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C Robertson

Publications and source records attributed to C Robertson.

At least 91 records · Page 5Linked to original sources
PubMed2000

Socioeconomic correlates of mortality differentials by local government area in rural northern New South Wales, 1981-1995.

OBJECTIVE: Many studies have examined the correlation between socioeconomic status (SES) and mortality in Australia, but little is known about the correlation in rural areas and most studies have not explored the trends in SES differentials in mortality. This ecological study examines this correlation and explores the impact of the national strategies to reduce SES differentials in mortality in a rural area. METHODS: Mortality data for residents in the New England Health Area, New South Wales (NSW), 1981 to 1995, were analysed. Twenty Local Government Areas (LGAs) in New England were ranked and aggregated into 4 groups according to a composite SES indicator from the 1996 census, and age/sex adjusted mortality rates were calculated for each group and compared. Poisson regression models were used to assess the linear trends in mortality for 1981-95. RESULTS: A strong relationship between working age adult mortality and SES was found for both sexes. The rates for the most disadvantaged LGAs were significantly higher than the least disadvantaged LGAs for both sexes. The mortality rate was consistently higher for the most disadvantaged LGAs than the least disadvantaged LGAs. CONCLUSION AND IMPLICATION: Although there has been an overall decline in death for all 4 groups of LGAs, the gap between the most disadvantaged and the least disadvantaged groups has widened over the last 15 years. This widening gap in death rates suggests that the strategies implemented as part of the Health for All initiative to reduce inequalities in mortality differentials have not been effective in this rural area.

Adolescent↗
PubMed2000

Inter-observer variation in histopathological diagnosis and grading of vulvar intraepithelial neoplasia: results of an European collaborative study.

OBJECTIVE: To evaluate the inter-observer variability of vulvar intraepithelial neoplasia diagnosis and grading system. DESIGN: Prospective study. SAMPLE: Histological sections of 66 vulvar biopsies. METHODS: Six consultant pathologists working at different European institutions independently reviewed 66 vulvar biopsies. The following variables were investigated: specimen adequacy, gross categorisation into benign or neoplastic changes, presence of atypical cytological pattern, presence of neoplastic architectural pattern, grade of vulvar intraepithelial neoplasia, presence of histopathologic associated findings for human papillomavirus infection. MAIN OUTCOME MEASURES: The degree of inter-observer variation for each histopathologic parameter was assessed by Kappa (kappa) statistics. The frequency and the degree of disagreement were calculated by a symmetrical agreement matrix showing the number paired classifications. RESULTS: A good agreement (overall weighted kappa = 0.65, unweighted kappa = 0.46) was observed for grading vulvar intraepithelial neoplasia. Human papillomavirus infection associated findings and specimen adequacy were the variables with less inter-observer agreement (overall weighted kappa 0.26 and 0.22, respectively). Exact agreement between two pathologists for grade of vulvar intraepithelial neoplasia was observed in 63.6% of paired readings; the rate of paired agreement reached 73.9% considering vulvar intraepithelial neoplasia 2 and 3 as a single class. Conversely, only 5.0% of vulvar intraepithelial neoplasia 1 diagnoses were concordant in paired analysis. CONCLUSIONS: Current terminology offers a reproducible tool in the hands of expert pathologists. While on the diagnosis of 'high grade' vulvar intraepithelial neoplasia (vulvar intraepithelial neoplasia 2 and 3) there is good agreement, the diagnostic category of vulvar intraepithelial neoplasia 1 is not reproducible.

Carcinoma in Situ↗
PubMed2000

Factors influencing the frequency of fluorescence transients as markers of peri-infarct depolarizations in focal cerebral ischemia.

