Chimney stove intervention to reduce long-term wood smoke exposure lowers blood pressure among Guatemalan women

Exposure Contrasts of Women Aged 40-79 Years during the Household Air Pollution Intervention Network Randomized Controlled Trial

Exposure to household air pollution has been linked to adverse health outcomes among women aged 40-79. Little is known about how shifting from biomass cooking to a cleaner fuel like liquefied petroleum gas (LPG) could impact exposures for this population. We report 24-h exposures to particulate matter (PM2.5), black carbon (BC), and carbon monoxide (CO) among women aged 40 to <80 years participating in the Household Air Pollution Intervention Network trial. 209 participants were randomized to the intervention and received an LPG stove and continuous fuel supply; controls used biomass (n = 209). Exposures were measured up to six times; we used mixed-effects models to estimate differences between intervention and control groups. Preintervention exposures between groups were comparable; median postintervention exposures were 62% (76.3 vs 29.3 μg/m3), 73% (10.4 vs 2.8 μg/m3), and 57% (1.4 vs 0.6 ppm) lower for PM2.5, BC, and CO among LPG users than for controls. Reductions were similar across countries; 70% of PM2.5 exposures after intervention were below the annual WHO interim target I (IT-1) value of 35 μg/m3. We provide evidence that implementing an LPG intervention can reduce air pollution exposure over an 18-month period to at or below the annual WHO IT-1 guideline.

The effect of chimney fitted improved stove on kitchen fine particulate matter (PM2.5) concentrations in rural Ethiopia: Evidence from a randomized controlled trial

BACKGROUND

Millions of Ethiopian people cook with biomass fuels using traditional stoves, releasing harmful pollutants and contributing to a significant public health crisis. Improved stoves offer a potential escape route, but their effectiveness needs close scrutiny. This study delves into the impact of chimney-fitted stoves on kitchen PM2.5 concentrations in rural Ethiopian households.

METHOD

We conducted a randomized controlled trial with 86 households equally divided (1:1 ratio) between intervention and control groups. The 24-h average kitchen PM2.5 concentrations was measured using Particle and Temperature Sensor (PATS+) at baseline and after intervention. All relevant sociodemographic and cooking related characteristics were collected at baseline and dynamic characteristics were updated during air monitoring visits. Three distinct statistical models, including independent sample t-tests, paired sample t-tests and one-way analysis of variance were used to analyze the data using Statistical Package for the Social Sciences (SPSS) software for Windows (v 24.0).

RESULT

At baseline, the average 24-h kitchen PM2.5 concentrations were 482 μg/m3 (95% CI: 408, 557) for the control and 405 μg/m3 (95% CI: 318, 492) for the intervention groups. Despite remaining elevated at 449 μg/m3 (95% CI: 401, 496) in the control group, PM2.5 concentrations reduced to 104 μg/m3 (95% CI: 90,118) in the intervention group, indicating a statistically significant difference (t = 6.97, p < 0.001). All three statistical analyses delivered remarkably consistent results, estimating a PM2.5 reductions of 74% with the before-and-after approach, 76% when comparing groups, and 74% for difference in difference analysis. Beyond the overall reduction, homes with primary school completed women, larger kitchens, smaller family size, and those specifically baking Injera (the traditional energy-intensive staple food), witnessed even greater drops in PM2.5 levels.

CONCLUSION

Pregnant women in our study encountered dangerously high PM2.5 exposures in their kitchens. While the intervention achieved a significant PM2.5 reductions, unfortunately remained above the WHO's safe limit, highlighting the need for further interventions.

Household Air Pollution Interventions to Improve Health in Low- and Middle-Income Countries: An Official American Thoracic Society Research Statement

Background: An estimated 3 billion people, largely in low- and middle-income countries, rely on unclean fuels for cooking, heating, and lighting to meet household energy needs. The resulting exposure to household air pollution (HAP) is a leading cause of pneumonia, chronic lung disease, and other adverse health effects. In the last decade, randomized controlled trials of clean cooking interventions to reduce HAP have been conducted. We aim to provide guidance on how to interpret the findings of these trials and how they should inform policy makers and practitioners.Methods: We assembled a multidisciplinary working group of international researchers, public health practitioners, and policymakers with expertise in household air pollution from within academia, the American Thoracic Society, funders, nongovernmental organizations, and global organizations, including the World Bank and the World Health Organization. We performed a literature search, convened four sessions via web conference, and developed consensus conclusions and recommendations via the Delphi method.Results: The committee reached consensus on 14 conclusions and recommendations. Although some trials using cleaner-burning biomass stoves or cleaner-cooking fuels have reduced HAP exposure, the committee was divided (with 55% saying no and 45% saying yes) on whether the studied interventions improved measured health outcomes.Conclusions: HAP is associated with adverse health effects in observational studies. However, it remains unclear which household energy interventions reduce exposure, improve health, can be scaled, and are sustainable. Researchers should engage with policy makers and practitioners working to scale cleaner energy solutions to understand and address their information needs.

Prenatal Household Air Pollution Exposure and Childhood Blood Pressure in Rural Ghana

BACKGROUND

The association between prenatal household air pollution (HAP) exposure and childhood blood pressure (BP) is unknown.

OBJECTIVE

Within the Ghana Randomized Air Pollution and Health Study (GRAPHS) we examined time-varying associations between a) maternal prenatal and b) first-year-of-life HAP exposure with BP at 4 years of age and, separately, whether a stove intervention delivered prenatally and continued through the first year of life could improve BP at 4 years of age.

METHODS

GRAPHS was a cluster-randomized cookstove intervention trial wherein n = 1,414 pregnant women were randomized to one of two stove interventions: a) a liquefied petroleum gas (LPG) stove or improved biomass stove, or b) control (open fire cooking). Maternal HAP exposure over pregnancy and child HAP exposure over the first year of life was quantified by repeated carbon monoxide (CO) measurements; a subset of women (n = 368 ) also performed one prenatal and one postnatal personal fine particulate matter (PM 2.5 ) measurement. Systolic and diastolic BP (SBP and DBP) were measured in n = 667 4-y-old children along with their PM 2.5 exposure (n = 692 ). We examined the effect of the intervention on resting BP z -scores. We also employed reverse distributed lag models to examine time-varying associations between a) maternal prenatal and b) first-year-of-life HAP exposure and resting BP z -scores. Among those with PM 2.5 measures, we examined associations between PM 2.5 and resting BP z -scores. Sex-specific effects were considered.

