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PubMed1985

Sex education and sexual experience among adolescents.

This paper examines the association between sex education and adolescent sexual behavior. Data from the 1981 National Survey of Children show that 15- and 16-year-olds who have been exposed to sex education are less likely to be sexually experienced, and are neither more nor less likely to discuss sex with parents at home. Retrospective or longitudinal data are needed to more directly test the casual link between sex education and experience.

Adolescent↗

PubMed1994

Physical activity and training: effects on stature and the adolescent growth spurt.

Statural growth (size attained), age at peak height velocity (PHV), and growth rate were compared in two samples of boys classified as habitually physically active and inactive, and in two samples of boys regularly training in sport (primarily team sports). Individual growth records were fitted mathematically in three of the samples (two as reported by the respective authors and one for the present report), while curves were fit to group means for the fourth sample. There were no differences in size, age at PHV, and PHV between active and inactive boys, but the parameters of the adolescent spurt for boys regularly involved in sport were characteristic of early maturers. Longitudinal data are less extensive for girls. Stature data for three samples of young athletes in gymnastics, swimming, and track/rowing indicated a stable pattern relative to reference data for nonathletes, i.e., swimmers, track athletes, and rowers were already taller and gymnasts already shorter than average during childhood and maintained their position relative to reference data during childhood and adolescence. Allowing for sample size and variation in descriptions of habitual physical activity and training for sport, the data suggest that regular physical activity, sport participation, and training for sport have no effect on attained stature, timing of PHV, and rate of growth in stature. Prospective data for the swimmers, track athletes, and rowers indicate no effect of training on the timing of menarche.

Adolescent↗

PubMed1999

How older people in the United States and Germany fared in the growth years of the 1980s: a cross-sectional versus a longitudinal view.

OBJECTIVES: The goal of the study was to show that cross-sectional and longitudinal data yield dramatically different answers to a basic question: "How did older persons fare in the recovery years of the 1980s?" METHODS: The United States Panel Study of Income Dynamics and the German Socio-Economic Panel are used cross-sectionally to capture changes in the economic well-being of older persons in the trough and peak years of the 1980s business cycle, and longitudinally to trace how the economic well-being of a given cohort of older persons changed over those years. Kernel density estimation is then used to show how the distribution of economic well-being of these populations changed over these years. RESULTS: Cross-sectional comparisons confirm that persons aged 65 and over in the peak year were better off than persons aged 65 and over in the trough year in both countries. Longitudinal comparisons, however, show that persons aged 65 and over in the trough year who survived to the peak year received a substantially smaller share of the rewards of economic recovery than cross-sectional comparisons imply. Moreover, the entire income distribution of older persons in the United States shifted downwards. DISCUSSION: Compositional changes in the cross-sectional data, caused by the entry of high-income persons who are young in the peak year but old in the trough year, obscure the decline in the economic well-being of the cohort of older persons who survived the trough year, in cross-sectional comparisons of older populations in the United States in the 1980s.

Age Factors↗

PubMed1993

Recurrent overeating: an empirical comparison of binge eating disorder, bulimia nervosa, and obesity.

The goal of the study was to contribute empirical data to the discussion of appropriate diagnostic classification of obese and nonobese, binging, and nonbinging eating disordered patients. The study consists of two parts: (1) patients with binge eating disorder (BED) (N = 22) are compared to a matched sample of patients with bulimia nervosa (BN) and to 16 patients with obesity (body mass index [BMI] > 30). These patient groups were cross-sectionally assessed using expert ratings (interview) and self-ratings. (2) A sample of 68 patients with BED were assessed longitudinally on admission and discharge of inpatient treatment and at a 3-year follow-up using the same instruments as in the first study. The study is the first to report longitudinal data on patients with BED. The general pattern of the cross-sectional data was that patients with BN not only had higher scores concerning disturbances of eating behavior and attitude but also for general psychopathology when compared to patients with obesity without marked binges. The scores of patients with BED had an intermediate position between BN and obesity but were closer to BN than to obesity. The BED group (and the obesity group) showed a high degree of body dissatisfaction, which, however, was accounted for by their high body weight. Concerning general psychopathology BED as well as BN had significantly higher scores than the obesity group in the Hopkin's Symptom Checklist (SCL) subscale anger and hostility, in the Complaint List, the PERI Demoralization Scale, and the Beck Depression Inventory. Results of the longitudinal study with BED showed marked improvement in specific and general psychopathology over time. Except for body weight this improvement largely persisted over the 3-year follow-up period. Severity of depression did not predict the course of body weight over time. Data are presented concerning the design of diagnostic criteria for eating disturbed patients not fitting criteria for BN or anorexia nervosa (AN). Arguments pro and contra the introduction of a new BED category in psychiatric diagnostic criteria are discussed. Although there is generally a need for developing or revising the diagnostic criteria for recurrent bingers, our data do not support inclusion of BED (as presently defined) as a separate diagnostic category in DSM-IV.

