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Chaix, B, Duncan D, Vallee J, Vernez-Moudon A, Benmarhnia T, Kestens Y.  2017.  The "Residential" Effect Fallacy in Neighborhood and Health Studies Formal Definition, Empirical Identification, and Correction. Epidemiology. 28:789-797.   10.1097/ede.0000000000000726   AbstractWebsite

Background: Because of confounding from the urban/rural and socioeconomic organizations of territories and resulting correlation between residential and nonresidential exposures, classically estimated residential neighborhood-outcome associations capture nonresidential environment effects, overestimating residential intervention effects. Our study diagnosed and corrected this "residential" effect fallacy bias applicable to a large fraction of neighborhood and health studies. Methods: Our empirical application investigated the effect that hypothetical interventions raising the residential number of services would have on the probability that a trip is walked. Using global positioning systems tracking and mobility surveys over 7 days (227 participants and 7440 trips), we employed a multilevel linear probability model to estimate the trip-level association between residential number of services and walking to derive a naive intervention effect estimate and a corrected model accounting for numbers of services at the residence, trip origin, and trip destination to determine a corrected intervention effect estimate (true effect conditional on assumptions). Results: There was a strong correlation in service densities between the residential neighborhood and nonresidential places. From the naive model, hypothetical interventions raising the residential number of services to 200, 500, and 1000 were associated with an increase by 0.020, 0.055, and 0.109 of the probability of walking in the intervention groups. Corrected estimates were of 0.007, 0.019, and 0.039. Thus, naive estimates were overestimated by multiplicative factors of 3.0, 2.9, and 2.8. Conclusions: Commonly estimated residential intervention-outcome associations substantially overestimate true effects. Our somewhat paradoxical conclusion is that to estimate residential effects, investigators critically need information on nonresidential places visited.

Benmarhnia, T, Rey L, Cartier Y, Clary CM, Deguen S, Brousselle A.  2014.  Addressing equity in interventions to reduce air pollution in urban areas: a systematic review. International Journal of Public Health. 59:933-944.   10.1007/s00038-014-0608-0   AbstractWebsite

Integration of equity in evidence-based public health is a great challenge nowadays. In this review we draw attention to the importance of considering equity in air pollution interventions. We also propose further methodological and theoretical challenges when assessing equity in interventions to reduce air pollution and we present opportunities to develop this research area.

Lewin, A, Brondeel R, Benmarhnia T, Thomas F, Chaix B.  2018.  Attrition bias related to missing outcome data: A longitudinal simulation study. Epidemiology. 29:87-95.   10.1097/ede.0000000000000755   AbstractWebsite

Background: Most longitudinal studies do not address potential selection biases due to selective attrition. Using empirical data and simulating additional attrition, we investigated the effectiveness of common approaches to handle missing outcome data from attrition in the association between individual education level and change in body mass index (BMI). Methods: Using data from the two waves of the French RECORD Cohort Study (N = 7,172), we first examined how inverse probability weighting (IPW) and multiple imputation handled missing outcome data from attrition in the observed data (stage 1). Second, simulating additional missing data in BMI at follow-up under various missing-at-random scenarios, we quantified the impact of attrition and assessed how multiple imputation performed compared to complete case analysis and to a perfectly specified IPW model as a gold standard (stage 2). Results: With the observed data in stage 1, we found an inverse association between individual education and change in BMI, with complete case analysis, as well as with IPW and multiple imputation. When we simulated additional attrition under a missing-at-random pattern (stage 2), the bias increased with the magnitude of selective attrition, and multiple imputation was useless to address it. Conclusions: Our simulations revealed that selective attrition in the outcome heavily biased the association of interest. The present article contributes to raising awareness that for missing outcome data, multiple imputation does not do better than complete case analysis. More effort is thus needed during the design phase to understand attrition mechanisms by collecting information on the reasons for dropout.

Benmarhnia, T, Oulhote Y, Petit C, Lapostolle A, Chauvin P, Zmirou-Navier D, Deguen S.  2014.  Chronic air pollution and social deprivation as modifiers of the association between high temperature and daily mortality. Environmental Health. 13   Artn 5310.1186/1476-069x-13-53   AbstractWebsite