RESULTS

Intention-to-treat analyses identified that DBP z -score at 4 years of age was lower among children born in the LPG arm (LPG β = - 0.20 ; 95% CI: - 0.36 , - 0.03 ) as compared with those in the control arm, and females were most susceptible to the intervention. Higher CO exposure in late gestation was associated with higher SBP and DBP z -score at 4 years of age, whereas higher late-first-year-of-life CO exposure was associated with higher DBP z -score. In the subset with PM 2.5 measurements, higher maternal postnatal PM 2.5 exposure was associated with higher SBP z -scores.

DISCUSSION

These findings suggest that prenatal and first-year-of-life HAP exposure are associated with child BP and support the need for reductions in exposure to HAP, with interventions such as cleaner cooking beginning in pregnancy. https://doi.org/10.1289/EHP13225.

Estimating personal exposures to household air pollution and plastic garbage burning among adolescent girls in Jalapa, Guatemala

Waste collection services are uncommon in rural areas of low-resource countries, causing waste accumulation and subsequent dumping and burning of garbage. Air pollution from household garbage burning, including plastics, has been observed in Jalapa, Guatemala in addition to household air pollution (HAP) from cooking. Adolescent girls often help with these cooking and household tasks, but little is known about their exposures. We characterized 24-h exposures to HAP and household garbage burning in adolescent girls by measuring fine particulate matter (PM2.5), black carbon (BC), urinary biomarkers of polycyclic aromatic hydrocarbons (PAHs), bisphenol A (BPA), and phthalates. We recruited 60 girls between 13 and 17 years of age who helped with cooking activities and lived with participants of the Household Air Pollution Intervention Network (HAPIN) trial. We recruited n = 30 girls each from the control (wood-burning stove) and intervention (liquefied petroleum gas stove) arms. We also measured real-time kitchen concentrations of BC in 20 homes (33%). PM2.5 and BC were measured in n = 21 control and n = 20 intervention participants. Median concentrations of personal PM2.5 and BC and kitchen BC were lower (p < 0.05) in the intervention arm by 87%, 80%, and 85%, respectively. PAH metabolite concentrations were lower (p < 0.001) for all nine metabolites in intervention (n = 26) compared to control participants (n = 29). Urinary BPA concentrations were 66% higher in participants who reported using cosmetics (p = 0.02), and phthalate concentrations were 63% higher in participants who had reported using hair products during the sample period (p = 0.05). Our results suggest that gas stoves can reduce HAP exposures among adolescents who are not primary cooks at home. Biomarkers of plastic exposure were not associated with intervention status, but some were elevated compared to age- and sex-matched participants of the National Health and Nutrition Examination Survey (NHANES).

Differential effects of PM2.5 and its carbon components on blood pressure in hypertensive and non-hypertensive populations: a panel study in Beijing

Published literature considering the association between ambient air pollution and blood pressure is highly inconsistent, which may be explained by the different proportions of susceptible subpopulations. We hypothesized that hypertensive patients are more sensitive to air pollution due to the disruption of neurohumoral system. The study aimed to reveal the association between PM2.5 and its carbon components and blood pressure, and whether this association is modified by hypertension status. We conducted a panel study in Beijing, China. Four repeated measurements were performed from 2016 to 2018. Linear mixed-effects models and generalized additive mixed models were performed to investigate the associations between PM2.5 and its carbon components and blood pressure. Subgroup analyses were performed by hypertension status to reveal potential effect modification. Among hypertensive patients, for every 1 μg/m3 increment of PM2.5, TC, OC, and EC in 1-day to 2-day MA, SBP increased from 0.16 mmHg (95% CI, 0.03 to 0.29) to 6.75 mmHg (95% CI, 2.82 to 10.68), and PP increased from 0.14 mmHg (95% CI, 0.02 to 0.26) to 6.03% (95% CI, 2.46 to 9.59%), but no significant association was observed among non-hypertensive subjects. The p values for the interaction between pollutants and hypertension status in 1-day to 2-day MA were less than 0.05. These findings suggest that hypertensive patients may be more susceptible to the adverse effects of air pollution than non-hypertensive subjects, which might provide guidance to hypertensive patients living in areas with high levels of particle pollution.

Systems toxicology of complex wood combustion aerosol reveals gaseous carbonyl compounds as critical constituents

Epidemiological studies identified air pollution as one of the prime causes for human morbidity and mortality, due to harmful effects mainly on the cardiovascular and respiratory systems. Damage to the lung leads to several severe diseases such as fibrosis, chronic obstructive pulmonary disease and cancer. Noxious environmental aerosols are comprised of a gas and particulate phase representing highly complex chemical mixtures composed of myriads of compounds. Although some critical pollutants, foremost particulate matter (PM), could be linked to adverse health effects, a comprehensive understanding of relevant biological mechanisms and detrimental aerosol constituents is still lacking. Here, we employed a systems toxicology approach focusing on wood combustion, an important source for air pollution, and demonstrate a key role of the gas phase, specifically carbonyls, in driving adverse effects. Transcriptional profiling and biochemical analysis of human lung cells exposed at the air-liquid-interface determined DNA damage and stress response, as well as perturbation of cellular metabolism, as major key events. Connectivity mapping revealed a high similarity of gene expression signatures induced by wood smoke and agents prompting DNA-protein crosslinks (DPCs). Indeed, various gaseous aldehydes were detected in wood smoke, which promote DPCs, initiate similar genomic responses and are responsible for DNA damage provoked by wood smoke. Hence, systems toxicology enables the discovery of critical constituents of complex mixtures i.e. aerosols and highlights the role of carbonyls on top of particulate matter as an important health hazard.

