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Results for “Longitudinal analysis”

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PubMed1978

A longitudinal analysis of artificial insemination with donor semen.

A longitudinal analysis of artificial insemination with donor semen (AID) in 114 consecutive couples revealed a 37% over-all pregnancy rate. The 45 pregnancies occurred in 39 patients, and approximately 90% of these pregnancies occurred within six cycles of AID. Pregnancy rates were higher in the age group 25 to 30, in those who received only fresh semen, and in those with a history of a previous pregnancy. Lower pregnancy rates were observed in patients age 31 or older, in those with pelvic disease, and in those randomly receiving freshly thawed semen or fresh semen. The use of a vaginal device for retaining semen, the use of patient positioning, or the duration of infertility did not appear to affect the success rate. When surgically correctable pelvic disease was treated, a pregnancy rate of 22% was obtained.

Adolescent↗
PubMed2000

Longitudinal analysis of the segregation of mtDNA mutations in heteroplasmic individuals.

The mutation load of the pathogenic LHON (Leber hereditary optic neuropathy) mtDNA mutation at nucleotide 3460 has been followed over time in the WBC/platelet fraction from members of a matrilineal pedigree. Longitudinal analysis over a sampling period of five to six years indicates that, in all five heteroplasmic family members, the mutation load decreases at a mean overall rate of approximately 1% per year. There was no change in mutation load in homoplasmic wildtype or in homoplasmic mutant individuals. For the purposes of comparison, a longitudinal analysis of a silent mtDNA polymorphism at nucleotide 14560 was also carried out for members of a second matrilineal pedigree. In contrast to the results for the pathogenic mtDNA mutation, there was no change in the proportion of the silent polymorphism in the WBC/platelet fraction of four family members over a period of seven years. These results indicate that the pathogenic 3460 LHON mutation segregates under negative selection in these cell populations. One possible mechanism through which selection may operate is that, in heteroplasmic individuals, the hematopoietic stem cells are generally homoplasmic, either for the wildtype or for the mutant allele. The homoplasmic mutant stem cells, because of their mitochondrial respiratory chain defect, produce fewer mature WBCs and platelets over time than do the wildtype stem cells. Alternatively, the stem cells may be heteroplasmic and selection may act to favor proliferation of mitochondria with lower levels of the pathogenic mutation in the WBC/platelet cell populations.

DNA Mutational Analysis↗
PubMed1984

Longitudinal analysis of a demonstration rural outreach alcoholism program.

A longitudinal analysis of the nature and impact of the information and education activities of an alcoholism rural outreach program (ROP) located in a rural setting was conducted during 1973-1975 via annual community surveys and program records. The study focused on the kinds and amounts of activities conducted and on the impact of these activities on community attitudes toward and knowledge about alcohol and alcoholism as well as awareness of local resources. The community education efforts had the most impact on increasing community familiarity with treatment issues, but attitudes toward these resources as well as acceptance of the disease concept of alcoholism declined over the 3 yr of the program. Knowledge about alcohol and alcoholism also declined over time, but these scores were at chance levels during each of the three community surveys. Several factors appeared to limit the impact of the ROP: (1) trying to accomplish too many different tasks with a small staff and operating budget; (2) subcontracting the program to a local mental health center, which absorbed a large proportion of staff time for nonprogram activities; and (3) the choice of community education efforts.

Adolescent↗
PubMed2003

Longitudinal analysis of cartilage atrophy in the knees of patients with spinal cord injury.

OBJECTIVE: A previous cross-sectional study indicated that the morphology of patellar and tibial cartilage is subject to change after spinal cord injury (SCI). The aim of this study was to perform a longitudinal analysis of cartilage atrophy in all knee compartments, including the femoral condyles, in SCI patients over 12 months. METHODS: The right knees of 9 patients with complete, traumatic SCI were examined shortly after the injury (mean +/- SD 9 +/- 4 weeks) and at 6 and 12 months postinjury. Three-dimensional morphology of the patellar, tibial, and femoral cartilage (mean and maximum thickness, volume, and surface area) was determined from coronal and transversal magnetic resonance images (fat-suppressed gradient-echo sequences) using validated postprocessing techniques. RESULTS: The mean thickness of knee joint cartilage decreased significantly during the first 6 months after injury (range 5-7%; P < 0.05). The mean change at 12 months was 9% in the patella, 11% in the medial tibia, 11% in the medial femoral condyle, 13% in the lateral tibia, and 10% in the lateral femoral condyle (P < 0.05 for all compartments). CONCLUSION: This is the first report of a longitudinal analysis of cartilage atrophy in patients with SCI. These data show that human cartilage atrophies in the absence of normal joint loading and movement after SCI, with a rate of change that is higher than that observed in osteoarthritis (OA). A potential clinical implication is that cartilage thinning after SCI may affect the stress distribution in the joint and render it vulnerable to OA. Future studies should focus on whether specific exercise protocols and rehabilitation programs can prevent cartilage thinning.