Adult↗

PubMed2003

Adult height and weight of breast-fed and bottle-fed Israeli infants.

BACKGROUND: Breast-fed infants grow more slowly than bottle-fed infants. This growth deceleration sometimes alarms health care personnel to the point of considering other forms of nutrition. OBJECTIVES: To evaluate the final adult anthropometric outcome associated with breast or formula feeding during infancy. DESIGN: Height and weight data were collected from eight well-baby clinics representing various ethnic origins, lifestyles, and socioeconomic backgrounds. Children were measured every 1 to 2 months for the first 6 months, every 3 months until 2 years of age, and yearly thereafter, until they reached their final height. Longitudinal data were collected from 1960 healthy children (961 boys). Overall, 613 of the children were breast fed for 1 year and 218 for 6 months. RESULTS: The magnitude of the decline in Z scores of breast-fed vs. bottle-fed infants, between birth and 1 year of age was not as great for height as for weight -0.2 and -0.3 respectively, and disappeared at 2 years of age. The weight for height decreased between birth and the end of the first year in breast-fed children by 0.3 (Z score). Children switched to bottle feeding exhibited a growth spurt. However, there was no difference in the final heights or weights of breast-fed children compared with bottle-fed children 165.3 +/- 6.2 (n = 134) versus 164.9 +/- 6.4 (n = 195) in females, respectively, and 175.3 +/- 6.8 (n = 122) versus 175.8 +/- 7.1 (n = 162) in males, respectively. Adult obesity in this sample population (n = 637) was correlated with maternal obesity. Maternal BMI SD correlated with offspring BMI SD at 18 years of age (r = 0.873, P < 0.001) but not with breast feeding. Adult BMI was similar between the breast-fed and bottle-fed groups. CONCLUSIONS: Despite their slower growth rate, breast-fed children reach the same final height as bottle-fed children. Breast-fed infants should be monitored according to specifically designed growth charts. Obesity in adult life is correlated with factors not related to breast feeding.

Body Height↗

PubMed2004

Use of structured antedependence models for the genetic analysis of growth curves.

Growth curve analysis is an important issue for many agricultural and laboratory species, for both phenotypic and genetic studies. The aim of this paper is to present the use of a novel statistical approach, namely the structured antedependence (SAD) models, to deal with this issue. The basic idea of these models is that an observation at time t can be explained by the previous observations. These models are especially appropriate to deal with cumulative traits such as growth, as BW at age t clearly depends on BW measures at ages (t -1), (t -2), etc. These models were applied on an INRA experimental Charolais herd data set. The data comprised BW records for 560 cows born over an 11-yr period (from 1988 to 1998) from 60 sires and 369 dams. The proposed SAD models were compared with the well-known random regression (RR) models that are already widely used in various areas of longitudinal data analysis. It was found that the SAD models fit the growth process better with far fewer parameters than the RR models (9 instead of 16 covariance parameters for the phenotypic analysis, and 14 instead of 21 for the genetic analysis). Despite this smaller number of covariance parameters, the likelihood value was found to be much higher with the SAD vs. the RR models, with a difference of 262.9 for the phenotypic analysis with a quartic polynomial for the RR and 751.5 for the genetic analysis with a cubic polynomial for both the genetic and environmental parts of the RR model. The SAD models also proved to be better able to interpolate missing values. Heritability, genetic, and environmental correlation coefficients were estimated for weights from birth to adulthood. The structured antedependence models proved, in this study, to be very appropriate to model growth data in a parsimonious and flexible way.

