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PubMed2005

Environmental and population dependency of genetic variability-fitness correlations in Rana temporaria.

Abstract Considerable effort has been invested in studying the relationship between fitness and genetic variability. While evidence exists both for and against positive genetic variability-fitness correlations (GFC), the possible environment and population-dependency of GFCs has seldom been tested. We investigated GFCs in common frog (Rana temporaria) tadpoles reared under different temperatures and feeding regimes in four replicate populations. Genetic variability in eight microsatellite loci in 238 parents was used to estimate heterozygosity (H) and mean expected d2 in 158-sibships (4515 offspring). Generalized linear mixed model analyses of offspring fitness traits (survival to metamorphosis, developmental and growth rate) revealed that offspring survival probability was positively correlated with H, and that relationships were similar in all four populations tested. However, significant interaction between other genetic variability measures (d2, relatedness) and treatment conditions indicated that GFCs were detectable in some, but not in all environments. Interestingly, GFCs between survival and both heterozygosity and relatedness were most pronounced in stressful environments (i.e. limited food). Developmental and growth rates were significantly associated with d2 but less with H and relatedness. Furthermore, many of these GFCs were population-specific. These results suggest--in line with the contention that expression of inbreeding depression can be environment dependent--that GFCs can also be highly sensitive to the environmental conditions under which they are measured. The results further suggest that the observed positive correlation between H and survival probability is likely to be explainable by the 'general', rather than by the 'local' or 'direct' effect hypotheses.

Animals↗

PubMed2005

Assessing the accuracy of Orbscan II post-LASIK: apparent keratectasia is paradoxically associated with anterior chamber depth reduction in successful procedures.

PURPOSE: To establish a relationship between the forward protrusion of the cornea (keratectasia), following successful LASIK, and anterior chamber depth. METHODS: One hundred and fifteen eyes of 59 patients who had undergone Zyoptix LASIK and 39 eyes of 21 patients who had undergone PlanoScan LASIK at the Eye Institute, Centre for Refractive Surgery, Remuera, Auckland, New Zealand, were included in the study. The results of Orbscan II acquisitions, taken before and 8.3 weeks +/- 4.0 (mean +/- standard deviation) following the procedure, were analysed to determine the amount of forward protrusion of the central 2 mm diameter of the posterior surface. The apparent keratectasia was then related to the Orbscan II anterior chamber depth (ACD) measurement in a linear mixed model analysis that included 'right or left eye', 'sex', 'type of LASIK procedure', 'change in pachymetry', 'postoperative pachymetry', 'change in anterior corneal curvature', 'postoperative anterior corneal curvature', 'planned ablation depth' and 'time until follow-up' as factors and covariates. RESULTS: The mean +/- SD amount of keratectasia determined by Orbscan II was 22.8 +/- 26.8 microm for the Zyoptix group and 16.9 +/- 24.6 microm for the PlanoScan group. The reduction in depth of the anterior chamber was 14.7 +/- 79.3 microm for the Zyoptix group and 18.2 +/- 68.8 microm for the PlanoScan group. The mixed model analysis demonstrated strong relationships with postoperative pachymetry and change in anterior corneal curvature (P < 0.001 and P < 0.001, respectively). Furthermore, the statistical model showed a marked significant difference in the Orbscan II assessment of keratectasia and change in ACD (P < 0.001). CONCLUSION: Using the Orbscan II device, the forward protrusion of the posterior corneal surface appears to coincide with a paradoxical reduction in depth of the anterior chamber. Although the keratectasia found in this study is accompanied by thin postoperative corneas and larger central pachymetry change, the contradictory decrease in anterior chamber depth creates uncertainty of measurement, and of ectasia as a mechanism of regression.

Adult↗

PubMed2005

Factors associated with glycaemic outcome of childhood diabetes care in Denmark.

