Funnel Plots for Assessing Institutional Performance

This thesis presents a comparison of maternal outcomes for births in New Zealand District Health Boards (DHBs).This is carried out through analysis of the National Minimum Dataset collected by the Ministry of Health for 2007. The outcome compared is postpartum haemorrhage (PPH) the results are displayed using funnel plots, a useful tool for displaying unbiased information on performance outcomes when comparing institutions. Exploration of the data found that there are differences in the demographics, maternal and birth characteristics among DHBs. The rates of PPH are different and the population mixes are made up of a range of different proportions of ethnic groups, ages and deprivation indexes. The exploratory analysis found that a large number of factors are associated with PPH. And that birth weight, parity and gestation had a large number of missing observations. These factors are not missing at random and require imputing prior to constructing the funnel plots. Results show that there is divergence amongst DHBs in the postpartum haemorrhage rate. First a raw PPH rate was plotted and the results indicated there were differences among DHBs. As there are many potential predictors for PPHa logistic regression model was applied to find the most important factors related to PPH. This allows us to apply an adjusted rate for the funnel plot. The risk adjusted funnel plot also indicated differences among DHBs. Two approaches are taken to account for the overdispersion. A winsorised estimate and a winsorised estimate with a random effects term are applied to the data. The approaches produced different results. The winsorised estimate widened the control limits and the random effects term narrowed the control limits. All four plots identified an extreme outlier and this was later removed from the analysis and the winsorisation funnel plots were rerun. The influential outlier made a difference and from this we can concluded that 2 out 20 DHBs lie outside the 95% control limits. These two DHBs could be stated as having a very low rate of PPH

Database Analysis Of State Surface Soil Regulatory Guidance Values

A 2001 study of Cleveland, Ohio brownfield surface soil contamination led to the examination of state regulatory guidance values for soils. Surface soils were of particular interest since these generally pose the greatest risk to human health at brownfield sites. This investigation initially focused on heavy metals, common contaminants at Cleveland brownfields. However, the observation of significant variability in guidance values applied to Cd, Cr, Cu, Pb, Ni, and Zn led to questions about other state-regulated components and ultimately to research examining the origins, magnitudes, and explanations for regulatory guidance value variability. The results presented here are based on the compilation of an 18,776 state surface soil database assembled from regulatory guidance for organic, inorganic, and element contaminants. All values were captured electronically from internet sources. The structure of each guidance value dataset was then standardized in a database-compatible format. Chemical Abstract Service (CAS) registry numbers were added to each record if they were not already provided. Identification of all records by CAS number resolves the problem of chemical synonyms. All value datasets were then assembled into the ACCESS database S3GVD (State Surface Soil Guidance Value Database) Statistical analysis is presented to characterize the nature and extent of variability in state surface soil guidance values. The organics, inorganics, and elements most and least commonly regulated and the range of guidance values are discussed. Log-scale Ordered Column Diagrams (LOCDs) are used to explore the nature of individual chemical guidance value distributions

Epidemiology and clinical outcomes associated with Theileria parva in a cohort of East African short horn zebu calves.

This thesis takes data from the Infectious Diseases of East African Livestock (IDEAL) project. The project was a longitudinal calf cohort study based in Western Kenya. Indigenous short horn zebu calves were recruited at birth and then visited every 5 weeks through their first year of life. The aim of this thesis was to improve understanding of the epidemiology of Theileria parva, with a particular focus on variation in host response. 362 of the 548 calves in the study cohort were classified as having seroconverted to T. parva, and 381 to T. mutans before 1 year old. The diagnostic tools used to identify exposure in the calf were compared, and environmental and calf level risk factors associated with the age at seroconversion were sought. Decreased elevation of the homestead and increased size of the herd were found to be significantly associated with an increased hazard of seroconversion to T. parva. There was little variation in hazard of T. mutans captured across the study site. The outcome ‘clinical episode’ was used to classify whether the calf was ill at each routine visit. A large number of calves passed through their first year of life without clinical disease being observed, and a minority of calves experienced the majority of clinical episodes. Multiple clinical episodes were apparently related in time, suggesting that they were due either to the same or connected pathogenic processes. A low birth weight, larger herds, and older farmers were all risk factors for being a sick calf. Both high helminth burden and T. parva were found to be significantly associated with clinical disease at a population level. A lot of variation was seen in the clinical presentation of disease. The clinical signs associated with fatal East Coast Fever (ECF), the clinical disease associated with T. parva infection, were found to be very variable. Although this may have been partly due to the varying times in the disease process that calves were observed prior to death, the complication of the clinical picture was also suggested to be due to co-infections. 71% of the cohort was infected with T. parva in their first year of life, but only a fraction (8.7%) went on to die from that infection. Unmatched and matched nested case control study formats were used to investigate the risk factors associated with death following T. parva infection (ECF death) in these calves. It was found that being infected young was a risk factor for death. Calves owned by older farmers were also at higher risk of death following infection. Going out grazing was found to be protective, and equivocal evidence was found for an association between prior T. mutans exposure and reduced odds of ECF death. If these initial findings from this work are correct, it is likely that T. mutans is influencing the clinical presentation of T. parva in endemic regions