Aging↗

PubMed1992

Epidemiology and aging: how gerontology has changed noncommunicable disease epidemiology in the United States of America.

Epidemiology is a continuously evolving discipline that has been greatly enriched by addressing the health problems of the elderly. In the United States of America, this has resulted in a large national data resource of functional and health measures on older populations, heretofore not available. In this article, suggestions are made for research priorities in the next 10 years in the epidemiological study of the elderly. They include: (i) a special emphasis on enhancing analytical methods, particularly for complex longitudinal data; (ii) an effort to understand the impact of the physiochemical environment on older persons, both in the household and workplace setting; (iii) the identification of new ways to determine early life exposures among older persons, so that hypotheses about early influences on aging processes can be tested; and (iv) a general effort to include function status and other geriatric measures as a routine part of the clinical record, so that secondary research on such records can be more conveniently performed.

Aged↗

PubMed2006

Multilevel logistic regression modelling with correlated random effects: application to the Smoking Cessation for Youth study.

A multilevel logistic regression model is presented for the analysis of clustered and repeated binary response data. At the subject level, serial dependence is expected between repeated measures recorded on the same individual. At the cluster level, correlations of observations within the same subgroup are present due to the inherent hierarchical setting. Two random components are therefore incorporated explicitly within the linear predictor to account for the simultaneous heterogeneity and autoregressive structure. Application to analyse a set of longitudinal data from an adolescent smoking cessation intervention that motivated this study is illustrated.

Adolescent↗

PubMed2006

Influence of family type and parenting behaviours on teenage sexual behaviour and conceptions.

BACKGROUND: Longitudinal data were used to explore relations between teenage pregnancy, sexual behaviour, and family type. The study examined whether students from lone parent and/or teenage mother initiated families more commonly report sex, lack of contraception at first sex, and/or conceptions by age 15/16, and whether such associations can be explained by low parental strictness, difficult parent-child communication, and/or low parental input into sex education. Up to date longitudinal UK research on family influences on conceptions is lacking, as is longitudinal research on family influences on sexual behaviour. No previous studies have comprehensively examined effects of parenting behaviours. Unlike previous research, this study tested theories suggesting that parenting deficits among lone parent and teenage initiated families increase risk of teenage pregnancy among their children. METHODS: Secondary analysis of data from a trial of sex education. RESULTS: Girls and boys from lone parent families or having mothers who were teenagers when they were born were more likely to report sex but not lack of contraception at first sex by age 15/16. Girls and boys with mothers having them as teenagers, and boys but not girls from lone parent families, were more likely to report being involved in conceptions by age 15/16. Only the association between teenage mother family and girls' conceptions was reduced by adjusting for a parenting behaviour measure. CONCLUSIONS: Students from lone parent families or having mothers who were teenagers when they were born are more likely to report early sexual debut and conceptions by age 15/16, but this is not generally explained by parenting style.

Adolescent↗

PubMed2004

Gender differences in depression: the role of personality factors.

The goal of the study was to determine the association between gender and the Big Five personality factors, and to identify the role of personality factors in the association between gender and depression among adults in the United States. Data were drawn from the Midlife Development in the United States Survey (N=3032). Multivariate analysis of variance (MANOVA) was used to examine gender differences on the Big Five personality factors (i.e. agreeableness, neuroticism, openness to experience, extraversion, and conscientiousness). Multivariate logistic regression analyses were conducted to examine the relation between gender and depression, and to test whether this association is moderated by neuroticism. Levels of neuroticism, agreeableness, extraversion, and conscientiousness were significantly higher among females than among males; in contrast, level of openness to experience was significantly higher among males. Female gender was associated with increased odds of experiencing depression. Results showed that neuroticism played a significant contributory role in the relationship between being female and major depression, though the role of gender remained statistically significant after adjustment. These data suggest that gender differences in personality factors, specifically neuroticism, may play a key role in the well-documented gender difference in depression. Our findings indicate that neuroticism may moderate the association between female gender and increased risk of depression among adults. These findings require replication using longitudinal data.