Background: Heat and air pollution are both associated with increases in mortality. However, the interactive effect of temperature and air pollution on mortality remains unsettled. Similarly, the relationship between air pollution, air temperature, and social deprivation has never been explored.Methods: We used daily mortality data from 2004 to 2009, daily mean temperature variables and relative humidity, for Paris, France. Estimates of chronic exposure to air pollution and social deprivation at a small spatial scale were calculated and split into three strata. We developed a stratified Poisson regression models to assess daily temperature and mortality associations, and tested the heterogeneity of the regression coefficients of the different strata. Deaths due to ambient temperature were calculated from attributable fractions and mortality rates were estimated.Results: We found that chronic air pollution exposure and social deprivation are effect modifiers of the association between daily temperature and mortality. We found a potential interactive effect between social deprivation and chronic exposure with regards to air pollution in the mortality-temperature relationship.Conclusion: Our results may have implications in considering chronically polluted areas as vulnerable in heat action plans and in the long-term measures to reduce the burden of heat stress especially in the context of climate change.

Benmarhnia, T, Huang J, Basu R, Wu J, Bruckner TA.  2017.  Decomposition analysis of black-white disparities in birth outcomes: The relative contribution of air pollution and social factors in California. Environmental Health Perspectives. 125   10.1289/ehp490   AbstractWebsite

BACKGROUND: Racial/ethnic disparities in preterm birth (PTB) are well documented in the epidemiological literature, but little is known about the relative contribution of different social and environmental determinants of such disparities in birth outcome. Furthermore, increased focus has recently turned toward modifiable aspects of the environment, including physical characteristics, such as neighborhood air pollution, to reduce disparities in birth outcomes. OBJECTIVES: To apply decomposition methods to understand disparities in preterm birth (PTB) prevalence between births of non-Hispanic black individuals and births of non-Hispanic white individuals in California, according to individual demographics, neighborhood socioeconomic environment, and neighborhood air pollution. METHODS: We used all live singleton births in California spanning 2005 to 2010 and estimated PTBs and other adverse birth outcomes for infants borne by non-Hispanic black mothers and white mothers. To compare individual-level, neighborhood-level, and air pollution [Particulate. Matter, 2.5 micrometers or less (PM2.5) and nitrogen dioxide (NO2)] predictors, we conducted a nonlinear extension of the. Blinder-Oaxaca method to decompose racial/ethnic disparities in PTB. RESULTS: The predicted differences in probability of PTB between black and white infants was 0.056 (95% CI: 0.054, 0.058). All included predictors explained 37.8% of the black-white disparity. Overall, individual (17.5% for PTB) and neighborhood-level variables (16.1% for PTB) explained a greater proportion of the black-white difference in birth outcomes than air pollution (5.7% for PTB). CONCLUSIONS: Our results suggest that, although the role of individual and neighborhood factors remains prevailing in explaining black-white differences in birth outcomes, the individual contribution of PM2.5 is comparable in magnitude to any single individual- or neighborhood-level factor.

Benmarhnia, T, Bailey Z, Kaiser D, Auger N, King N, Kaufman JS.  2016.  A Difference-in-Differences Approach to Assess the Effect of a Heat Action Plan on Heat-Related Mortality, and Differences in Effectiveness According to Sex, Age, and Socioeconomic Status (Montreal, Quebec). Environmental Health Perspectives. 124:1694-1699.   10.1289/EHP203   AbstractWebsite

BACKGROUND: The impact of heat waves on mortality and health inequalities is well documented. Very few studies have assessed the effectiveness of heat action plans (HAPs) on health, and none has used quasi-experimental methods to estimate causal effects of such programs.OBJECTIVES: We developed a quasi-experimental method to estimate the causal effects associated with HAPs that allows the identification of heterogeneity across subpopulations, and to apply this method specifically to the case of the Montreal (Quebec, Canada) HAP.METHODS: A difference-in-differences approach was undertaken using Montreal death registry data for the summers of 2000-2007 to assess the effectiveness of the Montreal HAP, implemented in 2004, on mortality. To study equity in the effect of HAP implementation, we assessed whether the program effects were heterogeneous across sex (male vs. female), age (>= 65 years vs. < 65 years), and neighborhood education levels (first vs. third tertile). We conducted sensitivity analyses to assess the validity of the estimated causal effect of the HAP program.RESULTS: We found evidence that the HAP contributed to reducing mortality on hot days, and that the mortality reduction attributable to the program was greater for elderly people and people living in low-education neighborhoods.CONCLUSION: These findings show promise for programs aimed at reducing the impact of extreme temperatures and health inequities. We propose a new quasi-experimental approach that can be easily applied to evaluate the impact of any program or intervention triggered when daily thresholds are reached.

