256 research outputs found
Forecasting age-specific breast cancer mortality using functional data models
No full textAccurate estimates of future age-specific incidence and mortality are critical for allocation of resources to breast cancer control programs and evaluation of screening programs. The purpose of this study is to apply functional data analysis techniques to model age-specific breast cancer mortality time trends, and forecast entire age-specific mortality function using a state-space approach. We use yearly unadjusted breast cancer mortality rates in Australia, from 1921 to 2001 in 5 year age groups (45 to 85+). We use functional data analysis techniques where mortality and incidence are modeled as curves with age as a functional covariate varying by time. Data is smoothed using nonparametric smoothing methods then decomposed (using principal components analysis) to estimate basis functions that represent the functional curve. Period effects from the fitted functions are forecast then multiplied by the basis functions, resulting in a forecast mortality curve with prediction intervals. To forecast, we adopt a state-space approach and an extension of the Pegels modeling framework for selecting among exponential smoothing methods. Overall, breast cancer mortality rates in Australia remained relatively stable from 1960 to the late 1990's but declined over the last few years. A set of K=4 basis functions minimized the mean integrated squared forecasting error (MISFE) and accounts for 99.3% of variation around the mean mortality curve. 20 year forecast suggest a continual decline at a slower rate and stabilize beyond 2010 and by age, forecasts show a decline in all age groups with the greatest decline in older women. We illustrate the utility of a new modelling and forecasting approach to model breast cancer mortality rates using a functional model of age. The methods have the potential to incorporate important covariates such as Hormone Replacement Therapy (HRT) and interventions to represent mammographic screening. This would be particularly useful for evaluating the impact of screening on mortality and incidence from breast cancer.Mortality, Breast Cancer, Forecasting, Functional Data Analysis, Exponential Smoothing
Cohort Profile: Melbourne Atopy Cohort study (MACS)
No full textAdvance Access Publication Date: 21 April 2016Adrian J Lowe, Caroline J Lodge, Katrina J Allen, Michael J Abramson, Melanie C Matheson, Paul S Thomas, Christopher A Barton, Catherine M Bennett, Bircan Erbas, Cecilie Svanes, Mathias Wjst, Francisco G, omez Real, Jennifer L Perret, Melissa A Russell, Melissa C Southey, John L Hopper, Lyle C Gurrin, Christine J Axelrad, David J Hill and Shyamali C Dharmag
Strengthening the social environment for Australian children: A reply to Parkinson
No full textWe thank Professor Parkinson for his response (Parkinson, 2013) to our paper published in the Journal of Family Studies (Lucas, Nicholson, & Erbas, 2013) and the opportunity to expand upon the position presented in our discussion. Parkinson argues that it was inappropriate for us to cite his report For Kids' Sake: Repairing the social environment for Australian children and young people (FKS) (Parkinson, 2011) as supporting claims that two biological parent households are superior environments for children to grow up in, and takes exception to our view that such a position is a 'simplistic view of the relationship between family structure and child outcomes' (Lucas et al., 2013). We acknowledge that the FKS report reviewed a considerable amount of contemporary family research that covered an array of viewpoints regarding the effects of living in a non-two-biological parent family on children. We also support the majority of recommendations made in the report
Forecasting age-related changes in breast cancer mortality among white and black US women: A functional approach
No full textThe disparity in breast cancer mortality rates among white and black US women is widening with higher mortality rates among black women. We apply functional time series models on age-specific breast cancer mortality rates for each group of women, and forecast their mortality curves using exponential smoothing state-space models with damping. The data were obtained from the Surveillance, Epidemiology and End Results (SEER) program of the US (SEER, 2007). Mortality data were obtained from the National Centre for Health Statistics (NCHS) available on the SEER*Stat database. We use annual unadjusted breast cancer mortality rates from 1969 to 2004 in 5-year age groups (45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84). Age-specific mortality curves were obtained using nonparametric smoothing methods. The curves are then decomposed using functional principal components and we fit functional time series models with four basis functions for each population separately. The curves from each population are forecast and prediction intervals are calculated. Twenty-year forecasts indicate an over-all decline in future breast cancer mortality rates for both groups of women. This decline is steeper among white women aged 55-73 and black women aged 60-84. For black women under 55 years of age, the forecast rates are relatively stable indicating no significant change in future breast cancer mortality rates among young black women in the next 20 years.Breast cancer mortality, racial and ethnic disparities, screening, trends, forecasting, functional data analysis
Child mental health after parental separation: The impact of resident/non-resident parenting, parent mental health, conflict and socioeconomics
No full textChildren of separated parents tend to have poorer mental health than children of intact families. Explanations to date have tended to focus on resident mothers, neglecting the potential importance of non-resident fathers. Using recent data from the Longitudinal Study of Australian Children, and independent teacher-reports of child mental health, this study 1) compares the mental health of children with resident and non-resident fathers and 2) explores predictors of poor mental health among children with a non-resident father. Children with a non-resident father had poorer mental health than those with a resident father, but this difference was explained fully by exposure to parental conflict, and to a lesser extent by socioeconomic status, parenting, and parent mental health. For children with a non-resident father, the strongest predictors of child mental health were mothers' employment and maternal parenting consistency. Policy implications are discussed
Asthma, atopy and serious psychological distress: prevalence and risk factors among young people in the Melbourne atopy cohort study
No full textBackground: While atopic conditions are associated with increased risk of mental health problems, the evidence that a range of allergic conditions are associated with psychological distress in young people is less clear. Methods: We recruited a longitudinal birth cohort study of 620 children with a family history of allergic disease. At the 18-year follow up, atopic sensitization was determined by skin prick testing. Surveys were used to determine psychological distress (Kessler 6), quality of life (SF12), respiratory symptoms and management, presence of current eczema and hay fever. Regression models were used to identify predictors of psychological distress and quality of life, while controlling for potential confounders. Results: Prevalence of serious psychological distress was quite low (n = 22, 5.3%), and there were no associations between psychological distress and current atopic sensitization, symptoms of hay fever, eczema or asthma. Smoking status and lower level of maternal education were associated with lower physical quality of life (SF12 PCS subscale). Psychological distress total score, lower maternal education, smoking, female sex, and current eczema were associated with worse mental quality of life (SF12 MCS subscale). Conclusion: We found relatively low levels of psychological distress in this cohort of young adults, despite a high prevalence of allergic diseases. Positive social factors may serve to buffer psychological distress amongst the cohort accounting for the low prevalence of serious psychological distress observed.Christopher A. Barton, Shyamali C. Dharmage, Caroline J. Lodge, Michael J.
