43 results found
Hodgson S, Namdeo A, Araujo-Soares V, et al., 2012, Towards an interdisciplinary science of transport and health: a case study on school travel, Journal of Transport Geography, Vol: 21, Pages: 70-79, ISSN: 1873-1236
Background and aimThis paper was conceptualised and informed by discussions at the 2nd Workshop in a UKTRC funded series on ‘Social Impacts and Equity in Transport’. Presentations made by a range of stakeholders as well as a specially commissioned play stimulated our thoughts on how to encourage better interaction between health and transport researchers. We chose school travel as a case study as it exemplifies two key aspects of the wider transport and health debates; (i) the increasing trend towards reliance on car travel, described here in the context of sedentary lifestyles, traffic congestion, pollution, and parental attitudes, and (ii) school travel occurs at a critical life-stage during which behaviour patterns are formed that are likely to be influential in later life, thus making it an important target point for interventions.MethodsWe present evidence from four distinct, but complementary, theoretical perspectives: transport, exposure, behaviour and sustainability. We draw common lessons and identify challenges using a range of conceptual frameworks: integrated psychological model of transport choices, Dahlgren and Whitehead’s ‘layers of influence’ model, Hosking et al.’s ‘pathways from transport to health’, and Hanlon et al.’s integral theory. We demonstrate the benefits and challenges of holistic interaction and collaboration between disciplines to better understand the key issues and develop policy interventions that are meaningful and effective.Results and conclusionsNone of the pre-existing conceptual models were fully able to encompass the societal and individual level influences on school travel. However, we present an interim model for further discussion and debate.
Forrest LF, Hodgson S, Parker L, et al., 2011, The influence of childhood IQ and education on social mobility in the Newcastle Thousand Families birth cohort, BMC Public Health, Vol: 11, ISSN: 1471-2458
Background: It has been suggested that social, educational, cultural and physical factors in childhood and earlyadulthood may influence the chances and direction of social mobility, the movement of an individual betweensocial classes over his/her life-course. This study examined the association of such factors with intra-generationaland inter-generational social mobility within the Newcastle Thousand Families 1947 birth cohort.Methods: Multivariable logistic regression was used to examine the potential association of sex, housingconditions at age 5 years, childhood IQ, achieved education level, adult height and adverse events in earlychildhood with upward and downward social mobility.Results: Childhood IQ and achieved education level were significantly and independently associated with upwardmobility between the ages of 5 and 49-51 years. Only education was significantly associated (positively) withupward social mobility between 5 and 25 years, and only childhood IQ (again positively) with upward socialmobility between 25 and 49-51 years. Childhood IQ was significantly negatively associated with downward socialmobility. Adult height, childhood housing conditions, adverse events in childhood and sex were not significantdeterminants of upward or downward social mobility in this cohort.Conclusions: As upward social mobility has been associated with better health as well as more general benefits tosociety, supportive measures to improve childhood circumstances that could result in increased IQ and educationalattainment may have long-term population health and wellbeing benefits.
Hodgson S, Khaw F-M, 2010, Epidemiological Methods for Attributing Illness, Environmental Medicine, Editors: Ayres, Harrison, Nichols, Maynard, Publisher: Hodder Arnold, ISBN: 9780340946565
Beale L, Hodgson S, Jose Abellan J, et al., 2010, Evaluation of Spatial Relationships between Health and the Environment: The Rapid Inquiry Facility, Environmental Health Perspectives, Vol: 118, Pages: 1306-1312, ISSN: 1552-9924
Background: The initiation of environmental public health tracking systems in the United Statesand the United Kingdom provided an opportunity to advance techniques and tools available forspatial epidemiological analysis integrating both health and environmental data.Objective: The Rapid Inquiry Facility (RIF) allows users to calculate adjusted and unadjusted standardizedrates and risks. The RIF is embedded in ArcGIS so that further geographical informationsystem (GIS) spatial functionality can be exploited or results can be exported to statistical packagesfor further tailored analyses where required. The RIF also links directly to several statistical packagesand displays the results in the GIS.Methods: The value of the RIF is illustrated here with two case studies: risk of leukemia in areassurrounding oil refineries in the State of Utah (USA) and an analysis of the geographical variationof risk of esophageal cancer in relation to zinc cadmium sulfide exposure in Norwich (UnitedKingdom).Results: The risk analysis study in Utah did not suggest any evidence of increased relative riskof leukemia, multiple myeloma, or Hodgkin’s lymphoma in the populations around the five oilrefiningfacilities but did reveal an excess risk of non-Hodgkin’s lymphoma that might warrantfurther investigation. The disease-mapping study in Norwich did not reveal any areas with higherrelative risks of esophageal cancer common to both males and females, suggesting that a commongeographically determined exposure was unlikely to be influencing cancer risk in the area.Conclusion: The RIF offers a tool that allows epidemiologists to quickly carry out ecological environmentalepidemiological analysis such as risk assessment or disease mapping.
