Regional cost effectiveness analyses for increasing radon protection strategies in housing in Canada.

The incremental cost effectiveness ratios for implementing a recent recommendation to install a more radon resistant foundation barrier were modelled for new and existing housing in 2016, for each province and territory in Canada. Cost-utility analyses were conducted, in which the health benefit of an intervention was quantified in quality-adjusted life years, to help guide policymakers considering increasing investment in radon reduction in housing to reduce the associated lung cancer burden shouldered by the health care system. Lung cancer morbidity was modelled using a lifetable analysis that incorporated lung cancer incidence and survival time for localized, regional, and distant stages of diagnoses for both non-small cell and small cell lung cancer. The model accounted for surgical or advanced lung cancer treatment costs avoided, and average health care costs incurred for radon-attributable lung cancer cases prevented by the intervention. The incremental implementation of radon interventions in the housing stock was modelled over a lifetime horizon, and a discount rate of 1.5% was adopted. This radon intervention in new housing was cost effective in all but one region, ranging from $18,075/QALY (15,704; 20,178) for the Yukon to $58,454/QALY (52,045; 65,795) for British Columbia. A sequential analysis was conducted to compare intervention in existing housing for mitigation thresholds of 200 and 100 Bq/m3. This intervention in existing housing was cost effective at a mitigation threshold of 200 Bq/m3 in regions with higher radon levels, ranging from $33,247/QALY (27,699; 39,377) for the Yukon to $61,960/QALY (46,932; 113,737) for Newfoundland, and more cost effective at a threshold of 200 than 100 Bq/m3. More lung cancer deaths can be prevented by intervention in new housing than in existing housing; it was estimated that the proposed intervention in new housing would prevent a mean of 446 (416; 477) lung cancer cases annually. The cost effectiveness of increased radon resistance in foundation barriers in housing varied widely, and would support adopting this intervention in new housing across Canada and in existing housing in higher radon regions. This study provides further evidence that the most cost effective way of responding to the geographically variable radon burden is by implementing specific regional radon reduction policies.

RADON INFILTRATION BUILDING ENVELOPE TEST SYSTEM: EVALUATION OF BARRIER MATERIALS.

The performance of radon barrier materials currently available for housing foundations was evaluated using a unique radon infiltration building envelope test system that was designed to test radon prevention and mitigation systems using real world construction techniques. The reduction in radon concentration measured across the air barrier in the foundations has been used to evaluate five representative barrier materials installed in the radon infiltration building envelope test facility. The reduction in radon concentration in the mock house varied from 68% for 6 mil polyethylene to 98% for the spray polyurethane foam. The five representative barrier materials were selected after determining the radon diffusion coefficient and the corresponding radon resistance from samples of 14 barrier materials in a radon diffusion testing chamber. The Canadian experience evaluating whether radon barrier materials would satisfy building code requirements was described.

An assessment of uncertainty using two different modelling techniques to estimate the cost effectiveness of mitigating radon in existing housing in Canada.

The burden of lung cancer associated with residential radon in existing housing can be reduced by interventions to screen and mitigate existing housing having radon levels above a mitigation threshold. The objective of this study is to estimate the cost effectiveness of radon interventions for screening and mitigation of existing housing for the 2016 population in Canada and to assess the structural uncertainty associated with the choice of model used in the cost-utility analysis. The incremental cost utility ratios are estimated using both a Markov cohort model and a discrete event simulation model. A societal perspective, a lifetime horizon and a discount rate of 1.5% are adopted. At a radon mitigation threshold of 200 (100) Bq/m3, the discounted ICERs for current rates of screening and mitigation of existing housing are 72,569 (68,758) $/QALY using a Markov cohort model and 84,828 (76,917) $/QALY using discrete event simulation. It appears that minimal structural uncertainty is associated with the choice of model used for this cost-utility analysis, and the cost effectiveness would improve at increased rates of radon testing and mitigation. The mitigation of radon in existing housing is estimated to be a practical policy option for reducing the associated lung cancer burden in Canada.

A cost effectiveness analysis of interventions to reduce residential radon exposure in Canada.

The objective of this analysis is to estimate the incremental cost effectiveness ratios for the 2012 populations in Canada, each province/territory, and 17 census metropolitan areas, for practical radon mitigation scenarios to reduce residential radon exposures. Sixteen intervention scenarios compare radon mitigation implemented at differing rates in new and existing housing relative to preventive measures installed at construction, using three different radon mitigation thresholds. A period life-table analysis was conducted using data derived from two recent Canadian radon surveys, along with Canadian mortality and quality of life data. Analyses adopted a lifetime horizon and a discount rate of 1.5%. It is practical to reduce residential radon and associated lung cancer mortality in Canada, and the most cost effective scenario at each radon mitigation threshold is the combination of the activation of the preventive measures in new housing and mitigation of existing housing.

