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Calendar Period (calendar + period)
Selected AbstractsAge,period,cohort models and disease mappingENVIRONMETRICS, Issue 5 2003Corrado Lagazio Abstract Joint modelling of space and time variation of the risk of disease is an important topic in descriptive epidemiology. Most of the proposals in this field deal with at most two time scales (age,period or age,cohort). We propose a hierarchical Bayesian model that can be used as a general framework to jointly study the evolution in time and the spatial pattern of the risk of disease. The rates are modelled as a function of purely spatial terms (local effects of risk factors that do not vary in time), time effects (on the three time axes: age, calendar period and birth cohort) and space,time interactions that describe area specific time patterns. Copyright © 2003 John Wiley & Sons, Ltd. [source] Trends in Parkinson's disease related mortality in England and Wales, 1993,2006EUROPEAN JOURNAL OF NEUROLOGY, Issue 9 2009A. Q. N. Mylne Background:, This paper describes changes in Parkinson's disease (PD) mortality in England and Wales between 1993 and 2006 using all information on death certificates. Methods:, Information on deaths was obtained from the Office for National Statistics. Mortality rates for any mention of PD on death certificates were directly age-standardized using the European standard population. Average yearly changes in mortality rates were estimated using linear regression. The underlying cause of death on death certificates where PD was mentioned was examined by sex and calendar period. Results:, Male PD age-standardized mortality rates for any mention of PD decreased from 15.0 to 11.7 per 100 000 between 1993 and 2006. Female PD mortality rates fell from 6.3 to 4.9 per 100 000. Decreases were greater for older age-groups. The proportion of deaths with PD recorded as the underlying cause increased by 50% in 2001 following implementation of the 10th revision of the International Classification of Diseases (ICD). Conclusion:, Parkinson's disease mortality rates in England and Wales are decreasing, especially for men and for older age-groups. Because of data limitations we are unable to ascertain whether the decrease of PD recorded on death certificates is because of a reduction in PD incidence, or to improved survival for PD patients resulting from advancements in PD treatments or to improvements in general medical care. The dramatic increase in PD as the underlying cause of death following ICD revision in 2001 demonstrates the dangers of using underlying cause of death to investigate mortality trends without being aware of the potential for artifacts. [source] Insights into reasons for discontinuation according to year of starting first regimen of highly active antiretroviral therapy in a cohort of antiretroviral-naïve patientsHIV MEDICINE, Issue 2 2010P Cicconi Objectives The aim of the study was to determine whether the incidence of first-line treatment discontinuations and their causes changed according to the time of starting highly active antiretroviral therapy (HAART) in an Italian cohort. Methods We included in the study patients from the Italian COhort Naïve Antiretrovirals (ICoNA) who initiated HAART when naïve to antiretroviral therapy (ART). The endpoints were discontinuation within the first year of ,1 drug in the first HAART regimen for any reason, intolerance/toxicity, poor adherence, immunovirological/clinical failure and simplification. We investigated whether the time of starting HAART (stratified as ,early', 1997,1999; ,intermediate', 2000,2002; ,recent', 2003,2007) was associated with the probability of reaching the endpoints by a survival analysis. Results Overall, the 1-year probability of discontinuation of ,1 drug in the first regimen was 36.1%. The main causes of discontinuation were intolerance/toxicity (696 of 1189 patients; 58.5%) and poor adherence (285 of 1189 patients; 24%). The hazards for all-reason change were comparable according to calendar period [2000,2002, adjusted relative hazard (ARH) 0.82, 95% confidence interval (CI) 0.69,0.98; 2003,2007, ARH 0.94, 95% CI 0.76,1.16, vs. 1997,1999; global P -value=0.08]. Patients who started HAART during the ,recent' period were less likely to change their initial regimen because of intolerance/toxicity (ARH 0.67, 95% CI 0.51,0.89 vs. ,early' period). Patients who started in the ,intermediate' and ,recent' periods had a higher risk of discontinuation because of simplification (ARH 15.26, 95% CI 3.21,72.45, and ARH 37.97, 95% CI 7.56,190.64, vs. ,early' period, respectively). Conclusions It seems important to evaluate reason-specific trends in the incidence of discontinuation in order to better understand the determinants of changes over time. The incidence of discontinuation because of intolerance/toxicity has declined over time while simplification strategies have become more frequent in recent years. Intolerance/toxicity remains the major cause of drug discontinuation. [source] Salmonella or Campylobacter gastroenteritis prior to a cancer diagnosis