Hodgson S, Shirley M, Bythell M, et al., 2009, Residential mobility during pregnancy in the north of England, BMC Pregnancy and Childbirth, Vol: 9, ISSN: 1471-2393
Background: Many epidemiological studies assign exposure to an individual's residence at a singletime point, such as birth or death. This approach makes no allowance for migration and may resultin exposure error, leading to reduced study power and biased risk estimates. Pregnancy outcomesare less susceptible to this bias, however data from North American populations indicate thatpregnant women are a highly mobile group. We assessed mobility in pregnant women in the northof England using data from the Northern Congenital Abnormality Survey (NorCAS).Methods: Data were extracted from NorCAS for 1985 to 2003. Eligible cases had a gestationalage at delivery of ≥ 24 weeks (a viable delivery) (n = 11 559). We assessed mobility betweenbooking appointment (average gestational age 13 weeks) and delivery for pregnancies where theaddress at booking appointment and delivery were known. The impacts on mobility of maternal ageand area-level socio-economic indicators were explored using standard descriptive statistics. Asensitivity analysis and a small validation exercise were undertaken to assess the impact of missingdata on the estimate of mobility.Results: Out of 7 919 eligible cases for whom addresses at booking and delivery were known, 705(8.9% (95% CI 8.3 - 9.5)) moved between booking and delivery; the mean and median movingdistance was 9.7 and 1.4 km respectively. Movers were significantly younger (25.4 versus 27.3 years,p < 0.01) and lived in more deprived areas (index of multiple deprivation score 38.3 versus 33.7, p< 0.01) than non movers.Conclusion: Mobility in the north of England (9%) is considerably lower than that reported inNorth America and the only other study from the UK (23%). Consistent with other studies,mobility was related to maternal age and socio-economic status, and the majority of moves wereover a relatively short distance. Although this population appears relatively stable, the mobility wehave observed may still introduce misclassification or e
Hodgson S, Khaw F-M, Pearce MS, et al., 2009, Predicting black smoke levels from deposit gauge and SO2 data to estimate long-term exposure in the United Kingdom, 1956-1961, Atmospheric Environment, Vol: 43, Pages: 3356-3363, ISSN: 1352-2310
BackgroundIn the UK air quality has been monitored systematically since 1914, providing valuable data for studies of the long-term trends in air pollution and potentially for studies of health effects of air pollutants. There are, however, challenges in interpreting these data due to changes over time in the number and location of monitored sites, and in monitoring techniques. Particulate matter was measured as deposited matter (DM) using deposit gauge monitors until the 1950s when black smoke (BS) filters were introduced. Estimating long-term exposure to particulates using data from both deposit gauge and BS monitors requires an understanding of the relationships between DM, SO2 and BS.AimsTo explore whether DM and/or SO2, along with seasonal and location specific variables can be used to predict BS levels.MethodsAir quality data were abstracted from hard copies of the monthly Atmospheric Pollution Bulletins for the period April 1956–March 1961 for any sites with co-located DM, SO2 and BS data for three or more consecutive years. The relationships between DM, SO2, and BS were assessed using mixed models.ResultsThere were 34 eligible sites giving 1521 triplets of data. There was a consistent correlation between SO2 and BS at all sites, but the association between DM and BS was less clear and varied by location. Mixed modelling allowing for repeat measurements at each site revealed that SO2, year, rainfall and season of measurement explained 72% of the variability in BS levels.ConclusionsSO2 can be used as a surrogate measure for BS in all monitoring locations. This surrogate can be improved upon by consideration of site specific characteristics, seasonal effects, rainfall and year of measurement. These findings will help in estimating historic, long-term exposure to particulates where BS or other measures are not available.
