Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “longitudinal”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources
PubMed2001

Gender differences in the longitudinal predictors of adolescent dating violence.

BACKGROUND: Adolescent dating violence is a public health problem. The public health approach to prevention is to identify predictors of problem behaviors and develop interventions to eliminate or reduce those predictors with the intention of altering the chain of causation. Longitudinal data are preferred for identifying predictors of behavior but all dating violence studies have used cross-sectional data. We use longitudinal data to examine predictors of adolescent dating violence from several domains guided by an ecological perspective. METHODS: Eighty percent (N = 1,965) of the 8th- and 9th-graders in one county completed baseline questionnaires in school and 90% (N = 1,759) of those adolescents completed questionnaires again 1&1/2 years later. Proportional odds models were used to identify cross-sectional correlates and longitudinal predictors of dating violence perpetration that occurred between baseline and follow-up. RESULTS: Most of the study variables were correlated with dating violence in cross-sectional analyses. Having friends who are victims of dating violence, using alcohol, and being of a race other than white predicted dating violence perpetration by females. Holding attitudes that are accepting of dating violence predicted dating violence perpetration by males. CONCLUSION: The findings suggest that intervention strategies should vary for males and females and that when basing interventions on cross-sectional findings, scarce resources may be stretched to address persons who may not truly be at risk of beginning to perpetrate dating violence.

Adolescent↗
PubMed1994

A cross-sectional and short-term longitudinal characterisation of NIDDM in Psammomys obesus.

The present study was undertaken to examine the cross-sectional and short-term longitudinal changes in glucose and insulin concentrations as well as measure the enzymatic activity of PEPCK and glycogen synthase in our Psammomys obesus colony. In the cross-sectional study, blood samples were taken from one group of animals at 19 weeks of age (n = 37) in the fed state and following a 4-h fast. In a separate group of 19-week-old animals (n = 69), samples were taken 1 h following an OGTT (1 g/kg body weight) in Psammomys subjected to a 16-h fast. In the longitudinal study, blood samples were taken from one group of animals in the fed state at 7, 11, 15 and 19 weeks of age. All of the cross-sectional data have described the classic inverted U-shaped curve (Starling's curve of the pancreas) in the relationship between glucose and insulin levels. This trend was also reflected by Psammomys subjected to the OGTT; a mild impairment in glucose tolerance was associated with an increase in the insulin response and a further impairment in glucose tolerance was associated with a reduction in the insulin response. Similar results were obtained following a 4-h fast. The short-term longitudinal glucose and insulin data revealed that of the 37 animals examined over the 12-week period, 16 progressed along the inverted U-shaped curve described by the cross-sectional data. Of the other animals, 8 remained unchanged, 7 were unclassifiable and 6 hyperglycaemic Psammomys developed normoglycaemia at the expense of elevated insulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Measurement and data quality in longitudinal research.

The importance of paying attention to scale levels is emphasized and it is pointed out that Steven's hierarchy of ratio, interval, ordinal, and nominal scales is too narrow; other important scale properties have to be considered. For instance, sometimes a carefully constructed variable on a nominal scale contains more information than a variable at a higher scale level. Direct versus indirect measurement and relative versus absolute measurement are also discussed and the effects of errors of measurement on the results are considered. It is not infrequent in a longitudinal setting to disregard sampling considerations, which can be very unfortunate. Such considerations, as well as the use of modern sampling theory, can considerably enhance the quality of a longitudinal study. Finally, a number of conclusions and recommendations are given for the carrying out of longitudinal research in relation to measurement issues.

Adolescent↗
PubMed1994

Neuropsychological changes in children with cancer: the treatment of missing data in longitudinal studies.

Researchers conducting longitudinal studies with children or adults are inevitably confronted with problems of attrition and missing data. Missing data in longitudinal studies is frequently handled by excluding from analyses those cases for whom data are incomplete. This approach to missing data is not optimal. On the one hand, if data are missing at random, then dropping incomplete cases ignores information collected on those cases that could be used to improve estimates of population parameters (e.g., means, variances, covariances, and growth rates) and improve the power of significance tests of statistical hypotheses. On the other hand, if data are not missing at random, then dropping incomplete cases leads to biased parameter estimates and hypothesis tests that may be internally and externally invalid. This study uses three years of follow-up data from a longitudinal investigation of neuropsychological outcomes of cancer in children to demonstrate the problems presented by missing data in repeated measures designs and some solutions. In evaluating potential biasing effects of attrition, the study extends previous research on neuropsychological outcomes in pediatric cancer by inclusion of patients whose disease had relapsed, and by comparison of surviving and nonsurviving patients. Although the data presented have specific relevance to the study of neuropsychological outcome in pediatric cancer, the problems of missing data and the solutions presented are relevant to a wide variety of diseases and conditions of interest to researchers in child and adult neuropsychology.