Assessing Lifetime Cancer Risk Associated with Population Exposure to PM-Bound PAHs and Carcinogenic Metals in Three Mid-Latitude Metropolitan Cities

Lifetime cancer risk characterization of ambient PM-bound carcinogenic metals and polycyclic aromatic hydrocarbons (PAHs) were examined in the cities of Los Angeles (USA), Thessaloniki (Greece) and Milan (Italy), which share similar Mediterranean climates but are different in their urban emission sources and governing air quality regulations. The samples in Milan and Thessaloniki were mostly dominated by biomass burning activities whereas the particles collected in Los Angeles were primary impacted by traffic emissions. We analyzed the ambient PM2.5 mass concentration of Cadmium (Cd), Hexavalent Chromium (Cr(VI)), Nickel (Ni), Lead (Pb), as well as 13 PAH compounds in the PM samples, collected during both cold and warm periods at each location. Pb exhibited the highest annual average concentration in all three cities, followed by Ni, As, Cr(VI), Cd and PAHs, respectively. The cancer risk assessment based on outdoor pollutants was performed based on three different scenarios, with each scenario corresponding to a different level of infiltration of outdoor pollutants into the indoor environment. Thessaloniki exhibited a high risk associated with lifetime inhalation of As, Cr(VI), and PAHs, with values in the range of (0.97-1.57) × 10-6, (1.80-2.91) × 10-6, and (0.77-1.25) × 10-6, respectively. The highest cancer risk values were calculated in Milan, exceeding the US EPA standard by a considerable margin, where the lifetime risk values of exposure to As, Cr(VI), and PAHs were in the range of (1.29-2.08) × 10-6, (6.08-9.82) × 10-6, and (1.10-1.77) × 10-6, respectively. In contrast, the estimated risks associated with PAHs and metals, except Cr(VI), in Los Angeles were extremely lower than the guideline value, even when the infiltration factor was assumed to be at peak. The lifetime cancer risk values associated with As, Cd, Ni, Pb, and PAHs in Los Angeles were in the range of (0.04-0.33) × 10-6. This observation highlights the impact of local air quality measures in improving the air quality and lowering the cancer risks in Los Angeles compared to the other two cities.

Impacts of household PM2.5 pollution on blood pressure of rural residents: Implication for clean energy transition

High blood pressure associated with PM_2.5 exposure is of great concern, especially for rural residents exposed to high PM_2.5 levels. However, the impact of short-term exposure to high PM_2.5 on blood pressure (BP) has not been well elucidated. Thus, this study aims to focus on the association between short-term PM_2.5 exposure with BP of rural residents and its variation between summer and winter. Our results showed that the summertime PM_2.5 exposure concentration was 49.3 ± 20.6 μg/m³, among which, mosquito coil users had 1.5-folds higher PM_2.5 exposure than non-mosquito coil users (63.6 ± 21.7 vs 43.0 ± 16.7 μg/m³, p < 0.05). The mean systolic and diastolic BP (SBP and DBP, respectively) of rural participants were 122 ± 18.2 and 76.2 ± 11.2 mmHg in summer, respectively. The PM_2.5 exposure, SBP, and DBP in summer were 70.7 μg/m³, 9.0 mmHg, and 2.8 mmHg lower than that in winter, respectively. Furthermore, the correlation between PM_2.5 exposure and SBP was stronger in winter than that in summer, possibly due to higher PM_2.5 exposure levels in winter. The transition of household energy from solid fuels in winter to clean fuels in summer would be benefit to the decline of PM_2.5 exposure as well as BP. Results from this study suggested that the reduction of PM_2.5 exposure would have positive effect on human health.

Can individual protective measures safeguard cardiopulmonary health from air pollution? A systematic review and meta-analysis

Evidence supporting the effect of individual protective measures (IPMs) on air pollution is relatively scarce. In this study, we performed a systematic review and meta-analysis to investigate the effects of air purifiers, air-purifying respirators, and cookstove changes on cardiopulmonary health outcomes. We searched PubMed, Scopus, and Web of Science until December 31, 2022, 90 articles and 39,760 participants were included. Two authors independently searched and selected the studies, extracted information, and assessed each study's quality and risk of bias. We performed meta-analyses when three or more studies were available for each IPMs, with comparable intervention and health outcome. Systematic review showed that IPMs were beneficial in children and elderly with asthma along with healthy individuals. Meta-analysis results showed a reduction in cardiopulmonary inflammation using air purifiers than in control groups (with sham/no filter) with a decrease in interleukin 6 by -0.247 μg/mL (95% confidence intervals [CI] = -0.413, -0.082). A sub-group analysis for air purifier as an IPMs in developing counties reduced fractional exhaled nitric oxide by -0.208 ppb (95% confidence intervals [CI] = -0.394, -0.022). However, evidence describing the effects of air purifying respirator and cook stove changes on cardiopulmonary outcomes remained insufficient. Therefore, air purifiers can serve as efficient IPMs against air pollution. The beneficial effect of air purifiers is likely to have a greater effect in developing countries than in developed countries.

Baseline associations between household air pollution exposure and blood pressure among pregnant women in the Household Air Pollution Intervention Network (HAPIN) multi-country randomized controlled trial

Cooking and heating using solid fuels can result in dangerous levels of exposure to household air pollution (HAP). HAPIN is an ongoing randomized controlled trial assessing the impact of a liquified petroleum gas stove and fuel intervention on HAP exposure and health in Guatemala, India, Peru, and Rwanda among households that rely primarily on solid cooking fuels. Given the potential impacts of HAP exposure on cardiovascular outcomes during pregnancy, we seek to characterize the relationship between personal exposures to HAP and blood pressure among pregnant women at baseline (prior to intervention) in the study. We assessed associations between PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm), BC (black carbon), and CO (carbon monoxide) exposures and blood pressure at baseline, prior to intervention, among 3195 pregnant women between 9 and 19 weeks of gestation. We measured 24-hour personal exposure to PM2.5/BC/CO and gestational blood pressure. Multivariable linear regression models were used to evaluate associations between personal exposures to three air pollutants and blood pressure parameters. Trial-wide, we found moderate increases in systolic blood pressure (SBP) and decreases in diastolic blood pressure (DBP) as exposure to PM2.5, BC, and CO increased. None of these associations, however, were significant at the 0.05 level. HAP exposure and blood pressure associations were inconsistent in direction and magnitude within each country. We observed effect modification by body mass index (BMI) in India and Peru. Compared to women with normal weights, obese women in India and Peru (but not in Rwanda or Guatemala) had higher SBP per unit increase in log transformed PM2.5 and BC exposures. We did not find a cross-sectional association between HAP exposure and blood pressure in pregnant women; however, HAP may be associated with higher blood pressure in pregnant women who are obese, but this increase was not consistent across settings.

