Introduction to statistical models for longitudinal observation, James Dwyer and Manning Feinleib Considerations in the design of longitudinal surveys of health, Lester Curtin and Manning Feinleib: PART I: MODELS FOR CONTINUOUS VARIABLES: Linear differential equation models for longitudinal data: Application: blood pressure and relative weight, James Dwyer Unconditional linear models for longitudinal data: Application: lead exposure and cognitive development in infants, Christine Waternaux, Nan Laird and James Ware Conditional linear models for longitudinal data: Application: cigarette smoking and respiratory function in adolescents, Bernard Rosner and Alvara Munoz Linear structural equation modelling with non-normal continuous variables: Application: relations among social support, drug use and health in young adults, Peter Bentler and Michael Newcomb: PART II MODELS FOR CATEGORICAL DATA: Use of the logistic and related models in longitudinal studies of chronic disease risk: Application: coronary heart disease mortality in Framingham, Norman Breslow Generalized linear models for longitudinal data: Application: xeropthalmia in Indonesia, Lawrence Moulton Some aspects of weighted least-squares analysis for longitudinal categorical data: Application: clinical trial of treatment for skin disorder, Garry Koch, Julio Singer and Maura Stokes: PART III: SPECIAL PROBLEMS IN THE MODELLING OF LONGITUDINAL OBSERVATIONS: Non-random attrition in the Framingham Heart Study: Application: age trends in blood pressure, Manning Feinleib and Joan Pinsky.

In an attempt to study and prevent the development of hypertension, there is a growing interest in measuring blood pressure in children. The aim of this is to detect and monitor those with a relatively high level of blood pressure. Until now, reference values on blood pressure in children are based on data from North-American youngsters. The present study provides percentile charts based on pooled data from studies on blood pressure conducted in six North-West European countries among 28 043 children. These blood pressure centiles are presented as age-, height- and gender-specific. Brief guidelines for blood pressure measurements in childhood and for detection of children with a relatively high blood pressure are included.

Patterns of leisure-time physical activity among 932 West Germany boys and girls from two distinct socioeconomic groups were examined longitudinally over a 2-year period beginning with seventh to eighth grade students. Activity indices reflect the weekly time spent in activities, the weekly frequency of participation, and the average duration per activity episode. The indices refer to all activities, to moderate or vigorous activities, or to each individual activity. The average seventh to eighth grade student spent 10.1hr/week engaged in all of the activities measured. Overall, the time devoted to these activities declined by 10% during the 2-year study period, with the relaive decrease being larger for vigous than for moderate activities. The decline in time spent in vigorous activity was due to a decreased frequency of participation; whereas the decline in moderate activity was primarily attributable to the decreased average duration per episode. Boys spent about 3 hr/week more in all activities than girls, with the difference largely being due to the boys greater participation in vigorous activities. Weekly activity time among girls did not vary substantially with socioeconomic status. However, compared with boys of higher socioeconomic status, boys in the lower socioeconomic grouping were 2–3 hr/wk more activity because they devoted more time to moderate activities. The results indicate that the identified activity patterns in the population strongly depend on the activity dimensions on which the measure focuses.

The current study was conducted to determine if smokers and nonsmokers differ in serum concentrations of high-density lipoprotein cholesterol (HDL-C) before smoking initiation and if a decline in HDL-C levels could be detected among adolescents during the first two years of smoking. Changes in HDL-C levels and smoking were observed longitudinally in 1983, 1984, and 1985 among 691 seventh and eighth graders (age range, 12 to 14 years) from two German cities; 82% were nonsmokers at baseline. For these baseline nonsmokers, no differences in baseline HDL-C concentrations were found between those who became smokers and those who remained nonsmokers. In contrast, those who became light (one to 39 cigarettes per week) or moderate (greater than or equal to 40 cigarettes per week) smokers by one or two years after the initial examination evidenced lower mean HDL-C concentrations relative to persistent nonsmokers at follow-up, constituting a decrement of -0.016 mmol/L [SE = .035] (-0.6 mg/dL) [SE = 1.4] for light smokers and -0.114 mmol/L [SE = .064] (-4.4 mg/dL) [SE = 2.5] for moderate smokers. These findings suggest that short-term exposure to cigarette smoke at low levels may have atherogenic consequences.