Utility gains from reductions in the modifiable burden of lung cancer attributable to residential radon in Canada.

RESEARCH QUESTION: The objective of this analysis is to estimate the modifiable burden of disease according to the annual number of lung cancer deaths prevented and the associated period gain in quality-adjusted life years (QALYs) for the 2012 populations in Canada from reductions in residential radon exposures. INTERVENTIONS: Two postulated interventions for residential radon mitigation in new construction are assessed, corresponding to a 50% reduction and an 85% reduction in radon nationally, in the provinces/territories, and in 17 census metropolitan areas in Canada. METHODS: Data were derived from two recent Canadian radon surveys conducted by the Radiation Protection Bureau, Health Canada, along with Canadian mortality and quality of life data. Analyses adopted a lifetime horizon and a discount rate of 1.5%. A period life-table analysis was conducted using age- and sex-specific all-cause and lung cancer mortality rates, adjusted for smoking, and the BEIR VI exposure-age-concentration model for radon-attributable risk of lung cancer mortality. RESULTS: A reduction in residential radon by 50% could prevent 681 lung cancer deaths, associated with a gain of 15,445 QALYs in the Canadian population at a discount rate of 1.5%; a reduction in radon by 85% could prevent 1263 lung cancer deaths, associated with a gain of 26,336 QALYs. On a per population basis, the Yukon was estimated to benefit most from radon mitigation. CONCLUSION: The magnitude of QALY gains in Canada estimated under the two radon mitigation scenarios is appreciable but varies considerably across provinces due to variability in indoor radon concentrations and smoking rates.

Global Estimate of Lung Cancer Mortality Attributable to Residential Radon.

BACKGROUND: Radon is the second most important cause of lung cancer, ranked by the World Health Organization as the fifth leading cause of mortality in 2010. An updated database of national radon exposures for 66 countries allows the global burden of lung cancer mortality attributable to radon to be estimated. OBJECTIVE: Our goal was to estimate the global population attributable burden of lung cancer mortality in 2012 from residential radon. METHODS: Estimates of the population attributable risk (PAR) of lung cancer mortality from radon were determined using the attributable fraction approach, using three models for excess relative risk of lung cancer from radon. RESULTS: The estimates of the median PAR of lung cancer mortality from residential radon in 2012 for the 66 countries having representative national radon surveys were consistent, as 16.5%, 14.4%, and 13.6% for the exposure-age-concentration (EAC) model (BEIR VI), the Hunter model, and the Kreuzer model, respectively. The mean PAR using the EAC model ranged from 4.2% (95% CI: 0.9, 11.7) for Japan, to 29.3% (95% CI: 22.9, 35.7) for Armenia, with a median for the 66 countries of 16.5%. Radon-attributable lung cancer deaths for all 66 countries totaled 226,057 in 2012 and represent a median of 3.0% of total cancer deaths. CONCLUSIONS: Consistent findings between the three models used to estimate excess relative risks of lung cancer from radon, and between the attributable fraction methodology and the life table analysis, confirm that residential radon is responsible for a substantial proportion of lung cancer mortality worldwide. https://doi.org/10.1289/EHP2503.

Determinants of neurological disease: Synthesis of systematic reviews.

Systematic reviews were conducted to identify risk factors associated with the onset and progression of 14 neurological conditions, prioritized as a component of the National Population Health Study of Neurological Conditions. These systematic reviews provided a basis for evaluating the weight of evidence of evidence for risk factors for the onset and progression of the 14 individual neurological conditions considered. A number of risk factors associated with an increased risk of onset for more than one condition, including exposure to pesticides (associated with an increased risk of AD, amyotrophic lateral sclerosis, brain tumours, and PD; smoking (AD, MS); and infection (MS, Tourette syndrome). Coffee and tea intake was associated with a decreased risk of onset of both dystonia and PD. Further understanding of the etiology of priority neurological conditions will be helpful in focusing future research initiatives and in the development of interventions to reduce the burden associated with neurological conditions in Canada and internationally.

Systematic reviews of factors associated with the onset and progression of neurological conditions in humans: A methodological overview.