Environment and chronic disease in rural areas of Heilongjiang, China (ECDRAHC)

PURPOSE

Environmental factors such as long-term exposure to cold can increase the risk of chronic diseases. However, few studies have focused on the impact of environmental factors and lifestyle changes on chronic diseases. To fully explore the association between exposure to environmental factors and the prevalent risk of various chronic diseases, we conducted a large cohort study (Environment and Chronic Disease in Rural Areas of Heilongjiang, China (ECDRAHC)). The ECDRAHC collected detailed questionnaire data covering 10 sections, physical measurements and blood and urine samples. In this study, we describe the design and implementation of the cohort study and present the findings for the first 10 000 participants.

PARTICIPANTS

The ECDRAHC study was carried out in rural areas where the annual average temperature is 2.9°C, and aimed to recruit 40 000 participants who are long-term residents aged 35-74 years. The participants will be followed up every 5 years. Currently, ECDRAHC has reached 26.7% (n=10 694) of the targeted population.

FINDINGS TO DATE

A total of 10 694 adults aged 35-74 years were recruited, including 61.7% women. The prevalence of current smokers was 46.8% in men and 35.4% in women. The mean blood pressure was 140.2/89.9 mm Hg and 135.7/85.0 mm Hg in men and women, respectively. The mean body mass index was 24.74 kg/m² in men and 24.65 kg/m² in women, with >7.3% being obese (>30 kg/m²). The main non-communicable diseases found in phase 1 were hypertension, diabetes, hypertriglyceridaemia and metabolic syndrome, with a higher prevalence of 51.0%, 21.6%, 46.8% and 42.6%, respectively.

FUTURE PLANS

We plan to complete the follow-up for the first phase of the ECDRAHC in 2024. The second and third phase of the cohort will be carried out steadily, as planned. This cohort will be used to investigate the relationship between environmental factors, lifestyle, and genetic and common chronic diseases.

Association between solid fuel use and nonfatal cardiovascular disease among middle-aged and older adults: Findings from The China Health and Retirement Longitudinal Study (CHARLS)

BACKGROUND

Few studies have been conducted on the association between domestic solid fuel combustion and incident nonfatal cardiovascular disease (CVD). We assessed the prospective association between domestic fuel type and incident nonfatal CVD among Chinese adults aged ≥45 years.

METHODS

This was a prospective cohort study using data from the China Longitudinal Study of Health and Retirement (CHARLS) that recruited 8803 participants ≥45 years in 2013. Household fuel types were assessed based on self-reports, including solid fuel (coal, crop residue, or wood fuel) and clean fuel (central heating, solar power, natural gas, liquefied petroleum gas, electricity, or marsh gas). Nonfatal CVD was defined as self-reported physician-diagnosed nonfatal CVD. We established Cox proportional hazard regression models with age as the time scale and strata by sex to evaluate the hazard ratios (HRs) and 95 % confidence intervals (95 % CIs).

RESULTS

After a median follow-up of five years, 970 (11.02 %) nonfatal CVD cases were documented, including 423 (9.96 %) in males and 547 (12.01 %) in females. Participants with exposure to solid fuel for cooking and clean fuel for heating [HR (95 % CI):2.01 (1.36-2.96)], solid fuel for heating and clean fuel for cooking [HR (95 % CI):1.45 (1.06-1.99)], and solid fuel for both heating and cooking [HR (95 % CI):1.43 (1.07-1.92)] had an elevated nonfatal CVD risk compared to users of cleaner fuel for both cooking and heating. Those whom self-reported switching from solid fuels to cleaner fuels for cooking had significantly decreased nonfatal CVD risk [HR (95 % CI):0.76 (0.58-0.99)] than participants who did not switch to cleaner fuels.

CONCLUSIONS

Exposure to domestic solid fuel burning for cooking or heating is associated with an elevated nonfatal CVD risk. Notably, switching cooking fuels from solid to cleaner fuels is related to a reduced risk of nonfatal CVD.

Countrywide cardiovascular disease prevention and control in 49 countries with different socio-economic status

Background

Cardiovascular disease (CVD) is the major noncommunicable disease (NCD) accounting for 17.9 million deaths. If current trends continue, the annual number of deaths from CVD will rise to 22.2 million by 2030. The United Nations General Assembly adopted a sustainable development goal (SDG) by 2030 to reduce NCD mortality by one-third. The purpose of this study was to analyze the CVD mortality trends in different countries implementing World Health Organization (WHO) NCD Action Plan and emphasize effective ways to achieve SDG.

Methods

WHO statistics, based on the Member-States unified mortality and causes-of-death reports were used for analyzing trends and different interventions.

Results

Reduction of CVD mortality from 2000 to 2016 in 49 countries was achieved for stroke at 43% and ischemic heart disease at 30%. Smoking prevalence and raised blood pressure (RBP) decreased in 84% and 55% of the countries. Eighty-nine percent of high-income countries (HIC) demonstrated a decline in tobacco smoking against 67% in middle-income countries (MIC). Sixty-nine percent of HIC demonstrated a decline in RBP against 15% in MIC. CVD management, tobacco, and unhealthy diet reduction measures are significantly better in HIC. The air pollution level was higher in MIC.

Conclusion

Building partnerships between countries could enhance their efforts for CVD prevention and successful achievement of SDG.

