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PubMed2003

Impact of socioeconomic status on the course of rheumatoid arthritis and on related use of health care services.

OBJECTIVE: To quantify the impact of socioeconomic status (SES) among patients with rheumatoid arthritis on 1) health outcomes and related health care utilization in relation to disease duration and 2) changes in health outcomes and related health care utilization over a 2-year period. METHODS: A questionnaire survey was conducted among 878 patients with rheumatoid arthritis (RA), varying in disease duration from 0 to more than 15 years. To determine the impact of SES on the health outcomes and health care use, patients were compared within and between 3 disease duration groups. Additionally, longitudinal changes in health outcomes and health care use were assessed with a followup questionnaire sent out 2 years later. RESULTS: Patients with low SES have worse disease activity, physical health, mental health, and quality of life than patients with high SES. These differences, however, decreased over time. Regarding health care use, we found that patients with low SES made considerably less use of allied health care than patients with high SES. CONCLUSION: Efforts should be undertaken in health care to alleviate the health disadvantages of RA patients in lower socioeconomic groups. In particular, the access to allied health care could be improved.

Arthritis, Rheumatoid↗
PubMed2007

Informative-transmission disequilibrium test (i-TDT): combined linkage and association mapping that includes unaffected offspring as well as affected offspring.

To date, there is no test valid for the composite null hypothesis of no linkage or no association that utilizes transmission information from heterozygous parents to their unaffected offspring as well as the affected offspring from ascertained nuclear families. Since the unaffected siblings also provide information about linkage and association, we introduce a new strategy called the informative-transmission disequilibrium test (i-TDT), which uses transmission information from heterozygous parents to all of the affected and unaffected offspring in ascertained nuclear families and provides a valid chi-square test for both linkage and association. The i-TDT can be used in various study designs and can accommodate all types of independent nuclear families with at least one affected offspring. We show that the transmission/disequilibrium test (TDT) (Spielman et al. [1993] Am. J. Hum. Genet. 52:506-516) is a special case of the i-TDT, if the study sample contains only case-parent trios. If the sample contains only affected and unaffected offspring without parental genotypes, the i-TDT is equivalent to the sibship disequilibrium test (SDT) (Horvath and Laird [1998] Am. J. Hum. Genet. 63:1886-1897. In addition, the test statistic of i-TDT is simple, explicit and can be implemented easily without intensive computing. Through computer simulations, we demonstrate that power of the i-TDT can be higher in many circumstances compared to a method that uses affected offspring only. Applying the i-TDT to the Framingham Heart Study data, we found that the apolipoprotein E (APOE) gene is significantly linked and associated with cross-sectional measures and longitudinal changes in total cholesterol.

Apolipoproteins E↗
PubMed2004

Psychiatric challenges in the first 6 years after traumatic brain injury: cross-sequential analyses of Axis I disorders.

OBJECTIVE: To examine the preinjury rates of Axis I disorders and the prospective rates within the first 6 years after traumatic brain injury (TBI). DESIGN: Cross-sectional, longitudinal, and cross-sequential. SETTING: Community-based research and training center. PARTICIPANTS: Persons (N=188) who had sustained TBI within 4 years of enrollment into the project were interviewed at either 2 and 3 assessments. Each assessment was approximately 1 year apart. Several Axis I diagnoses were analyzed to detect cross-sectional differences (by age and time postinjury) and average individual changes over the multiple measurement time points. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders. RESULTS: The odds ratios changed longitudinally within each subject, indicating a decreased probability of having an Axis I diagnosis over time. There were few cross-sectional differences in age; therefore, age at the time of injury had little impact on Axis I diagnoses. Cross-sectional time since injury was not associated with more psychiatric disorders, whereas cross-sectional preinjury history of psychiatric disorders was predictive of postinjury psychiatric disorders. After controlling for cross-sectional effects, the frequencies of Axis I disorders increased in depression, anxiety, and posttraumatic stress disorders in the first assessment postinjury and declined in subsequent assessments. CONCLUSIONS: Cross-sequential analyses that control for cross-sectional and longitudinal differences produced a more complete description of psychiatric disorders after TBI.