AIMS: To study how structure and process of care is associated with outcome assessed by HbA(1c). METHODS: Data for this cross-sectional study originated from the nationwide Danish Registry for Childhood Diabetes and two questionnaires. One questionnaire was sent to all children under 16 years of age with Type 1 diabetes in the year 2000 (N = 1087, response rate 80%). Another questionnaire was sent to the 19 centres in Denmark treating these children (response rate 100%). Simultaneously the children were asked to take a blood sample for central HbA(1c) analysis. Linear mixed models were used for analysis of associations between structure and process indicators and HbA(1c). Age, diabetes duration, sex, ethnicity, family structure and parents' occupational status were included as patient factors possibly affecting HbA(1c). RESULTS: More visits to the outpatient clinic and higher insulin dosage were significantly associated with higher HbA(1c) (P = 0.002 and P = 0.0001, respectively). Increased frequency of blood glucose monitoring (BGM/week) and completed nephropathy screening were significantly associated with lower HbA(1c) value (estimates -0.008 and -0.49, P = 0.02, respectively). The structure indicators were not associated with HbA(1c), but telephone hot-line was positively associated with the process indicator BGM (estimate 4.02, P = 0.04). Children without Danish parents performed BGM significantly less frequently (-7.11, P = 0.0005) and had higher HbA(1c) (0.41, P = 0.06). CONCLUSIONS: Most process indicators were significantly associated with HbA(1c), indicating relevant action of staff on glucose regulation. The structure indicators were not associated with outcome, necessitating more detailed studies on the influence of staffing resources, treatment strategies and targets in childhood diabetes management.

Adolescent↗

PubMed2005

The effect of surgical and nonsurgical treatment on longitudinal outcomes of lumbar spinal stenosis over 10 years.

OBJECTIVES: To assess the relative effect of initial surgical and nonsurgical treatment on longitudinal outcomes of patients with lumbar spinal stenosis over a 10-year follow-up period. DESIGN: A prospective observational cohort study. SETTING: Enrollment from community-based specialist practices throughout Maine. PARTICIPANTS: One hundred forty-four patients with lumbar spinal stenosis who had at least one follow-up: 77 initially treated surgically and 67 initially treated nonsurgically. INTERVENTION: Initial surgical or nonsurgical treatment. MEASUREMENTS: Clinical data were obtained at baseline and outcomes followed at regular intervals over 10 years with mailed questionnaires including patient-reported symptoms of back pain, leg symptoms, back-specific functional status, and satisfaction. Longitudinal data were analyzed using general linear mixed models. In addition to treatment (initial surgical or nonsurgical care), time period, and the interaction between treatment and time, the models included baseline score, patient age and sex, and a time-varying general health status score. The effects of these covariates in explaining differences between treatment groups were also examined. The effect of subsequent surgical procedures was assessed using different analysis strategies. RESULTS: The 10-year rate of subsequent surgical procedures was 23% and 38% for patients initially treated surgically and nonsurgically, respectively, and the overall 10-year survival rate was 69%. Patients undergoing initial surgical treatment had worse baseline symptoms and functional status than those initially treated nonsurgically. For all outcomes and at each time point, surgically treated patients reported greater improvement in symptoms and functional status and higher satisfaction scores, indicative of better outcomes, than nonsurgically treated patients. However, the relative magnitude of the benefit diminished over time such that the relative differences for low back pain and satisfaction were no longer significant over long-term follow-up (both P=.08 for treatment effect between 5 and 10 years after controlling for covariates). Regardless of initial treatment received, patients undergoing subsequent surgical procedures reported less improvement in outcomes over time than patients who did not undergo subsequent procedures, but the relative differences between treatment groups were similar in analyses that controlled for outcomes after subsequent procedures. CONCLUSION: After controlling for covariates, patients initially treated surgically demonstrated better outcomes on all measures than those initially treated nonsurgically. Although outcomes of initial surgical treatment remained superior over time, the relative benefit of surgery diminished in later years, especially for low back pain and satisfaction. Patients undergoing subsequent surgery had worse outcomes regardless of initial treatment received, but excluding them did not change overall treatment group comparisons. The analytical methods described may be helpful in the design and analysis of future studies comparing treatment outcomes for patients with lumbar spinal stenosis.