does not aggravate the prognosis: a population-based follow-up studyAPMIS, Issue 2 2010KIM O. GRADEL Gradel KO, Nørgaard M, Schønheyder HC, Dethlefsen C, Ejlertsen T, Kristensen B, Nielsen H. Salmonella or Campylobacter gastroenteritis prior to a cancer diagnosis does not aggravate the prognosis: a population-based follow-up study. APMIS 2010; 118: 136,42. We hypothesized that preceding zoonotic Salmonella or Campylobacter gastroenteritis aggravated the prognosis in cancer patients. Exposed patients comprised all of those diagnosed with first-time Salmonella/Campylobacter gastroenteritis from 1991 and with first-time cancer diagnosis thereafter (through 2003) in two Danish counties. These patients were matched for main cancer type, gender, age and calendar period to unexposed cancer patients, i.e. those without Salmonella/Campylobacter gastroenteritis. We compared cancer stage by age- and comorbidity-adjusted logistic regression analysis, survival by comorbidity-adjusted Cox's regression analysis and mortality dependent on the time period between Salmonella/Campylobacter gastroenteritis and cancer by spline regression curves. The study cohort comprised 272 Salmonella/Campylobacter -exposed cancer patients and 2681 unexposed cancer patients. Prevalence odds ratios [95% confidence intervals (CI)] in exposed as compared with unexposed patients were 0.96 (0.74,1.25) for localized tumours, 1.15 (0.87,1.54) for regional spread and 1.14 (0.84,1.55) for metastases. Adjusted mortality rate ratios (95% CI) were 0.93 (0.75,1.16) for 0,1 year, 1.08 (0.84,1.39) for 2,5 years and 1.02 (0.60,1.73) for the remaining period. Mortality estimates did not change in relation to the time period between gastroenteritis and cancer. Salmonella/Campylobacter gastroenteritis prior to cancer was associated with neither the cancer stage nor a poorer prognosis. [source] A multivariate time series approach to projected life tablesAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 6 2009Dorina Lazar Abstract The method of mortality forecasting proposed by Lee and Carter describes a time series of age-specific log-death rates as a sum of an independent of time age-specific component and a bilinear term in which one of the component is a time-varying factor reflecting general change in mortality and the second one is an age-specific parameter. Such a rigid model structure implies that on average the mortality improvements for different age groups should be proportional, regardless of the calendar period: a single time factor drives the future death rates. This paper investigates the use of multivariate time series techniques for forecasting age-specific death rates. This approach allows for relative speed of decline in the log death rates specific to the different ages. The dynamic factor analysis and the Johansen cointegration methodology are successfully applied to project mortality. The inclusion of several time factors allows the model to capture the imperfect correlations in death rates from 1 year to the next. The benchmark Lee,Carter model appears as a special case of these approaches. An empirical study is conducted with the help of the Johansen cointegration methodology. A vector-error correction model is fitted to Belgian general population death rates. A comparison is performed with the forecast of life expectancies obtained from the classical Lee,Carter model. Copyright © 2009 John Wiley & Sons, Ltd. [source] Prenatal diagnosis, pregnancy terminations and prevalence of Down syndrome in Atlanta,BIRTH DEFECTS RESEARCH, Issue 9 2004Csaba Siffel Abstract BACKGROUND The impact of prenatal diagnosis on the live birth prevalence of Down syndrome (trisomy 21) has been described. This study examines the prevalence of Down syndrome before (1990,1993) and after inclusion of prenatally diagnosed cases (1994,1999) in a population-based registry of birth defects in metropolitan Atlanta. METHODS We identified infants and spontaneous fetal deaths with Down syndrome (n = 387), and pregnancies electively terminated after a prenatal diagnosis of Down syndrome (n = 139) from 1990 to 1999 among residents of metropolitan Atlanta from a population-based registry of birth defects, the Metropolitan Atlanta Congenital Defects Program (MACDP). Only diagnoses of full trisomy 21 were included. Denominator information on live births was derived from State of Georgia birth certificate data. We compared the prevalence of Down syndrome by calendar period (1990,1993, 1994,1999), maternal age (<35 years, 35+ years), and race/ethnicity (White, Black, other), using chi-square and Fisher's exact tests. RESULTS During the period when case ascertainment was based only on hospitals (1990,1993), the prevalence of Down syndrome was 8.4 per 10,000 live births when pregnancy terminations were excluded and 8.8 per 10,000 when terminations were included. When case ascertainment also included perinatal offices (1994,1999), the prevalence of Down syndrome was 10.1 per 10,000 when terminations were excluded and 15.3 when terminations were included. During 1990,1993, the prevalence of Down syndrome was 