Abramson, Bircan Erbas and Adrian Low
Literature review on thunderstorm asthma and its implications for public health advice: Final report
No full textThis report, written by the Queensland University of Technology for the Department of Health and Human Services and published in May 2017, explores and details published reports on thunderstorm asthma. It will inform part of the Victorian Government’s response to the thunderstorm asthma outbreak that occurred on 21 November 2016. This review and evaluation of literature is designed to help better understand the factors leading to thunderstorm asthma, and highlight knowledge gaps that need to be filled to better predict and prevent the impact of future episodes
Statistical Methodological Issues in Studies of Air Pollution and Respiratory Disease
No full textEpidemiological studies have consistently shown short term associations between levels of air pollution and respiratory disease in countries of diverse populations, geographical locations and varying levels of air pollution and climate. The aims of this paper are: (1) to assess the sensitivity of the observed pollution effects to model specification, with particular emphasis on the inclusion of seasonally adjusted covariates; and (2) to study the effect of air pollution on respiratory disease in Melbourne, Australia
Air Pollution in Bogotá, Colombia: A Concentration-Response Approach
No full textMost of the evidence regarding the association between air pollution and health comes from studies in the USA. Nevertheless, air pollution has become a concern also for local authorities of Latin-American cities and Bogotá, Colombia is no exception. This paper will develop a model to define a concentration-response function between three of the most important air pollutants in Bogotá and the daily respiratory hospital admission counts in the city during the year of 1998. This article pretends to further work on this area by giving the first step towards a more detailed estimation of the costs of air pollution in BogotáAir Pollution, Health, Respiratory Hospital Admissions, Bogotá
Early-to-Midlife Body Mass Index Trajectories and Obstructive Sleep Apnoea Risk 10 Years Later
No full textBackground and Objective While short-term weight changes are known to influence obstructive sleep apnoea (OSA), the impact of body mass index (BMI) changes over the life course has been poorly documented. We examined the association between BMI trajectories from childhood to middle age and adult OSA, 10 years later. Methods Five BMI trajectories were previously identified in the population-based cohort Tasmanian Longitudinal Health Study (TAHS), using eight time-point BMI from age 5 to 43 years. The primary outcome was probable OSA at 53 years, defined using STOP-Bang questionnaire, with Berlin and OSA-50 questionnaires used to ensure consistency of findings. Clinically significant diagnosed OSA was defined as self-reported medical diagnosis or mild OSA with symptoms or moderate-to-severe OSA, using type-4 sleep studies. Associations were examined using multivariable logistic regression. Results Compared with the average BMI trajectory, the child average-increasing (aOR = 5.28, 95% CI 3.38–8.27) and persistently high trajectories (aOR = 3.73, 2.06–6.74) were associated with increased risk of probable OSA. These associations were consistent when using clinically significant diagnosed OSA (child average-increasing trajectory: aOR = 2.95, 1.30–6.72; high trajectory: aOR = 2.23, 0.82–6.09). Individuals belonging to the low trajectory were less likely than the average trajectory to have OSA. Notably, the child high-decreasing trajectory was not associated with OSA. Conclusion Physicians and the public should be aware of the potential risk of OSA in middle-aged adults when BMI is high or continuously increasing from childhood to mid-40s. Obese children who subsequently lose weight were not at higher risk of OSA in middle age—a novel and key finding.Yaoyao Qian, Jennifer L. Perret, Garun S. Hamilton, Michael J. Abramson, Caroline J. Lodge, Dinh S. Bui, Gulshan B. Ali, Anurika P. De Silva, Robert J. Adams, Bruce R. Thompson, Bircan Erbas, Eugene H. Walters, Chamara V. Senaratna, Shyamali C. Dharmag
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