Aged↗

PubMed2006

Clinical characteristics and longitudinal changes of informal cost of Alzheimer's disease in the community.

Most estimates of the cost of informal caregiving in patients with Alzheimer's disease (AD) remain cross-sectional. Longitudinal estimates of informal caregiving hours and costs are less frequent and are from assessments covering only short periods of time. The objectives of this study were to estimate long-term trajectories of the use and cost of informal caregiving for patients with AD and the effects of patient characteristics on the use and cost of informal caregiving. The sample is drawn from the Predictors Study, a large, multicenter cohort of patients with probable AD, prospectively followed annually for up to 7 years in three university-based AD centers in the United States (n=170). Generalized linear mixed models were used to estimate the effects of patient characteristics on use and cost of informal caregiving. Patients' clinical characteristics included cognitive status (Mini-Mental State Examination), functional capacity (Blessed Dementia Rating Scale (BDRS)), comorbidities, psychotic symptoms, behavioral problems, depressive symptoms, and extrapyramidal signs. Results show that rates of informal care use and caregiving hours (and costs) increased substantially over time but were related differently to patients' characteristics. Use of informal care was significantly associated with worse cognition, worse function, and higher comorbidities. Conditional on receiving informal care, informal caregiving hours (and costs) were mainly associated with worse function. Each additional point on the BDRS increased informal caregiving costs 5.4%. Average annual informal cost was estimated at $25,381 per patient, increasing from $20,589 at baseline to $43,030 in Year 4.

Aged↗

PubMedDate not supplied

An in vitro biomechanical comparison of the breaking strength and stiffness of polydioxanone (sizes 2, 7) and polyglactin 910 (sizes 3, 6) in the equine linea alba.

OBJECTIVE: To determine failure strength, stiffness, and failure mode of 4 suture materials in equine linea alba. STUDY DESIGN: Randomized complete block design. SAMPLE POPULATION: Linea albas collected from 12 adult horses (mean weight, 475 kg; mean age, 10 years). METHODS: The ventral abdominal fascia, including the linea alba, was collected and bisected along the linea alba into right and left halves. Each half was divided into four, 5-cm sections extending from the umbilicus cranially, and randomly assigned to 1 of 4 suture materials: 2 polydioxanone (2 PD), 3 polyglactin 910 (3 PG), 6 polyglactin 910 (6 PG), and 7 polydioxanone (7 PD). A single cycle to failure test was performed on each specimen at a distraction rate of 100 mm/min. Differences in failure strength and stiffness for the materials were evaluated using a mixed linear model with significance set at P<.05. RESULTS: In 94 of 96 test sections, constructs failed by suture failure. There were significant differences in failure strength (P<.0001) and stiffness (P<.001) among the suture/tissue constructs. 7 PD had the highest breaking strength (316.8 N) followed by 6 PG (281.3 N), 3 PG (229.9 N), and 2 PD (193.0 N). Six PG had the largest stiffness (14 N/mm) followed by 3 PG (12.7 N/mm), 7 PD (10.1 N/mm), and 2 PD (7.2 N/mm). Suture breaking strength and stiffness were not affected by linea or fascia thickness, individual horse, half of the linea alba, or abdominal wall position. Eighty-five (90.4%) suture loops failed adjacent the knot. CONCLUSIONS: When tested in single cycle to failure, suture material was more likely to fail than the linea alba. Larger suture materials had higher breaking strengths than smaller suture materials and stiffness was also affected by suture material and size. CLINICAL RELEVANCE: Given its high initial breaking strength and its relatively longer in vivo strength retention, 7 PD seems an appropriate choice of suture material for closure of the equine linea alba when maximal short-term failure strength is desired.

Abdominal Muscles↗

PubMed2004

Comparing methods of measurement for detecting drug-induced changes in the QT interval: implications for thoroughly conducted ECG studies.