As a component of the National Population Health Study of Neurological conditions, systematic reviews were conducted to identify risk factors associated with the onset and progression of 14 priority neurological conditions. Between 2011 and 2013, electronic databases and grey literature sources were searched to identify systematic reviews and primary studies reporting on the onset and progression of each condition. Inclusion was restricted to studies of humans reported in English or French. Additional condition-specific eligibility criteria were also applied. Titles and abstracts were screened by one reviewer with excluded records verified by a second reviewer. Full-text reports were screened independently by two reviewers. Disagreements were resolved by consensus or third party adjudication. Systematic reviews were quality appraised using the AMSTAR criteria, with only moderate and high quality reviews considered for inclusion. Primary studies were also sought to ensure that evidence from existing systematic reviews was supplemented with recent primary study findings (i.e., those published after the most recent systematic review). Evidence from primary studies was also considered if a systematic review was unavailable or of poor quality. Data were extracted using standardized forms. Where feasible, data were extracted independently by two reviewers. Otherwise, data were extracted by a single reviewer and independent data extraction by a second reviewer was conducted for a randomly selected sample of studies. An updated search was conducted in 2016 to identify systematic reviews published since the initial search in 2011-2013. A summary of the methodology used to conduct the systematic reviews is described. Illustrative results are provided for the risk of amyotrophic lateral sclerosis in relation to occupational exposure to lead and other heavy metals.

Factors associated with the onset and progression of neurotrauma: A systematic review of systematic reviews and meta-analyses.

Neurotrauma, including traumatic brain injury (TBI) and spinal cord injury (SCI), is a preventable condition that imposes an important burden on the Canadian society. In this study, the current evidence on risk factors for the onset and progression of neurotrauma is systematically reviewed and synthesized. Searches of the Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Medline and Medline in Process (via OVID), EMBASE and PsycINFO from inception to February 2013 were conducted to identify relevant systematic reviews and meta-analyses published in English or French. Two referees screened and assessed the quality of the studies using the AMSTAR tool. Thirty-two studies examined at least one risk factor for the onset of neurotrauma. Thirteen studies passed the quality assessment and the majority evaluated the impact of protective equipment in sports. Helmets effectively reduce TBI from bicycling, skiing, snowboarding, ice hockey and motorcycling. There was no evidence of a protective effect of helmets for SCI. No studies contributed evidence on risk factors for the onset of SCI. Of two studies examining risk factors for the progression of neurotrauma, only injury severity was found to be associated with poorer post-injury outcomes. Substantial evidence supports the use of helmets for the prevention of TBI in sports and motorcycling and face shields in ice hockey. Addressing bicycle helmet legislation across Canada may be an effective option for reducing TBI caused by bicycle accidents. Limited evidence on relevant risk factors for spinal cord injuries and neurotrauma progression was available.

Reducing Periconceptional Methylmercury Exposure: Cost-Utility Analysis for a Proposed Screening Program for Women Planning a Pregnancy in Ontario, Canada.

BACKGROUND: The assessment of neurodevelopmental effects in children associated with prenatal methylmercury exposure, from contaminated fish and seafood in the maternal diet, has recently been strengthened by adjustment for the negative confounding resulting from co-exposure to beneficial polyunsaturated fatty acids (PUFAs). OBJECTIVES: We aimed to determine the cost-effectiveness of a periconceptional screening program of blood mercury concentration for women planning to become pregnant in Ontario, Canada. Fish intake recommendations would be provided for those found to have blood mercury levels above the intervention threshold. METHODS: Analysis was conducted using a combined decision tree/Markov model to compare the proposed screening intervention with standard care from a societal perspective over a lifetime horizon. We used the national blood mercury distributions of women 20-49 years of age reported in the Canadian Health Measures Survey from 2009 through 2011 to determine the cognitive deficits associated with prenatal methylmercury exposure for successful planned pregnancies. Outcomes modeled included the loss in quality of life and the remedial education costs. Value of information analysis was conducted to assess the underlying uncertainty around the model results and to identify which parameters contribute most to this uncertainty. RESULTS: The incremental cost per quality-adjusted life year (QALY) gained for the proposed screening intervention was estimated to be Can$18,051, and the expected value for a willingness to pay of Can$50,000/QALY to be Can$0.61. CONCLUSIONS: Our findings suggest that the proposed periconceptional blood mercury screening program for women planning a pregnancy would be highly cost-effective from a societal perspective. The results of a value of information analysis confirm the robustness of the study's conclusions.