Adult↗
PubMed2002

Postural balance in elderly people: changes over a five-year follow-up and its predictive value for survival.

Postural balance in three test conditions (normal standing with eyes open, normal standing with eyes closed, and tandem standing with eyes open) was measured in samples of 75-year-old men and women (N=757) living in three Nordic localities (Glostrup in Denmark, Göteborg in Sweden, and Jyväskylä in Finland). The subjects were re-tested five years later when they had reached the age of 80 years (N=434). The results showed a highly significant longitudinal decline in balancing abilities in all localities and in both sexes. The longitudinal change was larger than suggested by cross-sectional comparisons. On both occasions women showed better results in the balance tests than men in all three localities. Inter-locality differences observed at baseline (somewhat poorer performance among the subjects from Göteborg) largely remained during the follow-up. The simplest balance test, normal standing with eyes open, was also a significant predictor for survival over the 5-year follow-up: the results at baseline were poorer in those subjects who died during the follow-up than in the survivors. It is concluded that postural balance deteriorates markedly from 75 to 80 years of age; at high ages a poor performance in balance tests may also indicate below-average survival.

Aged↗
PubMed2001

Longitudinal evaluation of cognitive disorder in Huntington's disease.

The study investigated longitudinal change in cognitive function in 87 patients with Huntington's disease (HD), using a range of neuropsychological tests, which tap mental manipulative abilities, memory, and frontal executive skills. Over a 1-year period the largest changes were noted in letter fluency, object recall, and Stroop Test performance, whereas no changes were noted over more than 3 years on the modified Wisconsin Card Sorting Test. Contrary to expectation, greater change was evident over 1 year for tasks with low compared to high cognitive demands. The differential sensitivity of tasks was attributed in part to inherent characteristics of the tests themselves: their capacity to detect minor gradations of change and their vulnerability to practice effects. However, the greater change for relatively automatic, speed-based tasks with low cognitive demands was interpreted as reflecting the evolution of HD, with a greater magnitude of change occurring in basal ganglia than cortical function. One purpose of the study was to identify tasks sensitive to the progression of HD and hence most suitable for the evaluation of therapies. Despite reaching statistical significance by virtue of the large group size, numerical differences in test scores over 1 year were very small, suggesting that the use of such tests to evaluate change in individuals or small groups of subjects would be problematic. The data highlight the slow progression of HD, the limitations of standard cognitive tests in detecting change over short periods, and the need for therapeutic studies that encompass a relatively prolonged time frame.

Adult↗
PubMed1999

Effect of natural grass pollen exposure on exhaled nitric oxide in asthmatic children.

Exhaled nitiric oxide (NO) is increased in exhaled breath of asthmatic patients. The aim of this study was to investigate the longitudinal changes of exhaled NO outside and during the pollen season in pollen-allergic asthmatic children. Twenty-one children (age 6 to 16 yr), with a seasonal allergic asthma sensitive to grass pollen, underwent measurements of exhaled NO and pulmonary function before (March), during (May), and after (November) the pollen season. Exhaled NO was measured by a tidal breathing method with a chemiluminescence analyzer and NO steady-state levels were recorded. The timing of the measurements during the pollen season was based on the atmospheric pollen count. Exhaled NO values of asthmatic children were compared with those of 21 sex- and age-matched healthy children. Pulmonary function and symptoms of asthma were also evaluated at each visit. The mean value of exhaled NO before the grass season was 12.7 +/- 5.1 ppb (mean +/- SD), significantly higher when compared with controls (7.8 +/- 2.7 ppb, p < 0.001). In the pollen season there was a significant (p < 0.001) twofold increase in exhaled NO (21.4 +/- 7.6 ppb) that, after the season, returned to values similar (12.8 +/- 5.8 ppb, p = NS) to those found before the season. There were no significant changes in FEV1 before and during the season (98.6% predicted versus 101% predicted, p = NS). We conclude that natural allergen exposure is related to an increase of exhaled NO in asthmatic grass pollen-allergic children even in absence of significant changes in airways function. We speculate that measurement of exhaled NO could be a sensitive noninvasive marker of asthma disease activity.