BACKGROUND AND PURPOSE: Peri-infarct depolarizations (PIDs) that occur in ischemic boundary zones of the cerebral cortex of experimental animals have been shown to promote rather than simply to indicate the evolution of the lesion and are especially prominent in the rat. To study the influence of one factor, species, on PID incidence, we compared the frequency of PIDs in a primate species, the squirrel monkey, with that in the cat after middle cerebral artery occlusion. Plasma glucose was reviewed as a possible cause of interexperiment variability in the cat experiments. METHODS: In open-skull experiments under chloralose anesthesia, changes in cortical fluorescence believed to indicate NADH/NAD(+) redox state, as markers of PIDs, were recorded by serial imaging of the cortical surface in vivo for 4 hours after middle cerebral artery occlusion. RESULTS: Fluorescence transients occurred in squirrel monkeys at a frequency (mean+/-SD) of 0.7+/-0.8 hours(-1) (n=5), which was not significantly less than in that observed in cats (1.3+/-1.6 hours(-1), n=8). Data from the cat experiments indicated a relationship between number of transients (dependent) and plasma glucose, with a striking increase in PID frequency in association with values of mean postocclusion plasma glucose <4.1 mmol/L (Mann-Whitney U=15.0, P=0.034); this observation agrees well with other published findings. CONCLUSIONS: Transient changes in fluorescence strongly suggestive of peri-infarct depolarizations, either transient or terminal, occur and propagate in the ischemic cerebral cortex of a nonhuman primate. The results also suggest that the relationship of frequency of peri-infarct depolarizations with plasma glucose requires further examination, to confirm the finding and to determine a safe lower limit for a target range for control of plasma glucose if insulin is used in the management of patients with cerebral ischemia.

Action Potentials↗
PubMed2000

Regional cerebral blood flow after cortical impact injury complicated by a secondary insult in rats.

BACKGROUND AND PURPOSE: Traumatic injury makes the brain susceptible to secondary insults. An uncomplicated mild lateral cortical impact injury (3 m/s, 2.5-mm deformation) that causes little or no permanent sequelae results in a large contusion at the impact site when the traumatic injury is complicated by a secondary insult, such as 40 minutes of bilateral carotid occlusion. METHODS: To determine whether the increased sensitivity to secondary insults in this model is caused by a vascular mechanism, cerebral blood flow (CBF) was measured with (14)C-isopropyliodoamphetamine quantitative autoradiography, and brain tissue PO(2) (PbtO(2)) was measured at the impact site and in the contralateral parietal cortex. RESULTS: In animals that underwent bilateral carotid occlusion 1 hour after the impact injury, CBF and PbtO(2) were lower at the impact site than they were in animals that had either the impact injury or the carotid occlusion alone. In the immediate area of the impact, CBF was 14+/-6 mL. 100 g(-1). min(-1) in the animals with the impact injury followed by carotid occlusion compared with 53+/-24 mL. 100 g(-1). min(-1) in the animals with the impact injury alone and 74+/-14 mL. 100 g(-1). min(-1) in the animals with the carotid occlusion alone (P<0.001). At the time of this very low CBF value in the animals with the carotid occlusion after the impact injury, PbtO(2) at the impact site averaged 1.3+/-1.6 mm Hg and was <3 mm Hg in 5 of the 6 animals. In contrast, PbtO(2) in the animals with the impact injury alone averaged 9.3+/-2.9 mm Hg, and none of the animals had a PbtO(2) of <3 mm Hg (P=0.008). CONCLUSIONS: The CBF and PbtO(2) findings in this model suggest that the reduced CBF after traumatic injury predisposes the brain to secondary insults and results in ischemia when confronted with a reduction in cerebral perfusion pressure.

Animals↗
PubMed2000

The implications of genetics studies of major mood disorders for clinical practice.

