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History Data (history + data)
Kinds of History Data Selected AbstractsAssociation and aggregation analysis using kin-cohort designs with applications to genotype and family history data from the Washington Ashkenazi StudyGENETIC EPIDEMIOLOGY, Issue 2 2001Nilanjan Chatterjee Abstract When a rare inherited mutation in a disease gene, such as BRCA1, is found through extensive study of high-risk families, it is critical to estimate not only age-specific penetrance of the disease associated with the mutation, but also the residual effect of family history once the mutation is taken into account. The kin-cohort design, a cross-sectional survey of a suitable population that collects DNA and family history data, provides an efficient alternative to cohort or case-control designs for estimating age-specific penetrance in a population not selected because of high familial risk. In this report, we develop a method for analyzing kin-cohort data that simultaneously estimate the age-specific cumulative risk of the disease among the carriers and non-carriers of the mutations and the gene-adjusted residual familial aggregation or correlation of the disease. We employ a semiparametric modeling approach, where the marginal cumulative risks corresponding to the carriers and non-carriers are treated non-parametrically and the residual familial aggregation is described parametrically by a class of bivariate failure time models known as copula models. A simple and robust two-stage method is developed for estimation. We apply the method to data from the Washington Ashkenazi Study [Struewing et al., 1997, N Engl J Med 336:1401,1408] to study the residual effect of family history on the risk of breast cancer among non-carriers and carriers of specific BRCA1/BRCA2 germline mutations. We find that positive history of a single first-degree relative significantly increases risk of the non-carriers (RR = 2.0, 95% CI = 1.6,2.6) but has little or no effect on the carriers. Genet. Epidemiol. 21:123,138, 2001. © 2001 Wiley-Liss, Inc. [source] The Virtual International Stroke Trials Archive (VISTA): results and impact on future stroke trials and management of stroke patientsINTERNATIONAL JOURNAL OF STROKE, Issue 2 2010C. Weimar Background The Virtual International Stroke Trials Archive was established to improve stroke care and trial design through the collation, categorization and potential access to data sets from clinical trials for the treatment of stroke. Methods Virtual International Stroke Trials Archive currently provides access to a combined data set of 29 anonymised acute stroke trials and one acute stroke registry with data on >27 500 patients aged between 18 and 103 (mean 71) years. Results Virtual International Stroke Trials Archive has facilitated research across a broad canvas. The prognosis was poor in patients with very high blood pressure at the time of admission or with a wide variability of systolic blood pressure during the acute phase. The late occurrence of hyperthermia following an ischaemic stroke worsens the prognosis. Stroke lateralisation is not an important predictor of cardiac adverse events or 90-day mortality. Haemorrhagic transformation is seen frequently in patients with cardio-embolic strokes and is associated with a poor prognosis when occurring after the acute phase. Virtual International Stroke Trials Archive has allowed various prognostic models for patients with ischaemic or haemorrhagic stroke to be established and validated. More direct outcomes such as lesion volume can be useful in phase II clinical trials for determining whether a phase III trial should be undertaken. New outcome measures such as ,home time' may also strengthen future trials. On a worldwide level, the prognosis of stroke patients differs considerably between various countries. Conclusion Virtual International Stroke Trials Archive provides an excellent opportunity for analysis of natural history data and prognosis. It has the potential to influence clinical trial design and implementation through exploratory data analyses. [source] Oral calcium supplementation associated with decreased likelihood of nephrolithiasis prior to surgery for hyperparathyroidismINTERNATIONAL JOURNAL OF UROLOGY, Issue 12 2007Matthew R Cooperberg Abstract: We aimed to assess the impact of oral calcium supplementation (OCS) on the prevalence of nephrolithiasis among a cohort of patients undergoing surgery for primary hyperparathyroidism (PHPT). There were 339 patients undergoing surgery for PHPT with detailed past medical history data that were analyzed. 73 patients (22%) had a history of nephrolithiasis prior to parathyroid surgery. Nephrolithiasis was more common among men than women (40% vs 15%, P < 0.001), despite the predominance of women (73% of patients) with hyperparathyroidism. 