Adolescent↗
PubMed2003

Bioelectrical impedance analysis in the clinical management of preeclamptic women with edema.

OBJECTIVE: The aim of this study was to correlate bioelectrical impedance analysis (BIA) with the clinical course of preeclampsia with edema. DESIGN: 440 pregnant women with apparently normal, single pregnancy participated in this longitudinal study. Anthropometric measurements and BIA were performed during pregnancy and postpartum period. RESULTS: All of the measurements were completed in 333 of the women; 279 of the women had a normal pregnancy (control group). The remaining 54 women developed edema during the third trimester of pregnancy. Of these, 40 women had only edema, and 14 women had edema followed by hypertension and/or proteinuria (preeclampsia group). The BIA index (the height squared divided by resistance) in the control group increased significantly towards late pregnancy, compared to that in early pregnancy. The indexes in the edema group were significantly higher during the third trimester compared to those of the control group at the same gestational week. The index in the preeclampsia group was higher relative to that in the control group. Moreover, a substantial increase in the index preceded the development of edema in the cases in which pregnancy was terminated due to deterioration of preeclampsia. CONCLUSIONS: Our results show that BIA is a useful method for monitoring longitudinal changes in total body water in pregnant women, and that BIA may be a powerful predictor of deterioration of preeclampsia preceded by edema.

Adult↗
PubMed1998

A longitudinal study of the growth and development of the dental arch width from childhood to adolescence in Japanese.

The purpose of this study was to evaluate the longitudinal changes in arch width from childhood to adolescence. The subjects were 28 persons (13 males and 15 females) with untreated normal occlusion. Dental casts were taken at bimonthly intervals from childhood to adolescence. These materials were measured; the changes in the dental arch were compared on the basis of the status of the tooth emergence of certain permanent teeth and also on the chronological age from 3 years to 20 years of age. In the maxilla and mandibula, the width between the deciduous canines, the width between the first deciduous molars, and the width between the second deciduous molars were nearly stable or slightly increased until 6 years of age. After that, all of the deciduous tooth widths gradually increased, especially in the width between the deciduous canine at the emergence of the permanent incisors. The width between the canines decreased until 13 years of age in the maxilla and until 15 years of age in the mandibula. After that, the width between the canines were nearly stable. Until 1 year after emergence, the width between the canines decreased, in particular during the transition to the canines, based on dental age observation. The maxillary first premolar width decreased until 6 months after emergence, based on dental age observation. Thereafter, the width between the maxillary first premolars showed no clear change. The width between the mandibular first premolars, the width between the maxillary second premolars, and the width between the mandibular second premolars increased until about 2-3 years after emergence, but they showed no clear changes thereafter. The width between the maxillary first molars gradually increased until 15 years of age; there was no clear change thereafter. The width between the mandibular first molars was nearly stable throughout the observation period. The width between the maxillary second molars decreased until 2 years after emergence; no clear change was observed thereafter. The width between the mandibular second molars was unstable until after about 2-3 years after emergence and then became nearly stable.

Adolescent↗
PubMed2006

A prospective study of hearing changes after beginning zidovudine or didanosine in HIV-1 treatment-naïve people.

