Randomized Controlled Trials in Environmental Health Research: Unethical or Underutilized?

<p>Randomized Controlled Trials in Environmental Health Research: Unethical or Underutilized?</p

The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

Background Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. Methods We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. Results The overall geometric mean (GM) one-week outdoor PM2.5 concentration was 47.9?g/m3 (95% CI: 44.6, 51.6?g/m3), with highest concentrations in winter (118.0?g/m3; 110.4, 126.2?g/m3). One-week indoor and outdoor PM2.5 concentrations were correlated (r=0.69). Indoor PM2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3?g/m3 (15.8, 18.8?g/m3) and 24.5?g/m3 (22.2, 27.0?g/m3), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. Conclusions Portable HEPA filter air cleaners can lower indoor PM2.5 concentrations and SHS exposures in highly polluted settings.Canadian Institute of Health Research (MOP 142380)Simon Fraser University, Faculty of Health Sciences (Mowafaghian Child Health Faculty Award

A randomized air filter intervention study of air pollution and fetal growth in a highly polluted community: the Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study

Background: Gestational exposure to fine particulate matter (PM2.5) and cadmium may impair fetal growth. Portable high efficiency particulate air (HEPA) filter air cleaners can reduce indoor PM2.5, but their effect on fetal growth has not been evaluated. Objectives: We assessed (1) HEPA cleaner effectiveness in reducing residential indoor PM2.5 and maternal blood cadmium, (2) the effect of HEPA cleaners on fetal growth, and (3) the relationship between maternal cadmium exposure and fetal growth, among non-smoking pregnant women in Ulaanbaatar, Mongolia. Methods: We randomized 540 participants at ≤ 18 weeks gestation to an intervention (1-2 HEPA cleaners in homes from early pregnancy until childbirth) or control (no HEPA cleaners) group. We collected exposure, health, and demographic data through home and clinic visits and from clinic records. We measured one-week indoor PM2.5 concentrations in early (~11 weeks gestation) and late (~31 weeks gestation) pregnancy, collected blood samples in late pregnancy for analysis of cadmium, and obtained birth data at delivery. We evaluated the effect of the intervention on our primary outcome, birth weight, and other fetal growth indicators using unadjusted linear and logistic regression and time-to-event analysis, in intention-to-treat analyses. We also used multiple linear and logistic regression to assess the relationships between log2-transformed blood cadmium and fetal growth. Results: HEPA cleaners reduced indoor PM2.5 and blood cadmium concentrations by 29% (95% CI: 21, 37%) and 14% (95% CI: 4, 23%), respectively. Among 463 live births, the median (25th, 75th percentile) birth weights for control and intervention participants were 3450 g (3150, 3800 g) and 3550 g (3200, 3800 g), respectively, but the intervention was not associated with an increase in birth weight (18 g; 95% CI: -84, 120 g). In a pre-specified subgroup analysis of 429 term births the intervention was associated with an 85 g (95% CI: 3, 167 g) increase in mean birth weight. A doubling of blood cadmium was associated with an 86 g (95% CI: 26, 145 g) reduction in birth weight. Conclusions: Our findings provide further evidence that PM2.5 and cadmium exposures during pregnancy impair fetal growth and that exposure reduction during pregnancy can reduce these effects. Portable HEPA cleaners are an effective household-level intervention but reductions in air pollution emissions are needed to realize the largest public health benefits

Infiltration of forest fire and residential wood smoke : an intervention study to asssess [sic] air cleaner effectiveness