24.7 per 10,000 among offspring to women 35+ years of age compared to 6.8 per 10,000 among offspring to women <35 years of age (rate ratio [RR] = 3.65, 95% confidence interval [CI] = 2.53,5.28). During 1994,1999, the prevalence of Down syndrome was 55.3 per 10,000 among offspring to women 35+ years compared to 8.5 per 10,000 among offspring to women <35 years (RR = 6.55, 95% CI = 5.36,7.99). There was no statistically significant variation in the prevalence of Down syndrome by race/ethnicity within maternal age and period of birth strata. During 1994,1999, the proportion of cases that were electively terminated was greater for women 35+ years compared to women <35 years (RR = 5.10, 95% CI = 3.14,8.28), and lower for Blacks compared to Whites among women 35+ years of age (RR = 0.33, 95% CI = 0.16,0.66). CONCLUSIONS In recent years, perinatal offices have become an important source of cases of Down syndrome for MACDP, contributing at least 34% of cases among pregnancies in women 35+ years of age. Variation in the prevalence of Down syndrome by race/ethnicity, before or after inclusion of cases ascertained from perinatal offices, was not statistically significant. Among Down syndrome pregnancies in mothers 35+ years we found a lower proportion of elective termination among Black women compared to White women. We suggest that future reports on the prevalence of Down syndrome by race/ethnicity take into account possible variations in the frequency of prenatal diagnosis or elective termination by race/ethnicity. Birth Defects Research (Part A) 70565,571, 2004. Published 2004 Wiley-Liss, Inc. [source] Role of antiretroviral therapies in mucocutaneous manifestations in HIV-infected children over a period of two decadesBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2005E. Seoane Reula Summary Background, Human immunodeficiency virus (HIV) infection causes a severe cellular immunodeficiency, which results in a greater susceptibility to infectious, inflammatory and malignant conditions. Among these, pathologies of the skin seem to be those most frequently observed in HIV+ patients. However, there are few reports on how antiretroviral therapy affects skin disorders in HIV-infected children. Objective, To study the incidence and prevalence of skin disorders in a cohort of HIV-infected children, in relation to the antiviral therapy [nontreated, monotherapy, combined therapy and highly active antiretroviral therapy (HAART)] received, and their impact on immunological and virological markers. The treatments were those available in different calendar periods in the history of antiviral treatment. Materials and methods, A retrospective, observational study in a cohort of 210 HIV-infected children was carried out. These children were followed up every 3 months throughout 22 years. The viral load (HIV RNA copies mL,1) was quantified using reverse transcriptase-polymerase chain reaction and the viral phenotype of HIV-1 isolates was determined by in vitro culture. T-lymphocyte subsets in peripheral blood were quantified by flow cytometry. Results, Mucocutaneous manifestations were diagnosed in 17% of the untreated infected children. Of the treated children in different treatment periods, 22% in the monotherapy period, 25% in the combined therapy period but only 10% on HAART had some type of mucocutaneous manifestation, concordant with a higher number of CD4+ T cells, a lower viral load and less cytopathic virus in the last group. Mucocutaneous manifestations of infectious aetiology were most frequently observed; they were detected in 13% of the children during the first calendar period (untreated children), 16% during the second and third periods (monotherapy and combined therapy) and only 5% in the last period (HAART). Interestingly, syncytium-inducing virus was present in 69% of all children with mucocutaneous manifestations of infectious aetiology. Conclusion, Only in the last calendar period (HAART) was a significant decrease observed in the prevalence of mucocutaneous manifestations with HIV infection associated with an increase in CD4+ T cells. In addition, we found a strong association between children who had mucocutaneous manifestations with an infectious aetiology and a more cytopathic (X4/SI) viral phenotype. [source] Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy,HIV MEDICINE, Issue 4 2008S Grabar Objectives To analyse the impact of combined antiretroviral treatment (cART) on survival with AIDS, according to the nature of the first AIDS-defining clinical illness (ADI); to examine trends in AIDS-defining causes (ADC) and non-AIDS-defining causes (non-ADC) of death. Methods From the French Hospital Database on HIV, we studied trends in the nature of the first ADI and subsequent survival in France during three calendar periods: the pre-cART period (1993,1995; 8027 patients), the early cART period (1998,2000; 3504 patients) and the late cART period (2001,2003; 2936 patients). Results The three most frequent initial ADIs were Pneumocystis carinii (jirovecii) pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's sarcoma (13.9%) in the