BACKGROUND: The aim of this study was to compare the reproducibility and sensitivity of four commonly used methods for QT interval assessment when applied to ECG data obtained after infusion of ibutilide. METHODS: Four methods were compared: (1) 12-lead simultaneous ECG (12-SIM), (2) lead II ECG (LEAD II), both measured on a digitizing board, (3) 3-LEAD ECG using a manual tangential method, and (4) a computer-based, proprietary algorithm, 12SL trade mark ECG Analysis software (AUT). QT intervals were measured in 10 healthy volunteers at multiple time points during 24 hours at baseline and after single intravenous doses of ibutilide 0.25 and 0.5 mg. Changes in QT interval from baseline were calculated and compared across ECG methods, using Bland-Altman plots. Variability was studied using a mixed linear model. RESULTS: Baseline QT values differed between methods (range 376-395 ms), mainly based on the number of leads incorporated into the measurement, with LEAD II and 3-LEAD providing the shortest intervals. The 3-LEAD generated the largest QT change from baseline, whereas LEAD II and 12-SIM generated essentially identical result within narrow limits of agreement (0.4 ms mean difference, 95% confidence interval +/- 20.5 ms). Variability with AUT (standard deviation 15.8 ms for within-subject values) was clearly larger than with 3-LEAD, LEAD II, and 12-SIM (9.6, 10.0, and 11.3 ms). CONCLUSION: This study demonstrated significant differences among four commonly used methods for QT interval measurement after pharmacological prolongation of cardiac repolarization. Observed large differences in variability of measurements will have a substantial impact on the sample size required to detect QT prolongation in the range that is currently advised in regulatory guidance.

Adult↗

PubMed2006

Effects of a physical exercise intervention on subjective physical well-being, psychosocial functioning and general well-being among office workers: a cluster randomized-controlled cross-over design.

The purpose of the study was to examine the effects of a workplace physical exercise intervention on subjective physical well-being, psychosocial functioning and general well-being. The study was a cluster randomized-controlled trial with the department (n=4) as the unit of randomization. The subjects (n=90) were office workers [mean age 45.7 (SD 8.5) years]. Psychosocial functioning and well-being variables were measured by descriptive visual rating scales. The cross-over design consisted of one 15-week intervention period of light resistance training and guidance and another 15-week period of no training and no guidance. The statistical analysis was based on linear mixed models. The active component of the intervention, light resistance training, resulted in a slight, but statistically significant, increase in subjective physical well-being (P=0.015). At the average training time of 5 min/working day (25 min/week) the average increase during the 15-week period was 4 units (95% confidence interval (CI) 1-7) and 5% (95% CI 1-9). The physical exercise intervention had no effect on somatic symptoms, anxiety, self-confidence, mood, mental stress at work, working atmosphere, life satisfaction or meaning of life. Daily light resistance training, conducted during the working day, had a positive direction on subjective physical well-being among office workers.

Cross-Over Studies↗

PubMed2004

Prospective study on late consequences of subclinical non-compliance with immunosuppressive therapy in renal transplant patients.

In this prospective study we compared the incidence of late acute rejections (LAR) and changes in serum-creatinine over time between compliers and noncompliers with immunosuppressive therapy more than 1 year post transplantation and explored the relative contribution of non-compliance and other risk factors in the occurrence of LAR. One hundred and forty-six adult renal transplant recipients were followed during a 5-year period. Patients were interviewed at the beginning of the study and categorized as non-compliers if they admitted to have skipped immunosuppressive medication on a regular basis during the previous 12 months. The occurrence of LAR during the follow-up period was recorded. We identified 22.6% non-compliers of which 21.2% experienced a late acute rejection compared with 8% in the group of compliers at 5 years postinclusion (p < 0.05). Kaplan-Meier survival analysis showed a decreased rejection free time in non-compliers compared with compliers (p = 0.03). Non-compliant patients had a 3.2 higher risk of LAR (Cox regression analysis, p = 0.005). Non-compliers experienced a higher increase in serum-creatinine over time (Linear Mixed Models, p < 0.001). Non-compliance in renal transplant patients more than 1-year post transplantation is associated with an increased risk for LAR and a higher increase in serum-creatinine during the following 5 years.