Adult↗

PubMed1989

Measuring the impact of locational characteristics on migration: interpreting cross-sectional analyses.

Methods that employ cross-sectional data to analyze the impact of locational characteristics on migration decisions may produce seriously biased results because migrant decisions at any one point in time reflect historical as well as contemporaneous forces. A comparison of results based on a typical cross-sectional analysis and those obtained with longitudinal data shows that these issues are of empirical importance. An alternative interpretation of the results of cross-sectional migration analyses is provided.

Choice Behavior↗

PubMed2006

Approximate entropy of self-reported mood prior to episodes in bipolar disorder.

BACKGROUND: Approximate entropy (ApEn) measures regularity in time series data, while traditional linear statistics measure variability. Using self-reported mood data from patients with bipolar disorder, this preliminary study addressed whether ApEn could distinguish (i) the 60 days prior to the start of a manic or depressed episode from the 60 days prior to a month of euthymia, and (ii) the 60 days prior to a manic episode from the 60 days prior to a depressed episode. METHODS: Self-reported mood data from 49 outpatients with bipolar disorder receiving standard treatment were analysed. The data contained 27 episodes (12 manic and 15 depressed), and 43 periods of 1 month of euthymia. For the 60 days prior to episode or euthymia, the ApEn, linear statistics and the correlation between linear and non-linear measures were calculated. RESULTS: ApEn was significantly greater in the 60 days prior to a manic or depressive episode than the 60 days prior to a month of euthymia. The onset of an episode was associated with greater irregularity in mood. Variability was also significantly larger and correlated with ApEn. ApEn was significantly greater in the 60 days prior to a manic episode than in the 60 days prior to a depressed episode, whereas measures of variability were not significantly different. Mood in the 60 days prior to mania was more irregular than prior to depression. CONCLUSIONS: Non-linear measures may complement traditional linear measures in the analysis of longitudinal data in bipolar disorder. A larger study is indicated.

Adult↗

PubMedDate not supplied

Preliminary validation of PRISM (Pictorial Representation of Illness and Self Measure) - a brief method to assess suffering.

BACKGROUND: Alleviation of suffering is widely acknowledged as one of the main goals of medicine. However, no measure to assess this crucial aspect of illness has been developed to date. AIMS: To validate PRISM (Pictorial Representation of Illness and Self-Measure) as a simple quantitative method of assessing the perceived burden of suffering due to illness. METHODS: Validity and reliability studies to date have involved over 700 patients with a variety of chronic physical illnesses. RESULTS: Reliability of PRISM is good (test-retest reliability r = 0.95; p < or = 0.001, interrater reliability r = 0.79; p < or = 0.001). Qualitative data indicate that the interpretation of the PRISM task is not only consistent among patients, but also consistent with that expected from existing literature on suffering. As expected, PRISM shows strong correlations with psychological variables (notably depression and coping resilience) and also correlates with SF-36 subscale scores. Prospective longitudinal data demonstrate that PRISM is sensitive to therapeutic change. It is very acceptable to patients and takes less than 5 min to administer. CONCLUSION: In the absence of a 'gold standard' measure of suffering, our validation data must be interpreted with caution. However, the performance of PRISM is entirely consistent with what would be expected of a measure of suffering, based on current published work.

Adult↗

PubMed2001

The effect of neurocranial surgery on basicranial morphology in isolated sagittal craniosynostosis.