pre-cART period. In the late cART period, the most frequent ADIs were tuberculosis (22.7%), PCP (19.1%) and oesophageal candidiasis (16.2%). The risk of death after a first ADI fell significantly after the arrival of cART. Lower declines were observed for progressive multifocal leukoencephalopathy, lymphoma and Mycobacterium avium complex infection. After an ADI, the 3-year risk of death from an ADC fell fivefold between the pre-cART and late cART periods (39%vs. 8%), and fell twofold for non-ADCs (17%vs. 9%). Conclusions The relative frequencies of initial ADI have changed since the advent of cART. Tuberculosis is now the most frequent initial ADI in France; this is probably the result of the increasing proportion of migrants from sub-Saharan Africa. After a first ADI, cART has a major impact on ADCs and a smaller impact on deaths from other causes. The risk of death from AIDS and from other causes is now similar. [source] The Incidence of Cancer in a Population-Based Cohort of Canadian Heart Transplant RecipientsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2010Y. Jiang To assess the long-term risk of developing cancer among heart transplant recipients compared to the Canadian general population, we carried out a retrospective cohort study of 1703 patients who received a heart transplant between 1981 and 1998, identified from the Canadian Organ Replacement Register database. Vital status and cancer incidence were determined through record linkage to the Canadian Mortality Database and Canadian Cancer Registry. Cancer incidence rates among heart transplant patients were compared to those of the general population. The observed number of incident cancers was 160 with 58.9 expected in the general population (SIR = 2.7, 95% CI = 2.3, 3.2). The highest ratios were for non-Hodgkin's lymphoma (NHL) (SIR = 22.7, 95% CI = 17.3, 29.3), oral cancer (SIR = 4.3, 95% CI = 2.1, 8.0) and lung cancer (SIR = 2.0, 95% CI = 1.2, 3.0). Compared to the general population, SIRs for NHL were particularly elevated in the first year posttransplant during more recent calendar periods, and among younger patients. Within the heart transplant cohort, overall cancer risks increased with age, and the 15-year cumulative incidence of all cancers was estimated to be 17%. There is an excess of incident cases of cancer among heart transplant recipients. The relative excesses are most marked for NHL, oral and lung cancer. [source] Role of antiretroviral therapies in mucocutaneous manifestations in HIV-infected children over a period of two decadesBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2005E. Seoane Reula Summary Background, Human immunodeficiency virus (HIV) infection causes a severe cellular immunodeficiency, which results in a greater susceptibility to infectious, inflammatory and malignant conditions. Among these, pathologies of the skin seem to be those most frequently observed in HIV+ patients. However, there are few reports on how antiretroviral therapy affects skin disorders in HIV-infected children. Objective, To study the incidence and prevalence of skin disorders in a cohort of HIV-infected children, in relation to the antiviral therapy [nontreated, monotherapy, combined therapy and highly active antiretroviral therapy (HAART)] received, and their impact on immunological and virological markers. The treatments were those available in different calendar periods in the history of antiviral treatment. Materials and methods, A retrospective, observational study in a cohort of 210 HIV-infected children was carried out. These children were followed up every 3 months throughout 22 years. The viral load (HIV RNA copies mL,1) was quantified using reverse transcriptase-polymerase chain reaction and the viral phenotype of HIV-1 isolates was determined by in vitro culture. T-lymphocyte subsets in peripheral blood were quantified by flow cytometry. Results, Mucocutaneous manifestations were diagnosed in 17% of the untreated infected children. Of the treated children in different treatment periods, 22% in the monotherapy period, 25% in the combined therapy period but only 10% on HAART had some type of mucocutaneous manifestation, concordant with a higher number of CD4+ T cells, a lower viral load and less cytopathic virus in the last group. Mucocutaneous manifestations of infectious aetiology were most frequently observed; they were detected in 13% of the children during the first calendar period (untreated children), 16% during the second and third periods (monotherapy and combined therapy) and only 5% in the last period (HAART). Interestingly, syncytium-inducing virus was present in 69% of all children with mucocutaneous manifestations of infectious aetiology. Conclusion, Only in the last calendar period (HAART) was a significant decrease observed in the prevalence of mucocutaneous manifestations with HIV infection associated with an increase in CD4+ T cells. In addition, we found a strong association between children who had mucocutaneous manifestations with an infectious aetiology and a more cytopathic (X4/SI) viral phenotype. [source] | |||||||||||||