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.

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.

Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk.

Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to <20% of the world's population. We used transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock.

An overview of radon research in Canada.

Based on new scientific information and broad public consultation, the Government of Canada updated the guideline for exposure to indoor radon and launched a multi-year radon programme in 2007. Major achievements in radon research accomplished in the past 7 y are highlighted here.

Radon mitigation in cold climates at Kitigan Zibi Anishinabeg.

Available radon mitigation results were gathered for 85 houses mainly by installing sub-slab depressurization systems (SSDS) with two types of discharge and fan locations: Above ground level discharge with the fan located in the basement (AGL) or above roof line discharge with the fan located in the attic (ARL). A comparative analysis was made of mitigation efficiency and of exhaust icing. Results show that both SSDS scenarios reduced radon levels similarly. The results of SSDS with AGL show that a sealed radon fan having proper fittings and sealed piping was able to reduce the radon to acceptable levels, and that these installations were less subject to obstructive icing of the exhaust in cold climates.

Results of simultaneous radon and thoron measurements in 33 metropolitan areas of Canada.

Radon has been identified as the second leading cause of lung cancer after tobacco smoking. (222)Rn (radon gas) and (220)Rn (thoron gas) are the most common isotopes of radon. In order to assess thoron contribution to indoor radon and thoron exposure, a survey of residential radon and thoron concentrations was initiated in 2012 with ∼4000 homes in the 33 census metropolitan areas of Canada. The survey confirmed that indoor radon and thoron concentrations are not correlated and that thoron concentrations cannot be predicted from widely available radon information. The results showed that thoron contribution to the radiation dose varied from 0.5 to 6% geographically. The study indicated that, on average, thoron contributes ∼3% of the radiation dose due to indoor radon and thoron exposure in Canada. Even though the estimated average thoron concentration of 9 Bq m(-3) (population weighted) in Canada is low, the average radon concentration of 96 Bq m(-3) (population weighted) is more than double the worldwide average indoor radon concentration. It is clear that continued efforts are needed to further reduce the exposure and effectively reduce the number of lung cancers caused by radon.

Residential radon mitigations at Kitigan Zibi Anishinabeg: comparison of above ground level (RIM JOIST) and above roof line discharge of radon mitigation SUB-SLAB depressurization systems.

Radon mitigations in nine houses were conducted by installing sub-slab depressurization systems (SSDS) with two types of discharge and fan locations: Ground level discharge with the fan located in the basement or roof-discharge with the fan located in the attic. This paper presents a detailed comparative analysis of the radon reduction efficiency, condensation problems, and the cost-effectiveness of both SSDS installation scenarios in nine houses. The mitigations from both SSDS scenarios were successful in reducing radon. The results of rim-joist installations discharging above ground level with the fans located in the basement show that a sealed radon fan with proper fittings and sealed piping were able to reduce the radon to acceptable levels in a cost-effective manner.

Achievements and current activities of the Canadian radon program.

Based on new scientific information and broad public consultation, the Government of Canada updated the guideline for exposure to indoor radon and launched a multi-year radon program in 2007. Major achievements accomplished in the past 3 y and current activities underway are highlighted here.

Polonium-210: lessons learned from the contamination of individual Canadians.

This paper describes the radioactive poisoning episode in London in 2006 and the Health Canada response to locate and test any Canadians who might have been contaminated by this event. The search strategies and testing methods are explained and the results given. The lessons learned are summarised and implications for vulnerable populations are discussed. The greatest public health impact was probably the generation of fear and concern, especially among those prone to health-related anxiety disorders. The groups of individuals at risk were effectively managed by a single point of contact system combined with rapid triage and counselling that was provided to everyone to address their individual concerns.

Biochemical effects of lead, zinc, and cadmium from mining on fish in the Tri-States District of northeastern Oklahoma, USA.

We assessed the exposure of fish from the Spring and Neosho Rivers in northeast Oklahoma, USA, to lead, zinc, and cadmium from historical mining in the Tri-States Mining District (TSMD). Fish (n = 74) representing six species were collected in October 2001 from six sites on the Spring and Neosho Rivers influenced to differing degrees by mining. Additional samples were obtained from the Big River, a heavily contaminated stream in eastern Missouri, USA, and from reference sites. Blood from each fish was analyzed for Pb, Zn, Cd, Fe, and hemoglobin (Hb). Blood also was analyzed for delta-aminolevulinic acid dehydratase (ALA-D) activity. The activity of ALA-D, an enzyme involved in heme synthesis, is inhibited by Pb. Concentrations of Fe and Hb were highly correlated (r = 0.89, p < 0.01) across all species and locations and typically were greater in common carp (Cyprinus carpio) than in other taxa. Concentrations of Pb, Zn, and Cd typically were greatest in fish from sites most heavily affected by mining and lowest in reference samples. The activity of ALA-D, but not concentrations of Hb or Fe, also differed significantly (p < 0.01) among sites and species. Enzyme activity was lowest in fish from mining-contaminated sites and greatest in reference fish, and was correlated negatively with Pb in most species. Statistically significant (p < 0.01) linear regression models that included negative terms for blood Pb explained as much as 68% of the total variation in ALA-D activity, but differences among taxa were highly evident. Positive correlations with Zn were documented in the combined data for channel catfish (Icralurus punctatus) and flathead catfish (Pylodictis olivaris), as has been reported for other taxa, but not in bass (Micropterus spp.) or carp. In channel catfish, ALA-D activity appeared to be more sensitive to blood Pb than in the other species investigated (i.e., threshold concentrations for inhibition were lower). Such among-species differences are consistent with previous studies. Enzyme activity was inhibited by more than 50% relative to reference sites in channel catfish from several TSMD sites. Collectively, our results indicate that Pb is both bioavailable and active biochemically in the Spring-Neosho River system.

Low level noble gas measurements in the field and laboratory in support of the Comprehensive Nuclear-Test-Ban Treaty.

Over 300 daily environmental radioxenon samples were analyzed using French developed SPALAX for automatic sample preparation including high-resolution gamma-spectrometry. The 133Xe sensitivity was significantly better than 1 mBq/m3 (specified criterion for Comprehensive Nuclear-Test-Ban Treaty verification). Radioxenon analysis was extended to include the X-ray region by improved detector window, sample cell design, efficiency calibration, line shape fitting and background analysis. The resulting analysis offers a 4-16 fold improvement in sensitivity for 133mXe and 131mXe, respectively.