Forest fires and residential wood-burning are significant sources of fine particle (PM2.5) air pollution. As PM2.5 exposure is associated with adverse health effects, populations need to be provided with exposure reduction strategies during smoke episodes that are practical, effective, and evidence-based. Public health recommendations typically include remaining indoors and use of air cleaners, yet little information is available on the effectiveness of these measures. Specific objectives of this study were to measure indoor infiltration of outdoor P M2.5 from forest fires/residential wood smoke, to determine effectiveness of High Efficiency Particulate Air (HEPA) filter air cleaners in reducing indoor PM2.5 and to investigate determinants of infiltration and air cleaner effectiveness in homes. Winter sampling at 21 homes was conducted in 2004 in a northern Canadian community affected by residential wood-burning. Summer (2004-5) sampling at 17 homes was conducted in southern British Columbian communities impacted by vegetation fire smoke. Indoor and outdoor 1-minute PM2.5 averages and a 48-hour outdoor PM2.5 filter sample were collected at each home. A portable HEPA filter air cleaner was operated indoors with the filter removed for one of two sampling days. Infiltration (Finf) was calculated for each home using a recursive model (Switzer & Ott, 1992; Allen et al., 2003). Housing characteristics data were used in multivariable modeling of infiltration and air cleaner efficiency (ACE). Valid samples were obtained from 19 homes in winter and 13 homes in summer. Mean Finf ± SD values of 0.27 ±0.18 and 0.61 ± 0.27 were found for winter and summer respectively, for days when the filter was removed, with lower values of 0.10 ± 0.08 and 0.19 ± 0.20 on corresponding days with filters in place. Mean ± SD ACE, calculated as [Finf without filter - Finf with filter]/ Finf without filter, in winter and summer were 55 ± 38% and 65 ± 35% respectively. Infiltration was predicted by the number of windows in a home and the season (p<0.001) while no significant predictors of ACE were identified. Remaining indoors combined with air cleaner use was concluded to effectively reduce PM2.5 exposure during forest fire and residential wood burning episodes.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat

Infections associated with Personal Service Establishments: Aesthetics. Vancouver, BC: National Collaborating Centre for Environmental Health;

Summary • Piercing and tattooing are associated with bacterial and viral infections, typically localized to the pierced or tattooed site. • Individuals with pre-existing heart conditions are at risk of developing infective endocarditis, a systemic infection involving the outer lining of the heart, when obtaining invasive procedures, such as piercing and tattooing. • There is a lack of published literature on infections associated with body modification procedures, including scarring and branding. • Poor infection control practices have been linked to outbreaks and individual cases of infection for both piercing and tattooing; these include use of contaminated sprays and moisturizers, improper cleaning and sterilization of tools, and re-use of tattooing ink between clients. • Use of tap water to dilute ink or rinse needles between colour changes has been implicated in outbreaks of mycobacterium infections during tattooing. • The majority of identified studies consists of case reports, which provide limited information on disease transmission risks for specific services

Infections associated with Personal Service Establishments: Aesthetics. Vancouver, BC: National Collaborating Centre for Environmental Health;

Summary • Piercing and tattooing are associated with bacterial and viral infections, typically localized to the pierced or tattooed site. • Individuals with pre-existing heart conditions are at risk of developing infective endocarditis, a systemic infection involving the outer lining of the heart, when obtaining invasive procedures, such as piercing and tattooing. • There is a lack of published literature on infections associated with body modification procedures, including scarring and branding. • Poor infection control practices have been linked to outbreaks and individual cases of infection for both piercing and tattooing; these include use of contaminated sprays and moisturizers, improper cleaning and sterilization of tools, and re-use of tattooing ink between clients. • Use of tap water to dilute ink or rinse needles between colour changes has been implicated in outbreaks of mycobacterium infections during tattooing. • The majority of identified studies consists of case reports, which provide limited information on disease transmission risks for specific services

A review of the experimental evidence on the toxicokinetics of carbon monoxide: the potential role of pathophysiology among susceptible groups