BACKGROUND: While hearing loss in HIV-infected people after beginning nucleoside reverse transcriptase inhibitors (NRTIs) has been reported, there have been no prospective studies that measured hearing changes longitudinally in treatment-naïve HIV-infected subjects following initiation of regimens containing NRTIs. The goal of this study was to conduct a prospective assessment of the contribution of zidovudine (ZDV) and didanosine (ddI) to hearing loss. METHODS/DESIGN: A prospective observational pilot study to determine whether ZDV or ddI, alone or in combination, are associated with sensorineural hearing loss in HIV-infected persons. Changes in hearing levels at all frequencies and in low and high frequency pure tone averages were measured at baseline, 16, and 32 weeks after initiating antiretroviral therapy. DISCUSSION: Treatment with ZDV and ddI did not result in loss of hearing, even after taking into account noise exposure, immune status and age. The results of this prospective pilot study do not support the notion that treatment with nucleoside antiretrovirals damages hearing.

Adult↗
PubMed2007

Quantitative analysis of local changes in patellar cartilage in spinal cord injured subjects.

Most studies investigating articular cartilage changes use global parameters and neglect the large topological variation in the response of cartilage to immobilization and remobilization. We hypothesized a registration-based semi-automatic segmentation method would be highly reproducible to detect local changes in patellar articular cartilage thickness. We also hypothesized thinning of the cartilage is detectable in the smaller subregions of the patella in patients with a spinal cord injury (SCI) and the use of difference maps would allow us to detect early local thinning of the patellar cartilage. To determine the reproducibility, magnetic resonance images of the knee of seven healthy volunteers were acquired four times. Longitudinal changes were measured in the knees of seven patients with SCI as soon as possible, 6 months, and 12 months after the injury. Thickness maps and morphologic parameters for the cartilage of the patella and the four sub-regions were computed. The individual difference maps of 43% of the patients showed local areas of substantial thinning 6 and 12 months after injury.

Adolescent↗
PubMed2007

Estimating the response rate in the presence of measurement error.

In clinical research, it is often of interest to estimate the response rate (i.e. the proportion of subjects who achieve a clinically meaningful threshold) for a particular variable. The standard estimator of the response rate is generally biased in the presence of measurement error. The estimation accounting for the measurement error utilizing fully nonparametric (NP) methods is complicated and may not be efficient. Therefore, we propose a model-based approach assuming a parametric model for the true value and only the first few moments for the measurement error. The estimator for the true response rate and the variance for the estimator are derived. An innovative method using bootstrap simulation is proposed to check the model assumption. Simulations show that the proposed estimator outperforms a fully NP estimator if the model assumption for X holds. This method is applied to address a commonly occurring question in osteoporosis regarding response to treatment in terms of longitudinal changes in bone mineral density (BMD). Bootstrap simulations showed that the model utilized is appropriate. The proposed method can also be applied in other fields of clinical research.

Absorptiometry, Photon↗
PubMed1998

Left ventricular geometric patterns and QT dispersion in borderline and mild hypertension: their evolution and regression.

To investigate whether QT dispersion increases in borderline and mild hypertension during a longitudinal observation of > 3 years and whether it is improved with medications, left ventricular geometric patterns and QT dispersion were studied with special regard to their longitudinal changes in 85 male borderline and mild hypertensive subjects with left ventricular mass index < 125 g/m2. These subjects were followed for > 3 years without medication. Thirty-two patients with a left ventricular mass index > 125 g/m2 at the end of follow-up period were further observed using antihypertensive drugs for an additional 3 years. Echocardiograms and electrocardiograms were obtained at the beginning and end of the follow-up period. At the end of the follow-up period, subjects were classified into four groups based on ventricular geometric patterns determined by left ventricular mass index and relative wall thickness in diastole. The QT dispersion was greater in patients with concentric hypertrophy (56+/-18 msec) than in patients with normal geometry (41+/-17 msec) (P < .05) and increased significantly in the former group during the follow-up period. After medication, the left ventricular mass index regressed and the QT dispersion decreased (from 55+/-21 to 50+/-26 msec, P < .01) in these patients. Thus, these findings suggest that changes in the QT dispersion reflect both concentric evolution and regression of left ventricular hypertrophy.

Adult↗
PubMed2000

Relationships between radiographic alveolar bone height and probing attachment level: data from healthy post-menopausal women.