BACKGROUND: This article is a selective review and synthesis of relevant research findings from genetic studies of major mood disorders and the application of these to clinical practice. METHOD: The article discusses the application of genetic research findings in major mood disorders, including epidemiologic and family study risk estimates, risk modifiers, and the concepts of etiologic and phenotypic heterogeneity, to 3 clinical domains: risk counseling, diagnosis, and treatment prediction. RESULTS: Epidemiologic and family studies have provided general risk estimates useful in counseling mood-disordered patients and their relatives. A complete and accurate family pedigree provides more individualized risk estimates for specific cases and is useful in identifying the phenotypic spectrum of the disorder being transmitted in the family. Both proband course parameters and familial loading for psychiatric illnesses may be relevant for the prediction of treatment response. However, the hypothesis of inherited pharmacologic selectivity remains to be proven. CONCLUSION: Genetic studies of mood disorders have not yet provided conclusive evidence of specific susceptibility genes or their pattern of inheritance. However, they have generated information that is useful to clinical practice.

Adult↗
PubMed2000

Association and linkage studies of candidate genes involved in GABAergic neurotransmission in lithium-responsive bipolar disorder.

OBJECTIVE: To test for genetic linkage and association with GABAergic candidate genes in lithium-responsive bipolar disorder. DESIGN: Polymorphisms located in genes that code for GABRA3, GABRA5 and GABRB3 subunits of the GABAA receptor were investigated using association and linkage strategies. PARTICIPANTS: A total of 138 patients with bipolar 1 disorder with a clear response to lithium prophylaxis, selected from specialized lithium clinics in Canada and Europe that are part of the International Group for the Study of Lithium-Treated Patients, and 108 psychiatrically healthy controls. Families of 24 probands were suitable for linkage analysis. OUTCOME MEASURES: The association between the candidate genes and patients with bipolar disorder versus that of controls and genetic linkage within families. RESULTS: There was no significant association or linkage found between lithium-responsive bipolar disorder and the GABAergic candidate genes investigated. CONCLUSIONS: This study does not support a major role for the GABAergic candidate genes tested in lithium-responsive bipolar disorder.

Alleles↗
PubMed2000

Ocular effects of fenretinide, a vitamin A analog, in a chemoprevention trial of bladder cancer.

Fenretinide is a vitamin A derivative under investigation in cancer prevention trials. Because all available pharmacologic and toxicologic data were obtained from breast cancer patients, we measured plasma drug, metabolite, and vitamin A levels and studied their relationship with visual and ocular symptoms in a cohort formed mostly by male subjects belonging to a bladder cancer prevention trial. After 1 year, the mean plasma retinol levels (+/- standard deviation [SD]) were 168.2 +/- 75.8 ng/ml in 31 subjects treated with fenretinide and 594.5 +/- 168.4 ng/ml in 36 control subjects (P < .001). Plasma retinol levels were correlated inversely to drug and metabolite concentrations, which in turn were correlated inversely to the interval from last drug intake. The decline of plasma vitamin A levels accounted for a 41.7% cumulative incidence of diminished dark adaptability in the retinoid arm as compared to 6.8% in the control arm (odds ratio = 13.8; 95% confidence interval, 2.9-66.1). Although compliance as assessed by capsule count was high, three subjects originally assigned to the treatment group who proved to be noncompliers (8.8%, or 3 of 34) had no detectable plasma drug or metabolite levels. Our data confirm the specific pharmacologic and visual effects of fenretinide also in a male population and strengthen the importance of multiple blood measurements to monitor treatment compliance in prevention trials.

Adult↗
PubMed1999

Finasteride in association with either flutamide or goserelin as combination hormonal therapy in patients with stage M1 carcinoma of the prostate gland. International Prostate Health Council (IPHC) Trial Study Group.