83 patients (25%) used OCS. OCS was associated with a lower prevalence of nephrolithiasis (9.6% vs 25.4% without OCS, P = 0.002). This protective effect included both men and women (rates of nephrolithiasis with and without supplements: men 19% vs 46%, P = 0.027; women 7% vs 17%, P = 0.04). The mechanism for the apparent protective effect of OCS on rates of nephrolithiasis is unclear, and further research is required to elucidate the variable penetrance of nephrolithiasis among PHPT patients. [source] Characteristics of 32 SupercentenariansJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2006Emily A. Schoenhofen BA OBJECTIVES: To report phenotypic characteristics of 32 age-validated supercentenarians. DESIGN: Case series. SETTING: U.S.-based recruitment effort. PARTICIPANTS: Thirty-two supercentenarians. MEASUREMENTS: Multiple forms of proof were used to validate age claims. Sociodemographic, activities of daily living, and medical history data were collected. RESULTS: Age range was 110 to 119. Fifty-nine percent had Barthel Index scores in the partially to totally dependent range, whereas 41% required minimal assistance or were independent. Few subjects had a history of clinically evident vascular-related diseases, including myocardial infarction (n=2, 6%) and stroke (n=4, 13%). Twenty-two percent (n=7) were taking medications for hypertension. Twenty-five percent (n=8) had a history of cancer (all cured). Diabetes mellitus (n=1, 3%) and Parkinson's disease (n=1, 3%) were rare. Osteoporosis (n=14, 44%) and cataract history (n=28, 88%) were common. CONCLUSION: Data collected thus far suggest that supercentenarians markedly delay and even escape clinical expression of vascular disease toward the end of their exceptionally long lives. A surprisingly substantial proportion of these individuals were still functionally independent or required minimal assistance. [source] The relative importance of dispersal limitation of vascular plants in secondary forest succession in Muizen Forest, BelgiumJOURNAL OF ECOLOGY, Issue 5 2001Kris Verheyen Abstract 1,Distribution patterns (frequency and percentage cover) of 18 forest plant species were studied in 34 ha of mixed deciduous forest (Muizen Forest, north Belgium). Stands varied in age between 6 and more than 223 years and both slow and fast colonizing species were studied. 2,Detailed land use history data were combined with the species distribution maps to identify species-specific colonization sources and calculate colonization distances. 3,A multiple logistic regression model was constructed with four covariables: pH (which can impose limits on the potential species-distribution), secondary forest age, distance from nearest colonization source and age,distance interaction, to allow us to account for the gradual completion of colonization over time. 4,We could distinguish species which are limited by both dispersal and recruitment (Primula elatior, Arum maculatum and Lamium galeobdolon), mainly by dispersal (Anemone nemorosa, Deschampsia cespitosa), mainly by recruitment (Paris quadrifolia and Polygonatum multiflorum) and by neither (Geum urbanum, Ranunculus ficaria, Glechoma hederacea, Aegopodium podagraria, Ajuga reptans, Adoxa moschatellina and Oxalis acetosella). 5,The low colonizing capacity of ancient forest plants cannot be attributed to a single cause; rather both dispersal and recruitment are limiting but the relative importance varies. [source] Selection, structure and the heritability of behaviourJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2002D. G. Stirling Characters which are closely linked to fitness often have low heritabilities (VA/VP). Low heritabilities could be because of low additive genetic variation (VA), that had been depleted by directional selection. Alternatively, low heritabilities may be caused by large residual variation (VR=VP , VA) compounded at a disproportionately higher rate than VA across integrated characters. Both hypotheses assume that each component of quantitative variation has an independent effect on heritability. However, VA and VR may also covary, in which case differences in heritability cannot be fully explained by the independent effects of elimination-selection or compounded residual variation. We compared the central tendency of published behavioural heritabilities (mean=0.31, median=0.23) with morphological and life history data collected by Mousseau & Roff (1987). Average behavioural heritability was not significantly different from average life history heritability, but both were smaller than average morphological heritability. We cross-classified behavioural traits to test whether