Adolescent↗
PubMed1995

A longitudinal study of depression in an urban Spanish pubertal population.

Depression characteristics were investigated in 507 adolescents using a two-stage longitudinal study design. The three-year longitudinal study started when the girls and boys were 11 and 12 years, respectively. In the initial (screening) phase the Children's Depression Inventory (CDI) was used to select subjects for phase-II of the study in which the Children's Depression Rating Scale-Revised (CDRS-R) interview was used. The caseness definition of Major Depression (MD) and Dysthymia (D) was based on the DSM-III-R criteria. Pubertal development was assessed by Tanner's staging. Estimated prevalence of Major Depression in the female sample for each increasing year of age was 2.2%, 2.7% and 4.1%. In the male sample the prevalence for the three years was 0.9%, 0.3% and 0.6%. There was no relation to age. The estimated mean prevalence of Dysthymia was 1.4% in girls and 0.8% in boys. No association between pubertal development and depression was found. Longitudinal data support the notion of chronic depression in early adolescence.

Adolescent↗
PubMed2006

Physical and psychological functioning of daily living in relation to physical activity. A longitudinal study among former elite male athletes and controls.

BACKGROUND AND AIMS: Physical exercise plays an important role in the prevention and reduction of disabilities in elderly people. The aim of this study was to determine the role of physical activity in the physical and psychological functioning of daily living in a cohort of former elite male athletes representing different sports, and controls of middle and old age. METHODS: Subjects were 664 former elite male athletes (mean age 64.4 years) and 500 controls (62.0 years) in middle and old age. Subjects were mailed "Physical activity and health survey" questionnaires in 1985 and 1995. The primary outcomes the physical and psychological functioning of daily living--were assessed in 1995 using items from the Mini-Finland Health Survey. Logistic regression was used for longitudinal as well as cross-sectional analyses to estimate odds ratios (OR) for poor physical and psychological functioning of daily living in relation to recreational physical activity adjusted for age, sport group, life-style, BMI, mood, chronic diseases, personality characteristics, life-events and socio-economic status. RESULTS: In the longitudinal analysis, low levels of physical activity (lowest MET quintile vs highest quintile) in 1985 (OR 4.91, 95% confidence interval (CI) 2.02-11.9), older age (> or =70 yrs vs under 60 yrs OR 9.93, 95% CI 4.90-20.2), depression (OR 2.03, 95% CI 1.01-4.09) and anxiety in 1995 (OR 2.67, 95% CI 1.34-5.32) increased the risk of poor physical functioning of daily living in 1995, whereas an increase in a physical activity between 1985-1995 (OR 0.89, 95% CI 0.83-0.95) protected against poor physical functioning of daily living. A history of participating in specific types of sports, especially among certain power sports (weight-lifting and track & field throwers) (OR 0.19, 95% CI 0.06-0.60) and team sports (OR 0.34, 95% CI 0.15-0.81) did reveal a significant protective effect against poor psychological functioning of daily living in the longitudinal analysis. CONCLUSIONS: This study suggests that an increase in physical exercise supports physical daily functionality. A specific history of sports participation promotes psychological well-being at an older age.

Activities of Daily Living↗
PubMed1998

Involvement of insulin-like growth factor I in development of ossification of the posterior longitudinal ligament of the spine.