High variability of food and nutrient intake exists across the Mediterranean Dietary Pattern- a systematic review

A Mediterranean style dietary pattern (MDP) is considered beneficial for health. The MD Score (MDS) definition has evolved, resulting in considerable variability in the foods and nutrients associated with MDS adherence. We systematically investigated food and nutrient composition of the MD between studies, countries, and methods of classifying the MDS. We searched Embase for MD systematic reviews and selected observational studies reporting intakes of foods, macronutrients, or micronutrients by categories of MDS adherence. The percentage differences in food and nutrient intakes between categories of high and low adherence to the MDS were calculated for each study. A total of 369 full-text primary papers were reviewed from the included systematic reviews and 74 papers selected (66 adults, 8 children). We found considerable differences in MDS definitions and scoring criteria. Between-study variation in food intake between high- and low-adherence MDS adherence categories ranged from a mean of −23% for meat, to 119% for fruit, and 278% for fish. Greater variability was evident in non-Mediterranean than Mediterranean regions. We conclude that few studies report food and nutrient intakes across the range of the MDP in adults and even fewer in children. The considerable variability in the foods and nutrients reported makes comparison of results from studies and translation into dietary guidelines difficult. We recommend that future publications of MD studies include full details of the range of food and nutrient intakes across the distribution of MD adherence in order to facilitate translation into health policy and practice

A Mediterranean Diet Is Positively Associated with Bone and Muscle Health in a Non-Mediterranean Region in 25,450 Men and Women from EPIC-Norfolk.

Research on Mediterranean diet (MD) adherence and musculoskeletal health is limited. The current study determined if adherence to the alternative MD score (aMED) and MD score (MDS), quantified from 7-d food diaries, was associated with fracture incidence, bone density (calcaneal broadband ultrasound attenuation (BUA)) and fat free mass (expressed over BMI (FFMBMI) using bioelectrical impedance) in 25,450 men and women recruited to the European Prospective Investigation into Cancer study in Norfolk, UK. During 17.4 years of follow up (443,178 total person years) 2195 incident fractures occurred. Higher aMED adherence was associated with 23% reduced total (Q5-Q1 HR 0.77; 95% CI 0.67, 0.88; p-trend < 0.01) and 21% reduced hip (Q5-Q1 HR 0.79; 95% CI 0.65, 0.96; p-trend = 0.01) fracture incidence, and significantly higher BUA (Q5-Q1 1.0 dB/MHz 95% CI 0.2, 1.9; p-trend < 0.01) and FFMBMI (Q5-Q1 0.05 kg/(kg/m2) 95% CI 0.04, 0.06; p-trend < 0.01), comparing extreme adherence quintiles. Higher MDS was also associated with reduced total fractures (Q5-Q1 HR 0.83; 95% CI 0.71, 0.96; p-trend = 0.03) and significantly higher BUA (Q5-Q1 1.4 dB/MHz 95% CI 0.5, 2.3; p-trend < 0.01) and FFMBMI (Q5-Q1 0.03 kg/(kg/m2) 95% CI 0.01, 0.04; p-trend < 0.01). This evidence supports the need to develop interventions to enhance MD adherence, particularly in women, where evidence for associations was stronger

Modeling tool for calculating dietary iron bioavailability in iron-sufficient adults