variation in heritability was related to selection (dominance, domestic/wild) or variance compounding (integration level). There was a significant three-way interaction between indices of selection and variance compounding, related to the absence of either effect at the highest integration level. At lower integration levels, high dominance variance indicated effects of selection. It was also indicated by the low CVA of domestic species. At the same time CVR increased disproportionately faster than CVA across integration levels, demonstrating variance compounding. However, neither CVR nor CVA had a predominant effect on heritability. The partial regression coefficients of CVR and CVA on heritability were similar and a path analysis indicated that their (positive) correlation was also necessary to explain variation in heritability. These results suggest that relationships between additive genetic and residual components of quantitative genetic variation can constrain their independent direct effects on behavioural heritability. [source] Homocysteine, the MTHFR 677 C,T polymorphism and family history of premature cardiovascular diseaseJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 3 2009A. Carey Background:, Cardiovascular disease (CVD) is the main cause of premature death in the UK and accounts for 36% of all premature male deaths and 27% of female deaths every year (British Heart Foundation, 2006). Although many risk factors for CVD are known, family history has been identified as being of particular importance in premature CVD (Lloyd-Jones et al., 2004). Recently, it was suggested that an elevated homocysteine (tHcy) may be associated with premature CVD (Homocystiene Studies Collaboration, 2002). The main genetic determinant of tHcy is the common 677 C,T polymorphism, in the enzyme methylenetetrahydrofolate reductase (MTHFR), which is prevalent in approximately 10% of the UK population. Relatively few studies have examined the association between tHcy and premature CVD and hardly any have considered the role of this polymorphism. The aim of this study therefore was to examine the relationships between the MTHFR 677 C,T polymorphism, tHcy and a family history of CVD in patients with established premature CVD. Methods:, An analysis was conducted on medical, lifestyle and family history data collected from patients and age-sex matched controls, recruited through the GENOVIT study in 2003. This case,control study involved n = 404 premature CVD patients and a similar number of age-sex matched controls, all of whom were screened for the TT genotype. A subset of patients (n = 196) and controls (n = 167) provided a blood sample, from which the tHcy concentration was established. Independent sample t -tests were used to determine differences between patients and controls and differences among genotype groups were examined using a one-way analysis of variance, followed by a Tukey's post hoc test. Results:, Plasma tHcy was significantly elevated in patients with a family history of CVD (compared to those without) (P = 0.013). A nonsignificant trend towards higher tHcy (compared to those without) was observed in patients with the TT genotype (P = 0.419). Furthermore, specifically in those with the TT genotype, those with a family history of CVD (compared to those without) showed significantly higher tHcy concentrations (P < 0.005). Those with the TT genotype who smoked had significantly higher tHcy (P < 0.05) than the CC and CT genotypes. Discussion:, The findings presented provide evidence to support an association between the MTHFR 677C,T polymorphism, elevated homocysteine and family history of premature CVD. Given that dietary levels of riboflavin have been shown to lower homocysteine specifically in individuals with the TT genotype (McNulty et al., 2006), these results have implications for the dietary management of premature CVD in those individuals with a genetic predisposition for elevated tHcy. In conclusion, further research in larger cohort numbers, regarding the correlation between family history, tHcy and the MTHFR polymorphism, would be beneficial for establishing their cause and effect relationship. References British Heart Foundation (2006) All Deaths and Deaths Under 75 by Cause and Sex, 2005, England, Wales, Scotland, N Ireland and United Kingdom. Available at http://www.bhf.org.uk/research_health_professionals/resources/heart_statistics.aspx. Homocystine Studies Collaboration (2002) Homocysteine and the risk of ishaemic heart disease and stroke. JAMA288, 2015,2022. Llyod-Jones, D.M., Nam, B.H., D'Agostino, R.B., Levy, D., Murabito, J.M., Wang, T.J., Wilson, P.W. & O'Donnell, C.J. (2004) Parental cardiovascular disease as a risk factor for cardiovascular disease in middle-aged