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PubMed1989

Longitudinal studies: social and psychological factors.

In spite of the great variety of longitudinal studies, one may consider two main orientations: on one hand the "comprehensive" studies, based on the combined or parallel observation of numerous psychosocial characteristics collected at successive stages of the child's development; on the other hand, studies focussed on limited topics based on the observation and longitudinal analysis of a restricted number of specific characteristics. Some examples of these different approaches are presented. The chapter considers, finally, several methodological issues, including new developments as well as constraints and problems. Recent methodological developments concern, i.a., videoscopic recording techniques which may be applied to the behaviour of mother and child (etc...) whether in the laboratory or in normal life-situations. Moreover, in view of the statistical analysis of the datas appropriate instruments are developed which at the same time keep the nuances and details of the clinical observation. Finally, some examples of problems linked to the attrition-rate of the observed sample are presented, as well as specific ethical issues raised by longitudinal studies.

Child↗

PubMed2002

Comparison of two Hologic DXA systems (QDR 1000 and QDR 4500/A) for in vivo bone mass measurement in the baboon (Papio ursinus).

Dual-energy X-ray absorptiometry (DXA) is the gold standard for bone mass measurement in humans. New generation osteodensitometers have been introduced and numerous studies have been performed to compare new and old devices for in vivo measurements of bone mineral density (BMD). However similar studies in nonhuman primates have yet to be performed. In this longitudinal study, two generation of osteodensitometers from the same manufacturer (Hologic QDR 1000 and Hologic QDR 4500/A) were used to detect bone changes in a cohort of 24 ovariectomized (OVX) Chacma baboons (Papio ursinus) during a period of 36 mo. Correlation between the same osteodensitometers were also obtained for the lumbar spine (L1-L4) area, BMD, and bone mineral content (BMC) in a cohort of 33 adult female baboons and for the total hip area, BMD, and BMC in a group of 25 adult female baboons. The QDR 1000 to QDR 4500/A area, BMC, and BMD correlation coefficient (r(2)) were 0.848, 0.939, and 0.916, respectively; r(2) for total hip BMD was 0.818. Percentage of variation (PV) among the total vertebral (L1-L4) area measured by the two osteodensitometers was 5.3 +/- 2.3 (mean +/- SD). BMC had the lowest PV and the highest r(2). The mean lumbar BMD was higher when measured by QDR 1000 with a PV% of 7.7 +/- 3.1 (mean +/- SD). The mean hip BMD was higher measured by QDR 1000 with a PV% of 9.3 +/- 7.1 (mean +/- SD). Slopes of two regression lines for the lumbar spine (L1-L4) and total hip BMD were 0.928 and 0.914, respectively. Longitudinal analysis of lumbar BMD in OVX baboons showed that QDR 4500/A detected a significant bone density increase at 36 and 48 mo post- OVX, compared to time 12, whereas the QDR 1000 did not. Our results indicate that both osteodensitometers can be used to measure bone changes in longitudinal studies in primates, but that before upgrading to a newgeneration osteodensitometer, a calibration curve has to be obtained so that both devices can be equally used in regular experimental study in nonhuman primates.

Absorptiometry, Photon↗

PubMed1990

Benefit-cost analysis of supported employment in Illinois: a statewide evaluation.

A benefit-cost analysis of supported employment in Illinois during Fiscal Year 1987 was presented. Benefits and costs were identified and valued from three perspectives. Society received a $.75 return for every $1.00 invested during this initial year, whereas taxpayers received a return of $.66. Supported employees earned an average of 37% more in supported employment than in alternative programs during this same time period. We recommended continuation of this financial analysis longitudinally, as it is critical to the development of supported employment as an efficient delivery system.

Adult↗

PubMed1980

Lymphocyte transformation with mitogens and antigens during normal human pregnancy: a longitudinal study.