Abstract Background Acute high level carbon monoxide (CO) exposure can cause immediate cardio-respiratory arrest in anyone, but the effects of lower level exposures in susceptible persons are less well known. The percentage of CO-bound hemoglobin in blood (carboxyhemoglobin; COHb) is a marker of exposure and potential health outcomes. Indoor air quality guidelines developed by the World Health Organization and Health Canada, among others, are set so that CO exposure does not lead to COHb levels above 2.0%, a target based on experimental evidence on toxicodynamic relationships between COHb and cardiac performance among persons with cardiovascular disease (CVD). The guidelines do not consider the role of pathophysiological influences on toxicokinetic relationships. Physiological deficits that contribute to increased CO uptake, decreased CO elimination, and increased COHb formation can alter relationships between CO exposures and resulting COHb levels, and consequently, the severity of outcomes. Following three fatalities attributed to CO in a long-term care facility (LTCF), we queried whether pathologies other than CVD could alter CO-COHb relationships. Our primary objective was to inform susceptibility-specific modeling that accounts for physiological deficits that may alter CO-COHb relationships, ultimately to better inform CO management in LTCFs. Methods We reviewed experimental studies investigating relationships between CO, COHb, and outcomes related to health or physiological outcomes among healthy persons, persons with CVD, and six additional physiologically susceptible groups considered relevant to LTCF residents: persons with chronic obstructive pulmonary disease (COPD), anemia, cerebrovascular disease (CBD), heart failure, multiple co-morbidities, and persons of older age (≥ 60 years). Results We identified 54 studies published since 1946. Six studies investigated toxicokinetics among healthy persons, and the remaining investigated toxicodynamics, mainly among healthy persons and persons with CVD. We identified one study each of CO dynamics in persons with COPD, anemia and persons of older age, and no studies of persons with CBD, heart failure, or multiple co-morbidities. Considerable heterogeneity existed for exposure scenarios and outcomes investigated. Conclusions Limited experimental human evidence on the effects of physiological deficits relevant to CO kinetics exists to support indoor air CO guidelines. Both experimentation and modeling are needed to assess how physiological deficits influence the CO-COHb relationship, particularly at sub-acute exposures relevant to indoor environments. Such evidence would better inform indoor air quality guidelines and CO management in indoor settings where susceptible groups are housed

From good Intentions to proven interventions : effectiveness of actions to reduce the health impacts of air pollution

Associations between air pollution and a multitude of health effects are now well established. Given ubiquitous exposure to some level of air pollution, the attributable health burden can be high, particularly for susceptible populations. Objectives: An international multidisciplinary workshop was convened to discuss evidence of the effectiveness of actions to reduce health impacts of air pollution at both the community and individual level. The overall aim was to summarize current knowledge regarding air pollution exposure and health impacts leading to public health recommendations. Discussion: During the workshop, experts reviewed the biological mechanisms of action of air pollution in the initiation and progression of disease, as well as the state of the science regarding community and individual-level interventions. The workshop highlighted strategies to reduce individual baseline risk of conditions associated with increased susceptibility to the effects of air pollution and the need to better understand the role of exposure duration in disease progression, reversal, and adaptation. C onclusion: We have identified two promising and largely unexplored strategies to address and mitigate air pollution–related health impacts: reducing individual baseline risk of cardiovascular disease and incorporating air pollution–related health impacts into land-use decisions.Education, Faculty ofEnvironmental Health (SOEH), School ofKinesiology, School ofMedicine, Department ofPopulation and Public Health (SPPH), School ofRespiratory Medicine, Division ofNon UBCMedicine, Faculty ofReviewedFacult

The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

Background Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. Methods We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. Results The overall geometric mean (GM) one-week outdoor PM2.5 concentration was 47.9?g/m3 (95% CI: 44.6, 51.6?g/m3), with highest concentrations in winter (118.0?g/m3; 110.4, 126.2?g/m3). One-week indoor and outdoor PM2.5 concentrations were correlated (r=0.69). Indoor PM2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3?g/m3 (15.8, 18.8?g/m3) and 24.5?g/m3 (22.2, 27.0?g/m3), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. Conclusions Portable HEPA filter air cleaners can lower indoor PM2.5 concentrations and SHS exposures in highly polluted settings.Canadian Institute of Health Research (MOP 142380)Simon Fraser University, Faculty of Health Sciences (Mowafaghian Child Health Faculty Award