adults, a prospective study of parents and offspring. JAMA291, 2204,2211. McNulty, H., Dowey le, R.C., Strain, J.J., Dunne, A., Ward, M., Molloy, A.M., McAnena. L.B., Hughes, J.P., Hannon-Fletcher, M. & Scott, J.M. Riboflavin lowers homocysteine in individuals homozygous for the MTHFR 677C->T polymorphism. Circulation113, 74,80. [source] Change in the Association Between Premarital Cohabitation and Separation, Australia 1945 , 2000JOURNAL OF MARRIAGE AND FAMILY, Issue 2 2009Belinda Hewitt We investigate change in the association between premarital cohabitation and the risk of separation. Using retrospective marriage history data from the first wave (2001) of the Household Income and Labor Dynamics in Australian survey, we examine 6,210 first marriages formed between 1945 and 2000. We find the association between premarital cohabitation and separation is changing. The increased risk of separation for cohabitors compared to noncohabitors diminishes each year for marriages before 1988. This association then reverses for marriages after 1988, where noncohabitors have an increased risk of separation. Our results indicate that, for more recent marriages, premarital cohabitation reduces the risk of separation; more research is needed to understand the underlying mechanisms for this reversal. [source] Putting the Five-Factor Model Into Context: Evidence Linking Big Five Traits to Narrative IdentityJOURNAL OF PERSONALITY, Issue 5 2006Peter Raggatt ABSTRACT The study examined relationships between the Big Five personality traits and thematic content extracted from self-reports of life history data. One hundred and five "mature age" university students (M=30.1 years) completed the NEO PI-R trait measure, and the Personality Web Protocol. The protocol examines constituents of identity by asking participants to describe 24 key "attachments" from their life histories (significant events, people, places, objects, and possessions). Participants sorted these attachments into clusters and provided a self-descriptive label for each cluster (e.g., "adventurous self"). It was predicted that the thematic content of these cluster labels would be systematically related to Big Five trait scores (e.g., that labels referring to strength or positive emotions would be linked to Extraversion). The hypothesized links were obtained for each of the Big Five trait domains except Conscientiousness. Results are discussed with a view to broadening our understanding of the Five-Factor Model in relation to units of personality other than traits. [source] The digestive tract and life history of small mammalsMAMMAL REVIEW, Issue 2 2002PETER LANGER ABSTRACT The type of food, differentiation of the large intestine and stomach, and methane production, as well as life history data, are considered in Insectivora, Rodentia and Lagomorpha. When food containing plant cell wall material is eaten, there is either a differentiation of the stomach or the large intestine. In animals with low body mass and little differentiation of the gastrointestinal tract, methane production is low, but structures essential for microbial digestion of plant cell wall material, such as haustration of the colon or formation of a caecum, can be found in many methane-producers. Animals with a body mass < 500 g and a weaning time < 20 days are non-producers of methane. Establishment of a balanced microbial population in the gastrointestinal tract requires some time. Many non-producers of methane wean their young in < 10 days, but many producers need > 50 days for the weaning process. Caviomorpha, Thryonomyidae and Hystricidae seem to have ,opened the door' to the use of low quality food by microbial fermentation, but some of them have to ,pay' for this extension of the food range by an extended weaning period, which also means an extended dependency on the mother. [source] Molecular ecology of social behaviour: analyses of breeding systems and genetic structureMOLECULAR ECOLOGY, Issue 2 2001Kenneth G. Ross Abstract Molecular genetic studies of group kin composition and local genetic structure in social organisms are becoming increasingly common. A conceptual and mathematical framework that links attributes of the breeding system to group composition and genetic structure is presented here, and recent empirical studies are reviewed in the context of this framework. Breeding system properties, including the number of breeders in a social group, their genetic relatedness, and skew in their parentage, determine group composition and the distribution of genetic variation within and between social units. This group genetic structure in turn influences the opportunities for conflict and cooperation to evolve within groups and for selection to occur among groups or clusters