Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “longitudinal changes”

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 1,189 records · Page 66Linked to original sources
PubMed2006

Exemestane after tamoxifen as adjuvant hormonal therapy in postmenopausal women with breast cancer: effects on body composition and lipids.

Recent studies have shown that administering the aromatase inhibitor exemestane after 2-3 years of tamoxifen therapy significantly improves disease-free survival in postmenopausal women with primary breast cancer in comparison with standard 5-year tamoxifen treatment. Although many of the adverse effects associated with exemestane and tamoxifen have been analysed, there are no comparative data concerning body weight and body composition. The aim of this randomised study was to evaluate the longitudinal changes in body composition and lipid profiles in postmenopausal women switched from tamoxifen to exemestane. In total, 60 overweight or obese postmenopausal patients were enrolled. Their anthropometric data, body composition, including fat mass (FM) and fat-free mass (FFM), and lipid profiles, caloric intake and physical activity were assessed 1 week before randomisation, and 6 and 12 months later. In all, 55 patients (27 on tamoxifen and 28 on exemestane) completed the 1-year study period. Fat mass had significantly decreased by month 12 in the exemestane, but not in the tamoxifen group; the between-group difference was statistically significant (P<0.01). The FFM/FM ratio had significantly increased in the exemestane group, but not the tamoxifen group; the between-group difference was statistically significant (P<0.05). Triglycerides and high-density lipoprotein cholesterol significantly decreased (P<0.01; P<0.05), and low-density lipoprotein cholesterol significantly increased (P<0.01) in the exemestane group at the end of the 1-year study period. Our findings suggest that switching patients to adjuvant exemestane treatment after at least 2 years of tamoxifen therapy may be associated with an advantage over continuing adjuvant tamoxifen treatment in terms of body composition.

Androstadienes↗
PubMed2004

Image analysis of optic nerve disease.

Existing methodologies for imaging the optic nerve head surface topography and measuring the retinal nerve fibre layer thickness include confocal scanning laser ophthalmoscopy (Heidelberg retinal tomograph), optical coherence tomography, and scanning laser polarimetry. For cross-sectional screening of patient populations, all three approaches have achieved sensitivities and specificities within the 60-80th percentile in various studies, with occasional specificities greater than 90% in select populations. Nevertheless, these methods are not likely to provide useful assistance for the experienced examiner at their present level of performance. For longitudinal change detection in individual patients, strategies for clinically specific change detection have been rigorously evaluated for confocal scanning laser tomography only. While these initial studies are encouraging, applying these algorithms in larger numbers of patients is now necessary. Future directions for these technologies are likely to include ultra-high resolution optical coherence tomography, the use of neural network/machine learning classifiers to improve clinical decision-making, and the ability to evaluate the susceptibility of individual optic nerve heads to potential damage from a given level of intraocular pressure or systemic blood pressure.

Diagnostic Imaging↗
PubMed1976

Blood pressure and its spontaneous variations in a northern Italian population.

1. Blood pressure has been measured in a random sample of 5852 subjects (both sexes, 20-64 years old). The prevalence of hypertension (blood pressure greater than or equal to 160 mmHg and/or 95 mmHg; 150 mmHg and/or 90 mmHg under the age of 30 years) was 29-5%. 2. In a cohort of 972 detected hypertensive subjects, longitudinal changes (2 and 5 months after the initial examination) were evaluated. The phenomenon of regression toward the mean value was evident. 3. The implications of the variability of blood pressure in a community control programme of hypertension are discussed.

Adult↗
PubMed1993

Craniofacial morphology of adolescent mandibular prognathism.

Morphological features of the craniofacial complex during orthopedic chin cup therapy were investigated in growing patients with mandibular prognathism. Lateral cephalograms of 30 subjects (15 boys and 15 girls, mean age: 9.04 +/- 1.29 years), taken at four different stages during treatment, were analyzed for 14 measurements. These measured values were standardized by use of Japanese controls and then evaluated to investigate longitudinal changes in the craniofacial morphology at the four different stages. Further, factor analysis was used to compare factors describing the craniofacial morphology for the initial and final stages. Dimensional changes of the mandible were not easily produced even if orthopedic treatment was conducted, whereas the maxilla exhibited a tendency to approach the normal range of the controls. Positional changes of the complex, the backward and downward repositioning of the mandible in particular, played an important role in altering a profile from prognathic before treatment to orthognathic at the end of treatment. Craniofacial morphology was similar pretreatment and posttreatment, although the orthognathic factor became more prominent when associated with positional changes of the mandible at the end of treatment.