Cross-sectional analysis of the association between personal exposure to household air pollution and blood pressure in adult women: Evidence from the multi-country Household Air Pollution Intervention Network (HAPIN) trial

Elevated blood pressure (BP) is a leading risk factor for the global burden of disease. Household air pollution (HAP), resulting from the burning of biomass fuels, may be an important cause of elevated BP in resource-poor communities. We examined the exposure-response relationship of personal exposures to HAP -fine particulate matter (PM2.5), carbon monoxide (CO), and black carbon (BC) - with BP measures in women aged 40-79 years across four resource-poor settings in Guatemala, Peru, India and Rwanda. BP was obtained within a day of 24-h personal exposure measurements at baseline, when participants were using biomass for cooking. We used generalized additive models to characterize the shape of the association between BP and HAP, accounting for the interaction of personal exposures and age and adjusting for a priori identified confounders. A total of 418 women (mean age 52.2 ± 7.9 years) were included in this analysis. The interquartile range of exposures to PM2.5 was 42.9-139.5 μg/m3, BC was 6.4-16.1 μg/m3, and CO was 0.5-2.9 ppm. Both SBP and PP were positively associated with PM2.5 exposure in older aged women, achieving statistical significance around 60 years of age. The exact threshold varied by BP measure and PM2.5 exposures being compared. For example, SBP of women aged 65 years was on average 10.8 mm Hg (95% CI 1.0-20.6) higher at 232 μg/m3 of PM2.5 exposure (90th percentile) when compared to that of women of the same age with personal exposures of 10 μg/m3. PP in women aged 65 years was higher for exposures ≥90 μg/m3, with mean differences of 6.1 mm Hg (95% CI 1.8-10.5) and 9.2 mm Hg (95% CI 3.3-15.1) at 139 (75th percentile) and 232 μg/m3 (90th percentile) respectively, when compared to that of women of the same age with PM2.5 exposures of 10 μg/m3. Our findings suggest that reducing HAP exposures may help to reduce BP, particularly among older women.

The Impact of Fine Particulate Matter 2.5 on the Cardiovascular System: A Review of the Invisible Killer

Air pollution exerts several deleterious effects on the cardiovascular system, with cardiovascular disease (CVD) accounting for 80% of all premature deaths caused by air pollution. Short-term exposure to particulate matter 2.5 (PM_2.5) leads to acute CVD-associated deaths and nonfatal events, whereas long-term exposure increases CVD-associated risk of death and reduces longevity. Here, we summarize published data illustrating how PM_2.5 may impact the cardiovascular system to provide information on the mechanisms by which it may contribute to CVDs. We provide an overview of PM_2.5, its associated health risks, global statistics, mechanistic underpinnings related to mitochondria, and hazardous biological effects. We elaborate on the association between PM_2.5 exposure and CVD development and examine preventive PM_2.5 exposure measures and future strategies for combating PM_2.5-related adverse health effects. The insights gained can provide critical guidelines for preventing pollution-related CVDs through governmental, societal, and personal measures, thereby benefitting humanity and slowing climate change.

Effects of a Liquefied Petroleum Gas Stove Intervention on Gestational Blood Pressure: Intention-to-Treat and Exposure-Response Findings From the HAPIN Trial

BACKGROUND

Approximately 3 to 4 billion people worldwide are exposed to household air pollution, which has been associated with increased blood pressure (BP) in pregnant women in some studies.

METHODS

We recruited 3195 pregnant women in Guatemala, India, Peru, and Rwanda and randomly assigned them to intervention or control groups. The intervention group received a gas stove and fuel during pregnancy, while the controls continued cooking with solid fuels. We measured BP and personal exposure to PM2.5, black carbon and carbon monoxide 3× during gestation. We conducted an intention-to-treat and exposure-response analysis to determine if household air pollution exposure was associated with increased gestational BP.

RESULTS

Median 24-hour PM2.5 dropped from 84 to 24 μg/m3 after the intervention; black carbon and carbon monoxide decreased similarly. Intention-to-treat analyses showed an increase in systolic BP and diastolic BP in both arms during gestation, as expected, but the increase was greater in intervention group for both systolic BP (0.69 mm Hg [0.03-1.35]; P=0.04) and diastolic BP (0.62 mm Hg [0.05-1.19]; P=0.03). The exposure-response analyses suggested that higher exposures to household air pollution were associated with moderately higher systolic BP and diastolic BP; however, none of these associations reached conventional statistical significance.

CONCLUSIONS

In intention-to-treat, we found higher gestational BP in the intervention group compared with controls, contrary to expected. In exposure-response analyses, we found a slight increase in BP with higher exposure, but it was not statistically significant. Overall, an intervention with gas stoves did not markedly affect gestational BP.

Association between personal exposure to household air pollution and gestational blood pressure among women using solid cooking fuels in rural Tamil Nadu, India

BACKGROUND

The Household Air Pollution Intervention Network (HAPIN) trial is an ongoing multi-center randomized controlled trial assessing the impact of a liquified petroleum gas (LPG) cookstove and fuel intervention on health. Given the potential impacts of household air pollution (HAP) exposure from burning solid fuels on cardiovascular health during pregnancy, we sought to determine whether baseline exposures to particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5), black carbon (BC) and carbon monoxide (CO) were associated with blood pressure among 799 pregnant women in Tamil Nadu, India, one of the HAPIN trial centers.

METHODS

Multivariable linear regression models were used to examine the association between 24-h personal exposure to PM2.5/BC/CO and systolic and diastolic blood pressure, controlling for maternal age, body mass index (BMI), mother's education, household wealth, gestational age, and season. At the time of measurement, women were between 9- and 20-weeks of gestation.

RESULTS

We found that systolic blood pressure (SBP) and diastolic blood pressure (DBP) were higher in pregnant women exposed to higher levels of HAP, though only the result for CO and DBP reached conventional statistical significance (p < 0.05). We observed a positive association between CO and DBP among the entire study cohort: a 1-log μg/m3 increase in CO exposure was associated with 0.36 mmHg higher DBP (95% confidence interval [CI]: 0.02 to 0.70). The effect was stronger in pregnant women with higher CO exposures (in the 3rd [≥ 0.9 and < 2.1 ppm] and 4th quartiles [≥ 2.1 and ≤ 46.9 ppm]). We also found that pregnant women with PM2.5 exposures in the highest quartile (≥ 129.9 and ≤ 2100 μg/m3) had a borderline significant association (p = 0.054) with DBP compared to those who had PM2.5 exposures in the lowest quartile (≥ 9.4 and < 47.7 μg/m3). No evidence of association was observed for BC exposure and blood pressure.