In a longitudinal analysis of immunological changes in normal human pregnancy, twenty-two pregnant women were studied, with blood samples taken before pregnancy, during its course, at delivery, and 3-5 months after delivery. The blood samples were frozen successively, using a cryobiological freezing system, and were stored until the whole longitudinal series was obtained. The collected material for a longitudinal series was then thawed and tested in one seance. Lymphocyte transformation tests were performed with stimulation with the mitogens phytohaemagglutinin (PHA), pokeweed mitogen (PWM), concanavalin A (Con A) and the specific antigens tuberculin purified protein derivative (PPD), Candida albicans (CA), Staphylococcus aureus (SA) and streptokinase/streptodornase (SK/SD). No changes were found in PHA or in PWM responses, whereas there were significant changes in the Con A response, with lowest values in the middle of pregnancy. PPD, CA, SA and SK/SD responses all reached lowest values towards the end of pregnancy, with increases subsequently, after delivery. These findings seem to show that T suppressor function is increased and B-lymphocyte function decreases during the course of pregnancy.

Candida albicans↗

PubMed1993

The Zurich study. XX. Social phobia and agoraphobia.

The problems in association with agoraphobia and social phobia were examined in an 11-year prospective longitudinal study of a Swiss cohort of young adults. The weighted prevalence rates according to DSM-III were 2.9% for agoraphobia and 3.8% for social phobia. Although the problem of agoraphobia was greater in females, an equal sex ratio was observed for social phobia. There was a significant degree of comorbidity between the two subtypes of phobia, with females exhibiting a significantly greater frequency of co-occurrence of both disorders than males. The course of the two disorders was quite similar. In general, subjects with both disorders reported a more severe course. Assessment of comorbidity of phobias and other disorders revealed that agoraphobia was most significantly associated with extended neurasthenia, sexual problems, and the consumption of cannabis. On the other hand, social phobia was associated with other disorders than agoraphobia, with the strongest associations emerging for simple phobia, extended insomnia, and alcohol abuse. These findings support the validity of the distinction between different subtypes of phobia. The longitudinal analysis revealed that also phobia in general was not stable at the diagnostic level phobic symptoms were quite persistent across time.

Adolescent↗

PubMed2005

The relationship among lower urinary tract symptoms, prostate specific antigen and erectile dysfunction in men with benign prostatic hyperplasia: results from the proscar long-term efficacy and safety study.

PURPOSE: We evaluated the associations among lower urinary tract symptoms, prostate specific antigen (PSA) and erectile dysfunction (ED) in men with benign prostatic enlargement enrolled in the Proscar (Merck, Whitehouse Station, New Jersey) Long-Term Efficacy and Safety Study. MATERIALS AND METHODS: The Proscar Long-Term Efficacy and Safety Study was a 4-year, randomized, double-blind, placebo controlled study that enrolled 3,040 men with moderate to severe lower urinary tract symptoms and an enlarged prostate gland. Two questions assessed ED. A logistic regression model, including the effect of patient age, was used to examine the relationships among quasi-American Urological Association Symptom Score (AUASS), PSA, and ED at baseline. Changes in ED scores from baseline to study closeout were analyzed with ANOVA. RESULTS: A total of 2,981 patients had baseline data available for analysis. Mean age was 64 years, mean quasi-AUASS was 15, mean PSA was 2.8 ng/ml and mean prostate volume was 55 cm. At baseline every 1 point increase in quasi-AUASS was associated with a 2% increased risk of ED even after controlling for age (p <0.001). At 48 months in placebo but not in finasteride treated men a 1-unit decrease in quasi-AUASS was associated with a slight but statistically significant decrease in ED. No association existed between increasing PSA and ED on baseline or longitudinal analysis. CONCLUSIONS: We found a moderately strong association between baseline quasi-AUASS and the ED rate in men with an enlarged prostate, a finding that was supported by longitudinal data in the placebo arm. The absence of a relationship between PSA and ED highlights the need for further investigation into the mechanisms of benign prostatic hyperplasia related sexual dysfunction.

Aged↗

PubMed2000

Dialysate cancer antigen 125 levels in children treated with peritoneal dialysis.