Adult↗

PubMed2005

Mass screening for antimicrobial resistant Escherichia coli in dairy cows in northern New South Wales.

OBJECTIVE: To describe aspects of the epidemiology of antimicrobial resistance in Escherichia coli shed in the faeces of milking cows in a dairying region of New South Wales. DESIGN: A survey based on multi-stage sampling with repeated measures made within herds for estimating within-herd correlation of resistance status, and with repeated measures made on identical specimens for estimating test-retest reliability. PROCEDURE: From a population of 110 dairy herds, 30 were selected at random and from each herd between 5 and 10 faecal specimens were obtained from fresh manure pats. E coli from faecal specimens were grown on hydrophobic grid membrane filters (HGMF) and replicated onto chromogenic agar and agar containing antimicrobials (gentamicin, ampicillin, tetracycline and sulfamethoxazole). Image analysis was used to assess colony growth. Data were analysed descriptively, by generalised linear mixed models and by Taylor series linearisation to account for attributes of the survey design. RESULTS: Of the 10,279 E coli isolates assessed, 91% expressed no resistance, 7.3% were resistant to sulfamethoxazole, 3.6% to tetracycline, 2.2% to ampicillin and 0.09% to gentamicin. The most common multiple resistance phenotype was ampicillin-tetracycline-sulfamethoxazole (1.8% of isolates). Most multiple resistant isolates appeared clustered within particular herds but were too rare to obtain valid estimates of variance, confidence intervals or intra-herd correlation. The estimated proportion of isolates in the population that were susceptible to all four antimicrobials was 97% (95% CI: 91% to 100%) and 55% of cows had no resistance detected in faecal E coli (95% CI: 27% to 83%). Within-herd correlation of shedding status (any resistance pattern) was absent and test-retest reliability of the measurement system was estimated to be at the lower end of good (0.40) but increased to excellent (0.89) after excluding sulfamethoxazole resistance, which had a greater measurement error. CONCLUSION: Antimicrobial resistance was uncommon in E coli in the population of dairy cows studied. HGMF and image analysis is an effective tool for detecting rare forms of resistant E coli that are not uniformly distributed in livestock populations.

Animals↗

PubMed2006

Artifactual changes in canine blood following storage, detected using the ADVIA 120 hematology analyzer.

BACKGROUND: Artifactual changes in blood may occur as a consequence of delayed analysis and may complicate interpretation of CBC data. OBJECTIVE: The aim of this study was to characterize artifactual changes in canine blood, due to storage, using the ADVIA 120 hematology analyzer. METHODS: Blood samples were collected into EDTA from 5 clinically healthy dogs. Within 1 hour after blood sample collection and at 12, 24, 36 and 48 hours after storage of the samples at either 4 degrees C or room temperature (approximately 24 degrees C), a CBC was done using the ADVIA 120 and multispecies software. A linear mixed model was used to statistically evaluate significant differences in values over time, compared with initial values. RESULTS: The HCT and MCV were increased significantly after 12 hours of collection at both 4 degrees C and 24 degrees C, and continued to increase through 48 hours. The MCHC initially decreased significantly at 12-24 hours and then continued to decrease through 48 hours at both temperatures. Changes in HCT, MCV, and MCHC were greater at 24 degrees C than at 4 degrees C at all time points. A significant increase in MPV and a decrease in mean platelet component concentration were observed at all time points at 24 degrees C. Samples stored at 24 degrees C for 48 hours had significantly higher percentages of normocytic-hypochromic RBCs, and macrocytic-normochromic RBCs, and lower platelet and total WBC counts. CONCLUSIONS: Delayed analysis of canine blood samples produces artifactual changes in CBC results, mainly in RBC morphology and platelet parameters, that are readily detected using the ADVIA 120. Refrigeration of specimens, even after 24 hours of storage at room temperature, is recommended to improve the accuracy of CBC results for canine blood samples.