Bohra, T, Benmarhnia T, McKinnon B, Kaufman JS.  In Press.  ecomposing educational inequalities in child mortality: a temporal trend analysis of access to Water and Sanitation in Peru. American Journal of Tropical Medicine and Hygiene.
Leas, EC, Pierce JP, Benmarhnia T, White MM, Noble ML, Trinidad DR, Strong DR.  2018.  Effectiveness of pharmaceutical smoking cessation aids in a nationally representative cohort of American smokers. Jnci-Journal of the National Cancer Institute. 110:581-587.   10.1093/jnci/djx240   AbstractWebsite

Background: Despite strong efficacy in randomized trials, the population effectiveness of pharmaceutical aids in long-term smoking cessation is lacking, possibly because of confounding (factors that are associated with both pharmaceutical aid use and difficulty quitting). Matching techniques in longitudinal studies can remove this confounding bias. Methods: Using the nationally representative Tobacco Use Supplement to the Current Population Survey (TUS-CPS), we assessed the effectiveness of medications to aid quitting among baseline adult smokers who attempted to quit prior to one year of follow-up in two longitudinal studies: 2002-2003 and 2010-2011. Pharmaceutical aid users and nonusers with complete data (n = 2129) were matched using propensity score models with 12 potential confounders (age, sex, race-ethnicity, education, smoking intensity, nicotine dependence, previous quit history, self-efficacy to quit, smoke-free homes, survey year, and cessation aid use). Using matched data sets, logistic regression models were fit to assess whether use of any individual pharmaceutical aid increased the proportion of patients who were abstinent for 30 days or more at follow-up. Results: Propensity score matching markedly improved balance on the potential confounders between the pharmaceutical aid use groups. Using matched samples to provide a balanced comparison, there was no evidence that use of varenicline (adjusted risk difference [aRD] = 0.01, 95% confidence interval (CI] = -0.07 to Oil), bupropion (aRD = 0.02, 95% CI = -0.04 to 0.09), or nicotine replacement (aRD = 0.01, 95% CI = -0.03 to 0.06) increased the probability of 30 days or more smoking abstinence at one-year follow-up. Conclusions: The lack of effectiveness of pharmaceutical aids in increasing long-term cessation in population samples is not an artifact caused by confounded analyses. A possible explanation is that counseling and support interventions provided in efficacy trials are rarely delivered in the general population.

Tresa, E, Benmarhnia T, Clemens T, Burazeri G, Czabanowska K.  2018.  Europeanization process impacts the patterns of alcohol consumption in the Western Balkans. European Journal of Public Health. 28:516-521.   10.1093/eurpub/ckx175   AbstractWebsite

Background: Western Balkan countries exhibit high levels of alcohol consumption, which constitutes a serious public health concern. We aimed to quantitatively assess the influence of the Europeanization process on levels of alcohol consumption in Western Balkans, an issue that has been under-researched. Methods: The process of Europeanization was defined as the penetration of European dimension, procedures, policy paradigms, beliefs and norms in national arenas of politics and policy development. Data about alcohol consumption in six Western Balkan countries from 1991 to 2011 were gathered from the World Bank and World Health Organization databases. Azerbaijan and Georgia were considered control countries. A difference-in-differences approach was used to assess the impact of Europeanization process on levels of alcohol consumption. Results: The Europeanization process impacts alcohol consumption in Western Balkan countries through the European Union directives and tax policies. After starting the Europeanization process, the spirits consumption in Croatia and The Former Yugoslav Republic of Macedonia decreased by 1.06 litter per capita (95% CI: from -1.63 to -0.49) and 1.02 litter per capita in Serbia (95% CI: from -1.9 to -0.1). Conclusion: Our analysis provides useful evidence about the possible influence of Europeanization process especially on spirits consumption levels in Western Balkans. These findings draw attention to the need to implement new policies in order to prevent alcohol health-related harm due to the possible increase of wine and beer consumption.

Zunzunegui, MV, Belanger E, Benmarhnia T, Gobbo M, Otero A, Beland F, Zunzunegui F, Ribera-Casado JM.  2017.  Financial fraud and health: the case of Spain. Gaceta Sanitaria. 31:313-319.   10.1016/j.gaceta.2016.12.012   AbstractWebsite