CONCLUSION

This study contributes to limited evidence regarding the relationship between HAP exposure and blood pressure among women during pregnancy, a critical window for both mother and child's life-course health. Results from this cross-sectional study suggest that exposures to PM2.5 and CO from solid fuel use are associated with higher blood pressure in pregnant women during their first or second trimester.

Metabolic syndrome in rural Peruvian adults living at high altitudes using different cookstoves

This study determined the prevalence of metabolic syndrome (MetS) in open fire stoves and improved cookstoves users (ICS) in the rural Peruvian Andes. Participants answered a socioeconomic questionnaire, one 24-hour food recall and underwent a physical examination. We analysed data from 385 participants, 190 (112 women and 78 men) were ICS users and 195 (123 women and 72 men) were open fire stove users. The prevalence of MetS was 21.3, 26.4% in women and 13.3% in men. We found no statistically significant association between the type of cookstove and MetS. Body mass index and altitude were important determinants of MetS. Research on cardiometabolic diseases and open fire stove use contributes to understanding the effect of household air pollution on health in high altitude populations.

Effects of a Household Air Pollution Intervention with Liquefied Petroleum Gas on Cardiopulmonary Outcomes in Peru. A Randomized Controlled Trial

Rationale: Approximately 40% of people worldwide are exposed to household air pollution (HAP) from the burning of biomass fuels. Previous efforts to document health benefits of HAP mitigation have been stymied by an inability to lower emissions to target levels. Objectives: We sought to determine if a household air pollution intervention with liquefied petroleum gas (LPG) improved cardiopulmonary health outcomes in adult women living in a resource-poor setting in Peru. Methods: We conducted a randomized controlled field trial in 180 women aged 25-64 years living in rural Puno, Peru. Intervention women received an LPG stove, continuous fuel delivery for 1 year, education, and behavioral messaging, whereas control women were asked to continue their usual cooking practices. We assessed for stove use adherence using temperature loggers installed in both LPG and biomass stoves of intervention households. Measurements and Main Results: We measured blood pressure, peak expiratory flow (PEF), and respiratory symptoms using the St. George's Respiratory Questionnaire at baseline and at 3-4 visits after randomization. Intervention women used their LPG stove exclusively for 98% of days. We did not find differences in average postrandomization systolic blood pressure (intervention - control 0.7 mm Hg; 95% confidence interval, -2.1 to 3.4), diastolic blood pressure (0.3 mm Hg; -1.5 to 2.0), prebronchodilator peak expiratory flow/height² (0.14 L/s/m²; -0.02 to 0.29), postbronchodilator peak expiratory flow/height² (0.11 L/s/m²; -0.05 to 0.27), or St. George's Respiratory Questionnaire total score (-1.4; -3.9 to 1.2) over 1 year in intention-to-treat analysis. There were no reported harms related to the intervention. Conclusions: We did not find evidence of a difference in blood pressure, lung function, or respiratory symptoms during the year-long intervention with LPG. Clinical trial registered with www.clinicaltrials.gov (NCT02994680).

The effect of clean cooking interventions on mother and child personal exposure to air pollution: results from the Ghana Randomized Air Pollution and Health Study (GRAPHS)

BACKGROUND

Clean cooking interventions to reduce air pollution exposure from burning biomass for daily cooking and heating needs have the potential to reduce a large burden of disease globally.

OBJECTIVE

The objective of this study is to evaluate the air pollution exposure impacts of a fan-assisted efficient biomass-burning cookstove and a liquefied petroleum gas (LPG) stove intervention in rural Ghana.

METHODS

We randomized 1414 households in rural Ghana with pregnant mothers into a control arm (N = 526) or one of two clean cooking intervention arms: a fan-assisted efficient biomass-burning cookstove (N = 527) or an LPG stove and cylinder refills as needed (N = 361). We monitored personal maternal carbon monoxide (CO) at baseline and six times after intervention and fine particulate matter (PM_2.5) exposure twice after intervention. Children received three CO exposure monitoring sessions.

RESULTS

We obtained 5655 48-h maternal CO exposure estimates and 1903 for children, as well as 1379 maternal PM_2.5 exposure estimates. Median baseline CO exposures in the control, improved biomass, and LPG arms were 1.17, 1.17, and 1.30 ppm, respectively. Based on a differences-in-differences approach, the LPG arm showed a 47% reduction (95% confidence interval: 34-57%) in mean 48-h CO exposure compared to the control arm. Mean maternal PM_2.5 exposure in the LPG arm was 32% lower than the control arm during the post-intervention period (52 ± 29 vs. 77 ± 44 μg/m³). The biomass stove did not meaningfully reduce CO or PM_2.5 exposure.

CONCLUSIONS

We show that LPG interventions lowered air pollution exposure significantly compared to three-stone fires. However, post-intervention exposures still exceeded health-relevant targets.

SIGNIFICANCE

In a large controlled trial of cleaner cooking interventions, an LPG stove and fuel intervention reduced air pollution exposure in a vulnerable population in a low-resource setting.

The effect of clean cooking interventions on mother and child personal exposure to air pollution: results from the Ghana Randomized Air Pollution and Health Study (GRAPHS)

BACKGROUND

Clean cooking interventions to reduce air pollution exposure from burning biomass for daily cooking and heating needs have the potential to reduce a large burden of disease globally.

OBJECTIVE

The objective of this study is to evaluate the air pollution exposure impacts of a fan-assisted efficient biomass-burning cookstove and a liquefied petroleum gas (LPG) stove intervention in rural Ghana.

METHODS

We randomized 1414 households in rural Ghana with pregnant mothers into a control arm (N = 526) or one of two clean cooking intervention arms: a fan-assisted efficient biomass-burning cookstove (N = 527) or an LPG stove and cylinder refills as needed (N = 361). We monitored personal maternal carbon monoxide (CO) at baseline and six times after intervention and fine particulate matter (PM2.5) exposure twice after intervention. Children received three CO exposure monitoring sessions.