BACKGROUND: It was very reasonable to consider that the combination of the 5alpha-reductase, finasteride, and a pure antiandrogen such as flutamide should provide an effective form of maximal androgen blockade (MAB). Finasteride decreases intraprostatic levels of 5alpha-dihydrotestosterone (DHT), and the antiandrogen would restrain the biological action of the residual DHT by interfering with its association with androgen receptor. This form of MAB should sustain the concentration of testosterone in plasma, thereby maintaining sexual function and reasonable quality of life. In order to investigate this, a randomized multicenter phase II clinical trial of patients with untreated M1 cancer of the prostate was developed and undertaken. METHODS: Patients were randomly allocated to one of three treatment schedules: 1) goserelin, 3.6 mg, s.c., monthly in combination with flutamide, 250 mg., t.i.d. and a placebo, daily, in the image of 2 x 5 mg finasteride; 2) goserelin, 3.6 mg., s.c., monthly in combination with finasteride, 10 mg (2 x 5 mg, daily) and a placebo (t.i.d.) in the image of flutamide; and 3) finasteride, 10 mg (2 x 5 mg, daily) in combination with flutamide (250 mg, t.i.d.). The reduction in concentration of serum PSA at 24 weeks was the endpoint of interest. RESULTS: Baseline prostate-specific antigen (PSA) levels of the patients in the three groups were very similar. There was a substantial decrease in levels of PSA in the three groups prior to the end of the study, the percent decrease in the groups being: 1) goserelin and flutamide combination, 99.1% (95% Confidence interval (CI), 97.7, 99.6); 2) goserelin and finasteride combination, 98.75% (95% CI, 97.1, 99.5); and 3) finasteride and flutamide combination, 97.6%, 95% CI, 94.5, 98.9). In the Generalized linear model (GLM) analysis, there was no center by treatment group interaction (P = 20), and there were no significant differences between centers (P = 0.059) nor among the three treatment groups (P = 0.16). CONCLUSIONS: The decrease in levels of PSA in such a group of patients with M1 cancer of the prostate over a 24-week period was surprisingly large, and the differences in these decreased levels between the three treatment arms were remarkably small. There were no apparent differences in bone scan scores, World Health Organization (WHO) performance status, and pain scores between the arms. With regard to sexual function associated with quality of life, there were the understandable difficulties of data collection from patients treated with goserelin.

5-alpha Reductase Inhibitors↗
PubMed1999

A hierarchical Bayesian approach to age-specific back-calculation of cancer incidence rates.

We propose a Bayesian hierarchical model to estimate age-specific cancer incidence per year from age-specific cancer mortality. The model is based upon the empirical Bayesian approach of Liao and Brookmeyer (1995) and extends that model by consideration of the dependence on age. The incident cases per year are considered as observations from a discrete-time stochastic process following an autoregressive structure within a Poisson regression model. The model assumes that the survival probability among those with cancer is known. We have investigated the sensitivity of the model to the choice of this distribution and have found that this is the most sensitive part of the model. By comparison the predictions of the model are relatively robust to changes in other key areas, such as the number of years an incident case contributes before death, assumptions about parameter equality for identification and the initial prior distributions. The proposed methodology has been investigated using lung cancer mortality data from Scotland. Parameter estimates were obtained through Markov chain Monte Carlo methods, implemented using BUGS.

Age Factors↗
PubMed1999

Sentinel lymph node biopsy and axillary dissection in breast cancer: results in a large series.

BACKGROUND: Axillary lymph node dissection is an established component of the surgical treatment of breast cancer, and is an important procedure in cancer staging; however, it is associated with unpleasant side effects. We have investigated a radioactive tracer-guided procedure that facilitates identification, removal, and pathologic examination of the sentinel lymph node (i.e., the lymph node first receiving lymphatic fluid from the area of the breast containing the tumor) to predict the status of the axilla and to assess the safety of foregoing axillary dissection if the sentinel lymph node shows no involvement. METHODS: We injected 5-10 MBq of 99mTc-labeled colloidal particles of human albumin peritumorally in 376 consecutive patients with breast cancer who were enrolled at the European Institute of Oncology during the period from March 1996 through March 1998. The sentinel lymph node in each case was visualized by lymphoscintigraphy, and its general location was marked on the overlying skin. During breast surgery, the sentinel lymph node was identified for removal by monitoring the acoustic signal from a hand-held gamma ray-detecting probe. Total axillary dissection was then carried out. The pathologic status of the sentinel lymph node was compared with that of the whole axilla. RESULTS: The sentinel lymph node was identified in 371 (98.7%) of the 376 patients and accurately predicted the state of the axilla in 359 (95.5%) of the patients, with 12 false-negative findings (6.7%; 95% confidence interval = 3.5%-11.4%) among a total of 180 patients with positive axillary lymph nodes. CONCLUSIONS: Sentinel lymph node biopsy using a gamma ray-detecting probe allows staging of the axilla with high accuracy in patients with primary breast cancer. A randomized trial is necessary to determine whether axillary dissection may be avoided in those patients with an uninvolved sentinel lymph node.

