Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Longitudinal analysis”

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 127 records · Page 7Linked to original sources
PubMed1995

A longitudinal analysis of human papillomavirus 16 infection, nutritional status, and cervical dysplasia progression.

To evaluate the effect of potential risk factors, especially human papillomavirus type 16 (HPV-16) infection and nutritional status on the course of cervical dysplasia, we analyzed data from an intervention trial conducted from 1985 to 1990, in Birmingham, Alabama. With the use of data of four repeated evaluations of dysplasia at an interval of 2 months, specific relationships between HPV-16 infection, plasma retinol and zinc levels, and dysplasia progression were evaluated through longitudinal data analysis of generalized estimating equations. Repeated assessments of nutritional status from blood samples, HPV-16 infection, and dysplasia diagnosis were available from 206 women. Dysplasia diagnosis was confirmed by both Papanicolaou smear and colposcopy examinations and was classified as normal, low, or high grade squamous intraepithelial lesions according to the Bethesda system and assigned a score of 0, 1, or 2, respectively. Generalized estimating equation analyses were performed with assumptions of variance of Poisson and link of logarithm. Separate analyses were also conducted for HPV-16-positive and HPV-16-negative women. By multivariate modeling with adjustment for age, race, smoking, oral contraceptive use, and plasma levels of nutrients, HPV-16 infection was found to be related to the progression of cervical dysplasia, with a relative risk of 1.19 and a 95% confidence interval of 1.03-1.38. High plasma levels of retinol were related to the regression of cervical dysplasia, especially in HPV-16-positive women. A protective effect was also observed for high levels of zinc.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

Longitudinal analysis of T-cell receptor variable beta chain repertoire in patients with acute graft-versus-host disease after allogeneic stem cell transplantation.

T-cell receptor variable beta chain (TCRBV) repertoire spectratyping involves the estimation of CDR3 length distributions for monitoring T-cell receptor diversity and has proven useful for analyses of immune reconstitution and T-cell clonal expansions in graft-versus-host disease (GVHD) and graft-versus-leukemia after allogeneic stem cell transplantation. We performed a longitudinal spectratype analysis of 23 TCRBV families in 28 patients who underwent allogeneic T cell-depleted peripheral blood stem cell transplantation. Sixteen patients subsequently developed acute GVHD. We recently developed statistical methods that bring increased power and flexibility to spectratype analysis and allow us to analyze TCRBV repertoire development under appropriately complex statistical models. Applying these methods, we found that patients with acute GVHD demonstrated TCRBV repertoire development statistically distinct from that repertoire development in patients without GVHD. Specifically, GVHD patients showed spectratypes indicative of lower diversity and greater deviation from the spectratypes expected in healthy individuals at intermediate times. Most individual TCRBV subfamilies had spectratypes statistically distinguishable between GVHD and non-GVHD patients at 6 months after transplantation. These results suggest that the T-cell receptor repertoire perturbations associated with acute GVHD are widely spread throughout the TCRBV families.

Acute Disease↗
PubMed2003

The Trp(64)Arg polymorphism of the beta(3)-adrenergic receptor gene is not associated with body weight or body mass index in Japanese: a longitudinal analysis.

The beta(3)-adrenergic receptor (ADRB3) is expressed mainly in visceral adipose tissue and is thought to contribute to lipolysis and the delivery of free fatty acids to the portal vein. Although many studies have examined the relationship between the Trp(64)Arg mutation of ADRB3 and obesity, the results have been inconsistent. We examined the cross-sectional relationship of ADRB3 variants with indexes of obesity, and their longitudinal changes over 10 yr, in men and women, aged 40-69 yr, who were randomly selected from the Japanese rural population. The study considered both dietary energy intake and physical activity levels. Among the 746 participants, the genotype frequencies of the Trp(64)Trp, Trp(64)Arg, and Arg(64)Arg variants were 483, 224, and 39, respectively. The cross-sectional analysis showed no significant differences in height, weight, body mass index, blood pressure, serum total and high density lipoprotein cholesterols, and hemoglobin A(1c) among the genotype groups even after adjustments for gender, age, smoking, alcohol drinking, physical activity, and energy intake. No significant differences in the weight changes between the genotype groups were evident in the longitudinal analysis. We conclude that the Trp(64)Arg mutation of ADRB3 has little or no influence on either body weight or body mass index in the general Japanese population.

Adult↗
PubMed2002

The effect of health related quality of life on reported use of health care resources in patients with osteoarthritis and rheumatoid arthritis: a longitudinal analysis.