of groups. Thus, molecular studies of social groups provide the starting point for analyses of the selective forces involved in social evolution, as well as for analyses of other fundamental evolutionary problems related to sex allocation, reproductive skew, life history evolution, and the nature of selection in hierarchically structured populations. The framework presented here provides a standard system for interpreting and integrating genetic and natural history data from social organisms for application to a broad range of evolutionary questions. [source] Environmental stability and the distribution of the sexes: insights from life history experiments with the geographic parthenogen Eucypris virens (Crustacea: Ostracoda)OIKOS, Issue 6 2008Maria Joćo Fernandes Martins In many species with mixed reproduction, parthenogens cover a wider geographic range than sexuals. In freshwater ostracods this pattern referred to as geographic parthenogenesis is traditionally explained by ascribing a higher potential for dispersal to parthenogens. For example, the postglacial invasion hypothesis states that the lack of males in northern Europe is caused by the relatively slow range expansion of sexual lineages after deglaciation. An alternative explanation for the contemporary distribution of the sexes is based on spatial and temporal variations in ecological habitat stability. To test this hypothesis, we compared life history data of Eucypris virens individuals originating from bisexual and all-female populations. Populations with males are only found around the Mediterranean, whereas parthenogens cover most of Europe. The animals were hatched and grown in environments mimicking temperature and photoperiod conditions observed in Belgium and Spain. The data confirm the higher potential for population growth in parthenogens. In particular their faster hatching response, possibly higher fecundity (as derived from a difference in body height) and the absence of a cost of males should allow them to out-compete sexuals under stable conditions. However, the comparison of the hatchling accumulation curves of bisexual and all-female populations suggests that sexuals have an advantage in highly unpredictable environments. Indeed, under conditions mimicking those in southern Europe, bisexual populations exhibit a bet-hedging strategy, while parthenogenetic resting eggs hatch on average earlier and more synchronously. Overall, the life history data stress the importance of short term environmental fluctuations for the distribution of the sexes in E. virens, and probably many other inhabitants of ephemeral water bodies. [source] ,One Household/Two Systems'PACIFIC ECONOMIC REVIEW, Issue 1 2002Calla Wiemer Under China's dual-track approach to reform, ,one household/two systems', or combining state and private employment within a family, connotes having the best of both worlds. Drawing upon work history data for 5000 households, the present study looks at who is employed in the private sector. Findings are that marriage to a state-employed spouse actually reduces the probability of one's holding a private sector job and that the effects of living with a state-connected parent are mixed. Were households more actively pursuing a one-household/two-systems strategy, the transition from state dependence would be expedited. [source] Metabolic alkalosis with hypoelectrolytemia in infants with cystic fibrosisPEDIATRICS INTERNATIONAL, Issue 3 2002Stojka Fustik Abstract Background: Infants with cystic fibrosis (CF) can develop episodes of hyponatremic hypochloremic dehydration with metabolic alkalosis when they sweat excessively, which is not caused by sweating in normal infants. We investigated the incidence of the metabolic alkalosis with hypoelectrolytemia in CF infants, the possible risk factors for its occurrence and the importance of the manifestation in the diagnosis of CF. Methods: In order to evaluate the incidence and the risk factors for the development of this sweat-related metabolic disorder in CF, we reviewed the records of all children diagnosed as having CF before the age of 12 months in a 10-year period. Data analysis included medical history data, clinical features, biochemical parameters (blood pH, serum bicarbonate, sodium, chloride and potassium levels), sweat chloride test values, as well as genetic analysis data. Results: The prevalence of metabolic alkalosis in association with low serum electrolyte concentrations (hyponatremia, hypochloremia, and hypokalemia) in infant CF population in our region was 16.5%. We found no season predilection in its occurrence. Early infant age, breast-feeding, delayed CF diagnosis, heat exhaustion and the presence of severe CF transmembrane conductance regulator mutations