Albumins↗
PubMed1999

Slowed cognitive processing and high workload in Parkinson's disease.

It is suggested that cognitive slowing in Parkinson's disease (PD) may be evident on a task with high cognitive load. This hypothesis was tested using a workload design with a progressive increase in task difficulty, on a group of Parkinson patients and normal controls. Using measures of Reaction Time (RT) and Event Related Potentials (ERP), results showed that RT and ERP waveforms increased in line with task difficulty. The RT data was not significantly different between groups but the ERP showed a much reduced P300 in the patient group. These results are indicative of cognitive slowing in PD, at the stage of stimulus evaluation but not for response selection. An interpretation of the literature in terms of reduced activation in relation to cognitive slowing is discussed.

Adult↗
PubMed1999

Hyperamylasemia in bulimia nervosa and hyperemesis gravidarum.

OBJECTIVES: The exact causes of hyperamylasemia detected in bulimia nervosa are unknown but it is presumed to be due either to repeated binging or to vomiting. This study set out to investigate the importance of vomiting in producing the raised serum amylase and to clarify whether the amylase in pancreatic or salivary. METHODS: Patients suffering from hyperemesis gravidarum who were repeatedly vomiting in pregnancy but not binge eating had their total serum and pancreatic amylase measured. Bulimic patients and a control sample of nonvomiting pregnant women were similarly studied. An assessment of the frequency and duration of vomiting and binging was also made. RESULTS: Results show 45% (5) of bulimic patients had raised serum amylase, but none had a raised pancreatic amylase. Twenty-four percent (7) of the hyperemetic patients also had a raised serum amylase level, all with a normal pancreatic amylase level. None of the nonvomiting pregnant patients had a raised amylase. DISCUSSION: Of patients with hyperemesis gravidarum who repeatedly vomit but do not binge, a significant number had raised amylase. This suggests that it is the vomiting rather than the binge behavior that increases amylase in bulimic patients. This increased amylase probably comes from the salivary gland.

Adult↗
PubMed1999

Three-step radioimmunotherapy with yttrium-90 biotin: dosimetry and pharmacokinetics in cancer patients.