Adolescent↗
PubMed1995

Speaking rate, articulatory speed, and linguistic processing in children and adolescents with severe traumatic brain injury.

Two studies were conducted to examine speaking rate following traumatic brain injury (TBI) in childhood and adolescence. Study 1 focused on longitudinal changes in speaking rate in 9 subjects with severe TBI and their age-matched control subjects. Physical measurements of speaking rate (in syllables/sec) were made from spontaneous speech samples obtained from each subject during three sampling sessions over a 13-month period. Although the average speaking rate of the group with TBI was slower than that of the control group at all three sampling sessions, an examination of the data from individual subject pairs revealed markedly slower speaking rates in only 5 of the 9 subjects with TBI at the final sampling session. The perceptual significance of slowed speaking rates in these 5 subjects was confirmed through subjective ratings by naive listeners. In Study 2, the contributions of two potential causes of slowed speaking rate were explored: reduced articulatory speed and increased pausing believed to be associated with linguistic processing difficulties. It is hypothesized that articulatory speed and linguistic processing speed may contribute independently to slowed speaking rates more than 1 year after TBI.

Adolescent↗
PubMed1994

The incidence of pressure sores within a National Health Service Trust hospital during 1991.

The prevalence of pressure sores has been frequently reported. However, such measures fail to identify how many patients develop sores, while longitudinal changes in prevalence rates are difficult to interpret. This paper provides the first report of the incidence of pressure sores across the population of a single NHS Trust hospital. During 1991, 360 patients developed sores, an incidence of 4.03 patients per 100 admissions. Within orthopaedic wards, the incidence was higher, with 10.3 patients per 100 admissions developing sores.

England↗
PubMed2002

Phylogeography of the common ivy (Hedera sp.) in Europe: genetic differentiation through space and time.

We studied the phylogeography of ivy (Hedera sp.), a liana widespread in Europe, throughout its natural range. The populations sampled belong to four closely related species differing by ploidy levels and morphological characters. Chloroplast (cp) markers were used and 13 haplotypes were detected, usually shared across species, contrary to ribosomal internal transcribed spacer (ITS) variants. We demonstrated the existence of a strong overall cpDNA phylogeographical structure. Several methods of data analysis were conducted to describe how this structure and the genetic diversity change through space and time. Southern populations, especially those from Spain, are the most divergent. Pairwise estimates of differentiation point to isolation by distance, and the existence of a latitudinal gradient of divergence was demonstrated using a regression procedure. Similarly, latitudinal differences in haplotype richness and diversity exist, as shown by population permutations ('differentiation through space'). Finally, we measured differentiation by taking into account successive levels of divergence between haplotypes ('differentiation through time'). Genetic differentiation turns out to be much greater when differences between closely related haplotypes are not considered. Further, these results indicate that the phylogeographical structure is essentially due to the relative distribution of the most similar haplotypes. Diversity decreases from south to north, whereas haplotype frequencies change longitudinally. It appears that Hedera survived in Spanish and Balkan refugia during the last ice age. A third refugium must have been present in the Alps or in Italy. During the northward expansion, the decrease in overall diversity was attenuated by some mixing of lineages at intermediate latitudes, resulting in comparatively higher levels of differentiation in the south.

Biological Evolution↗
PubMed2000

Prevalence of coeliac disease and longitudinal follow-up of antigliadin antibody status in children and adolescents with type 1 diabetes mellitus.