are predisposed factors for the development of metabolic alkalosis with hypoelectrolytemia. Conclusions: The results from our study suggest that metabolic alkalosis with hypoelectrolytemia is a relatively common manifestation of CF in infancy. The possibility of CF should be seriously considered in any infant with this metabolic disorder. [source] Physical activity, physical exertion, and miscarriage risk in women textile workers in Shanghai, ChinaAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2010E.Y. Wong PhD Abstract Background Strenuous occupational physical activity and physical demands may be risk factors for adverse reproductive outcomes. Methods A retrospective study in the Shanghai, China textile industry study collected women's self-reported reproductive history. Occupational physical activity assessment linked complete work history data to an industry-specific job-exposure matrix. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by multivariate logistic regression for the first pregnancy outcome and utilized generalized estimating equations to consider all pregnancies per woman. Results Compared with women employed in sedentary jobs, a reduced risk of miscarriage was found for women working in jobs with either light (OR 0.18, 95% CI: 0.07, 0.50) or medium (OR 0.24, 95% CI: 0.08, 0.66) physical activity during the first pregnancy and over all pregnancies (light OR 0.32, 95% CI: 0.17, 0.61; medium OR 0.43, 95% CI: 0.23, 0.80). Frequent crouching was associated with elevated risk (OR 1.82, 95% CI: 1.14, 2.93; all pregnancies per woman). Conclusions Light/medium occupational physical activity may have reduced miscarriage risk, while specific occupational characteristics such as crouching may have increased risk in this cohort. Am. J. Ind. Med. 53:497,505, 2010. © 2010 Wiley-Liss, Inc. [source] Family History of Psychiatric Disorders and Alcohol and Substance Misuse in Patients with Bipolar I Disorder, Substance Use Disorder, or BothTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 3 2007Alfredo Sbrana MD Family history data were collected on first-degree relatives of 78 patients with bipolar I disorder (BD) and substance use disorder (SUD), 47 with BD only, and 35 with SUD only. The prevalence of psychiatric disorders was significantly higher in first-degree relatives of patients with BD + SUD (64%) and BD (61%) compared with first-degree relatives of SUD patients (20%). The prevalence of alcohol misuse was significantly higher in first-degree relatives of patients with BD + SUD (23.1%) and SUD alone (28.6%) compared to first-degree relatives of patients with BD (4.3%). Our findings suggest that BD and SUD do not share familial risk factors. [source] Stochastic wealth dynamics and risk management among a poor population,THE ECONOMIC JOURNAL, Issue 498 2004Travis J. Lybbert We use herd history data collected among pastoralists in southern Ethiopia to study stochastic wealth dynamics among a poor population. Although covariate rainfall shocks plainly matter, household-specific factors, including own herd size, account for most observed variability in wealth dynamics. We find no support for the tragedy of the commons hypothesis. Past studies may have conflated costly self-insurance with stocking rate externalities. Biophysical shocks move households between multiple dynamic wealth equilibria , the lowest suggesting a poverty trap , according to nonconvex path dynamics. These findings have broad implications for development and relief strategies among a poor population vulnerable to climatic shocks. [source] Comparisons of age, growth, and maturity between male and female, and diploid and triploid individuals in Carassius auratus from Okinawa-jima Island, JapanAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Mikumi Takada Abstract 1.Carassius auratus, a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages, is distributed widely in and around the Eurasian continent and is especially common in East Asia. East Asian C. auratus diverged genetically to form local endemic populations in different regions, and those distributed in the Ryukyu Archipelago form a local endemic population that can be regarded as an evolutionarily significant unit because of its high phylogenetic independence and evolutionary distinctiveness. Although the evolutionary uniqueness of this population should be conserved, its distribution area and population size are decreasing rapidly, and some island populations are currently considered endangered or already extinct. 2.To develop effective conservation measures to stop the current decline of Ryukyuan C. auratus, ecological data need to be collected. In this study, life history data for a C. auratus population distributed in the Hiji River system were collected by estimating age, growth, and spawning season. 