Peritoneal mesothelial cells are important for local host defense and membrane integrity. Dialysate cancer antigen 125 (dCA125) has been shown to be a good marker for the mesothelial cell mass in adult peritoneal dialysis (PD) patients. In children on PD, no information is available yet. We measured dCA125 in 65 dialysate samples from 24 PD children with a median age of 9.2 years (range: 2-18 years) and a median treatment time of 2.6 years (range: 0.1-9.3 years) on PD. The median dCA125 concentration was 8 U/mL (range: 2.3-30.7 U/mL), and the CA125 appearance rate (CA125AR) was 66.5 U/min/1.73 m2 (range: 18-282 U/min/1.73 m2). On cross-sectional analysis, a negative correlation was found between dCA125 and duration of PD treatment (r = -0.3, p = 0.04). No relation was found between age and dCA125 or CA125AR when the first measurement from each child was considered. No correlation was found between dCA125 and the mass transfer area coefficient of creatinine (MTACcreat). Longitudinal analysis showed a negative trend in CA125AR with duration of PD treatment (p = 0.03). No relation was found between peritonitis incidence and dCA125 or CA125AR. In conclusion, no influence of age on dCA125 and CA125AR was found. Levels of dCA125 declined with the duration of PD treatment, reflecting mesothelial cell mass, but they did not correlate with the MTACcreat or the peritonitis incidence in stable PD children.

Adolescent↗

PubMed1999

Cross-sectional versus longitudinal estimates of cognitive change in nondemented older people: a CERAD study. Consortium to Establish a Registry for Alzheimer's Disease.

OBJECTIVES: To investigate the effect of increasing age on cognition in nondemented older people. DESIGN: A cross-sectional and longitudinal analysis. PARTICIPANTS: A total of 454 control subjects for Alzheimer's cases from the cohort assembled by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD). MEASUREMENT: The Mini-Mental State Examination (MMSE) to assess cognitive function. RESULTS: Cross-sectional estimates were derived by generalized linear models and longitudinal estimates by generalized estimating equations. The cross-sectional model indicated a small but significant decline in MMSE of -.4 points per 10 years. The longitudinal model indicated a small but significant increase in MMSE of about +.6 points per 10 years. Evidence of an early learning effect and nonrandom dropout exists. CONCLUSIONS: The question of "normal" aging can be approached by considering cross-sectional information and, usually separately, longitudinal information. This study does both using recently developed statistical methods. We conclude that there is a small but significant decline in scores on the MMSE with increasing population age. The effect can be masked in longitudinal cohorts by a learning effect (especially early in follow-up) and other factors associated with repeated testing.

Aged↗

PubMed2026

Longitudinal Prediction of Retinal Sensitivity Based on Disease Progression Quantified From Optical Coherence Tomography in Geographic Atrophy.

PURPOSE: The purpose of this study was to analyze the association between disease progression of geographic atrophy (GA) from optical coherence tomography (OCT) with retinal sensitivity (RS) in microperimetry (MP) over a 2-year follow-up period. METHODS: This is a longitudinal analysis of the OAKS Phase-III clinical trial. Both study and fellow eyes with GA that underwent imaging with the Spectralis OCT and consecutive MP examination were eligible. Pointwise quantification of ellipsoid zone (EZ) thickness, EZ and retinal pigment epithelium (RPE) loss from OCT volumes was correlated with localized RS. A longitudinal predictive model using a Markov Chain framework was implemented to predict RS change over time based on OCT biomarkers. The modeling of morphological and functional progression was based on the fellow-eye cohort. RESULTS: A total of 39,681 MP points from 406 patients were analyzed. In the fellow eye cohort, baseline (BSL) EZ thickness was positively associated with RS (0.3 decibel [dB]/µm, P < 0.001). Decrease in EZ thickness between visits during follow-up was significantly associated with decrease in RS (0.1 dB / 1 µm change). RS was significantly lower in MP points within EZ loss during follow-up compared with MP points within the retina with measurable EZ (P < 0.001). The largest functional decline was observed within RPE loss, also associated with the highest probability of absolute scotoma (P < 0.001). Morphological progression to EZ and RPE loss was influenced by EZ thickness and the morphology of adjacent MP points (P < 0.001). CONCLUSIONS: Two exploratory endpoints were developed, namely quantification of EZ thickness and loss, and localized RS within high-risk OCT areas. RS decline during follow-up is associated with automatically quantified disease progression in OCT.