Adolescent↗
PubMed1987

Nurses' job satisfaction: a longitudinal analysis.

A causal model of nurses' job satisfaction was tested using longitudinal analysis of 13 causal determinants and five correlates measured at Time 1, and job satisfaction measured at Time 2. Data were collected from 370 registered nurses at five hospitals using questionnaires mailed eight months apart. Four different models were analyzed using the LISREL maximum likelihood procedure to estimate the path coefficients. Variables reaching statistically significant levels included, in order of importance, routinization, promotional opportunity, distributive justice, age, day shift, workload, kinship responsibility, and opportunity for jobs outside the employing hospital. With the prior level of job satisfaction controlled, only the effects of day shift remained significant.

Adult↗
PubMedDate not supplied

[The problem of repeated measurements. Longitudinal analysis in epidemiology].

In longitudinal analyses subjects are repeatedly measured along time. They are mixed designs, characterised for their simultaneous consideration of two or more dimensions of analysis, in which time is one of the dimensions.Longitudinal analyses have important advantages with respect other designs. The most important is that they are more efficient, since they allow to distinguish between-individual and within-individual variation.Longitudinal analyses can be approached marginal and conditionally. Whereas the former allows to draw poblational, or average, inferences, the latter permits to draw individual inferences.The statistical models to use depend on the type of response variable. If the dependent variable is normally distributed one will use linear mixed models. When the response is a count one will use mixed Poisson regressions. Mixed binomial or multinomial logistic regressions should be used when the response would be categorical.

Epidemiologic Studies↗
PubMed2005

Headache after moderate and severe traumatic brain injury: a longitudinal analysis.

OBJECTIVES: To measure longitudinally headache (HA) after moderate and severe traumatic brain injury (TBI) and to examine potential association with demographic, injury, and psychologic factors. DESIGN: Cohort study. SETTING: Four Veterans Administration rehabilitation facilities (Minneapolis, Palo Alto, Richmond, Tampa) within the Defense and Veterans Brain Injury Center. PARTICIPANTS: Consecutive patients (military or veteran beneficiaries) with moderate or severe TBI (N=109) who during acute rehabilitation consented to data collection and who completed 6- and 12-month follow-up evaluations. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: HA frequency, location, type, and incapacitation levels measured during prospective neurologic assessments. RESULTS: Nearly 38% (41/109) of patients had acute posttraumatic headache (PTHA) symptoms; most often in a frontal location (20/41), most often of daily frequency (31/41), and showing no relation to injury severity, emotional, or demographic variables. Postacutely, PTHA symptom severity declined within the group. Better individual improvement was associated with less anxiety and depression at 6-month follow-up. Almost all subjects (21/22) with PTHA symptoms that persisted into the 6-month follow-up period reported symptoms again at 12-month follow-up. CONCLUSIONS: PTHA severity in this sample of persons with moderate and severe TBI showed a pattern of improvement that leveled off by 6 months posthospitalization.

Adolescent↗
PubMed1997

The impact of Hurricane Andrew on deviant behavior among a multi-racial/ethnic sample of adolescents in Dade County, Florida: a longitudinal analysis.

Findings from a longitudinal study are presented on the relationships between the problems and stresses resulting from Hurricane Andrew and posthurricane minor deviant behavior. The sample (N = 4,978) included Hispanic, African-American, and White non-Hispanic middle school students enrolled in Dade County, Florida public schools. Two waves of data were collected prior to the hurricane; a third was obtained approximately 6 months following the storm. Results indicated that females were likely to report higher levels of hurricane-related stress symptoms than males. After controlling for prehurricane levels of minor deviance, family support, and race/ethnicity, hurricane stress symptom level remained a significant predictor of posthurricane minor deviant behavior. The findings lend support to stress theories of social deviance.

Adolescent↗
PubMedDate not supplied

Longitudinal analysis of mammary cancer multiplicity in chemoprevention studies.