Animals↗

PubMed2026

Premature closure underlies bias in medical diagnosis in students: A randomised controlled experiment.

OBJECTIVE: The purpose of the study reported in this article was to shed light on the cognitive mechanism mediating between biasing information and diagnostic error. The literature suggests at least two different hypotheses: premature closure leading biased participants to spend less time on diagnosis or increased competition between diagnostic hypotheses. The latter hypothesis predicts that biased participants would spend more time reaching a diagnosis. METHOD: Using the salient distracting findings (SDF) experimental paradigm, we biased 58 fourth-year medical students while diagnosing 12 clinical vignettes in a within-group incomplete block design under three conditions: cases presented without SDF, with SDF at the beginning and with SDF at the end. For each of these conditions, diagnostic accuracy, the number of SDF-related mistakes and time per word needed to process the case were recorded. The data were analysed using linear mixed modelling. Estimated marginal mean scores were reported. RESULTS: Participants confronted with salient distracting features (SDFs) at the beginning of a clinical case demonstrated significantly lower diagnostic accuracy (mean 0.11) compared with the No-SDF condition (0.27), representing a 61% reduction (F2,693 = 11.995, p < 0.001), and made more SDF-related mistakes (F2, 693 = 16.395, p < 0.001). When SDFs were presented at the end of the case, diagnostic accuracy was also reduced (mean 0.17; 36% reduction), but processing time did not differ from the No-SDF condition. Only early presentation of SDFs was associated with reduced processing time per word (F2,636 = 4.799, p < 0.01), consistent with premature closure. CONCLUSION: These findings demonstrate that biasing information increases diagnostic error in medical students and that only early bias is associated with reduced information processing. The data do not support the competition hypothesis for early bias, as processing time did not increase under biasing conditions. Premature closure can therefore be directly observed rather than inferred, inviting further research.

Humans↗

PubMed2026

Longitudinal study of prevalence and antimicrobial resistance of thermotolerant Campylobacter spp. in German organic meat chicken farms.

Widespread prevalence of fluoroquinolone-resistant Campylobacter spp. in meat chicken is a major concern for public health. We examined the prevalence and antimicrobial resistance of thermotolerant Campylobacter spp. in 14 German organic meat chicken farms rearing slow-growing broilers, male layer hybrids, or dual-purpose cockerels in a longitudinal study. Most farms participated with four subsequent flocks. Each flock was sampled three times: approximately 1 month after hatching (before outdoor access), 2 weeks after first outdoor access, and at the end of the fattening period. Strikingly, most flocks were already Campylobacter-positive before first outdoor access. At the end of the fattening period, 98% of all flocks were positive, with C. jejuni being the predominant species. Antimicrobial resistance of 405 C. jejuni and 79 C. coli revealed overall high levels of ciprofloxacin and tetracycline resistance but absence of macrolide resistance. Ertapenem resistance was observed in individual farms. Generalized linear mixed models with random factors for farm and flocks within farm were used to assess predictors for the occurrence of ciprofloxacin- and tetracycline-resistant C. jejuni. Season, fattening type, and the interaction of sampling time point and fattening type were significant fixed effects. Results for flocks within farms showed clustering effects (ICCCIP = 0.447; ICCTET = 0.412). Whole-genome sequencing of representative isolates confirmed great overall genetic variety, with farm- or fattening type-dependent dissemination of certain multi-locus sequence types. ST21 clonal complex for sequenced C. jejuni and ST828 clonal complex for sequenced C. coli were most commonly detected.IMPORTANCECampylobacter spp. are major foodborne pathogens associated with the consumption and handling of chicken meat. This longitudinal study provides further insight into the prevalence and antimicrobial resistance of thermotolerant C. jejuni and C. coli in German organic meat chicken farms, a growing sector with strict limitations on antibiotic treatment. We included multiple flocks of farms fattening either slow-growing broilers, male layer hybrids, or dual-purpose cockerels to account for a variety of fattening types. Consequently, we were able to demonstrate significant differences in the occurrence of ciprofloxacin- and tetracycline-resistant C. jejuni based on fattening type, sampling time point, and season. Our findings highlight the successful spread and persistence of ciprofloxacin-, tetracycline-, and ertapenem-resistant C. jejuni and C. coli among all three types of organic meat chicken regardless of the lack of antibiotic treatment.