Objective: To examine whether financial fraud is associated with poor health sleeping problems and poor quality of life. Methods: Pilot study (n = 188) conducted in 2015-2016 in Madrid and Leon (Spain) by recruiting subjects affected by two types of fraud (preferred shares and foreign currency mortgages) using venue-based sampling. Information on the monetary value of each case of fraud; the dates when subjects became aware of being swindled, lodged legal claim and received financial compensation were collected. Intergroup comparisons of the prevalence of poor physical and mental health, sleep and quality of life were carried according to type of fraud and the 2011-2012 National Health Survey. Results: In this conventional sample, victims of financial fraud had poorer health, more mental health and sleeping problems, and poorer quality of life than comparable populations of a similar age. Those who had received financial compensation for preferred share losses had better health and quality of life than those who had not been compensated and those who had taken out foreign currency mortgages. Conclusion: The results suggest that financial fraud is detrimental to health. Further research should examine the mechanisms through which financial fraud impacts health. If our results are confirmed psychological and medical care should be provided, in addition to financial compensation. (C) 2017 SESPAS. Published by Elsevier Espatia, S.L.U.

Benmarhnia, T, Delpla I, Schwarz L, Rodriguez MJ, Levallois P.  2018.  Heterogeneity in the relationship between disinfection by-products in drinking water and cancer: A systematic review. International Journal of Environmental Research and Public Health. 15   10.3390/ijerph15050979   AbstractWebsite

The epidemiological evidence demonstrating the effect of disinfection by-products (DBPs) from drinking water on colon and rectal cancers is well documented. However, no systematic assessment has been conducted to assess the potential effect measure modification (EMM) in the relationship between DBPs and cancer. The objective of this paper is to conduct a systematic literature review to determine the extent to which EMM has been assessed in the relationship between DBPs in drinking water in past epidemiological studies. Selected articles (n = 19) were reviewed, and effect estimates and covariates that could have been used in an EMM assessment were gathered. Approximately half of the studies assess EMM (n = 10), but the majority of studies only estimate it relative to sex subgroups (n = 6 for bladder cancer and n = 2 both for rectal and colon cancers). Although EMM is rarely assessed, several variables that could have a potential modification effect are routinely collected in these studies, such as socioeconomic status or age. The role of environmental exposures through drinking water can play an important role and contribute to cancer disparities. We encourage a systematic use of subgroup analysis to understand which populations or territories are more vulnerable to the health impacts of DBPs.

Benmarhnia, T, Alexander S, Price K, Smargiassi A, King N, Kaufman JS.  2018.  The heterogeneity of vulnerability in public health: a heat wave action plan as a case study. Critical Public Health. 28:619-625.   10.1080/09581596.2017.1322176   AbstractWebsite

The concept of vulnerability is frequently used in public health policies to develop tailored interventions or dedicate proportionately more resources to certain sub-populations. However, once segments of the population are identified as vulnerable, they are rarely consulted regarding whether this label is acceptable before instituting interventions. Instead, it is implicitly assumed that the targeted individuals identify themselves as vulnerable and experience an unambiguous and consistent need for public health assistance. In this paper, using public health interventions during heat waves as a case study, we question such assumptions. A qualitative study was conducted in Montreal, Canada involving two focus groups among populations specifically targeted by the heat action plan as vulnerable: one composed of individuals diagnosed with schizophrenia, and one composed of individuals who have alcohol or drug addictions. Findings revealed significant heterogeneity in the definition and experience of vulnerability as it is used in the context of a heat action plan in Montreal. We found differences between the two focus groups in several areas including sources of information they had access to within the heat action plan measures and their perspectives regarding the appropriateness of specific measures in the heat action plan. We then observed differences within each of the focus groups in several areas including their social networks relationships. The concept of vulnerability is often used in public health policies. Yet, while this concept may be convenient for shaping policies to reduce inequalities in health, the heterogeneity of populations defined as vulnerable should not be underestimated.

Benmarhnia, T, Dionna PA, Tchouaket E, Fansi A, Brousselle A.  In Press.  How effective does a Healthy Lifestyle Habits Promotion Strategy need to be to make it cost-neutral. IJPH.
Vijayaraghavan, M, Benmarnhia T, Pierce JP, White MM, Kempster J, Shi YY, Trinidad DR, Messer K.  2018.  Income disparities in smoking cessation and the diffusion of smoke-free homes among US smokers: Results from two longitudinal surveys. Plos One. 13   10.1371/journal.pone.0201467   AbstractWebsite