BACKGROUND: The effect of chemopreventive agents on cancer multiplicity is of primary interest in animal studies. The nature of data collected from chemoprevention studies may be analyzed by a longitudinal analysis of repeatedly measured cancer multiplicity data. METHODS: We determined the number of mammary cancers over the entire follow-up period for varying doses of two chemopreventive agents. Longitudinal analyses were performed to model the number of cancers over different time intervals. RESULTS: There was a significant increase in the number of cancers between six to seven weeks post-carcinogen administration in the control group. Varying patterns of cancer development were observed at different doses of chemopreventive agents including a delay in onset of tumor growth compared to the control group. CONCLUSION: Longitudinal data analysis complements traditional analyses by providing detailed information regarding the effect of chemopreventive agents on the pattern of tumor development throughout the follow-up period. Importantly, some chemopreventive agents may delay time to appearance of mammary cancers without causing a significant difference in cancer multiplicity.

Animals↗
PubMed2005

Breastfeeding and overweight: longitudinal analysis in an Australian birth cohort.

OBJECTIVE: To examine adiposity in relation to breastfeeding using longitudinal analysis in an Australian birth cohort. STUDY DESIGN: Repeated surveys from 16 weeks gestation to 8 years in a cohort (N = 2087) recruited through antenatal clinics. Overweight was defined by National Center for Health Statistics 95th percentiles for weight-for-length at 1 year and body mass index (BMI) at 3, 6, and 8 years. Overweight was examined using Generalized Estimating Equations with results summarized as OR. BMI Z scores were analyzed in mixed models. RESULTS: At 1 year, infants breastfed >12 months were the leanest group (mean Z score -0.16, 95% CL -0.28, -0.04; not breastfed 0.16, 95% CL 0.02, 0.29; breastfed < or = 4 months 0.31, 95% CL 0.22, 0.40; 5-8 months 0.17, 95% CL 0.06, 0.27; 9-12 months 0.11, 95% CL 0.01, 0.22). From 1 to 8 years, children breastfed < or = 4 months had the greatest risk of overweight (OR 1.29, 95% CL 0.89, 1.97) and the highest prevalence of maternal obesity, smoking, and lower education. CONCLUSIONS: Infants breastfed >12 months were leaner at 1 year but not at 8 years. Breastfeeding < or = 4 months was associated with greatest risk of overweight and adverse maternal lifestyle. Familial factors may modify associations between breastfeeding and adiposity beyond infancy.

Body Mass Index↗
PubMed1985

Longitudinal analysis of categorical epidemiological data: a study of Three Mile Island.

The accident at the Three Mile Island nuclear power plant in 1979 led to an unprecedented set of events with potentially life threatening implications. This paper focusses on the analysis of a longitudinal study of the psychological well-being of the mothers of young children living within 10 miles of the plant. The initial analyses of the data utilize loglinear/logit model techniques from the contingency table literature, and involve the fitting of a sequence of logit models. The inadequancies of these analyses are noted, and a new class of mixture models for logistic response structures is introduced to overcome the noted shortcomings. The paper includes a brief outline of the methodology relevant for the fitting of these models using the method of maximum likelihood, and then the model is applied to the TMI data. The paper concludes with a discussion of some of the substantive implications of the mixture model analysis.

Accidents↗
PubMed2001

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface associated with herpes zoster ophthalmicus.

PURPOSE: Longitudinal analysis of varicella-zoster virus DNA on the ocular surface of patients with herpes zoster ophthalmicus. METHODS: Clinical specimens were obtained from the bulbar conjunctival surface with a cotton-tipped swab at weekly intervals for 6 consecutive weeks from 21 patients with acute ophthalmic zoster with a skin rash duration of less than 7 days. All patients received oral valacyclovir 1000 mg three times daily for 10 days without additional corticosteroids. The swabs were analyzed by means of polymerase chain reaction for the presence of varicella-zoster virus and herpes simplex virus type 1 DNA. Conjunctival swabs were also obtained from a control group of 20 patients with cataract. RESULTS: On inclusion, varicella-zoster virus DNA was present on the ocular surface of 19 of the 21 patients. Six varicella-zoster virus DNA-positive patients had no signs of ocular inflammation. All control swabs were negative for both varicella-zoster virus and herpes simplex virus DNA. The duration of varicella-zoster virus DNA detection from rash onset varied from 2 to 34 days. The number of days between the onset of herpes zoster skin rash and the latest positive varicella-zoster virus DNA test was significantly longer in patients whose age was equal to or above the median age of 66 years than in the younger patients (Mann-Whitney test: P =.0004). At 6-week follow-up, all conjunctival swabs were negative for varicella-zoster virus DNA. However, at that time, the eyes of seven patients were still inflamed. CONCLUSION: The duration of varicella-zoster virus DNA shedding in herpes zoster ophthalmicus is highly variable and age dependent, and is probably related to the host immune response.