Coeliac disease (CD) is more prevalent in individuals with type 1 diabetes mellitus (DM), and when untreated is associated with a number of medical complications, including poor glycaemic control. Identification of patients with CD has been facilitated in recent years by serological screening, including the use of antigliadin antibodies (AGAs) and endomysial antibodies (EMAs). The aim of this study was to assess the prevalence of CD in a clinic-based paediatric population with type 1 DM, and to study longitudinal changes in AGA status. Two-hundred-and-eighty-one children and adolescents with type 1 DM aged 9.9 +/- 3.8 yr were screened using AGAs of immunoglobulin A (IgA) and immunoglobulin G (IgG) classes (AGA-IgA and AGA-IgG). Thirty-five patients had both antibodies positive and underwent gastro-duodenoscopy and multiple biopsies. Fifteen of the 35 patients had histological evidence of CD, and the overall clinic prevalence of CD was 5.7%. A number of patients did not exhibit florid symptoms, and recurrent unexplained hypoglycaemia was a significant finding. Patients who perceived themselves to be asymptomatic had more problems with compliance with a gluten-free diet (GFD). Ninety-seven patients had follow-up AGAs performed after 2.5 +/- 1.5 yr. One patient with initially normal AGAs developed positive antibodies and histological findings of CD. Antibody status has fluctuated in other patients. CD is common in patients with DM, and diagnosis is important to detect to minimize long-term morbidity related to both disorders. Initial normal screening does not exclude CD and repeat screening is indicated.

Journal Article↗
PubMed2000

Post-earthquake quality of life and psychological well-being: longitudinal evaluation in a rural community sample in northern China.

This study aims to observe longitudinal change of quality of life (QOL) and psychological well-being in a community sample affected by an earthquake and to examine the relationship between QOL and disaster exposure, post-disaster support and other related variables. The subjects, from two villages at different distances from the epicenter, were assessed using the brief version of the World Health Organization Quality of Life Assessment (WHOQOL-BREF) and three subscales of a symptoms checklist at 3 months (n=335) and 9 months (n=253) after the earthquake, respectively. Exposure to the earthquake was associated with multidimensional impairment in QOL, including physical, psychological and environmental domains at 3 months, and psychological and environmental domains at 9 months. The victims also suffered significantly more psychological distress in terms of depression, somatization and anxiety. At both assessment points the group that experienced lower initial exposure but then received less post-disaster help reported poorer QOL and psychological well-being. The two victim groups also differed significantly in changing trend along time. The group that received more support showed a general improvement in post-disaster well-being from 3 months to 9 months. The results confirm that post-disaster variables could be as important to post-disaster psychosocial outcomes as variables of pre-disaster vulnerability and disaster per se. A comprehensive and prospective assessment of disaster effects is imperative for the better organization of disaster relief programs and psychosocial interventions.

Adolescent↗
PubMed1998

Influence of hematocrit on the measurement of lipoproteins demonstrated by the example of lipoprotein(a).

BACKGROUND: The measurement of many parameters of human blood is usually performed in plasma or serum. Since lipoproteins or apolipoproteins, for example, are found almost exclusively in the plasma fraction after low-speed centrifugation, these parameters can be expected to be distributed in a different plasma volume depending on the hematocrit value. Therefore, the measured plasma levels might be relatively too low or too high in comparison to the whole blood concentrations in the case of abnormal hematocrit levels. The aim of our experiments was to evaluate the extent of differences between whole blood and plasma concentrations, taking as an example lipoprotein(a) [Lp(a)] in hemodialysis patients with documented decreased hematocrit values. METHODS: Lp(a) was measured in plasma as well as whole blood of 15 hemodialysis patients with low hematocrit values (0.29 +/- 0.02) in comparison to 11 control subjects (0.45 +/- 0.04). RESULTS: Plasma concentrations were 27% higher in patients than in controls (19.7 vs. 15.5 mg/dl). The relative difference was twice as high (59%) when measured in whole blood (13.5 vs. 8.5 mg/dl). Similar relative differences were observed when whole blood concentrations of 125 hemodialysis patients and 256 controls were calculated with the formula [Lp(a)plasma * (1-hematocrit)]. CONCLUSIONS: Our findings clearly demonstrate that hematocrit is a strong confounding variable of lipoprotein measurement in epidemiological studies when concentrations are measured in plasma, especially in cases of abnormal hematocrit values. Furthermore, studies investigating the longitudinal changes of lipoproteins should consider potential hematocrit changes.

Blood Chemical Analysis↗
PubMed1999

National trend of the incidence of urolithiasis in Japan from 1965 to 1995.