OBJECTIVE: To determine the cross-sectional and longitudinal relationships between radiographic alveolar bone height and probing attachment level in a population of healthy postmenopausal women. MATERIALS AND METHODS: The 81 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure sensitive probe at 6 sites on each tooth. Vertical bitewing radiographs were digitized, and 6 linear measurements corresponding to probing-site measurements were made from the cementoenamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals for three years. Data were analyzed both by site and by patient. RESULTS: Moderately strong correlations were found between cross-sectional measurements of probing attachment height and radiographic bone height. Correlations were stronger for patient data (r=0.44-0.61) than for site data (r=0.19-0.36). No relationships were found between longitudinal changes in alveolar bone height and attachment level in either the site data (r=-0.10-0.04). or the patient data (r=-0.005-0.10). CONCLUSION: Healthy patients may experience sporadic, temporary changes in attachment level or alveolar bone height which are resolved without one affecting the other.

Alveolar Bone Loss↗
PubMed1997

Longitudinal assessment of deficit unawareness in Alzheimer's disease.

Longitudinal progression of impaired deficit awareness across varied functional domains was evaluated in 28 patients diagnosed with probable Alzheimer's disease (AD). Unawareness, as measured by patient-caregiver rating discordance, was first assessed in reference to patient memory, health status, self-care skills, anxiety, depression and irritability. The identical protocol was then repeated an average of 16.4 months later. Results indicated that, compared with caregiver ratings, patients tended to underestimate their deficits across functional domains. Patient-caregiver rating discrepancies were most pronounced in judgment of memory and self-care decline, indicating domain-specific differences in degree of unawareness. However, patient-caregiver rating discrepancies increased on most measures from time 1 to time 2 with no differences in the magnitude of these increases, suggesting a nonspecific longitudinal progression of unawareness. Although unawareness of deficits increased with time, longitudinal change in unawareness was not related to other disease and demographic variables such as age, education, age at onset, or duration of illness.

Activities of Daily Living↗
PubMed1995

Bioelectrical impedance analysis and dual energy x-ray absorptiometry to monitor nutritional status.

There exists an imperative to monitor changes in body composition in all dialysis patients on a regular basis to avoid overt malnutrition. In this regard, the absolute measurement of the fat-free mass assessment may not be as crucial as the serial measurement of fat-free mass with the same modality. A significant difference in measured fat and fat-free mass should be expected if different techniques are employed. Therefore, when attempting to monitor patients over time or to assess the effects of changes in therapeutic regimens, a single methodology should be employed. Our data validate the use of BIA in the stable PD patient, indicating that BIA can predict the DXA results. Considering the ease with which BIA measurements can be obtained and the lack of dependency on operator interpretation, BIA is an ideal technique for use in the clinical setting. The applicability of this technique for use in monitoring longitudinal changes in body composition has, in fact, been well established (25, 30, 31). BIA appears to be an excellent method for routine fat-free mass measurement in dialysis patients. In as much as malnutrition continues to remain a significant problem in PD patients, measuring and monitoring body composition is strongly recommended.

Absorptiometry, Photon↗
PubMed1996

Application of random-effects regression models in relapse research.

This article describes and illustrates use of random-effects regression models (RRM) in relapse research. RRM are useful in longitudinal analysis of relapse data since they allow for the presence of missing data, time-varying or invariant covariates, and subjects measured at different timepoints. Thus, RRM can deal with "unbalanced" longitudinal relapse data, where a sample of subjects are not all measured at each and every timepoint. Also, recent work has extended RRM to handle dichotomous and ordinal outcomes, which are common in relapse research. Two examples are presented from a smoking cessation study to illustrate analysis using RRM. The first illustrates use of a random-effects ordinal logistic regression model, examining longitudinal changes in smoking status, treating status as an ordinal outcome. The second example focuses on changes in motivation scores prior to and following a first relapse to smoking. This latter example illustrates how RRM can be used to examine predictors and consequences of relapse, where relapse can occur at any study timepoint.