3.The spawning season of C. auratus in the Hiji River extended from March to September, peaking during March,May. Females became sexually mature in their second year, but males reached maturity and were able to spawn as early as in the late spawning season of their year of hatching. Once having reached sexual maturity, males probably continuously stay ripe throughout their life. 4.Sagittal otoliths of C. auratus proved to be useful ageing structures because one annual increment is formed on the sagittal otolith before the spawning season in each year. The oldest fish observed were a 10-year-old female and an 11-year-old male. Females showed faster somatic growth and higher final standard length than males, and a sexual size dimorphism was observed. 5.The standard length at each age class did not differ between diploid and triploid C. auratus, suggesting that triploid growth rates were almost equal to those of diploids. Copyright © 2009 John Wiley & Sons, Ltd. [source] Water fluoridation in the Blue Mountains reduces risk of tooth decayAUSTRALIAN DENTAL JOURNAL, Issue 4 2009RW Evans Abstract Background:, In April 1992, the fluoride concentration in the Blue Mountains water supply was adjusted to 1 mg/L. Baseline dmft/DMFT has been determined in children attending schools in the region and in the adjacent reference region of Hawkesbury, fluoridated since 1968. The aim of this study was to evaluate the effect of the water fluoridation programme in the Blue Mountains. Methods:, In 2003, children attending the same schools were sampled. Residential history data were obtained by questionnaire and caries experience was assessed according to WHO guidelines. The analysis was restricted to lifelong resident children aged 5,11 years. Results:, The baseline and follow-up dmft scores for Blue Mountains children aged 5,8 years were 2.36 and 0.67, respectively. The age-adjusted decrease in odds of experiencing one or more dmft due to fluoridation was 0.26 (CI95 0.19, 0.37). The corresponding DMFT scores for Blue Mountains children aged 8,11 were 0.76 and 0.21 and the corresponding decrease in odds of experiencing one or more DMFT due to fluoridation was 0.25 (CI95 0.16, 0.40). Conclusions:, Tooth decay reduction observed in the Blue Mountains corresponds to high rates reported elsewhere and demonstrates the substantial benefits of water fluoridation. [source] Occupational magnetic field exposures of garment workers: Results of personal and survey measurementsBIOELECTROMAGNETICS, Issue 5 2003Michael A. Kelsh Abstract To explore the feasibility of performing an epidemiologic study of female breast cancer and magnetic field (MF) exposures, we chose to study garment workers, who reportedly have some of the highest MF exposures. We collected personal exposure (PE, n,=,48) and survey measurements (n,=,77) near commercial sewing machines at three garment facilities and conducted a pilot interview among 25 garment workers asking about exposure duration, activities, and machine characteristics. MF levels were higher for older machines with alternating current (AC) than newer machines with direct current (DC) motors. MF levels were comparable for both idling and sewing activities. Most interviewed workers could describe duration of exposure and machine type (automatic/manual), but not other machine characteristics. Measurements were lower than previously reported for garment workers but were higher than exposures to most women. A historical exposure assessment can be conducted by linking duration of exposure with reconstructed exposure measurements but may be limited by the accuracy of work history data. Bioelectromagnetics 24:316-326, 2003. © 2003 Wiley-Liss, Inc. [source] Competing Risks and Time-Dependent CovariatesBIOMETRICAL JOURNAL, Issue 1 2010Giuliana Cortese Abstract Time-dependent covariates are frequently encountered in regression analysis for event history data and competing risks. They are often essential predictors, which cannot be substituted by time-fixed covariates. This study briefly recalls the different types of time-dependent covariates, as classified by Kalbfleisch and Prentice [The Statistical Analysis of Failure Time Data, Wiley, New York, 2002] with the intent of clarifying their role and emphasizing the limitations in standard survival models and in the competing risks setting. If random (internal) time-dependent covariates are to be included in the modeling process, then it is still possible to estimate cause-specific hazards but prediction of the cumulative incidences and survival probabilities based on these is no longer feasible. This article aims at providing some possible strategies for dealing with these prediction