Longitudinal data from the «Berlin-Bremen Study on Health Behavior» are used to investigate smoking transitions between different stages of smoking. 1357 seventh and eighth graders were asked about their smoking behavior, their expectations with regard to smoking, smoking in their environment, and their self-image in Fall, 1983. 86% and 81% participated again one and two years later, respectively. Analyses of carbon monoxide and serum thiocyanate levels revealed adequate validity for self-reported smoking behavior. Rates of smoking were dramatically different for different educational strata. Direct and indirect functions of smoking are distinguished. The «indirect» function refers to smoking as a means of obtaining access to peer groups, thus increasing one’s psychological well-being. Direct functions refer to social and affective effects of smoking such as looking older or calming down. In line with expectations, indirect functions were found to be more important for younger adolescents and for smoking onset. In contrast, direct functions were better predictors of the smoking behavior of older adolescents and of the transition to regular smoking.

In an exploratory study involving 818 pupils 12-16 years of age blood pressure, total serum cholesterol, and smoking behavior were studied. 38.3% of the boys (N = 154) and 47.3% of the girls (N = 143) aged 15-16 demonstrated singular or combined elevated risk variables, cigarette smoking being the most predominant risk factor. 44.5% of the pupils of this age group answered to be regular smokers. 59.8% (N = 183) of secondary school pupils stated to be regular smokers as compared to 15.7% (N = 166) of grammar school pupils. The most important socialpsychological process variables were attitude of friends towards smoking, smoking experience of friends, and social function of smoking within groups. The importance of these variables showed differences according to type of school as well as gender which should be taken into account modelling preventing programmes.

An international collaborative health screening project was undertaken to stimulate interest in child health education, to study feasibility of health screening in young children from diverse cultures, and to compare the distribution of chronic disease risk factors among 15 countries. Data for the 13-year-old participants showed that risk factors defined by cholesterol greater than 180 mg/dl, systolic blood pressure greater than 130 mm Hg, and daily or occasional smoking were present, to varying degrees, in children from each country. We found no relationship between obesity and cholesterol or blood pressure for these children. The acceptability of the screening, the children's enjoyment in participation, and the prevalence of risk factors at this young age lead to the conclusion that school-based health education programs should be initiated during childhood.

In preparation for a comprehensive intervention project concerned with smoking behavior, physical activity, nutrition, and alcohol, an exploratory study of 800 public school and gymnasium pupils in the seventh and ninth grades (12–16 years old) was undertaken. The median of total serum cholesterol dropped from 4.8 mmol/liter in 12-year-old pupils to 4.2 mmol/liter in 16-year-olds. The decrease was greater in boys than in girls (0.7 versus 0.4 mmol/liter). The systolic and diastolic blood pressures rose slightly with age in boys and girls. The prevalence of occasional and daily smokers was 19.8 and 21%, respectively. The proportion of daily smokers was 36.4% among public school students (lower socioeconomic status) versus 4.1% among gymnasium pupils (higher socioeconomic status). Similar differences were found for the serum thiocyanate levels.

Seit dem zweiten Weltkrieg ist in alien industrialisierten Ländern eine außerordentliche Zunahme der kardiovaskulären Morbidität und Mortalität beobachtet worden. Ein ähnlich starker Anstieg war bei keiner anderen Todesursachengruppe, Krebs eingeschlossen, festzustellen. Herz-Kreislauf-Krankheiten rückten unter den Todesursachen an die erste Stelle. Diese Entwicklung war mit der Vorverlegung des Krankheitsbe-ginns in jüngere Jahrgänge verbunden und führte damit zu einem besonders ausgeprägten Morbiditätsanstieg im Erwerbstätigenalter.