In order to investigate the pathogenesis of ossification of the posterior longitudinal ligament (OPLL) of the spine, we examined the distribution of insulin-like growth factor I (IGF-I) in the posterior longitudinal ligaments of OPLL patients, and analyzed the effects of IGF-I on the cultured spinal ligament cells. For that purpose we established eight varieties of OPLL and non-OPLL cell lines obtained from spinal ligaments of corresponding patients, respectively. In contrast to non-OPLL cases, all the OPLL cases were histologically shown to contain round-shaped cartilage-like cells in the transitional region from preossifying to ossifying ligaments, and these cells were strongly stained with an antibody for IGF-I. In the vicinity of preossifying cartilaginous tissues, ligament cells also had a rod-like appearance and were positive for IGF-I immunohistochemically. The effects of IGF-I on cultured spinal ligament cells were assayed by alkaline phosphatase (AP) activity, DNA synthesis, and the amounts of collagen produced. The number of OPLL cell lines that increased AP activity, responding to IGF-I irrespective of 1,25(OH)2D3, was significantly larger than that of non-OPLL cell lines, although IGF-I stimulated DNA and procollagen type I carboxyl-terminal peptide synthesis in most of both OPLL and non-OPLL cell lines. These data demonstrate the dominant expression of IGF-I in the posterior longitudinal ligaments of OPLL patients, and suggest that IGF-I preferentially induces osteogenic differentiation in OPLL cells rather than in non-OPLL cells. IGF-I, therefore, may be involved in the local ossification process of spinal ligaments observed in OPLL patients.

Adult↗
PubMed2003

Extrastriatal dopamine D(2) receptors in Parkinson's disease: a longitudinal study.

Most antiparkinsonian drugs are known to act through central dopamine D(2) receptor agonism. A previous longitudinal positron emission tomography (PET) study has indicated that, in the striatum of Parkinson's disease (PD) patients, dopamine D(2) receptor binding declines at a relatively fast annual rate of 2-4% (compared to the rate of <1%/year in healthy individuals). In the present study, the examination of longitudinal changes in D(2) receptors was extended to extrastriatal brain regions in PD. Eight early PD patients were examined twice with PET, approximately 3 years apart, using a high-affinity extrastriatal D(2)/D(3) receptor tracer, [(11)C]FLB 457. Both the MRI-referenced region-of-interest method and the voxel-based statistical analysis method were used independently in the analysis. Regional D(2)-like availabilities (binding potentials) in the left dorsolateral prefrontal cortex, the left temporal cortex and the left and right medial thalami were significantly decreased at the second examination by 20-37% (corresponding to an annual decline of 6-11%). Thus, the annual loss of extrastriatal D(2) availability in PD is up to three times faster than the rate previously reported in the putamen. Our longitudinal study shows first evidence concerning cortical D(2) receptor loss in the progression of PD, although it is not possible to distinguish between the effects of the therapy and the disease.

Aged↗
PubMed2006

The effects of cumulative risks and promotive factors on urban adolescent alcohol and other drug use: a longitudinal study of resiliency.

Resiliency theory provides a conceptual framework for studying why some youth exposed to risk factors do not develop the negative behaviors they predict. The purpose of this study was to test compensatory and protective models of resiliency in a longitudinal sample of urban adolescents (80% African American). The data were from Years 1 (9th grade) and 4 (12th grade). The study examined effects of cumulative risk and promotive factors on adolescent polydrug use including alcohol, tobacco and marijuana. Cumulative measures of risk/promotive factors represented individual characteristics, peer influence, and parental/familial influences. After controlling for demographics, results of multiple regression of polydrug use support the compensatory model of resiliency both cross-sectionally and longitudinally. Promotive factors were also found to have compensatory effects on change in adolescent polydrug use. The protective model of resiliency evidenced cross-sectionally was not supported in longitudinal analysis. The findings support resiliency theory and the use of cumulative risk/promotive measures in resiliency research. Implications focused on utilizing multiple assets and resources in prevention programming are discussed.

Adolescent↗
PubMed2006

Analysis of longitudinal health-related quality of life data with terminal events.

Longitudinal health-related quality of life data arise naturally from studies of progressive and neurodegenerative diseases. In such studies, patients' mental and physical conditions are measured over their follow-up periods and the resulting data are often complicated by subject-specific measurement times and possible terminal events associated with outcome variables. Motivated by the "Predictor's Cohort" study on patients with advanced Alzheimer disease, we propose in this paper a semiparametric modeling approach to longitudinal health-related quality of life data. It builds upon and extends some recent developments for longitudinal data with irregular observation times. The new approach handles possibly dependent terminal events. It allows one to examine time-dependent covariate effects on the evolution of outcome variable and to assess nonparametrically change of outcome measurement that is due to factors not incorporated in the covariates. The usual large-sample properties for parameter estimation are established. In particular, it is shown that relevant parameter estimators are asymptotically normal and the asymptotic variances can be estimated consistently by the simple plug-in method. A general procedure for testing a specific parametric form in the nonparametric component is also developed. Simulation studies show that the proposed approach performs well for practical settings. The method is applied to the motivating example.