BACKGROUND: A nationwide survey of urolithiasis in Japan was made in order to evaluate the chronological trend of upper urinary tract stones in the Japanese. It succeeded previous studies done in 1955, 1966, 1979, and 1990. METHODS: All outpatient visits to urologists that resulted in a diagnosis of first-episode upper urinary tract stones in the years 1990 and 1995 were enumerated, irrespective of admission and treatment. The study enrolled all of the Japanese Board of Urology-approved hospitals, thereby covering nearly all urologists practicing in Japan. The annual incidence by sex and age was estimated and compared with the incidences in the previous nationwide surveys. RESULTS: The age-adjusted annual incidence of first-episode upper urinary tract stones in 1995 was estimated as 68.9 per 100,000 (100.1 in men and 55.4 in women), a steady increase from 54.2 in 1965. The annual incidence has increased in all age groups, except in those of the first three decades. The peak age for both sexes has shifted in toward the older population's direction. Estimations of longitudinal changes between 1965 and 1995 showed that the annual incidence has more than doubled for the cohort of the 1965 census population (from 43.7 in 1965 to 110.9 in 1995) and that younger generations have had progressively higher annual incidences. CONCLUSIONS: The annual incidence of upper urinary tract stones in Japan has increased steadily over the past 30 years and will continue to do so in the near future, but it still is lower than in the United States.

Adolescent↗
PubMed2000

Health-related quality of life outcomes measures.

OBJECTIVE: To review critically the features of measures of generic health-related quality of life (HRQOL) for disability outcomes research. DATA SOURCES: A search of electronic databases, summary reviews, books, and government documents was performed. Comment and experiences from participants of a conference on outcomes research were also incorporated. STUDY SELECTION: English language literature from scientists from a broad range of disciplines and research settings, including medicine, nursing, social science, and public health, and health services research and practice. DATA EXTRACTION: A critical review of measures that have been or might be used to measure disability outcomes. DATA SYNTHESIS: Commonly used generic measures of HRQOL can be applied to disability outcomes research with some caveats. Three common tools are the Medical Outcomes Study Short-Form Health Survey (SF-36), Sickness Impact Profile (SIP), and Quality of Well-Being (QWB) scale. The SF-36 and SIP have been used with some success in research with people with disability. The QWB scale has been used less frequently. CONCLUSION: Most studies using generic HRQOL tools are of groups with specific impairments rather than heterogeneous groups of people with disability. None of the tools appears to measure HRQOL without some potential biases (eg, inappropriate wording) for people with disability, but more specific testing of these problems is needed. Also needed are studies to determine whether these tools can measure meaningful longitudinal changes.

Persons with Disabilities↗
PubMed2005

Interleukin-12 and -18 levels in peritoneal dialysate effluent correlate with the outcome of peritonitis in patients undergoing peritoneal dialysis: implications for the Type I/Type II T-cell immune response.

BACKGROUND: We previously showed that a positive impact of peritoneal defense response on the outcome of peritoneal dialysis (PD)-related peritonitis is characterized by an increased pattern of peritoneal CD4/CD8 T-cell ratio with a predominant CD4(+)-T helper subtype 1 phenotype. To further explore longitudinal changes in peritoneal immunity during PD-related peritonitis, we examined the production of interleukin 12 (IL-12), IL-18, and interferon gamma (IFN-gamma) in peritoneal dialysate effluent (PDE) and kinetic expression of the transcription factors T box expressed in T cells (T-bet) and guanine adenine thymine adenine (GATA) binding protein 3 (GATA-3) in peritoneal T cells during peritonitis. Correlations between these observations and responses to antibiotics were analyzed. METHODS: IL-12, IL-18, and IFN-gamma protein and IFN-gamma, T-bet, and GATA-3 messenger RNA (mRNA) were measured in PDE during various phases of peritonitis in 40 patients undergoing PD. Patients were divided into 2 groups according to whether they had a rapid versus delayed response to antibiotic treatment. RESULTS: In the early phase of peritonitis, IL-12, IL-18, and IFN-gamma levels in PDE were significantly greater in the rapid-response group (P < 0.05). Changes in peritoneal IL-12 and IL-18 levels preceded changes in IFN-gamma levels. The kinetics of IFN-gamma, T-bet, and GATA-3 mRNA expression in peritoneal T cells, measured by means of real-time polymerase chain reaction, differed between the 2 groups. In the rapid-response group, IFN-gamma and T-bet mRNA expression increased, whereas that of GATA-3 decreased over time. Results were opposite in the delayed-response group, with IFN-gamma and T-bet levels decreasing and GATA-3 levels increasing over time. CONCLUSION: These data suggest that local IL-12 and IL-18 production is part of a protective early immune response to PD-related peritonitis. High IL-12 and IL-18 levels in PDE during the early phase of peritonitis correlated with a predominant type 1 immune response and favorable outcome.

