracking along a constant percentile curve for systolic pressure was moderately high, as evidenced by a tracking index of .78 explaining 81% of the variance, but less strong for diastolic (tracking index of .60) where tracking along a percentile explained 66% of the variance. The value of the more general analysis of blood pressure patterns may lie in the assessment of adolescent risk factors for elevated adult blood pressure. Using adolescent patterns determined by either statistical model, adult systolic at age 38 was predicted (R2 = .22) by the concept of a systolic fixed percentile curve in adolescence, and similarly for diastolic (R2 = .21). However, the more general analysis based on longitudinal principal components further suggests that boys who have a larger than usual systolic peak at age 14 years, which is near the time of the adolescent physical growth spurt in these boys, may be more likely to have higher systolic pressures at age 38. Because the adult data were incomplete and highly unbalanced, these findings were obtained using random-effects models for longitudinal data.

Longitudinal analysis of incomplete adolescent data.

An approach is illustrated for the analysis of longitudinal variables collected during adolescence. Since the method requires complete data, three techniques are compared for application when some individuals have missing values. These methods are implemented in a study of systolic blood pressures and dietary fat intakes collected longitudinally in adolescent girls. The value of adolescent systolic and fat variables in predicting systolic pressure in adult women is investigated.

Long-term memory of body weight and past weight satisfaction: a longitudinal follow-up study.

Recalled body weight and self-reported current weight were validated in a longitudinal study population by comparing recalls at 50 y to actual measures taken at ages 18, 30, 40, and 50 y. Recalled body weights were also compared with reported desired weights at these same ages. Self-reported weights at 50 y were equally accurate for both males and females; the mean reporting underestimate was -1.98 kg for males and -1.86 kg for females. Males' self reports at age 50 y were influenced by years of education (P less than 0.005) and current body size (P less than 0.0001) whereas females' were not. Correlations between recall of past weights and measured weights ranged from r = 0.87 at 18 y to 0.95 at 40 y. Recalls of past body weight were not significantly influenced by the passage of time, the number of years of education, or the accuracy of current weight reports. Current body size (wt/ht2) was significantly associated with life-time weight dissatisfaction in both sexes (P less than 0.0005).

Accuracy of recall by middle-aged participants in a longitudinal study of their body size and indices of maturation earlier in life.

The validity of long-term recall and current assessments of height, weight, and fatness relative to peers was investigated among 91 middle-aged participants in a longitudinal growth study. The recollections of 50-year-old participants concerning perceived body size in comparison to peers during childhood (aged 5-7 years), adolescence (aged 10-18 years), and at ages 30, and 40 years were compared with physical measurements taken at these times. Correlations between perceived and actual body size at all ages from childhood through middle-age were moderate but significant (P less than 0.005) and were influenced by gender and phases of physical growth (early and late adolescence). In general, accuracy of self-reports of current body size were not significantly better than recalls of body size up to 50 years earlier. Respondents' recall of various physiological events was also assessed. Females' actual and recalled year of menarche were correlated (r = 0.67; P less than 0.0001). Age at menarche was recalled within 1 year of the actual event by 84% of the females. Fifty percent of both sexes recalled their year of maximal growth in height within 1 year and recalled the timing of their maturation (early, average, or late) in relationship to their peers equally well (P less than 0.001).

Memory of food intake in the distant past.

Long term recalls of dietary intake are frequently used in case-control studies, but their validity and reliability have not been established. In this study, 91 middle-aged adults (median age, 50 years) who were participants in the Longitudinal Study of Child Health and Development at the Harvard School of Public Health in Boston, Massachusetts, starting in the early 1930s, were asked in 1984-1985 to report present food intake and to recall food intakes at ages 5-7 years. 18 years, and 30 years using food frequency questionnaires. Their recalled intakes were validated by comparison with historical records of intake collected during the earlier time periods. Recall of food intake in the distant past was a better predictor of historical intake than was current diet. However, correlations between recalled and historical consumption for individual foods and food groups were generally low, rarely exceeding 0.3. Current intakes exerted a powerful influence on accuracy of recall. The consideration of participant characteristics did not prove to be consistently useful in explaining variations in food item and food group-related recall. The authors conclude that recall of food intake in the distant past may be a sufficiently valid estimate of past intake to justify its collection.

Medical services and socioeconomic factors: determinants of infant mortality in Greece.

Socioeconomic factors are at least as important as narrowly defined medical care factors in determining the health status of the population. They also provide a stimulus for further research in the field of socioeconomic epidemiology.

Accuracy of recalled smoking data.

Validity of recalled cigarette data was assessed among 87 middle-aged adults by comparing recall to longitudinal records. Agreement on smoking status and amount smoked 20 years ago occurred for 87 per cent and 71 per cent of subjects, respectively. Corresponding proportions for 32-year recall were 84 per cent and 55 per cent. Gender did not influence recall accuracy. Ex-smokers tended to make the most errors. Accuracy of recalled smoking information 20 years ago was comparable to that of alcohol status and consumption frequency category.

Recall of childhood illnesses.

Recall of eight childhood communicable diseases and other illnesses was validated among 95 adults by comparison to longitudinal childhood health records. Self-reports at age 50 of several illnesses were highly accurate; however, German measles was correctly recalled by only 34% of subjects. Similar levels of accuracy were consistently found among a subset who also completed health history interviews 8 and 20 years earlier. Over-reporting of some health events was common. Past exposure to viral or bacterial agents is sometimes assessed in case-control studies by self-reports. Misclassification of prior exposure due to faulty recall may distort true associations between childhood illness and chronic disease in later life.

Social factors and professional attitudes as determinants of the frequency of small surgical procedures among children in Greece.