A three-step avidin-biotin approach has been applied as a pretargeting system in radioimmunotherapy (RIT) as an alternative to conventional RIT with directly labelled monoclonal antibodies (MoAbs). Although dosimetric and toxicity studies following conventional RIT have been reported, these aspects have not previously been evaluated in a three-step RIT protocol. This report presents the results of pharmacokinetic and dosimetric studies performed in 24 patients with different tumours. Special consideration was given to the dose delivered to the red marrow and to the haematological toxicity. The possible additive dose to red marrow due to the release of unbound yttrium-90 was investigated. The protocol consisted in the injection of biotinylated MoAbs (first step) followed 1 day later by the combined administration of avidin and streptavidin (second step). After 24 h, biotin radiolabelled with 1.85-2.97 GBq/m2 of 90Y was injected (third step). Two different chelating agents, DTPA and DOTA, coupled to biotin, were used in these studies. Indium-111 biotin was used as a tracer of 90Y to follow the biodistribution during therapy. Serial blood samples and complete urine collection were obtained over 3 days. Whole-body and single-photon emission tomography images were acquired at 1, 16, 24 and 40 h after injection. The sequence of images was used to extrapolate 90Y-biotin time-activity curves. Numerical fitting and compartmental modelling were used to calculate the residence time values (tau) for critical organs and tumour, and results were compared; the absorbed doses were estimated using the MIRDOSE3.1 software. The residence times obtained by the numerical and compartmental models showed no relevant differences (<10%); the compartmental model seemed to be more appropriate, giving a more accurate representation of the exchange between organs. The mean value for the tau in blood was 2.0+/-1.1 h; the mean urinary excretion in the first 24 h was 82.5%+/-10.8%. Without considering any contribution of free 90Y, kidneys, liver, bladder and red marrow mean absorbed doses were 1.62+/-1.14, 0.27+/-0.23, 3.61+/-0.70 and 0. 11+/-0.05 mGy/MBq, respectively; the effective dose was 0.32+/-0.06 mSv/MBq, while the dose to the tumour ranged from 0.62 to 15.05 mGy/MBq. The amount of free 90Y released after the injection proved to be negligible in the case of 90Y-DOTA-biotin, but noteworthy in the case of 90Y-DTPA-biotin (mean value: 5.6%+/-2.5% of injected dose), giving an additive dose to red marrow of 0.18+/-0.08 mGy per MBq of injected 90Y-DTPA-biotin. Small fractions of free 90Y originating from incomplete radiolabelling can contribute significantly to the red marrow dose (3.26 mGy per MBq of free 90Y) and may explain some of the high levels of haematological toxicity observed. These results indicate that pretargeted three-step RIT allows the administraton of high 90Y activities capable of delivering a high dose to the tumour and sparing red marrow and other normal organs. Although 90Y-biotin clears rapidly from circulation, the use of DOTA-biotin conjugate for a stable chelation of 90Y is strongly recommended, considering that small amounts of free 90Y contribute significantly in increasing the red marrow dose.

Antibodies, Monoclonal↗
PubMed1999

Antibody-guided three-step therapy for high grade glioma with yttrium-90 biotin.

While the incidence of brain tumours seems to be increasing, median survival in patients with glioblastoma remains less than 1 year, despite improved diagnostic imaging and neurosurgical techniques, and innovations in treatment. We have developed an avidin-biotin pre-targeting approach for delivering therapeutic radionuclides to gliomas, using anti-tenascin monoclonal antibodies, which seems potentially effective for treating these tumours. We treated 48 eligible patients with histologically confirmed grade III or IV glioma and documented residual disease or recurrence after conventional treatment. Three-step radionuclide therapy was performed by intravenous administration of 35 mg/m2 of biotinylated anti-tenascin monoclonal antibody (1st step), followed 36 h later by 30 mg of avidin and 50 mg of streptavidin (2nd step), and 18-24 h later by 1-2 mg of yttrium-90-labelled biotin (3rd step). 90Y doses of 2.22-2.96 GBq/m2 were administered; maximum tolerated dose (MTD) was determined at 2.96 GBq/m2. Tumour mass reduction (>25%-100%), documented by computed tomography or magnetic resonance imaging, occurred in 12/48 patients (25%), with 8/48 having a duration of response of at least 12 months. At present, 12 patients are still in remission, comprising four with a complete response, two with a parital response, two with a minor response and four with stable disease. Median survival from 90Y treatment is 11 months for grade IV glioblastoma and 19 months for grade III anaplastic gliomas. Avidin-biotin based three-step radionuclide therapy is well tolerated at the dose of 2.2 GBq/m2, allowing the injection of 90Y-biotin without bone marrow transplantation. This new approach interferes with the progression of high-grade glioma and may produce tumour regression in patients no longer responsive to other therapies.

Adolescent↗
PubMed1999

Biokinetics and dosimetry in patients administered with (111)In-DOTA-Tyr(3)-octreotide: implications for internal radiotherapy with (90)Y-DOTATOC.