Background Lower rates of successful quitting among low-income populations in the United States may be from slower dissemination of smoke-free homes, a predictor of cessation. Objectives To explore the role of smoke-free homes in cessation behavior across income levels. Participants Current smokers who were >= 18 years and who participated in the longitudinal 2002-2003 (n = 2801) or 2010-2011 (n = 2723) Tobacco Use Supplements to the Current Population Survey. Measurements We categorized income as multiples of the federal poverty level (FPL) (<300% FPL versus >= 300% FPL). We examined the association of smoke-free homes with 1+day quit attempts and 30+days abstinence at 1-year follow-up. We then conducted a mediation analysis to examine the extent that smoke-free homes contributed to income disparities in 30+days abstinence. Results Between the two surveys, heavy smoking (>= 1 pack/day) declined by 17%, and smoking prevalence declined by 15% among those with higher-incomes (>300%FPL). Although similar in 2002, the prevalence of smoke-free homes was 33% lower among individuals living <300% FPL than those living >= 300% FPL. Although the quit attempt rate was similar, the 30 +days abstinence rate was higher in the 2010-11 cohort than in 2002-3 cohort (20.6% versus 15.5%, p<0.008). Whereas smoking >= 1 pack/ day was associated with lower odds of 30 +days abstinence (Adjusted odds ratio [AOR] 0.7; 95% CI 0.5-0.9), having a higher income (AOR 1.9, 95% CI 1.4-2.6) and a smoke-free home (AOR 1.6, 95% CI 1.2-2.1) were associated with greater odds of 30+day abstinence. Differential changes in smoke-free homes across income groups between the two surveys contributed to 36% (95% CI 35.7-36.3) of the observed income disparity in 30+days abstinence. Conclusions Increasing the diffusion of smoke-free homes among low-income populations may attenuate at least a third of the income disparities in smoking cessation, highlighting the need for interventions to increase adoption of smoke-free homes among low-income households.

Delpla, I, Benmarhnia T, Lebel A, Levallois P, Rodriguez MJ.  2015.  Investigating social inequalities in exposure to drinking water contaminants in rural areas. Environmental Pollution. 207:88-96.   10.1016/j.envpol.2015.08.046   AbstractWebsite

Few studies have assessed social inequalities in exposure to drinking water contaminants. This study explores this issue in 593 rural municipalities of Quebec, Canada. Quartiles of an ecological composite deprivation index were used as a proxy of socioeconomic status. Total trihalomethanes (TTHMs) and lead were chosen as proxies of chemical drinking water quality. The results show that the majority of deprived rural municipalities apply no treatment to their water (26%) or use a basic treatment (51%), whereas a relative majority of the wealthiest municipalities (40%) use advanced treatment. The proportion of municipalities having important lead (>5 mu g/L) levels is highest in most deprived municipalities. Moreover, most deprived municipalities have a higher risk of high tap lead levels (RR = 1.33; 95% Cl: 1.30, 1.36). Conversely, most deprived municipalities have a lower risk of high TTHMs levels (RR = 0.78; 95%CI: 0.69, 0.86). These findings suggest an environmental inequality in drinking water contaminants distribution in rural municipalities. (C) 2015 Elsevier Ltd. All rights reserved.

Beck, F, Richard JB, Deutsch A, Benmarhnia T, Pirard P, Roudier C, Peretti-Watel P.  2013.  Knowledge about radon and its associated risk perception in France. Cancer Radiotherapie. 17:744-749.   10.1016/j.canrad.2013.06.044   AbstractWebsite

Purpose. - Radon exposure is a major environmental risk in health. It remains badly known by the general population. It is the second cause of lung cancer, after tobacco smoking. The aim of this cross-sectional general population survey was to describe radon exposure risk knowledge and the socioeconomic factors related to this knowledge.Materials and methods. - The Cancer Barometer survey 2010 questioned the French population about its knowledge of radon as such and as health risk factor. This survey was a two-stage random sampling with computer-assisted telephone interview that was performed from April 3, 2010 to August 7, 2010 on a sample of 3,359 people aged 15 to 75 years old.Results. - Among people aged 15 to 75 years old, only one in five knows that radon is a natural gas coming from the ground. This knowledge is more frequent among people living in an area that is directly concerned by radon, among men and increases with age, with the level of education and the level of income. Radon risk remains still widely underestimated by the general public, including in areas concerned by this risk. When people were confronted with radon exposure, few intended to remedy by improving their home.Conclusion. - The success of prevention initiatives implies the support and the collaboration of various national and local actors. To improve their impact for the prevention of lung cancers, it could be more effective to couple these actions with prevention messages on tobacco. (C) 2013 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

Benmarhnia, T, Huang J, Jones C.  In Press.  Lost in Translation: Considering the representation of uncertainty in the presentation of empirical findings in WHO policy statements. International Journal of Health Policy and Management.
Schinasi, LH, Benmarhnia T, De Roos AJ.  2018.  Modification of the association between high ambient temperature and health by urban microclimate indicators: A systematic review and meta-analysis. Environmental Research. 161:168-180.   10.1016/j.envres.2017.11.004   AbstractWebsite