Alcoholism↗
PubMed2005

Differential endocrine responses to rosiglitazone therapy in new mouse models of type 2 diabetes.

Polygenic mouse models for obesity-induced type 2 diabetes (T2D) more accurately reflect the most common manifestations of the human disease. Two inbred mouse strains (NON/Lt and NZO/HlLt) separately contributed T2D susceptibility- conferring quantitative trait loci to F1 males. Although chronic administration of rosiglitazone (Rosi) in diet (50 mg/kg) effectively suppressed F1 diabetes, hepatosteatosis was an undesired side effect. Three recombinant congenic strains (designated RCS1, -2, and -10) developed on the NON/Lt background carry variable numbers of these quantitative trait loci that elicit differential weight gain and male glucose intolerance syndromes of variable severity. We previously showed that RCS1 and -2 mice responded to chronic Rosi therapy without severe steatosis, whereas RCS10 males were moderately sensitive. In contrast, another recombinant congenic strain, RCS8, responded to Rosi therapy with the extreme hepatosteatosis observed in the F1. Longitudinal changes in multiple plasma analytes, including insulin, the adipokines leptin, resistin, and adiponectin, and plasminogen activator inhibitor-1 (PAI-1) allowed profiling of the differential Rosi responses in steatosis-exacerbated F1 and RCS8 males vs. the resistant RCS1 and RCS2 or moderately sensitive RCS10. Of these biomarkers, PAI-1 most effectively predicted adverse drug responses. Unexpectedly, mean resistin concentrations were higher in Rosi-treated RCS8 and RCS10. In summary, longitudinal profiling of multiple plasma analytes identified PAI-1 as a useful biomarker to monitor for differential pharmacogenetic responses to Rosi in these new mouse models of T2D.

Adiponectin↗
PubMed2004

Severe acute respiratory syndrome: temporal lung changes at thin-section CT in 30 patients.

PURPOSE: To evaluate lung abnormalities on serial thin-section computed tomographic (CT) scans in patients with severe acute respiratory syndrome (SARS) during acute and convalescent periods. MATERIALS AND METHODS: Serial thin-section CT scans in 30 patients (17 men, aged 42.5 years +/- 12.2 [SD]) with SARS were reviewed by two radiologists together for predominant patterns of lung abnormalities: ground-glass opacities, ground-glass opacities with superimposed linear opacities, consolidation, reticular pattern, and mixed pattern (consolidation, ground-glass opacities, and reticular pattern). Scans were classified according to duration in weeks after symptom onset. Longitudinal changes of specific abnormalities were documented in 17 patients with serial scans obtained during 3 weeks. Each lung was divided into three zones; each zone was evaluated for percentage of lung involvement. Summation of scores from all six lung zones provided overall CT score (maximal CT score, 24). RESULTS: Median CT scores increased from 1 in the 1st week to 12.5 in the 2nd week. Ground-glass opacities with or without smooth interlobular septal thickening and consolidation were predominant patterns found during the 1st week. Ground-glass opacities with superimposed irregular reticular opacities, mixed pattern, and reticular opacities were noted from the 2nd week and peaked at or after the 4th week. After the 4th week, 12 (55%) of 22 patients had irregular linear opacities with or without associated ground-glass opacities and CT scores greater than 5; five of these patients had bronchial dilatation. When specific opacities were analyzed in 17 patients, consolidation generally resolved completely (n = 4) or to minimal residual opacities; six (55%) of 11 patients with ground-glass opacities had substantial residual disease (CT scores > 5) on final scans. CONCLUSION: There is a temporal pattern of lung abnormalities at thin-section CT in SARS. Predominant findings at presentation are ground-glass opacities and consolidation. Reticulation is evident after the 2nd week and persists in half of all patients evaluated after 4 weeks. Long-term follow-up is required to determine whether the reticulation represents irreversible fibrosis.

Adult↗