C. coli↗

PubMed2005

Urinary CTX-II levels are associated with radiographic subtypes of osteoarthritis in hip, knee, hand, and facet joints in subject with familial osteoarthritis at multiple sites: the GARP study.

OBJECTIVE: To assess the relation between the urinary concentrations of type II collagen C-telopeptide (UCTX-II) and radiographic signs of osteoarthritis (ROA) in the GARP (Genetics, Arthrosis and Progression) study. METHODS: UCTX-II levels were measured in GARP study participants, who are sibling pairs predominantly with symptomatic osteoarthritis at multiple sites. Kellgren and Lawrence scores were used to assess ROA in the knees, hips, hands, and vertebral facet joints, and spinal disc degeneration. A proportionate score was made for each joint location, based on the number of joints with ROA. The sum total ROA score represents a measure of cartilage abnormalities within each patient. By using linear mixed models the total ROA score and the joint site specific ROA scores were correlated with the UCTX-II level. RESULTS: In 302 subjects the mean (SD) and median (range) for UCTX-II were 265 (168) and 219 (1346) ng/mmol creatine, respectively. There was a significant association between the total ROA score and UCTX-II levels. Subsequent multivariate analysis showed that the joint site specific ROA score at all joint sites, except for spinal disc degeneration, contributed independently to this association. CONCLUSIONS: The total ROA score of GARP patients, representing cartilage abnormalities at the most prevalent ROA joint locations, showed an excellent correlation with UCTX-II levels. The specific ROA scores at the hip, hand, facet, and knee joints additively and independently explained this association. Even in patients with osteoarthritis at multiple sites, UCTX-II may be a sensitive quantitative marker of ROA.

Adult↗

PubMed2006

Trends in physical activity and sedentary behaviour in adolescence: ethnic and socioeconomic differences.

OBJECTIVE: To assess developmental trends in physical activity and sedentary behaviour in British adolescents in relation to sex, ethnicity and socioeconomic status (SES). DESIGN: A 5-year longitudinal study of a diverse cohort of students aged 11-12 years at baseline in 1999. SETTING: 36 London schools sampled using a stratified random sampling procedure. PARTICIPANTS: A total of 5863 students categorised as white, black or Asian, and stratified for SES using the Townsend Index. MAIN OUTCOME MEASURES: Number of days per week of vigorous activity leading to sweating and breathing hard. Hours of sedentary behaviour, including watching television and playing video games. Data were analysed using multilevel, linear, mixed models. RESULTS: Marked reductions in physical activity and increases in sedentary behaviour were noticed between ages 11-12 and 15-16 years. Boys were more active than girls, and the decline in physical activity was greater in girls (46% reduction) than in boys (23%). Asian students were less active than whites, and this was also true of black girls but not boys. Black students were more sedentary than white students. Levels of sedentary behaviour were greater in respondents from lower SES. Most differences between ethnic and SES groups were present at age 11 years, and did not evolve over the teenage years. CONCLUSIONS: Physical activity declines and sedentary behaviour becomes more common during adolescence. Ethnic and SES differences are observed in physical activity and sedentary behaviour in British youth that anticipate adult variations in adiposity and cardiovascular disease risk. These are largely established by age 11-12 years, so reversing these patterns requires earlier intervention.

Adolescent↗

PubMed2005

Long term follow up of patients treated for Helicobacter pylori infection.

