Isabelle Valadian

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.

Midgrowth spurt in height of Boston children

SummaryA mid-childhood growth spurt in height was found in 17 of 67 boys and in 0 of 67 girls followed from age two years to adulthood. The growth spurt was detected analytically from variable knot cubic splines which were fitted to the longitudinal height data of each child.

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.

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.

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.

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 womens 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.

PROTEIN NEEDS OF CHILDREN: A PRELIMINARY REPORT OF STUDIES OF INDIVIDUAL DIFFERENCES

Children differ widely among themselves at any age in all aspects of health, growth, development, and adaptation. AIany of these variables are known to affect protein as well as other nutritional needs, but little is known about the extent to which these factors do so, age by age, individually or collectively. Levine‘ has reviewed the principal factors on which a child’s needs depend. I t is difficult to individualize the application of recommended allowances, The problem of recognizing those children whose protein needs are high or low because of basic attributes, or those who temporarily have such needs for special reasons, is difficult because frequent measurement of such needs in the laboratory is impracticable and because the early signs of unmet needs are nonspecific. Accurate clinical observation or measurement of those features of growth and development that are known to influence protein needs is likewise difficult. This paper deals with a limited aspect of a project that has been in progress a t the Department of Maternal and Child Health over the past 26 years under the title of “Longitudinal Studies of Child Health and Devel~prnent .”~ I n this project, individual children have been followed periodicallyt in a multidisciplinary manner from birth to 18 years of age, including limited studies of the mothers during the pregnancies and, thereafter, of the families and environments. TWO hundred and thirty-two children were followed from birth to 6 or more years, 131 of these being followed to 18 years. The staff is now involved with the analysis of the extensive data in hand and in preparing both monodisciplinary and multidisciplinary reports of the findings. Primary emphasis is being placed on the recognition of individual difference throughout entire childhoods, in patterns of growth and development on the one hand and in dietary intakes, illness experiences, and environmental circumstances on the other, as well as upon identifying interrelationships between these data. ’This paper constitutes a preliminary report on one small aspect of the research described, and it does so primarily from the standpoints of exploring * The research project from which the studies reported in this paper are derived has been supported in various aspects and in different years hy grants from many sources. The major support for the areas of research dealt with here has been provided Ijy: The General Education Fund of the Rockefeller Foundation, New York, N. Y. (1933 to 1943); The James Foundation of New York, New York, N. Y . (1944 to 1949); The Nutrition Foundation, Inc., New York, N. Y. (1945 to date); and the Research Grants Division of the I’ublic Health Service, Rethestla, Md. (1047 to date). t The routine followed provided interval histories and a series of examinations at I i r th , 2 weeks, 3, 6 , 9 , and 12 months of age, and every 6 months to 10 or 12 years, and yearly thereafter. The data regularly collected included body measurements, photographs, roentgenograms of several areas, pediatric, orthopedic, and dental evaluations, hemoglobin tleterminations, histories of illness experiences, dietary intakes, habits, activities, and psychosocial problems. Psychological tests and other special examinations also were included less regularly. Basal metabolic determinations were made only during the early years, and no biochemical or nitrogen-balance studies were included.

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.

Adolescent Antecedents to Gynecological Health

Are there factors occurring in childhood and adolescence that influence the reproductive and gynecological health of women? The logic that leads to this possibility includes: The reproductive organs increase greatly in size and weight during pre-adolescence and adolescence. During periods of rapid growth (critical periods) body organs are most vulnerable to insults. The rate of growth and development can be slowed or otherwise modified by disease, deficient diet or other more obscure factors. If factors (such as undernutrition) are imposed on organs while cell division is occurring, the process slows and may stop before full organ growth. If this does occur the number of cells in the organ will always be too few. Body organs with abberrations in cell number or cell size have altered patterns of functioning. Therefore, the overall aim of this study is to identify factors which occur during adolescence that may affect adult reproductive system functioning.