Health Status↗
PubMed1991

Longitudinal Gompertzian analysis of primary malignant brain tumor mortality in the U.S., 1962-1987: rising mortality in the elderly is the natural consequence of competitive deterministic dynamics.

Age-adjusted mortality rates for primary malignant brain tumors (PMBT) in the United States from 1962 to 1987 were subjected to longitudinal Gompertzian analysis. Age-adjusted PMBT mortality rate distributions between age 25 and 65 years were determined by a variable environmental factor and a common intersect point. The environmental factor declined (improved) 1.58-fold for men and 2.34-fold for women in 1987 as compared to 1962. The age at the common intersect point was 68.4 years for men and 64.1 years for women. Between 1962 and 1987, non-age-standardized annual crude PMBT mortality rates increased 14.5% for men and 37.8% for women. However, PMBT mortality rates at age 77.5 years rose 259% for men and 409% for women between 1962 and 1987. Longitudinal Gompertzian analysis of PMBT mortality data suggests that rapidly rising PMBT mortality rates in the elderly are the natural consequence of competitive deterministic mortality dynamics and should not be attributed to environmental factors, past or present, that are directly contributing to PMBT mortality. Furthermore, longitudinal Gompertzian analysis demonstrates that PMBT mortality should not be studied in isolation, but rather should be examined in relation to other causes of death. When viewed from this perspective, the basis for the dramatic rise in PMBT mortality in the elderly becomes quite evident.

Adult↗
PubMed1991

Longitudinal Gompertzian analysis of prostate cancer mortality in the U.S., 1962-1987: a method of demonstrating relative environmental, genetic and competitive influences upon mortality.

Age-specific mortality rates for prostate cancer (PC) in the United States from 1962 to 1987 were subjected to longitudinal Gompertzian analysis. Age-specific PC mortality rate distributions between age 55 and 85 years were determined by a variable competitive factor and a common intersect point. The intersect point for PC occurred at age 61.5 years and mortality rate 27.9 per 100,000 and reflects genetic and environmental influences upon mortality. Between 1962 and 1987, non-age-standardized annual crude PC mortality rates increased 41.6%. Longitudinal Gompertzian analysis suggests that rising PC mortality rates in the United States are the natural consequence of competitive deterministic mortality dynamics. Moreover, longitudinal Gompertzian analysis is a method that demonstrates the relative contribution of environmental, genetic and competitive influences upon disease specific mortality.

Age Factors↗
PubMed1991

Longitudinal Gompertzian analysis of lung cancer mortality in the U.S., 1968-1986. Rising lung cancer mortality is the natural consequence of competitive deterministic mortality dynamics.

Age-adjusted mortality rates for lung cancer (LC) in the United States from 1968 to 1986 were subjected to longitudinal Gompertzian analysis. Age-adjusted LC mortality rate distributions between age 20 and 50 years were determined by a variable environmental factor and a common intersect point. The environmental factor declined (improved) 1.89-fold for men and 3.11-fold for women in 1986 as compared to 1968. The age at the common intersect point was 47.2 years for men and 39.1 years for women. Between 1968 and 1986, the non-age-standardized annual crude LC mortality rate increased 44.8% for men and 217.6% for women. Longitudinal Gompertzian analysis of LC mortality data suggests that the rising LC mortality rates in the United States are the natural consequence of competitive deterministic mortality dynamics and not a reflection of an environment that is directly more conductive to LC mortality. That is, more people are dying of LC because they are not dying from other diseases such as ischemic heart disease and stroke. Longitudinal Gompertzian analysis demonstrates that single disease mortality should not be studied in isolation, but rather examined in relation to other causes of death. When viewed from this perspective, the basis for the more dramatic rise in LC mortality in women becomes immediately evident.

Adult↗
PubMed1990

Longitudinal and cross-sectional comparisons of young children's cognitive ERPs and behavior in a picture-matching task: preliminary findings.