Background: Landscape characteristics, including vegetation and impervious surfaces, influence urban micro climates and may lead to within-city differences in the adverse health effects of high ambient temperatures. Objective: Our objective was to quantitatively summarize the epidemiologic literature that assessed microclimate indicators as effect measure modifiers (EMM) of the association between ambient temperature and mortality or morbidity. Methods: We systematically identified papers and abstracted relative risk estimates for hot and cool micro climate indicator strata. We calculated the ratio of the relative risks (RRR) and 95% confidence intervals (95% CI) to assess differences in health effects across strata, and pooled the RRR estimates using random effects meta analyses. Results: Eleven papers were retained. In the pooled analyses, people living in hotter areas within cities (based on land surface temperature or modeled estimates of air temperature) had 6% higher risk of mortality/morbidity compared to those in cooler areas (95% CI: 1.03-1.09). Those living in less vegetated areas had 5% higher risk compared to those living in more vegetated areas (95% CI: 1.00-1.11). Discussion: There is epidemiologic evidence that those living in hotter, and less vegetated areas of cities have higher risk of morbidity or mortality from higher ambient temperature. Further research with improved assessment of landscape characteristics and investigation of the joint effects of physiologic adaptation and landscape will advance the current understanding. Conclusion: This review provides quantitative evidence that intra-urban differences in landscape characteristics and micro-urban heat islands contribute to within-city variability in the health effects of high ambient temperatures.

Perchoux, C, Nazare JA, Benmarhnia T, Salze P, Feuillet T, Hercberg S, Hess F, Menai M, Weber C, Charreire H, Enaux C, Oppert JM, Simon C.  2017.  Neighborhood educational disparities in active commuting among women: the effect of distance between the place of residence and the place of work/study (an ACTI-Cites study). Bmc Public Health. 17   10.1186/s12889-017-4464-8   AbstractWebsite

Background: Active transportation has been associated with favorable health outcomes. Previous research highlighted the influence of neighborhood educational level on active transportation. However, little is known regarding the effect of commuting distance on social disparities in active commuting. In this regard, women have been poorly studied. The objective of this paper was to evaluate the relationship between neighborhood educational level and active commuting, and to assess whether the commuting distance modifies this relationship in adult women. Methods: This cross-sectional study is based on a subsample of women from the Nutrinet-Sante web-cohort (N = 1169). Binomial, log-binomial and negative binomial regressions were used to assess the associations between neighborhood education level and (i) the likelihood of reporting any active commuting time, and (ii) the share of commuting time made by active transportation modes. Potential effect measure modification of distance to work on the previous associations was assessed both on the additive and the multiplicative scales. Results: Neighborhood education level was positively associated with the probability of reporting any active commuting time (relative risk = 1.774; p < 0.05) and the share of commuting time spent active (relative risk = 1.423; p < 0.05). The impact of neighborhood education was greater at long distances to work for both outcomes. Conclusions: Our results suggest that neighborhood educational disparities in active commuting tend to increase with commuting distance among women. Further research is needed to provide geographically driven guidance for health promotion intervention aiming at reducing disparities in active transportation among socioeconomic groups.

Deguen, S, Petit C, Delbarre A, Kihal W, Padilla C, Benmarhnia T, Lapostolle A, Chauvin P, Zmirou-Navier D.  2015.  Neighbourhood characteristics and long-term air pollution levels modify the association between the short-term nitrogen dioxide concentrations and all-cause mortality in Paris. Plos One. 10   ARTN e013146310.1371/journal.pone.0131463   AbstractWebsite