Thomas LDK, Hodgson S, Nieuwenhuijsen M, et al., 2009, Early Kidney Damage in a Population Exposed to Cadmium and Other Heavy Metals, Environmental Health Perspectives, Vol: 117, Pages: 181-184, ISSN: 1552-9924
Background: Exposure to heavy metals may cause kidney damage. The population living near theAvonmouth zinc smelter has been exposed to cadmium and other heavy metals for many decades.Objectives: We aimed to assess Cd body burden and early signs of kidney damage in theAvonmouth population.Methods: We used dispersion modeling to assess exposure to Cd. We analyzed urine samples fromthe local population (n = 180) for Cd (U-Cd) to assess dose (body burden) and for three biomarkersof early kidney damage [N-acetyl-β-d-glucosaminidase (U-NAG), retinol-binding protein, and α-1-microglobulin]. We collected information on occupation, intake of homegrown vegetables, smoking,and medical history by questionnaire.Results: Median U-Cd concentrations were 0.22 nmol/mmol creatinine (nonsmoking 0.18/smoking0.40) and 0.34 nmol/mmol creatinine (nonsmoking 0.31/smoking 0.46) in non-occupationallyexposed men and women, respectively. There was a significant dose–response relationship betweenU-Cd and the prevalence of early renal damage—defined as U-NAG > 0.22 IU/mmol—with oddsratios of 2.64 [95% confidence interval (95% CI), 0.70–9.97] and 3.64 (95% CI, 0.98–13.5) forU-Cd levels of 0.3 to < 0.5 and levels ≥ 0.5 nmol/mmol creatinine, respectively (p for trend = 0.045).Conclusion: U-Cd concentrations were close to levels where kidney and bone effects have been foundin other populations. The dose–response relationship between U-Cd levels and prevalence of U-NAGabove the reference value support the need for measures to reduce environmental Cd exposure.
Hodgson S, Thomas L, Fattore E, et al., 2008, Bone mineral density changes in relation to environmental PCB exposure, Environmental Health Perspectives, Vol: 116, Pages: 1162-1166, ISSN: 1552-9924
BACKGROUND: Bone toxicity has been linked to organochlorine exposure following a few notablepoisoning incidents, but epidemiologic studies in populations with environmental organochlorineexposure have yielded inconsistent results.OBJECTIVES: The aim of this study was to investigate whether organochlorine exposure was associatedwith bone mineral density (BMD) in a population 60–81 years of age (154 males, 167 females)living near the Baltic coast, close to a river contaminated by polychlorinated biphenyls (PCBs).METHODS: We measured forearm BMD in participants using dual energy X-ray absorptiometry;and we assessed low BMD using age- and sex-standardized Z-scores. We analyzed blood samplesfor five dioxin-like PCBs, the three most abundant non-dioxin-like PCBs, and p,p´-dichlorophenyldichloroethylene(p,p´-DDE).RESULTS: In males, dioxin-like chlorobiphenyl (CB)-118 was negatively associated with BMD; theodds ratio for low BMD (Z-score less than –1) was 1.06 (95% confidence interval, 1.01–1.12) per10 pg/mL CB-118. The sum of the three most abundant non-dioxin-like PCBs was positively associatedwith BMD, but not with a decreased risk of low BMD. In females, CB-118 was positivelyassociated with BMD, but this congener did not influence the risk of low BMD in women.CONCLUSIONS: Environmental organochlorine exposures experienced by this population samplesince the 1930s in Sweden may have been sufficient to result in sex-specific changes in BMD.
Beale L, Abellan JJ, Hodgson S, et al., 2008, Methodologic issues and approaches to spatial epidemiology, Environmental Health Perspectives, Vol: 116, Pages: 1105-1110, ISSN: 1552-9924
Spatial epidemiology is increasingly being used to assess health risks associated with environmentalhazards. Risk patterns tend to have both a temporal and a spatial component; thus, spatial epidemiologymust combine methods from epidemiology, statistics, and geographic informationscience. Recent statistical advances in spatial epidemiology include the use of smoothing in riskmaps to create an interpretable risk surface, the extension of spatial models to incorporate the timedimension, and the combination of individual- and area-level information. Advances in geographicinformation systems and the growing availability of modeling packages have led to an improvementin exposure assessment. Techniques drawn from geographic information science are beingdeveloped to enable the visualization of uncertainty and ensure more meaningful inferences aremade from data. When public health concerns related to the environment arise, it is essential toaddress such anxieties appropriately and in a timely manner. Tools designed to facilitate the investigationprocess are being developed, although the availability of complete and clean health data,and appropriate exposure data often remain limiting factors. Key words: disease mapping, environmentalepidemiology, geographic information systems (GIS), risk analysis, spatial epidemiology,uncertainty
Hodgson S, Nieuwenhuijsen MJ, Colvile R, et al., 2007, Assessment of exposure to mercury from industrial emissions: comparing "distance as a proxy" and dispersion modelling approaches, Occupational and Environmental Medicine, Vol: 64, Pages: 380-388, ISSN: 1470-7926
Background: The Runcorn area, north-west England, contains many pollution sources, the health effects of which have been under discussion for over 100 years. Preliminary investigations revealed an excess risk of mortality from kidney disease in people living nearest to several point sources of pollution, using distance as a proxy for exposure. Ongoing epidemiological investigations into the effect of ambient mercury exposure on dose and renal effect required a more refined assessment of exposure.Methods: Atmospheric dispersion modelling was used to assess mercury dispersion from three mercury-emitting sources (including a large chlor alkali plant), based on knowledge of emissions, local meteorology and topography.Results: The model was sensitive to various input parameters, with different dispersion patterns and ground-level concentrations, and therefore different exposed populations identified when different input parameters were defined. The different approaches to exposure assessment also had an impact on the epidemiological findings. The model output correlated well with weekly monitoring data collected in the local area, although the model underestimated concentrations in close proximity to the chlor alkali plant. The model identified that one point source did not contribute significantly to ground-level mercury concentrations, so that inclusion of this source when using the “distance as a proxy” approach led to significant exposure misclassification.Conclusions: The model output indicates that assessment of ambient exposure should give consideration to the magnitude of emissions, point source characteristics, local meteorology and topography to ensure that the most appropriate exposure classification is reached. Even if dispersion modelling cannot be undertaken, these data can be used to inform and improve the distance as a proxy approach, and improve the interpretability of the epidemiological findings.