OBJECTIVE: In today's cost conscious environment, health services researchers are consistently trying to find ways to predict future health care resource utilization (HCRU) and its associated costs. We evaluated the impact of health related quality of life (HRQL) on future HCRU in patients with arthritis. METHODS: A total of 642 patients with rheumatoid arthritis (RA) and 395 patients with osteoarthritis (OA) completed at least 2 and as many as 6 consecutive surveys at 6 mo intervals. Information collected included demographics, HRQL questionnaires [Medical Outcome Study Short Form 36 (SF-36), Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and the Stanford Health Assessment Questionnaire (HAQ)], and HCRU over the previous 6 months. Longitudinal data analysis was perfomed to assess the effect of HRQL on future HCRU. RESULTS: Statistically significant associations between HCRU and HRQL variables were noted. Higher rates of HCRU were found in those in the worst quarter compared with those in the best quarter of HRQL. With the HAQ, OA and RA patients in the worst quarter reported a 199% (p < 0.05) and 48% (p < 0.05) increase in rheumatologist visits, respectively. With the WOMAC Function, increases were as high as 196% (p < 0.05) in rheumatologist visits for patients with OA. Patients with RA with a high level of HRQL as measured by the SF-36 (physical component score) reported a decrease of 31% (p < 0.01) in general practitioner visits and a decrease of 52% (p < 0.01) in hospitalization (mental component score). CONCLUSION: These findings suggest that HRQL may be used to predict future health care consumption. Such an approach may lead to a more efficient allocation of resources by providing useful information to health care providers and health care decision makers.

Activities of Daily Living↗
PubMed2003

[Longitudinal analysis of factors influencing direct costs of schizophrenia treatment].

In a prospective longitudinal study with 5 points of measurement the direct service costs as well as the clinical and social characteristics of 307 outpatients with the diagnosis of schizophrenia (ICD 10 F 20.0) were assessed over a period of 2.5 years. A random-effect regression model was computed for the assessment of the impact of clinical and social variables on cost variance. Within-effect and between-effect of independent variables on the cost variance were identified by comparing of within and between effect models. Results of the study show that 10 % of the within variance and 32 % of the between variance were explained by the random effect model. Significant within effects were found for a deterioration of emotional health status and for general level of functioning. Significant between effects were found for living situation, partnership, number of inpatient episodes, psychopathological symptoms, depression, alcohol abuse and number of life events. The study results suggest that interventions aiming at the reduction of direct costs should not be restricted to medical treatment but must also include psychosocial interventions for the enhancement of general functioning. However, the explained proportions of within and between variance reveal that the possibilities of manipulating direct treatment costs by means of patient-related interventions may be limited.

Adult↗
PubMed2000

A longitudinal analysis of the pediatric surgeon workforce.

OBJECTIVE: To describe the trends in the pediatric surgeon workforce during the last 25 years and to provide objective data useful for planning graduate medical education requirements. SUMMARY BACKGROUND DATA: In 1975, the Study on U.S. Surgical Services (SOSSUS) was published, including a model to survey staffing. A pediatric surgeon workforce study was initiated in conjunction with SOSSUS as a population, supply, and need-based study. The study has been updated every 5 years using the same study model, with the goals of determining the number and distribution of pediatric surgeons in the United States, the number needed and where, and the number of training programs and trainee output required to fill estimated staffing needs. This is the only such longitudinal workforce analysis of a surgical specialty. METHODS: Questionnaires were sent to 100 pediatric surgeons representing the 62 standard metropolitan statistical areas (SMSAs) in the United States with a population of 200,000 or more to verify the names and locations of all active pediatric surgeons and to gain information about the 5-year need for new pediatric surgeons by region. A program was developed to predict the number of pediatric surgeons relative to the total population and the 0-to-17-year-old population in the subsequent 30 years using updated data on the present number and ages of pediatric surgeons, age-specific death and retirement rates, projections of U.S. population by age group, and varying numbers of trainees graduated per year. As each 5-year update was done, previous projections were compared with actual numbers of pediatric surgeons found. The trends during the last 25 years were analyzed and compared and additional information regarding the demographics of practice, trends in reimbursement, and volume and scope of surgery was obtained. RESULTS: The birth rate has been stable since 1994. The 0-to-17-year-old population has been increasing at 0.65% per year; a 0.64% annual rate is projected to 2040. At present, 661 pediatric surgeons are distributed in every SMSA of 200,000 or more population, with an average age of 45 and an average age of retirement 65. The actual number of pediatric surgeons in each 5-year survey has consistently validated previous projections. Trainee output has increased markedly in the past 10 years. The rate of growth of the pediatric surgeon workforce at present is 50% greater than the forecasted rate of increase in the pediatric age group, and during the past 25 years the rate of growth of the pediatric surgeon workforce has been double that of the pediatric population growth. Nationally, significant changes in reimbursement, volume of surgery, and demographics of practice have occurred.