Humans↗

PubMed2001

Novel Plasmodium falciparum clones and rising clone multiplicities are associated with the increase in malaria morbidity in Ghanaian children during the transition into the high transmission season.

A survey of Plasmodium falciparum infection and clone multiplicity in Ghanaian children was carried out to study the effect of the onset of the malaria transmission season on disease incidence. Fortnightly blood samples were collected from 40 children living in the rural town of Dodowa, between February and August 1998. P. falciparum parasite densities were calculated and PCR genotyping was carried out using the polymorphic MSP-1 and MSP-2 genes as target loci for the estimation of the number of parasite clones in each sample. The average clone number was estimated using maximum likelihood techniques and the minimum number of clones per patient was analysed for the effects of age, sex, season, minimum number of clones per child, level of parasitaemia and parasite genotype. The statistical analysis indicated that the more clones a child carried, the more likely they were to have a clinical malaria episode. This was true after adjusting for age and season effects and for the measured circulating parasitaemia. The probability of clinical disease also increased if the MSP-1 MAD 20 and the MSP-2 FC 27 alleles were present. This longitudinal analysis thus indicates that the probability of a Ghanaian child having a symptomatic malaria episode is positively associated with both increasing numbers and novel types of P. falciparum clones.

Animals↗

PubMed2002

Development of the EEG from 5 months to 4 years of age.

OBJECTIVES: This report provides a systematic longitudinal analysis of the EEG from infancy into early childhood. Particular emphasis is placed on the empirical confirmation of a 6-9 Hz alpha-range frequency band that has previously been used in the infant EEG literature. METHODS: EEG data in 1-Hz bins from 3 to 12 Hz were analyzed from a longitudinal sample of 29 participants at 5, 10, 14, 24, and 51 months of age. RESULTS: Inspection of power spectra averaged across the whole sample indicated the emergence of a peak in the 6-9 Hz range across multiple scalp regions. Coding of peaks in the power spectra of individual infants showed a clear developmental increase in the frequency of this peak. A rhythm in the 6-9 Hz emerged at central sites that was independent of the classical alpha rhythm at posterior sites. The relative amplitude of this central rhythm peaked in the second year of life, when major changes are occurring in locomotor behavior. CONCLUSIONS: The 6-9 Hz band is a useful alpha-range band from the end of the first year of life into early childhood. The findings also complement other research relating the infant central rhythm with the adult sensorimotor mu rhythm.

Aging↗

PubMed1983

The La Trobe Twin Study: a genetic approach to the structure and development of cognition in twin children.

Twins are particularly useful for developmental behavior genetics, if adequate consideration is given to the possibilities of twin-singleton differences and of data from twins being unrepresentative of the entire population. As an alternative to existing analyses in the developmental behavior genetics of cognition, the covariance structure analysis method in biometrical genetics involving twins and other relatives has the potential for dissecting the determinants of the structure of cognitive abilities and how these change during childhood, as well as checking on the adequacy of twin data. Designed with these aims in mind, the La Trobe Twin Study is a mixed longitudinal analysis of 1,356 twins, their siblings, and cousins, who are followed between the ages of 3 and 15 years on a battery of physical and behavioral tests. The criteria for choosing behavioral tests in such a project are discussed, along with the comprehensive series of questionnaires necessary to examine the children's development in the context of the stresses a multiple birth may impose on a family. In discussion of methods of analysis, 2 points are emphasized: (1) Twin-singleton differences are specific to particular abilities rather than being general, and (2) the incidence of family changes and stresses in such that these should be considered among the environmental effects on development along with the more usual indices of family environment.

Adolescent↗

PubMed1998

Analysis of hepatitis C virus-inoculated chimpanzees reveals unexpected clinical profiles.