Hodgson S, Nieuwenhuijsen MJ, Elliott P, et al., 2007, Kidney disease mortality and environmental exposure to mercury, American Journal of Epidemiology, Vol: 165, Pages: 72-77, ISSN: 1476-6256
Runcorn, North West England, has been a site of industrial activity for over 100 years. Preliminary investigations have revealed excess risk of renal mortality in the population living closest to several sources of pollution. Exposure to airborne mercury has been highlighted as a possible cause, although there is also concomitant exposure to solvents and other heavy metals in this population. The authors used validated air dispersion modeling to identify mercury-exposed populations. Standardized mortality ratios for kidney disease were computed using the North West government region as the reference. There was a significant exposure-response relation between modeled estimates of mercury exposure and risk of kidney disease mortality (test for trend: p = 0.02 for men and p = 0.03 for women), and this relation was more pronounced for estimated historical exposure (test for trend: p = 0.01 for men and p < 0.001 for women). These findings suggest that exposure to mercury is a possible cause of the excess kidney disease mortality in this population, indicating that there might still be a health legacy of the historically high levels of industrial activity in the Runcorn area.
Key J, Hodgson S, Omar RZ, et al., 2006, Meta-analysis of studies of alcohol and breast cancer with consideration of the methodological issues, Cancer Causes & Control, Vol: 17, Pages: 759-770, ISSN: 1573-7225
Objective To give an up-to-date assessment of the associationof alcohol with female breast cancer, addressingmethodological issues and shortfalls in previous overviews.Methods Meta-analysis of studies (any language) providingoriginal data on incidence of first primary breastcancer and alcohol. Two reviewers independently extracteddata. Study quality assessed by objective criteria includingdegree of control for confounding; funnel plots examinedfor publication bias; meta-regression techniques to exploreheterogeneity. Risks associated with drinking versus notdrinking and dose–response not constrained through theorigin estimated using random effects methods.Results Ninety-eight unique studies were included,involving 75,728 and 60,653 cases in drinker versus nondrinkerand dose–response analyses, respectively. Findingswere robust to study design and analytic approaches in themeta-analyses. For studies judged high quality, controlledfor appropriate confounders, excess risk associated withalcohol drinking was 22% (95% CI: 9–37%); each additional10 g ethanol/day was associated with risk higher by10% (95% CI: 5–15%). There was no evidence of publicationbias. Risk did not differ significantly by beveragetype or menopausal status. Estimated population attributablerisks were 1.6 and 6.0% in USA and UK, respectively.Conclusions Taking account of shortcomings in the studybase and methodological concerns, we confirm the alcohol–breastcancer association. We compared our results tothose of an individual patient data analysis, with similarfindings. We conclude that the association between alcoholand breast cancer may be causal.
Hodgson S, Nieuwenhuijsen MJ, Hansell A, et al., 2004, Excess risk of kidney disease in a population living near industrial plants, Occupational and Environmental Medicine, Vol: 61, Pages: 717-719, ISSN: 1470-7926
Runcorn has been a site of chemical industry activity for over a century, where tons of toxic chemicals are released annually to air and water. Excess kidney disease mortality (nephritis, nephrotic syndrome, and nephrosis) was found in the population living within 2 km of the industrial plants (standardised mortality ratio (SMR) in males 131 (95% CI 90 to 185) and females 161 (95% CI 118 to 214)) compared to a reference population (northwest England)). Risk of hospital admissions for kidney disease in Halton (comprising the towns of Runcorn and Widnes) was higher than in the less industrial, nearby town of Warrington. The standardised admission ratio (SAR) in Halton was 115 (95% CI 107 to 124) for males and 126 (95% CI 117 to 137) for females; and in Warrington 91 (95% CI 85 to 97) for males and 84 (95% CI 78 to 91) for females compared to the Warrington and Halton area as a whole. The excess risk of kidney disease in the Runcorn area requires further investigation.
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