Adolescent↗
PubMed2000

Ontogeny of spatial discrimination in mice: a longitudinal analysis in the modified open-field with objects.

The present longitudinal study investigated the emergence of spatial discrimination and reaction to novelty in CD-1 mice, using a modified open-field test with four objects, a test in which responses to both spatial rearrangement of familiar objects and object novelty are assessed. Male and female mice were tested on postnatal days (pnd) 18, 28, 46 and 90. Locomotor activity was highest on pnd 90, whereas time spent on objects before rearrangement was highest on pnd 46. Eighteen-day old mice were unable to detect both object rearrangement and object novelty, suggesting immaturity in processing spatial information. On days 28 and 46 mice showed a clear response to object novelty, actively exploring the unfamiliar object placed in the arena, while at these ages object displacement elicited a generalized increase of exploration, not directed towards the displaced objects. A clear and selective response to object displacement emerged only at adulthood (day 90).

Animals↗
PubMedDate not supplied

"Flat" versus "weighted" reimbursement formulas: a longitudinal analysis of statewide special education funding practices.

Tennessee data were analyzed longitudinally from 1979-80 to 1987-88 in terms of numbers of children placed in a variety of service options. In 1983-84, the Tennessee funding formula was changed from a "flat" rate to a "weighted" formula. The weighted formula was associated with a statistically significant decrease in less restrictive placements and a reliable increase in more restrictive placements. A statewide survey of district special education directors suggested that service needs may have been more likely than monetary incentives to explain the observed changes.

Child↗
PubMed1987

Social support and coping: a longitudinal analysis.

This paper examined the interrelation between social support and coping in a longitudinal study of 380 clinically depressed individuals. A two-wave, two-variable panel analysis revealed that connections between support and coping varied by gender and across the specific sources of support and modes of coping examined. In the family context, increases in support were related to increases in problem-solving coping among women and to a decline in emotional discharge coping among men. In the work context, increases in social support were related to a greater reliance on affective regulation among women and to more information/support seeking among men. Overall, the results suggest that specific aspects of support and coping processes jointly mediate the link between stress and adjustment among depressed individuals.

Adaptation, Psychological↗
PubMed1992

A longitudinal analysis of factors related to survival in old age.

Data from a longitudinal study of the elderly in rural North Wales are used in an exploratory study of the relationships between very broadly defined social circumstances and longevity. A statistical modeling approach is adopted and has some nonroutine features necessitated by missing data on dates of death. A variety of demographic, socioeconomic, social network, quality-of-life, dependence, and health variables are found, individually, to be related to survival. Multivariate analysis demonstrated that many of these relationships are spurious and, in particular, there is no prima facie evidence that survival is affected by social networks or quality-of-life factors. However, socioeconomic factors emerge as important for the old elderly.

Aged↗
PubMed1984

The effect of alcohol beverage restrictions on consumption: a 25-year longitudinal analysis.

This project analyzed the impact of state regulation and control measures on per capita apparent distilled spirits consumption using a 25-year period, 1955-1980. The project was an effort to determine if statistically significant associations between regulation of spirits and per capita consumption could be found for the 48 states of the continental United States. A series of regression models was employed to obtain estimates of the effects of a set of independent variables, including alcoholic beverage control laws, price and price-related variables, and social/cultural control variables on apparent distilled spirits consumption. Most previous studies of the relationship of restrictions on spirits availability have led to a belief that control efforts have little or no impact on per capita consumption. This study was undertaken with the expectation of similar findings. What was found instead was that certain laws and regulations do seem to play a significant role in holding down distilled spirits consumption. The regression models developed predict a decrease of about two drinks per month per person if the state was to shift its regulatory laws (including the price of liquor, which is not always subject to regulation) from being relatively loose to being relatively strict. This decrease in drinking would cut down the level of consumption in the median state by nearly one-fourth.

Alcohol Drinking↗
PubMed1979

Longitudinal analysis of the dynamics and risk of coronary heart disease in the Framingham Study.