BACKGROUND: Helicobacter pylori infection induces progressive inflammatory changes in the gastric mucosa that may lead to gastric cancer. Understanding long term effects resulting from the cure of this infection is needed to design cancer prevention strategies. METHODS: A cohort of 795 adults with preneoplastic gastric lesions was randomised to receive anti-H pylori treatment and/or antioxidants. At the end of six years of intervention, those who did not receive anti-H pylori treatment were offered it. Gastric biopsies were obtained at baseline, and at 3, 6, and 12 years. A histopathology score was utilised to document changes in gastric lesions. Non-linear mixed models were used to estimate the cumulative effect of H pylori clearance on histopathology scores adjusted for follow up time, interventions, and confounders. RESULTS: Ninety seven per cent of subjects were H pylori positive at baseline, and 53% were positive at 12 years. Subjects accumulated 1703 person years free of infection. A multivariate model showed a significant regression in histopathology score as a function of the square of H pylori negative time. Subjects who were H pylori negative had 14.8% more regression and 13.7% less progression than patients who were positive at 12 years (p = 0.001). The rate of healing of gastric lesions occurred more rapidly as years free of infection accumulated, and was more pronounced in less advanced lesions. CONCLUSIONS: Preneoplastic gastric lesions regress at a rate equal to the square of time in patients rendered free of H pylori infection. Our findings suggest that patients with preneoplastic gastric lesions should be treated and cured of their H pylori infection.

Acute Disease↗

PubMed2004

Effects of asbestos and smoking on the levels and rates of change of lung function in a crocidolite exposed cohort in Western Australia.

BACKGROUND: Increased rates of death from asbestos related diseases have been reported in former workers and residents exposed to crocidolite (blue asbestos) at Wittenoom, Western Australia. Exposure to asbestos is associated with reduced static lung volumes, gas transfer and lung compliance, and a restrictive ventilatory abnormality. METHODS: The effects of crocidolite exposure and smoking history on levels and rates of change of lung function were evaluated using a linear mixed model. Lung function was measured as forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC. RESULTS: Cumulative doses of asbestos and the presence of radiographic asbestosis were associated with lower levels of FEV1 and FVC and a steeper decline during the period of observation. Subjects exposed to asbestos at a younger age had lower levels of FEV1 and FVC. Current smokers had lower levels and a steeper decline in lung function than never smokers. No significant interactions between crocidolite exposure and smoking on the levels or rates of change of lung function were found. CONCLUSIONS: The deleterious effects of crocidolite exposure on lung function persist in this population, despite asbestos exposure having ceased more than 30 years ago. No significant interactions were found in this population between asbestos and smoking at the first visit or longitudinally.

Asbestos, Crocidolite↗

PubMed2006

Longitudinal pulmonary function of childhood bronchiectasis and comparison with cystic fibrosis.

BACKGROUND: Little has been published on the progression of non-cystic fibrosis bronchiectasis (BX), especially in childhood. Data are needed for prognosis and evaluation of the effectiveness of treatments. A study was undertaken to evaluate the change in lung function over time in children with BX, and to consider covariates and compare them with the local cystic fibrosis (CF) population. METHODS: Children with BX or CF and > or =3 calendar years of lung function data were identified from hospital clinics. Diagnosis was made by high resolution CT scans, sweat tests, and genetic studies. Lung function performed on a single plethysmograph between 6 and 15 years of age and > or =6 weeks after diagnosis was analysed longitudinally (linear mixed model). The impact of reference equation and "best annual" versus "all data" approaches were evaluated. RESULTS: There were 44 children in each of the BX and CF groups with an overall mean 5.7 calendar years follow up data. The estimated forced expiratory volume in 1 second (FEV(1)) in the BX group had an intercept of 68% predicted (Polgar) at 10 years of age which fell at a rate of 1.9% per annum using "best annual" data compared with 63% and 0.9% using "all data". Those with post-infectious BX or chronic Haemophilus influenzae infection had more severe disease. In CF the FEV(1) ("best annual") intercept was 85% predicted with a slope of -2.9% per annum. The choice of reference equation affected the magnitude of the result but not the conclusions. CONCLUSION: Children with BX have significant airway obstruction which deteriorates over time, regardless of analysis strategy or reference. Effective interventions are needed to prevent significant morbidity and adult mortality.

Adolescent↗