BackgroundWhile a great number of papers have been published on the short-term effects of air pollution on mortality, few have tried to assess whether this association varies according to the neighbourhood socioeconomic level and long-term ambient air concentrations measured at the place of residence. We explored the effect modification of 1) socioeconomic status, 2) long-term NO2 ambient air concentrations, and 3) both combined, on the association between short-term exposure to NO2 and all-cause mortality in Paris (France).MethodsA time-stratified case-crossover analysis was performed to evaluate the effect of short-term NO2 variations on mortality, based on 79,107 deaths having occurred among subjects aged over 35 years, from 2004 to 2009, in the city of Paris. Simple and double interactions were statistically tested in order to analyse effect modification by neighbourhood characteristics on the association between mortality and short-term NO2 exposure. The data was estimated at the census block scale (n=866).ResultsThe mean of the NO2 concentrations during the five days prior to deaths were associated with an increased risk of all-cause mortality: overall Excess Risk (ER) was 0.94% (95% CI=[0.08;1.80]. A higher risk was revealed for subjects living in the most deprived census blocks in comparison with higher socioeconomic level areas (ER=3.14% (95% CI=[1.4-14.90], p<0.001). Among these deprived census blocks, excess risk was even higher where long-term average NO2 concentrations were above 55.8 mu g/m(3) (the top tercile of distribution): ER=4.84%(95% CI=[1.56;8.24], p for interaction= 0.02).ConclusionOur results show that people living in census blocks characterized by low socioeconomic status are more vulnerable to air pollution episodes. There is also an indication that people living in these disadvantaged census blocks might experience even higher risk following short-term air pollution episodes, when they are also chronically exposed to higher NO2 levels.

Benmarhnia, T, Grenier P, Brand A, Fournier M, Deguen S, Smargiassi A.  2015.  Quantifying Vulnerability to Extreme Heat in Time Series Analyses: A Novel Approach Applied to Neighborhood Social Disparities under Climate Change. International Journal of Environmental Research and Public Health. 12:11869-11879.   10.3390/ijerph120911869   AbstractWebsite

Objectives: We propose a novel approach to examine vulnerability in the relationship between heat and years of life lost and apply to neighborhood social disparities in Montreal and Paris. Methods: We used historical data from the summers of 1990 through 2007 for Montreal and from 2004 through 2009 for Paris to estimate daily years of life lost social disparities (DYLLD), summarizing social inequalities across groups. We used Generalized Linear Models to separately estimate relative risks (RR) for DYLLD in association with daily mean temperatures in both cities. We used 30 climate scenarios of daily mean temperature to estimate future temperature distributions (2021-2050). We performed random effect meta-analyses to assess the impact of climate change by climate scenario for each city and compared the impact of climate change for the two cities using a meta-regression analysis. Results: We show that an increase in ambient temperature leads to an increase in social disparities in daily years of life lost. The impact of climate change on DYLLD attributable to temperature was of 2.06 (95% CI: 1.90, 2.25) in Montreal and 1.77 (95% CI: 1.61, 1.94) in Paris. The city explained a difference of 0.31 (95% CI: 0.14, 0.49) on the impact of climate change. Conclusion: We propose a new analytical approach for estimating vulnerability in the relationship between heat and health. Our results suggest that in Paris and Montreal, health disparities related to heat impacts exist today and will increase in the future.

Benmarhnia, T, Auger N, Stanislas V, Lo E, Kaufman JS.  2015.  The relationship between apparent temperature and daily number of live births in Montreal. Maternal and Child Health Journal. 19:2548-2551.   10.1007/s10995-015-1794-y   AbstractWebsite

Temperature is a hypothesized determinant of early delivery, but seasonal and long term trends, delayed effects of temperature, and the influence of extreme cold temperatures have not yet been addressed. We aim to study the influence of apparent temperature on daily number of births, considering lag structures, seasonality and long term trends.We used daily number of births in conjunction with apparent outdoor temperatures between 1981 and 2010 in Montreal. We used Poisson regression combined with a distributed lag nonlinear model to consider non-linear relationships between temperature and daily number of births across specific lag periods.We found that apparent temperature was associated with the daily number of births in Montreal, with a 1-day delay. We found an increase in births on hot days, and decrease on cold days, both offset by a harvesting effect after 4 and 5 days.This study suggests that the number of births is affected by extreme temperatures. Obstetric and perinatal service providers should be prepared for spikes in the number of births caused by extreme temperatures.

Wang, Q, Benmarhnia T, Li CC, Knibbs LD, Bao JZ, Ren M, Zhang HH, Wang SH, Zhang YW, Zhao QG, Huang CR.  2019.  Seasonal analyses of the association between prenatal ambient air pollution exposure and birth weight for gestational age in Guangzhou, China. Science of the Total Environment. 649:526-534.   10.1016/j.scitotenv.2018.08.303   AbstractWebsite