Statistical methods designed specifically for the analysis of chronic disease incidence and progression in longitudinal studies are presented. These method model the risk of acute phases of chronic disease separately from the temporal change in risk variables. This could be accomplished because, under a specific biological model of the disease mechanism, the problems of estimating the risk of an acute event and of predicting the change in risk variables are independent. Specifically, a quadratic equation relating risk variable values to chronic disease risk and a system of linear equations predicting future risk variable values from present values may beestimated separately. Taken together, they utilize the full information available in a longitudinal study on the temporal dimension of chronic disease progression. In addition, the model is found to possess a number of attractive statistical and theoretical properties. These methods are applied to longitudinal data from the Framingham Study on coronary heart disease (CHD) in males. A quadratic function relating the risk of a CHD event to selected risk variables (age, and the natural logarithms of serum cholesterol, uric acid, diastolic blood pressure and pulse pressure) was estimated from measurements made at four points equally spaced in time (two years) with a further morbidity follow-up at a fifth point. The risk function was found to predict CHD risk accurately. It showed that, apart from the linear effects of the risk variables, cohort effects, quadratic effects and interaction effects were important predictors of CHD risk. The linear regression equations used to predict future risk variable values showed that there was an intricate network of cross-temporal associations. Study of the two types of equations jointly show that putative risk variables could affect the risk of CHD incidence both directly, by being associated with higher levels of risk, and indirectly, by causing other risk variable values to change with time. The results led us to identify several different roles that risk variables might play in CHD incidence.

Coronary Disease↗
PubMed2006

Development of relative weight, overweight and obesity from childhood to young adulthood. A longitudinal analysis of individual change of height and weight.

BACKGROUND: To investigate individual longitudinal change of relative weight, overweight and obesity from age 5 to 25 years by gender. METHODS: A cohort was imbedded in four surveys conducted 1992/1993, 1995/1996, 1998/1999 and 2004/2005 in three areas in Germany. Twelve-year-follow-up of 2183 children initially aged 5-13 years at baseline. Main measurements are body mass index (BMI) and international obesity task force (IOTF)-cut point defined overweight and obesity. A special longitudinal random effects model for cohort data was applied, which uses age as meta-meter of follow-up time and takes age at study entry into account. RESULTS: BMI, overweight and obesity increases with linear and squared age. Girls have a significant higher growth rate than boys in BMI (BMI: 0.89 vs. 0.75 kg/m(2) per 1 year age increment), whereas there is no statistical significant gender difference for overweight [odds ratio (OR) = 1.08 per 1 year] or obesity (OR = 1.11 per 1 year). Longitudinal change rates of BMI vary substantially between individuals [95% reference range (beta +/- 1.96 x SD) for linear change per 1 year is -0.14 to 1.98 in females and -0.29 to 1.83 in males; the 95% range of quadratic change rates are -0.09 to 0.04 in females and -0.08 to 0.05 in males]. Moreover, a steeper increase in BMI over time is observed for children with a higher baseline relative weight. CONCLUSION: Increases in BMI and the propensity of overweight and obesity follow a quadratic growth curve with the steepest increase before and during puberty. However, the substantial variability of relative weight gain within individuals indicate, that more research in individual change patterns is needed.

Adolescent↗
PubMedDate not supplied

Effects of long-term abstinence on psychological functioning: a prospective longitudinal analysis comparing alcohol-dependent patients and healthy volunteers.

Using a prospective longitudinal design, differences between abstinent alcohol-dependent patients (n = 15) and abstinent healthy volunteers (n = 11) were determined with respect to their psychological functioning and alcohol consumption patterns following abstinence. Results showed no differences in alcohol consumption. In 20% of the patients and 9% of the controls more than 10% of protocols indicated alcohol intake, and in 27% of the patients and 27% of the controls less than 10% of protocols indicated alcohol intake. Total abstinence was reported by 53% of the patients and by 64% of the controls. For patients, validation of self-reported alcohol consumption was carried out via biological markers. Patients and controls differed in terms of increased sleep, euphoria, concentration, initiative, anxiety, negative and positive craving, pessimistic thoughts, autonomic disturbances, and humour. A gradual normalization back to baseline levels was observed for some symptoms. These results suggest that affective/mood states may be unstable for alcoholics, and further, that these symptoms may be related to the protracted withdrawal syndrome or may represent residual symptomatology.

5-Hydroxytryptophan↗
PubMed1994

Metalloproteinase activation cascade after burn injury: a longitudinal analysis of the human wound environment.

In this paper, we present a longitudinal study on metalloproteinases in wound-fluid samples collected from three patients with partial- to full-thickness burn wounds. Gelatin zymography showed that 92-kDa gelatinase (MMP-9) and its 225-kDa complex could be detected in burn fluid beginning as early as 4-8 h after injury. Marked increases in MMP-9 levels as well as activation of the proenzyme occurred between day 0 and day 2. The 72-kDa gelatinase (MMP-2) proenzyme was not detected until day 2 and activated enzyme did not appear until day 4. Stromelysin (MMP-3), both proenzyme and activated-enzyme forms, was first observed on day 4. Fluid-phase proteinase activity detected by azocoll degradation roughly corresponded with the level of stromelysin rather than the gelatinases. Our results provide evidence for a regulated metalloproteinase activation cascade following acute traumatic injury and demonstrate in vivo expression of metalloproteinase activity.

Adult↗