Background: Values for dietary iron bioavailability are required for setting dietary reference values. These are estimated from predictive algorithms, nonheme iron absorption from meals, and models of iron intake, serum ferritin concentration, and iron requirements. Objective: We developed a new interactive tool to predict dietary iron bioavailability. Design: Iron intake and serum ferritin, a quantitative marker of body iron stores, from 2 nationally representative studies of adults in the United Kingdom and Ireland and a trial in elderly people in Norfolk, United Kingdom, were used to develop a model to predict dietary iron absorption at different serum ferritin concentrations. Individuals who had raised inflammatory markers or were taking iron-containing supplements were excluded. Results: Mean iron intakes were 13.6, 10.3, and 10.9 mg/d and mean serum ferritin concentrations were 140.7, 49.4, and 96.7 mg/L in men, premenopausal women, and postmenopausal women, respectively. The model predicted that at serum ferritin concentrations of 15, 30, and 60 mg/L, mean dietary iron absorption would be 22.3%, 16.3%, and 11.6%, respectively, in men; 27.2%, 17.2%, and 10.6%, respectively, in premenopausal women; and 18.4%, 12.7%, and 10.5%, respectively, in postmenopausal women. Conclusions: An interactive program for calculating dietary iron absorption at any concentration of serum ferritin is presented. Differences in iron status are partly explained by age but also by diet, with meat being a key determinant. The effect of the diet is more marked at lower serum ferritin concentrations. The model can be applied to any adult population in whom representative, good-quality data on iron intake and iron status have been collected. Values for dietary iron bioavailability can be derived for any target concentration of serum ferritin, thereby giving risk managers and public health professionals a flexible and transparent basis on which to base their dietary recommendations. This trial was registered at clinicaltrials.gov as NCT01754012

Is there a role for vitamin C in preventing osteoporosis and fractures?:A review of the potential underlying mechanisms and current epidemiological evidence

Osteoporosis and related fractures are a major global health issue, but there are few preventative strategies. Previously reported associations between higher intakes of fruits and vegetables and skeletal health have been suggested to be partly attributable to vitamin C. To date, there is some evidence for a potential role of vitamin C in osteoporosis and fracture prevention but an overall consensus of published studies has not yet been drawn. The present review aims to provide a summary of the proposed underlying mechanisms of vitamin C on bone and reviews the current evidence in the literature, examining a potential link between vitamin C intake and status with osteoporosis and fractures. The Bradford Hill criteria were used to assess reported associations. Recent animal studies have provided insights into the involvement of vitamin C in osteoclastogenesis and osteoblastogenesis, and its role as a mediator of bone matrix deposition, affecting both the quantity and quality of bone collagen. Observational studies have provided some evidence for this in the general population, showing positive associations between dietary vitamin C intake and supplements and higher bone mineral density or reduced fracture risk. However, previous intervention studies were not sufficiently well designed to evaluate these associations. Epidemiological data are particularly limited for vitamin C status and for fracture risk and good-quality randomised controlled trials are needed to confirm previous epidemiological findings. The present review also highlights that associations between vitamin C and bone health may be non-linear and further research is needed to ascertain optimal intakes for osteoporosis and fracture prevention

Mediterranean diet reduces risk of incident stroke in a population with varying cardiovascular disease risk profiles

Background and Purpose: Although some evidence has found that the Mediterranean Diet (MD)is protective for stroke risk, few studies have investigated whether this relationship differs by sex or cardiovascular disease (CVD) risk. Methods: We investigated the relationship between adherence to the MD score (MDS),estimated using 7-day dietary diaries (7DD) and risk of incident stroke in an observational prospective population-based cohort study of 23,232 men and women(54.5% women) aged 40-77 years who participated in the European Prospective Investigation into Cancer study in Norfolk, UK. Risk of incident stroke was calculated using multivariable Cox-regression, in the whole population, and also stratified by gender and CVD risk profile, using the Framingham Risk Score(FRS). Results: During 17.0 years of follow up (395,048 total person years) 2009 incident strokes occurred. Risk of stroke was significantly reduced with greater adherence to the MDS (Q4 vs Q1 HR 0.83:95% CI 0.74-0.94; P-trend <0.01) in the whole population and in women (Q4 vs Q1 HR 0.78; 95% CI 0.65, 0.93; P-trend<0.01) but not in men (Q4 vs Q1 HR 0.94; 95% CI 0.79, 1.12; P-trend =0.55).There was reduced risk of stroke in those at high risk of CVD and across categories of the MDS (Q4 vs Q1 HR 0.87:95% CI 0.76-0.99; P-trend =0.04).However, this was driven by the associations in women (Q4 vs Q1 HR 0.80:95% CI0.65-0.97; P-trend =0.02). Conclusion: Greater adherence to the MD wasassociated with lower risk of stroke in a UK Caucasian population. For thefirst time in the literature, we also investigated the associations between theMDS in those at both low and high risk of CVD. Although the findings in ourstudy were driven by the associations in women, they have implications for thegeneral public and clinicians for prevention of stroke