Event-related brain potentials (ERPs) were recorded from 19 children (6-8 years old at initial testing) performing cognitive tasks in two longitudinal testing sessions administered one year apart. The task used was a modification, using pictorial stimuli, of Posner's (1978) letter-matching experiments. In separate blocks of trials, subjects had to decide whether two sequentially-presented slides were physically identical, shared the same name, or came from the same semantic category. Subjects indicated their choice via a same-different delayed response following the second slide. Behavioral data showed large effects of longitudinal Age reflecting increases in accuracy from Run 1 to Run 2. These effects were corroborated by analyses of cross-sectional Age, suggesting that the performance changes reflected cognitive growth, rather than practice effects. In a similar fashion, both N400 and P700 (classical 'P300') showed reductions in peak latency that appeared to be true age changes, since these latencies shortened as a function of Run of testing as well as cross-sectional Age, and there were no Run by Age interactions. Small sample sizes as well as methodological shortcomings of the current design limit the conclusions that can be drawn from these data. Nevertheless, this study demonstrates the feasibility and usefulness of a cross-sectional/short-term longitudinal design and provides information on the extent and direction of behavioral and ERP changes that can be observed over this limited age range.

Child↗
PubMed1991

Longitudinal study on age-related changes of working and reference memory in the rat.

Age-related changes of working memory and reference memory were examined using different age groups of Fischer 344 rats (cross-sectional study) and one group of the same strain which was repeatedly tested at different age points (longitudinal study). Delayed non-matching test in a T-maze revealed 3 points as follows: (1) since motivation by food deprivation in the task performance seemed to decrease with aging, it was needed to adjust the food deprivation level so as to attain a similar degree of motivation in different age groups; (2) scores in reference memory task remained very high in the aged in both cross-sectional and longitudinal studies; and on the other hand (3) performance of working memory task declined with aging to the same degree in both cross-sectional and longitudinal studies, suggesting that working memory progressively deteriorates in advancing age.

Aging↗
PubMedDate not supplied

Perception of friends' use of alcohol, cigarettes, and marijuana among urban schoolchildren: a longitudinal analysis.

Relations between adolescents' substance use and perceptions of their friends' substance use were examined cross-sectionally and longitudinally in a predominantly African-American school district. Fourth- and fifth-grade students were surveyed and tracked for 4 consecutive years. Cross-sectional samples included 3,073, 5,955, 7,701, and 6,616 students in years 1 to 4, respectively; the longitudinal sample included 1,802 students surveyed in every year. Self-reported substance use of friends and classmates also was assessed. Perceived friends' substance use had a stronger association with prior substance use than friends' self-reported substance use in every year. Perceived family use and classmates' self-reported use also made independent contributions to regression models. Longitudinal structural equation analyses indicated that perceived friends' use is more likely to be a product of an adolescent's previous substance use than a precursor of subsequent substance use. The findings contradict prevailing theories on the influence of peers on substance use.

Black or African American↗
PubMed1991

Factors encouraging cohort maintenance in a longitudinal study.

Maintenance of the cohort is one of the primary challenges of a longitudinal study. At the end of 3 years of follow up in the Framingham Children's Study, a longitudinal study of young children and their parents, 100 of the original 106 families (94.3%) have remained in the study. A questionnaire was administered to identify factors contributing to the high rate of follow up to this point in the study. The attitudes of the staff, feedback to the subjects, the staff's handling of questions and problems, and association with the Framingham Heart Study emerged as the most important factors influencing continued participation in the study. In addition, 99% of the subjects stated that they believed the medical research to be important. We conclude that the quality of the communication with study participants and the subjects' perceived importance of the research have been the key factors in maintaining the cohort in this longitudinal epidemiologic study.

Attitude of Health Personnel↗
PubMed2006

The use of GEE for analyzing longitudinal binomial data: a primer using data from a tobacco intervention.

Longitudinal study designs in addictive behaviors research are common as researchers have focused increasingly on how various explanatory variables affect responses over time. In particular, such designs are used in intervention studies that have multiple follow-up points. These designs typically involve repeated measurement of participants' responses, and thus correlation within each participant is expected. Correct inferences can only be obtained by taking into account this within-participant correlation between repeated measurements, which can complicate the analysis of longitudinal data. In recent years, generalized estimating equations (GEE) has become a standard method for analyzing non-normal longitudinal data, yet it often is not utilized by addiction researchers. The goal of this article is to provide an overview of the GEE approach for analyzing correlated binary data for behavioral researchers, using data from an intervention study on the prevention of relapse to tobacco smoking.

Adult↗