RESULTS

We obtained 5655 48-h maternal CO exposure estimates and 1903 for children, as well as 1379 maternal PM2.5 exposure estimates. Median baseline CO exposures in the control, improved biomass, and LPG arms were 1.17, 1.17, and 1.30 ppm, respectively. Based on a differences-in-differences approach, the LPG arm showed a 47% reduction (95% confidence interval: 34-57%) in mean 48-h CO exposure compared to the control arm. Mean maternal PM2.5 exposure in the LPG arm was 32% lower than the control arm during the post-intervention period (52 ± 29 vs. 77 ± 44 μg/m3). The biomass stove did not meaningfully reduce CO or PM2.5 exposure.

CONCLUSIONS

We show that LPG interventions lowered air pollution exposure significantly compared to three-stone fires. However, post-intervention exposures still exceeded health-relevant targets.

SIGNIFICANCE

In a large controlled trial of cleaner cooking interventions, an LPG stove and fuel intervention reduced air pollution exposure in a vulnerable population in a low-resource setting.

Impact of the wood-burning Justa cookstove on fine particulate matter exposure: A stepped-wedge randomized trial in rural Honduras

TRIAL DESIGN

We evaluated the impact of a biomass stove intervention on fine particulate matter (PM2.5) concentrations using an individual-level, stepped-wedge randomized trial.

METHODS

We enrolled 230 women in rural Honduran households using traditional biomass stoves and randomly allocated them to one of two study arms. The Justa stove, the study intervention, was locally-sourced, wood-burning, and included an engineered combustion chamber and chimney. At each of 6 visits over 3 years, we measured 24-hour gravimetric personal and kitchen PM2.5 concentrations. Half of the households received the intervention after Visit 2 and half after Visit 4. We conducted intent-to-treat analyses to evaluate the intervention effect using linear mixed models with log-transformed kitchen or personal PM2.5 (separately) as the dependent variable, adjusting for time. We also compared PM2.5 concentrations to World Health Organization (WHO) guidelines.

RESULTS

Arms 1 and 2 each had 115 participants with 664 and 632 completed visits, respectively. Median 24-hour average personal PM2.5 exposures were 81 μg/m3 (25th-75th percentile: 50-141 μg/m3) for the traditional stove condition (n=622) and 43 μg/m3 (25th-75th percentile: 27-73 μg/m3) for the Justa stove condition (n=585). Median 24-hour average kitchen concentrations were 178 μg/m3 (25th-75th percentile: 69-440 μg/m3; n=629) and 53 μg/m3 (25th-75th percentile: 29-103 μg/m3; n=578) for the traditional and Justa stove conditions, respectively. The Justa intervention resulted in a 32% reduction in geometric mean personal PM2.5 (95% confidence interval [CI]: 20-43%) and a 56% reduction (95% CI: 46-65%) in geometric mean kitchen PM2.5. During rainy and dry seasons, 53% and 41% of participants with the Justa intervention had 24-hour average personal PM2.5 exposures below the WHO interim target-3 guideline (37.5 μg/m3), respectively.

CONCLUSION

The Justa stove intervention substantially lowered personal and kitchen PM2.5 and may be a provisional solution that is feasible for Latin American communities where cleaner fuels may not be available, affordable, or acceptable for some time. Clinicaltrials.gov: NCT02658383.

Contributions of biomass/solid fuel burning to blood pressure modification in women: A systematic review and meta-analysis

OBJECTIVES

Approximately 2½ billion people worldwide rely on solid/biomass fuel as fuel for cooking/heating the home. Environmental exposure to the smoke associated with biomass fuel burning has been associated respiratory diseases, cardiac disorders, and altered blood pressure. Therefore, a systematic review and meta-analysis was conducted to study this relationship across multiple studies.

METHODS

Searches were performed using PRISMA guidelines for articles using Web of Science, PubMed, Toxline, and Web of Science of peer reviewed papers with no beginning time restriction until February 2017. The search yielded 10 manuscripts after application of inclusion criteria, which encompassed 93 724 participants. Outcomes included (a) the proportion of people with a clinical diagnosis of hypertension in an exposed (vs. unexposed) population or (b) correlation coefficients examining degree of exposure and systolic/diastolic blood pressure.

RESULTS

The four studies reporting effect sizes for hypertension (N = 92 042) had a weighted mean effect size of r = .12 [-0.02, 0.27], z = 1.66, p = 0.097. The six studies reporting effect sizes for systolic and diastolic blood pressure (N = 1682) had weighted mean effect sizes of r = .15 [0.06, 0.24], p = 0.001, and r = .09 [0.03, 0.15], p = 0.002, respectively.

CONCLUSION

These analyses revealed that there is a small-but-significant relationship between biomass fuel exposure and an increase in both systolic and diastolic blood pressure, but the relationship between biomass fuel and hypertension specifically remains unclear.

Heterogeneous Urban Exposures and Prevalent Hypertension in the Helsinki Capital Region, Finland

Urban dwellers are simultaneously exposed to several environmental health risk factors. This study aimed to examine the relationship between long-term exposure to fine particulate matter (PM_2.5, diameter < 2.5 µm) of residential-wood-burning and road-traffic origin, road-traffic noise, green space around participants’ homes, and hypertension. In 2015 and 2016, we conducted a survey of residents of the Helsinki Capital Region to determine their perceptions of environmental quality and safety, lifestyles, and health statuses. Recent antihypertensive medication was used as an indicator of current hypertensive illness. Individual-level exposure was estimated by linking residential coordinates with modelled outdoor levels of wood-smoke- and traffic-related PM_2.5, road-traffic noise, and coverage of natural spaces. Relationships between exposure and hypertension were modelled using multi-exposure and single-exposure binary logistic regression while taking smooth functions into account. Twenty-eight percent of the participants were current users of antihypertensive medication. The odds ratios (95% confidence interval) for antihypertensive use were 1.12 (0.78–1.57); 0.97 (0.76–1.26); 0.98 (0.93–1.04) and 0.99 (0.94–1.04) for wood-smoke PM_2.5, road-traffic PM_2.5, road-traffic noise, and coverage of green space, respectively. We found no evidence of an effect of the investigated urban exposures on prevalent hypertension in the Helsinki Capital Region.