Adult↗
PubMed2001

Apolipoprotein E polymorphism modulates the association between obesity and dyslipidemias during young adulthood: The Bogalusa Heart Study.

To elucidate to what extent apolipoprotein (apo) E polymorphism modulates obesity-induced dyslipidemias during young adulthood, longitudinal data on 759 individuals (72% white/28% black; initial and follow-up mean age, 25.9 and 32.7 years) were examined. Among both races and the total sample, the apo E2 group (with E2/2 or E2/3 phenotype) had significantly lower and the apo E4 (with E4/4 or E3/4 phenotype) group higher low-density lipoprotein (LDL) cholesterol than the apo E3 (with E3/3 phenotype) group at both examinations. In addition, the apo E2 group displayed higher high-density lipoprotein (HDL) cholesterol in the total sample. No allele-specific effect was noted for the longitudinal changes (Delta). An increase in Delta adiposity, measured as Delta body mass index (BMI), was accompanied by higher increase in Delta LDL cholesterol in the e4 carriers than the e2 carriers among the whites (P <.05) and the total sample (P <.01); an increase in Delta triglycerides and decrease in Delta HDL cholesterol in the e2 carriers than the e4 carriers among all the groups (P <.05 to.001). Among the apo E phenotype groups, the incidence of high (>75th percentile specific for race and sex) LDL cholesterol at follow-up was in the order E4 > E3 > E2 both in the obese (BMI > 30; P for trend =.033) and the nonobese (BMI < 25; P for trend =.035) groups. Although the increase of low (<25th percentile specific for race and sex) HDL cholesterol or high triglycerides showed no apo E phenotype-specific trend, the incidence of high triglycerides without high LDL cholesterol was in the order E2 > E3 > E4 only in the obese group (P for trend =.025). The prevalence trend for dyslipidemias at follow-up among the persistently obese and nonobese groups also gave similar results. Thus, apo E gene locus influences not only the levels of certain lipoprotein variables during young adulthood, but also modulates the association between obesity and dyslipidemias.

Adult↗
PubMed2002

Family reactions during infants' hospitalization in the neonatal intensive care unit.

The purpose of this investigation is to assess family stress, coping, perceptions of their infant, and alterations in mood that may result from the hospitalization of their critically ill newborn infant. Eligible patients were those infants hospitalized in the Special Care Nursery (SCN) at Christiana Care Health Services, who were born up to 31 weeks' gestational age. Twenty-seven families (mothers and/or fathers) completed four questionnaires at 2-week intervals during the course of their premature infants' hospitalization. Data were primarily evaluated by using analysis of variance (ANOVA)/multivariate analysis of variance (MANOVA). A score for neonatal acute physiology (SNAP) was obtained in each infant to assess the effect of the severity of neonatal illness on the questionnaire variables. Families with high stress scores on the Parental Stressor Scale had different coping strategies than those with less stress scores. A high level of maternal depressive symptomatology was associated with altered methods of coping, general stress, and perception of infant health. There was no relationship between the SNAP score on the overall level of stress families. Families who completed more than two questionnaires differed from those who only completed two or less questionnaires, although the sample size was too small to assess longitudinal changes in this study population. Level of stress and depressive symptoms are two major influences of how families cope with the current hospitalization of a premature infant. The degree of neonatal illness is not a major contributor to the parents' coping ability. Healthcare providers need to understand these dynamics when supporting families during the hospitalization of their premature infant.

Adaptation, Psychological↗
PubMed2003

Effect of parathyroidectomy on bone mineral density in hemodialysis patients with secondary hyperparathyroidism: possible usefulness of preoperative determination of parathyroid hormone level for prediction of bone regain.