OBJECTIVE: Isolated sagittal craniosynostosis produces a scaphocephalic neurocranium associated with abnormal basicranial morphology, providing additional evidence of the developmental relationship of the neurocranium and basicranium. Corrective surgical procedures vary, but the immediate impact of the surgical procedure is restricted to the neurocranium. This study addresses the secondary effects of neurocranial surgery on the cranial base. DESIGN: Three-dimensional (3-D) computed tomography (CT) scans were obtained for preoperative (n = 25) and postoperative (n = 12) patients with isolated sagittal synostosis. Landmark data from 14 landmarks on and around the cranial base were collected from 3-D CT reconstructions and analyzed using Euclidean distance matrix analysis. Subsamples of age-matched patients were used to identify basicranial differences in pre- and postoperative patients and to compare postoperative growth patterns identified in longitudinal data with preoperative growth patterns characterized in cross-sectional data. RESULTS: Statistically significant differences (p < or = 0.10) were found in the morphology of the cranial base in preoperative and postoperative patients. The relative positions of the landmarks nasion, right asterion, and left asterion are similar in preoperative and postoperative patients. However, the position of these landmarks relative to the cranial base is different in the two groups, being positioned relatively more anteriorly in postoperative patients. In addition, we found that the cranial base angle, on average, neither increases nor decreases in the first postoperative year. These morphological differences are associated with divergent growth trajectories in the operated and unoperated cranial base. CONCLUSION: Regardless of specific procedure, neurocranial surgery in sagittal synostosis patients affects growth patterns of the cranial base. The lack of change in the postoperative cranial base angle suggests that neurocranial surgery alleviates the occipital rotation and decreased cranial base angle described in the sagittal synostosis basicranium.

Case-Control Studies↗

PubMed1995

Growth in stature in fragile X families: a mixed longitudinal study.

The effect of fragile X on growth in stature was estimated in individuals aged 5-20 years from 50 fragile X families. The multivariate normal model for pedigree analysis was applied to the mixed longitudinal data, which varied with regard to intervals between the measurements and their number in individual subjects, totalling 349 measurement data points from fragile X families, and 292 data points from unrelated normal subjects. The results of genetic and regression analysis showed that, in fragile X boys and girls, total pubertal height gain is impaired, whereas the rate of growth during the preadolescent period is increased, compared with the growth rate of nonfragile X subjects. Moreover, the growth parameters in fragile X males were found to be correlated with the size of CGG trinucleotide expansion. The hypothesis of premature activation of the hypothalamo-pituitary gonadal axis is postulated as the cause of growth impairment in fragile X boys and girls, which should be verified by data on the timing of pubertal stages, hormone levels, and bone maturation.

Adolescent↗

PubMed1989

Lung function values from a longitudinal study of healthy children and adolescents.

From a cohort of 543 healthy children and adolescents, subjects were studied annually to obtain longitudinal data so that precise predictive values for lung volumes and flows from ages 8 to 19 years could be obtained. Strict guidelines for subject selection and pulmonary function testing were used. These data are presented in a readily usable form as equations, graphs, and tables.

Adolescent↗

PubMed2000

Results of a meta-analysis of cost-benefit research: is this a question worth asking?

We attempted a meta-analysis of telemedicine research studies of the costs associated with telemedicine. First, we performed a search of six well known databases with a variety of relevant keywords. After discarding non-English publications, books and duplicate publications resulting from the same study, we were left with 551 articles for analysis. Our second step was to separate the articles into two groups: those with and those without quantitative cost data. Only 38 articles contained any type of real data. Because many of these 38 studies proved to be inadequately designed or conducted, we were unable to perform a traditional meta-analysis. Furthermore, there were a number of disturbing features common to these studies, including the omission of the number of consultations or patients, almost non-existent longitudinal data collection and lack of uniformity in cost analyses. We conclude that it is premature for any statements to be made, either positive or negative, regarding the cost-effectiveness of telemedicine in general.

Cost-Benefit Analysis↗

PubMedDate not supplied

A radiographic study of the development of the human mandibular dentition.

This paper presents new data on the absolute timing of the growth of the mandibular permanent teeth, with an emphasis on the timing of the completion of the enamel crown. Two collections of cranio-dental radiographs were analyzed: (1) 267 juveniles from a contemporary pediatric dental clinic (Case Western Reserve University School of Dentistry, Cleveland, Ohio), and (2) 36 individuals sampled longitudinally from the Bolton-Brush Growth Study Center. The ages of the individuals span from three months to 18 years of age and the study includes both cross-sectional and longitudinal data. Comparisons of the ages of attainment of the Cleveland samples with other schedules of dental development are made. The relative contribution of the multiple underlying sources of variation producing the differences between the radiographically based developmental schedules remain elusive.

Adolescent↗