problems. In a multi-state framework, a first approach uses internal covariates to define additional (intermediate) transient states in the competing risks model. Another approach is to apply the landmark analysis as described by van Houwelingen [Scandinavian Journal of Statistics 2007, 34, 70,85] in order to study cumulative incidences at different subintervals of the entire study period. The final strategy is to extend the competing risks model by considering all the possible combinations between internal covariate levels and cause-specific events as final states. In all of those proposals, it is possible to estimate the changes/differences of the cumulative risks associated with simple internal covariates. An illustrative example based on bone marrow transplant data is presented in order to compare the different methods. [source] Survival of Bowhead Whales, Balaena mysticetus, Estimated from 1981,1998 Photoidentification DataBIOMETRICS, Issue 4 2002Judith Zeh Summary. Annual survival probability of bowhead whales, Balaena mysticetus, was estimated using both Bayesian and maximum likelihood implementations of Cormack and Jolly-Seber (JS) models for capture-recapture estimation in open populations and reduced-parameter generalizations of these models. Aerial photographs of naturally marked bowheads collected between 1981 and 1998 provided the data. The marked whales first photographed in a particular year provided the initial ,capture' and ,release' of those marked whales and photographs in subsequent years the ,recaptures'. The Cormack model, often called the Cormack-Jolly-Seber (CJS) model, and the program MARK were used to identify the model with a single survival and time-varying capture probabilities as the most appropriate for these data. When survival was constrained to be one or less, the maximum likelihood estimate computed by MARK was one, invalidating confidence interval computations based on the asymptotic standard error or profile likelihood. A Bayesian Markov chain Monte Carlo (MCMC) implementation of the model was used to produce a posterior distribution for annual survival. The corresponding reduced-parameter JS model was also fit via MCMC because it is the more appropriate of the two models for these photoidentification data. Because the CJS model ignores much of the information on capture probabilities provided by the data, its results are less precise and more sensitive to the prior distributions used than results from the JS model. With priors for annual survival and capture probabilities uniform from 0 to 1, the posterior mean for bowhead survival rate from the JS model is 0.984, and 95% of the posterior probability lies between 0.948 and 1. This high estimated survival rate is consistent with other bowhead life history data. [source] Incidence and time course of bleeding after long-term amenorrhea after breast cancer treatmentCANCER, Issue 13 2010A prospective study Abstract BACKGROUND: The incidence of chemotherapy-induced amenorrhea (CIA) and the time to subsequent menstrual bleeding in premenopausal breast cancer patients treated with current standard chemotherapy regimens was examined. METHODS: Four hundred sixty-six women ages 20 to 45 years at the time of diagnosis of a stage I to III breast cancer were recruited between January 1998 and July 2002. Patients completed monthly bleeding calendars from the time of study recruitment. Updated medical history data were obtained at 6-month intervals. RESULTS: Most women received doxorubicin and cyclophosphamide (AC); doxorubicin, cyclophosphamide, and paclitaxel (ACT); or cyclophosphamide, methotrexate, and 5-fluorouracil (CMF). Approximately 41% of women experienced an initial 6 months of CIA, and an additional 29% had at least 1 year of CIA. Approximately half of the women with 6 months of CIA and 29% of those with 1 year of CIA resumed bleeding within the subsequent 3 years, usually in the year after their amenorrheic episode. Resumption of bleeding differed significantly by treatment regimen after 6 months of CIA (P = .002; 68% with AC, 57% with ACT, and 23% with CMF), but not after 1 year of CIA (P = .5). Of the 23% of women who experienced an initial 2-year period of CIA, 10% resumed bleeding within the ensuing 3 years after their amenorrheic episode, but none had regular menses. CONCLUSIONS: A considerable proportion of women treated with chemotherapy will experience periods of CIA, but many will resume bleeding. Newer treatment regimens such as ACT appear to have a higher resumption of bleeding compared with CMF. This finding may have implications for choice of anti-estrogen treatment and for future potential pregnancies/fertility. Cancer 2010. © 2010 American Cancer Society. [source] | ||||||||||||||||||||||