Ambient air pollution has been linked to small for gestational age (SGA); however, the relationship with large for gestational age (ILA) is unclear and very few studies have investigated seasonal effects on the association between air pollution and SGA or LGA. Using birth registry data of 506,000 singleton live births from 11 districts in Guangzhou, China between January 2015 and July 2017, we examined associations between ambient air pollutants (PM2.5, PM10, NO2, SO2, and O-3) and SGA/LGA, and further assessed the modification effect of season. Daily concentrations of air pollutants from 11 monitoring stations were used to estimate district-specific exposures for each participant based on their district of residence during pregnancy. Two-level binary logistic regression models were used to evaluate associations between air pollution and SGA/LGA. Stratified analyses by season and a Cochran Q test were performed to assess the modification of season. Exposure to PM2.5, NO2, SO2, and O-3 was significantly associated with increased risk of SGA, especially for exposure during the second and trimester. For an interquartile range (IQR) increase in PM2.5(6.5 mu g/m(3)), NO2 (12.7 mu g/m(3)), SO2 (2.8 mu g/m(3)) and O-3 (20.8 mu g/m(3)) during the entire pregnancy, SGA risk increased by 2% (OR - 1.02, 95% CI: 1.00-1.04), 8% (OR = 1.08, 95% CI: 1.04-1.12), 2% (OR - 1.02, 95% CI: 1.01-1.03), and 14% (1.14, 1.11-1.17), respectively. A decreased risk of WA was found for PM2.5, PM10, SO2, and O-3 during the first trimester or entire pregnancy. When examined by season, significant associations between air pollutants and SGA were observed for women who conceived during summer or fall, and the patterns were consistent for all pollutants. Our study suggests that conception during different seasons might modify the association between ambient air pollution and SGA. (C) 2018 Elsevier B.V. All rights reserved.

Benmarhnia, T, Kihal-Talantikite W, Ragettli MS, Deguen S.  2017.  Small-area spatiotemporal analysis of heatwave impacts on elderly mortality in Paris: A cluster analysis approach. Science of the Total Environment. 592:288-294.   10.1016/j.scitotenv.2017.03.102   AbstractWebsite

Background: Heat-waves have a substantial public health burden. Understanding spatial heterogeneity at a fine spatial scale in relation to heat and related mortality is central to target interventions towards vulnerable communities. Objectives: To determine the spatial variability of heat-wave-related mortality risk among elderly in Paris, France at the census block level. We also aimed to assess area-level social and environmental determinants of high mortality risk within Paris. Methods: We used daily mortality data from 2004 to 2009 among people aged >65 at the French census block level within Paris. We used two heat wave days' definitions that were compared to non-heat wave days. A Bernoulli cluster analysis method was applied to identify high risk clusters of mortality during heat waves. We performed random effects meta-regression analyses to investigate factors associated with the magnitude of the mortality risk. Results: The spatial approach revealed a spatial aggregation of death cases during heat wave days. We found that small scale chronic PM10 exposure was associated with a 0.02 (95% CI: 0.001; 0.045) increase of the risk of dying during a heat wave episode. We also found a positive association with the percentage of foreigners and the percentage of labor force, while the proportion of elderly people living in the neighborhoodwas negatively associated. We also found that green space density had a protective effect and inversely that the density of constructed feature increased the risk of dying during a heat wave episode. Conclusion: We showed that a spatial variation in terms of heat-related vulnerability exists within Paris and that it can be explained by some contextual factors. This study can be useful for designing interventions targeting more vulnerable areas and reduce the burden of heat waves. (C) 2017 Elsevier B.V. All rights reserved.

Schwarz, L, Benmarhnia T, Laurian L.  2015.  Social Inequalities Related to Hazardous Incinerator Emissions: An Additional Level of Environmental Injustice. Environmental Justice. 8:213-219.   10.1089/env.2015.0022   AbstractWebsite

Environmental justice (EJ) research focuses on disproportionate population exposures to multiple point and non-point pollution sources. The hazardous pollutants released by waste incinerators can contribute to uneven (or unjust) spatial and social distributions of environmental risks. The EJ literature has already revealed that the geographical distribution of incinerators generates distinct social inequalities. In the French context, these inequalities are evident when considering the proportion of unemployed people, the proportion of recent immigrants and the proportion of persons born abroad (each increases the likelihood that a town hosts an incinerator). In this article, we seek to determine whether additional social injustices occur due to disproportionate quantities of incinerator emissions. We collected annual nitrogen oxide (NOx) emissions from all incinerators in France for 2009-2010. We found that incinerators in French municipalities with higher unemployment and higher proportions of immigrants and persons born abroad have higher NOx emission levels, even when controlling for population size and broader regional social and environmental deprivation indices. This indicates that incinerators in France generate higher social inequalities than initially thought, both due to their spatial distribution and to the amount of emissions they release. We recommend that unequal social impacts should be considered in waste management planning, facility siting decisions, and decisions affecting emission controls for existing and possible future incinerators in France.