Data concerning histories of Adenoidectomy (Ad), Tonsillectomy (T) and Appendectomy (Ap) were collected from the escorts (mainly mothers) of 2296 children 3-12 years-old. The children were admitted as outpatients at the First Department of Paediatrics of the University of Athens or the Polyclinic of the Children's Welfare Center of PIKPA in Pireaus, during the last six months of 1983. Among children with median age of about six years, 12 percent had already had at least one operation (Ad, T or Ap); this proportion increased to about 25 percent among children with median age of about 10 years. The cumulative incidence of Ad and/or T was higher among boys, whereas the cumulative incidence of Ap was higher among girls. The age adjusted cumulative incidence of Ap was significantly higher in the lower social class, whereas there was no social gradient with respect to Ad or T. There were strong intra-individual correlations among the three studied operations; in particular the age adjusted cumulative incidence of Ap was 2.9 times higher among children with Ad and/or T than among children without any of these operations. Since there are no apparent biomedical reasons to account for the observed intra-individual associations, it appears likely, that these associations reflect parental or physician's attitudes leading to unjustifiable operations in some of the children.

Growth in "new" vegetarian preschool children using the Jenss-Bayley curve fitting technique.

Length and weight measurements obtained on 142 vegetarian and 229 nonvegetarian school children from a normative population were fitted to growth curves using the asymptotic nonlinear regression equation of Jenss and Bayley. All of the children were Caucasian and age ranged from a few weeks to 6 yr. The growth curves obtained for vegetarian children were from 0.5 to 1.0 kg and 1 to 2 cm lower, depending on age, sex, and diet, than were curves for reference populations of nonvegetarian children. Length was affected more than weight. Macrobiotic vegetarian children's curves were more depressed than those of the other vegetarian children, indicating that there was a good deal of heterogeneity in growth within vegetarians which was associated with dietary group characteristics. Measurements of females were more consistently affected than males, and their diets were also more far reaching with respect to animal food avoidances. The analysis of food records available provided evidence that energy intakes of the vegetarians were below recommended levels, whereas protein intakes did not appear to be limiting.

Longitudinal growth standards for preschool children.

The appropriateness of a preschool child's size at a particular age is usually assessed by comparing the child's measurement against growth charts. When the child has measurements at more than one age, the child's percentile status at one age is sometimes compared with the percentile status at a subsequent age, with the purpose of assessing the child's pattern over time or growth rate. This second use of growth charts is not entirely appropriate, for it assumes a high degree of 'tracking' in the population. Healthy children frequently cross percentile lines, the amount of shifting depending upon the age range under consideration, the child's sex, and whether the measurements are length or weight. Thus the correct evaluation of percentile-level changes over time is difficult. We present here conditional standards for length and weight in preschool children, which assess a child's length or weight taking into account previous measurements and/or a current measurement of a second anthropometric variable. The approach can be very flexible as regards ages of measurement, although complete flexibility requires use of a computer. In addition to its clinical application, this approach can be used to predict the future size of a child and may be valuable as an analytic tool in research situations in which control populations are not feasible.

Changes over thirty years in an index of gynaecological health.

The gynaecological index (GYNDEX) was developed to facilitate observing differences in gynaecological health among and between groups of women. It takes into account menstrual characteristics, premenstrual changes, and gynaecological diagnoses and treatments. The objective of this study is to contribute to knowledge of the changes in gynaecological health at different times in the reproductive life cycles of women and to develop a measurement technique which can be used in future studies in women's health. In this investigation a GYNDEX is determined for each of the first three decades postmenarche in a sample of 54 women who have been followed in a longitudinal study since birth, and the characteristics of the changes in the GYNDEX over time are analysed. There is a significant increase in the GYNDEX (P less than 0.05) in each successive decade. Further studies are being done to determine to what extent factors that occurred in the childhood and adolescence act as predictors of adult gynaecological health. Knowledge of these relationships will provide a rationale for planning health care programmes for women of all ages.

Size, obesity, and leanness in vegetarian preschool children.

Alterations in a series of anthropometric measurements taken on 142 vegetarian preschool children adhering to macrobiotic or other vegetarian regimens were studied. Length, subscapular skinfolds, and arm-muscle cirumferences differed from expectations. Dietary group and age, but not sex, were associated with these variations. Measurements were more likely to be depressed among children on a macrobiotic diet. Differences were significant among children twelve to thirty-five months of age for length and subscapular skinfolds and among children thirty-six months or older for arm circumference and subscapular skinfolds. Fewer vegetarian children were obese, and more were lean, than would be expected from norms.

Preschoolers on alternate life-style diets. Associations between size and dietary indexes with diets limited in types of animal foods.

One hundred nineteen vegetarian preschool children whose parents volunteered were studied in their homes. Length, weight, triceps and subscapular skinfolds, and head circumference were measured. Information on extensiveness of avoidances of animal food groups, parental dietary group, birth weight, parental heights, and the child's status with respect to breast feeding at the time of measurement was obtained by parental report. All infants under six months old were breast fed. More of the children's measurements were below the Harvard 50th percentiles for length and weight than would have been expected after six months of age, but not until then. Vegetarian children were also leaner (triceps and subscapular skinfolds) after six months of age than would be expected from Tanner-Whitehouse standards. Head circumferences were similar to standards and within normal limits at all ages. An association between smallness, lightness, and leanness was found among the vegetarians, with these characteristics being more pronounced among the older, non-breast fed, macrobiotic children on diets with limited variety in terms of animal food. While smallness and low weight-for-length were associated with leanness, largeness and high weight-for-length did not imply obesity in these subjects.