The clinical course of hepatitis C virus (HCV) infections in a chimpanzee cohort was examined to better characterize the outcome of this valuable animal model. Results of a cross-sectional study revealed that a low percentage (39%) of HCV-inoculated chimpanzees were viremic based on reverse transcription (RT-PCR) analysis. A correlation was observed between viremia and the presence of anti-HCV antibodies. The pattern of antibodies was dissimilar among viremic chimpanzees and chimpanzees that cleared the virus. Viremic chimpanzees had a higher prevalence of antibody reactivity to NS3, NS4, and NS5. Since an unexpectedly low percentage of chimpanzees were persistently infected with HCV, a longitudinal analysis of the virological profile of a small panel of HCV-infected chimpanzees was performed to determine the kinetics of viral clearance and loss of antibody. This study also revealed that a low percentage (33%) of HCV-inoculated chimpanzees were persistently viremic. Analysis of serial bleeds from six HCV-infected animals revealed four different clinical profiles. Viral clearance with either gradual or rapid loss of anti-HCV antibody was observed in four animals within 5 months postinoculation. A chronic-carrier profile characterized by persistent HCV RNA and anti-HCV antibody was observed in two animals. One of these chimpanzees was RT-PCR positive, antibody negative for 5 years and thus represented a silent carrier. If extrapolated to the human population, these data would imply that a significant percentage of unrecognized HCV infections may occur and that silent carriers may represent potentially infectious blood donors.

Alanine Transaminase↗

PubMed2006

Impacts of telehomecare on patients, providers, and organizations.

Over the last decades, development of home care services is an important component of ongoing health care systems reforms. However, their full integration into hospital or primary care services is still progressing slowly. It appears that telehomecare (THC) could help create networks of services between hospital and primary care providers. Even though their potential to increase access to services and improve quality of care and health outcomes is recognized, their widespread adoption has not yet been achieved. Various barriers need to be overcome. In this paper, we present our comparative exploratory process analysis of the use of THC to follow the treatment of elderly people suffering from severe chronic conditions (chronic obstructive pulmonary disease [COPD], hypertension, cardiac insufficiency). The technology was first introduced as a pilot project in three sites (one site in Quebec and two sites in Manitoba, Canada). Our study is based on qualitative methods. It includes a longitudinal analysis of implementation processes and monitoring of results. Our analysis allows us to identify some of the major impacts on patients and providers, and explain how they may be achieved. Also, because of the major changes in work processes, THC introduces new models of home care delivery. Two models are identified: a specialized model and a planned polyvalent model. Such profound changes raise two major challenges for managers and providers. First, the organisation of work, traditionally based upon preestablished intervention plans, must adapt to respond to ad hoc patients' needs and alerts. Second, constant linkages between the traditional and new models of services delivery become mandatory.

Aged↗

PubMed1990

Occupational exposure and incidence of chronic respiratory symptoms among residents of Cracow followed for 13 years.

We analyzed the relationship between incidence rates of chronic respiratory symptoms over 13 years and occupational exposure during the first five years of follow-up. The study group contained 1132 males and 1598 females, 19 to 60 years of age, randomly selected from residents of Cracow, Poland. The data was collected in three surveys conducted in 1968, five and 13 years later. Prolonged occupational exposure (i.e. reported in the initial survey and 5 years later) to dusts doubled the odds for the appearance of chronic phlegm and attacks of breathlessness in all men, and of chronic bronchitis in men aged 41 to 50, initially free of the symptom. In women, this exposure doubled the odds for new chronic cough and for chronic bronchitis. Prolonged exposure to chemicals doubled the incidence rates of attacks of breathlessness and dyspnea in all women and of chronic bronchitis in women with the lowest level of education. Prolonged work in variable temperatures doubled the risk of wheeze in women. The effects of discontinuation or start of exposure during the initial 5 years of the study were also seen on the incidence rates of the symptoms but were less pronounced. The detected effects of occupational exposure were not modified by cigarette smoking or living in areas of the city with various levels of air pollution. This longitudinal analysis confirms the results of cross-sectional studies which have indicated deleterious effects of even moderate occupational exposures on respiratory symptoms.