PURPOSE: To examine longitudinal changes of bone mineral density (BMD) after parathyroidectomy (PTx) in patients undergoing maintenance hemodialysis (HD) with severe secondary hyperparathyroidism (HPT) to determine which factor contributes most to bone changes. METHODS: Fifteen Japanese HD patients who had been refractory to medical therapy were subject to PTx with autotransplantation. We measured BMD by dual energy X-ray absorptiometry (DXA) at the lumbar spine (L2 - 4 BMD) and the distal 1/3 region of the radius (1/3R BMD) at 1, 3, 6, 12, 24, and 36 months after PTx. RESULTS: Baseline Z-score of BMD was markedly low at 1/3R (- 3.07) and slightly low at L2 - 4 (-0.59) in this group. A significant increase in L2 - 4 BMD was observed as early as one month after PTx, which was sustained afterwards. Annual percent changes in L2 - 4 and 1/3R BMD were + 15.6 % and + 6.4 %, respectively. The annual percent changes in BMD at both sites were positively associated with preoperative intact PTH levels (L2 - 4; r = 0.642, p = 0.010, 1/3R; r = 0.884, p < 0.001) and total alkaline phosphatase (ALP) levels (L2 - 4; r = 0.663, p = 0.007, 1/3R; r = 0.858, p < 0.001). Stepwise multiple regression analysis revealed that serum levels of intact PTH and ALP were the best predictors of both percentage and net changes in radial BMD with high determination coefficients (r 2 > 0.8). CONCLUSION: Successful PTx following appropriate supplementation with vitamin D and calcium provides a marked increase in lumbar BMD and a modest increase in radial BMD in HD patients with secondary HPT. Preoperative levels of PTH and ALP are useful for predicting postoperative changes in bone mass.

Absorptiometry, Photon↗
PubMed2004

Relationship between the area of cartilage shown on the magnetic resonance imaging middle-slice image of the medial and lateral tibial cartilages with cartilage volume and grade of osteoarthritis over time.

OBJECTIVE: Knee cartilage volume measurement requires significant time and training. Simplifying the measurement may improve feasibility. We investigated whether the area of cartilage shown on the middle slice of the medial and lateral tibial cartilages on sagittal MRI correlates with radiological features of osteoarthritis (OA), cartilage volume, and longitudinal change in cartilage volume. METHODS: One hundred and seventy-three subjects (normal and osteoarthritic), who had serial magnetic resonance imaging (cartilage volume measured) and baseline weight-bearing antero-posterior radiographs of the same knee were examined. RESULTS: In the lateral compartment, with increasing grade of OA there was a significant reduction in cartilage area. In the medial compartment, this was true for medial joint-space narrowing (after adjusting for gender). There was a moderate to strong association between cartilage area and volume, especially in those with early or no OA. However, when change over time was examined, the strength of these relationships was weak. CONCLUSION: Our data suggests that cartilage area may provide a simple surrogate measure of cartilage volume, in cross-sectional studies, after adjustment for gender: especially in subjects with early disease. However, before it can be widely used, further investigation will be required.

Aged↗
PubMed2000

Effect of different grouping strategies in developing estimates of personal exposures: specificity versus precision.

There has been increasing interest in recent years in developing strategies in epidemiology for the summarization of occupational exposures, strategies that serve to clarify observed relationships between occupational exposure and health outcomes. Where source occupational exposure data are scarce, it is common to assemble exposure groups with the goal of increasing the extent to which data-based exposure estimates are available for an entire cohort. There has been little guidance, however, on the effect of different grouping strategies on the observed fit between exposure and health outcome. This investigation examined the effect of the use of different exposure summarization strategies on observed relationships between dust exposure and lung function decline among coal mine workers. The dust exposure and spirometry data employed were gathered in the National Study of Coalworkers' Pneumoconiosis. An analysis of variance procedure was carried out to characterize the variability of the dust exposure data, employing single variables relating to mine identity, occupation, and year, as well as two- and three-way multivariate combinations of these variables. The resulting combinations were ranked according to the standard deviation of the observed exposure range to reflect the relative specificity of the various approaches. Sequential arrangements of single- and multiple-variable combinations were constructed, alternately employing highly specific codes or broad categories for mine, occupation, and year. Annual exposure estimates were constructed on the basis of these sequences and used in tandem with longitudinal change in forced expiratory volume (FEV1) in linear multiple regression procedures. Height, age, smoking status, and dust exposure were employed as predictor variables. The results show that the use of broad categorization approaches had a substantial impact on observed regression coefficients. The largest change was observed for categorization according to occupation, which resulted in two- to three-fold increases in the magnitude of observed regression coefficients. These results suggest that the use of highly specific exposure summarization approaches may result in regression outcomes which are marked by a high degree of attenuation, and that consideration of the precision of summarized exposure estimates is an important component of an effective exposure assessment strategy.

Adult↗