Acyclovir↗
PubMed1986

Personality, coping, and family resources in stress resistance: a longitudinal analysis.

Earlier cross-sectional analyses have made causal inferences about stress-resistance variables problematic. This study used a longitudinal analysis where stress-resistance factors in the areas of personality, coping, and family support assessed at an initial testing were used to predict psychological and physical adjustment one year later, controlling for initial adjustment. The study involved a survey of 245 men and 248 women in randomly selected families in the San Francisco Bay area. Findings demonstrated that feelings of self-confidence, an easy-going disposition, a disinclination to use avoidance coping, and the availability of family support operate jointly to protect individuals from negative psychological consequences of life stress. For women the stress-resistance index also predicted psychosomatic complaints experienced one year after initial testing.

Adaptation, Psychological↗
PubMed1992

A longitudinal analysis of the impact of dietary intake and physical activity on weight change in adults.

The current investigation is a longitudinal analysis of the relationship between dietary intake, physical activity, and body weight change in adult men (n = 142) and women (n = 152). Measures of dietary intake, physical activity, and cigarette and alcohol consumption were obtained for 3 y. Results indicated a different pattern of predictors of weight change for men vs women. For women a high dietary energy and fat intake as well as increases in total energy intake were related to higher weight gain and increases in work activity levels were related to decreased weight gain. For men weight gain was predicted by increases in dietary fat intake. Sex differences are discussed as a possible moderator variable in the energy balance equation.

Adult↗
PubMed1996

Longitudinal analysis of specific domains of internal control and depressive symptoms in patients with recurrent cancer.

The relation between perceptions of control and depressive symptoms was examined in a longitudinal study of patients with recurrent cancer. Five domains of control (self-blame, control over cancer onset, control over symptoms, control over the course of the illness, and overall control over life events) were found to be independent of one another. In cross-sectional analyses, depression symptomatology was negatively correlated with illness course control, symptom control, and overall control. Cross-lagged longitudinal analyses using structural equation modeling suggested only onset control and overall control were significantly associated with depressive symptomatology over the 8-month interval. Greater baseline onset control predicted greater follow-up depression, whereas higher baseline depression predicted lower follow-up overall control. The importance of developing and using domain-specific measures of control and investigating the association of control and adjustment in longitudinal analysis are discussed.

Adult↗
PubMed2003

A longitudinal analysis of the impact of social and clinical characteristics on the costs of schizophrenia treatment.

OBJECTIVE: The aim of the study was the longitudinal analysis of the influence of social and clinical factors on the mid-term costs of schizophrenia treatment. METHOD: Treatment costs as well as clinical and social characteristics of 307 patients with the ICD-10 diagnosis of schizophrenia were assessed at five follow-ups over 2.5 years. Between and within effects of clinical and social characteristics on treatment costs were estimated by error component regression models. RESULTS: Effects caused by differences between individuals were found for age, partnership, in-patient history, objective and subjective role functioning, life-events and psychotic relapse. Effects of idiosyncratic transitory changes of social and clinical characteristics were found for symptoms, psychotic relapse, and for social role-functioning. CONCLUSION: Treatment costs can be reduced to a limited extent not only by the prevention of psychotic symptoms and relapse but also by the improvement of role-functioning capacities.

Adult↗
PubMed1992

Longitudinal analysis of point mutations of the N-ras proto-oncogene in patients with myelodysplasia using archived blood smears.

We performed a longitudinal analysis of point mutations of the N-ras proto-oncogene in patients with myelodysplasia and a follow-up of at least 2.5 years after diagnosis. Point mutations at codons 12, 13, and 61 of the N-ras oncogene were analyzed after in vitro amplification of N-ras specific sequences followed by dot-blot hybridization. Lysed cells scraped from archived blood and bone marrow smears were used as template for a polymerase chain reaction. In 3 of 90 patients tested (3.3%), a mutation in codon 12 could be detected in the most recent blood smears. All available blood and bone marrow samples of these patients were subsequently analyzed for the occurrence of that particular mutation. In all three cases the mutation was not detectable at diagnosis, but was acquired later during the course of the disease. In two of these patients this event was associated with rapid deterioration and transformation to acute leukemia. However, the third patient showed a protracted course during a period of 5 years after acquisition of the mutation. These results indicate that activation of the N-ras protooncogene in these three patients represents a secondary phenomenon associated with disease progression in some cases, but compatible with stable disease in others.

Aged↗