Adult↗

PubMedDate not supplied

Twelve-year clinical course of schizophrenia from 1971/73 to 1983. A longitudinal study of clinical course and a cross-sectional study 12 years after hospital or night-clinic treatment.

Two samples of 46 schizophrenic patients, one of new attendees at a night clinic in 1971-73 and the other of hospitalized patients matched for age and sex, were followed up 12 years later. Seven of the former and two of the latter had died, all from self-destructive acts. Of the survivors, one-third were rated inconspicuous with regard to psychopathology, one-fifth as conspicuous only to a psychiatrist, and only one-quarter as very conspicuous, even to a layperson. During the first 4 years the night clinic patients showed signs of an insidious chronic course; substantially fewer (17.6% compared with 28.6%) were hospitalized at the time of follow-up, though far more were receiving outpatient or semi-inpatient care. In both samples self-isolation and inadequate rehabilitation for work were marked; 72% and 62% respectively were dependent on a disability pension, and only 15% and 20% were employed at work in keeping with their training and experience. Just under half lived alone, and 30-40% had no contact with friends/acquaintances. Longitudinal analysis disclosed a marked decrease in the number and duration of overt phases and stays in hospital, progressive aggravation or residual symptoms in quiescent intervals, and similar decline in ability to work and earn a living. Covariance analysis revealed a significantly greater reduction in total hospitalization in night clinic patients.

Activities of Daily Living↗

PubMed2003

Distribution of two species of malaria, Plasmodium falciparum and Plasmodium vivax, on Lombok Island, Indonesia.

Medical and entomological surveys were conducted to determine the risk factors of Plasmodium falciparum and P. vivax infections on Lombok Island, Indonesia, to find the risk factors and the main mosquito vectors for each malaria. Multivariate longitudinal analysis demonstrated two significant risk factors for infection with P. falciparum: disappearance of P. vivax parasitemia (p<0.001) and a specific study site (p<0.001). In contrast, younger age (p=0.024) and the interpolated virtual density of An. subpictus (p=0.041) were significantly associated with increased risk of infection with P. vivax. Thus, it seems that the distribution of P. vivax was determined largely by the presence of An. subpictus, whilst that of P. falciparum was influenced by antagonism with P. vivax. This result shows the importance of following-up treated P. vivax patients to identify recrudescence of P. falciparum in this area.

Adolescent↗

PubMed2000

Is there carotid artery aneurysm formation following saphenous vein patch endarterectomy?

The use of saphenous vein patching following carotid endarterectomy is reported to produce aneurysmal dilatation with the risk of thrombosis and possible rupture. The authors have studied patients who have had saphenous vein patch angioplasty following carotid endarterectomy to assess whether there is any progressive arterial dilatation. Thirty-five patients who had undergone saphenous vein patch carotid endarterectomy were age- and sex-matched with 31 subjects that had direct closure endarterectomy. All participants underwent carotid duplex scanning. The external diameters of the mid common carotid artery, the bulb and the proximal internal carotid artery were measured bilaterally. The diameters of the endarterectomized carotid were compared with the contralateral side using a paired t-test. Using an unpaired t-test, the saphenous vein angioplasty group was compared with the directly closed group. A graph was plotted of the ratio of internal carotid artery diameter of the saphenous vein angioplasty group (endarterectomized artery to the contralateral artery) against the length of follow-up, and the Pearson correlation coefficient was calculated. When the saphenous vein angioplasty group was compared with the directly closed group there was a significant difference between the carotid bulb (11.6 versus 9.7mm, P < 0.001) and internal carotid artery diameters (9.0 versus 7.0mm, P < 0.001). Longitudinal analysis of the saphenous vein angioplasty group showed that the increased diameter of the endarterectomized internal carotid artery progressed with time after surgery (r = 0.51, P < 0.005, and r = 0.56, P < 0.001). Vein patching increases the diameter of the internal carotid artery, and this may further increase with time possibly predisposing to aneurysm formation. Further longitudinal studies of paired data are required.

Adult↗