Recent advances in receptor-mediated tumour imaging have resulted in the development of a new somatostatin analogue, DOTA-dPhe(1)-Tyr(3)-octreotide. This new compound, named DOTATOC, has shown high affinity for somatostatin receptors, ease of labelling and stability with yttrium-90 and favourable biodistribution in animal models. The aim of this work was to evaluate the biodistribution and dosimetry of DOTATOC radiolabelled with indium-111, in anticipation of therapy trials with (90)Y-DOTATOC in patients. Eighteen patients were injected with DOTATOC (10 microg), labelled with 150-185 MBq of (111)In. Blood and urine samples were collected throughout the duration of the study (0-2 days). Planar and single-photon emission tomography images were acquired at 0.5, 3-4, 24 and 48 h and time-activity curves were obtained for organs and tumours. A compartmental model was used to determine the kinetic parameters for each organ. Dose calculations were performed according to the MIRD formalism. Specific activities of >37 GBq/ micromol were routinely achieved. Patients showed no acute or delayed adverse reactions. The residence time for (111)In-DOTATOC in blood was 0.9+/-0.4 h. The injected activity excreted in the urine in the first 24 h was 73%+/-11%. The agent localized primarily in spleen, kidneys and liver. The residence times in source organs were: 2.2+/-1.8 h in spleen, 1.7+/-1.2 h in kidneys, 2.4+/-1.9 h in liver, 1.5+/-0.3 h in urinary bladder and 9. 4+/-5.5 h in the remainder of the body; the mean residence time in tumour was 0.47 h (range: 0.03-6.50 h). Based on our findings, the predicted absorbed doses for (90)Y-DOTATOC would be 7.6+/-6.3 (spleen), 3.3+/-2.2 (kidneys), 0.7+/-0.6 (liver), 2.2+/-0.3 (bladder), 0.03+/-0.01 (red marrow) and 10.1 (range: 1.4-31.0) (tumour) mGy/MBq. These results indicate that high activities of (90)Y-DOTATOC can be administered with low risk of myelotoxicity, although with potentially high radiation doses to the spleen and kidneys. Tumour doses were high enough in most cases to make it likely that the desired therapeutic response desired would be obtained.

Adult↗
PubMed1999

Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.

BACKGROUND: Little is known about the prevalence of atopic eczema outside Northern Europe. OBJECTIVES: We sought to describe the magnitude and variation in the prevalence of atopic eczema symptoms throughout the world. METHODS: A cross-sectional questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries throughout the world. Those children with a positive response to being questioned about the presence of an itchy relapsing skin rash in the last 12 months that had affected their skin creases were considered to have atopic eczema. Children whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. RESULTS: Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 years in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Iran to over 16% in Japan and Sweden in the 6 to 7 year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Higher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Central Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. CONCLUSIONS: Atopic eczema is a common health problem for children and adolescents throughout the world. Symptoms of atopic eczema exhibit wide variations in prevalence both within and between countries inhabited by similar ethnic groups, suggesting that environmental factors may be critical in determining disease expression. Studies that include objective skin examinations are required to confirm these findings.

Adolescent↗
PubMed1999

Age-period-cohort models: a comparative study of available methodologies.

This article compares the estimates produced by a number of solutions to the identifiability problem in age-period-cohort models using a series of disease rates with known structure. The results suggest that only those methods that are based on the estimable functions such as curvatures can be recommended for use in all circumstances. The other common approaches that give parameter estimates that are easier to interpret all have induced bias in the estimates. In particular methods based on the minimization of a penalty function to achieve identifiability are only of use if there is no change in the rates with time. Any drift in the rates tends to be expressed as a cohort-based trend. The methods based on individual records introduce a bias if there is a strong age effect in the direction of a decreasing cohort trend and a compensating increase based on period effects. The nonparametric testing method has little power to detect trends in the rates in small tables but ascribes a strong drift in the rates to both period and cohort trends. With careful interpretation, all methods estimate nonlinear components correctly.

Age Factors↗