Short-term differences in cardiac function following controlled exposure to cookstove air pollution: The subclinical tests on volunteers exposed to smoke (STOVES) study

BACKGROUND

Exposure to household air pollution from solid fuel combustion for cooking and heating is an important risk factor for premature death and disability worldwide. Current evidence supports an association of ambient air pollution with cardiovascular disease but is limited for household air pollution and for cardiac function. Controlled exposure studies can complement evidence provided by field studies.

OBJECTIVES

To investigate effects of short-term, controlled exposures to emissions from five cookstoves on measures of cardiac function.

METHODS

Forty-eight healthy adults (46% female; 20-36 years) participated in six, 2-h exposures ('treatments'), including emissions from five cookstoves and a filtered-air control. Target fine particulate matter (PM2.5) exposure-concentrations per treatment were: control, 0 µg/m3; liquefied petroleum gas, 10 µg/m3; gasifier, 35 µg/m3; fan rocket, 100 µg/m3; rocket elbow, 250 µg/m3; and three stone fire, 500 µg/m3. Participants were treated in a set (pre-randomized) sequence as groups of 4 to minimize order bias and time-varying confounders. Heart rate variability (HRV) and cardiac repolarization metrics were calculated as 5-min means immediately and at 3 h following treatment, for analysis in linear mixed-effects models comparing cookstove to control.

RESULTS

Short-term differences in SDNN (standard deviation of duration of all NN intervals) and VLF (very-low frequency power) existed for several cookstoves compared to control. While all cookstoves compared to control followed a similar trend for SDNN, the greatest effect was seen immediately following three stone fire (β = -0.13 ms {%}; 95% confidence interval = -0.22, -0.03%), which reversed in direction at 3 h (0.03%; -0.06, 0.13%). VLF results were similar in direction and timing to SDNN; however, other HRV or cardiac repolarization results were not similar to those for SDNN.

DISCUSSION

We observed some evidence of short-term, effects on HRV immediately following cookstove treatments compared to control. Our results suggest that cookstoves with lower PM2.5 emissions are potentially capable of affecting cardiac function, similar to stoves emitting higher PM2.5 emissions.

Health Benefits of Air Pollution Reduction

Air pollution is a grave risk to human health that affects nearly everyone in the world and nearly every organ in the body. Fortunately, it is largely a preventable risk. Reducing pollution at its source can have a rapid and substantial impact on health. Within a few weeks, respiratory and irritation symptoms, such as shortness of breath, cough, phlegm, and sore throat, disappear; school absenteeism, clinic visits, hospitalizations, premature births, cardiovascular illness and death, and all-cause mortality decrease significantly. The interventions are cost-effective. Reducing factors causing air pollution and climate change have strong cobenefits. Although regions with high air pollution have the greatest potential for health benefits, health improvements continue to be associated with pollution decreases even below international standards. The large response to and short time needed for benefits of these interventions emphasize the urgency of improving global air quality and the importance of increasing efforts to reduce pollution at local levels.

Household air pollution and personal exposure from burning firewood and yak dung in summer in the eastern Tibetan Plateau

This study assessed the sources, magnitudes, and chemical compositions of household air pollution (HAP) and personal exposure in traditional Tibetan households. We measured 24-h personal exposures to PM_2.5 and kitchen area black carbon (BC) concentrations, using MicroPEMs and microAeths, respectively. Particulate polycyclic aromatic hydrocarbon (PAH) and inorganic element concentrations were quantified via post analyses of a subset of MicroPEM sample filters. Household surveys regarding participant demographics, cookstove usage, household fuel, cooking behaviors, and lifestyles were collected. The results reaffirm that burning firewood and yak dung, mainly for cooking, leads to high PM_2.5 and BC exposures. The geometric mean concentration (95% confidence interval, CI) was 74.3 (53.6, 103) μg/m³ for PM_2.5 and the arithmetic mean ± standard deviation (SD) concentration was 4.90 ± 5.01 μg/m³ for BC and 292 ± 364 ng/m³ for 15 identified PAHs, respectively. The arithmetic mean ± SD of mass concentrations of 24 detected elements ranged from 0.76 ± 0.91 ng/m³ (Co) to 1.31 ± 1.35 μg/m³ (Si). Our statistical analyses further illustrated that the high concentrations of PM_2.5, BC, and most PAHs and metals, are significantly associated with nomadic village, poorer stove/chimney conditions and yak dung burning. The results from this study show that substantial HAP exposure is prevalent in Tibetan households and requires immediate actions to mitigate potential negative environmental health impacts. The observational data also revealed the possibility of other important sources (e.g. traffic and garbage burning) that have contributed to personal exposures. These findings improve our understanding of HAP exposure and potential health risks in Tibetan communities and will help inform strategies for reducing HAP in Tibetan households and beyond.

The Association of Cooking Fuel Use, Dietary Intake, and Blood Pressure among Rural Women in China

Household air pollution (HAP) from solid cooking fuels continues to affect 600 million people in China and has been associated with high blood pressure. The role of diet in HAP-associated high blood pressure has yet to be evaluated in China. The aim of this study was to estimate the impact of cooking fuel on change in blood pressure and evaluate whether intake of antioxidant- and omega-3 fatty acid-rich foods (fruits, vegetables, and seafood) attenuates any adverse effects of solid fuel use on blood pressure. We analyzed longitudinal data collected between 1991 and 2011 from nonpregnant women aged 18 to 80 years living in rural areas of China. We used linear mixed effects models to estimate the association between cooking fuel (coal or wood versus clean [electric or liquid petroleum gas]) and blood pressure. Possible mediation of the fuel effect by diet was assessed by the difference method. A total of 6671 women were included in this study. Women less than 40 years of age cooking with cleaner fuels over time had lower rates of change in systolic blood pressure compared to women cooking with coal (p = 0.004), and this effect was not mediated by dietary intake. Associations between fuel use and change in diastolic blood pressure were not significant. These findings lend further support for there being a direct effect of reducing HAP on improvements in blood pressure, independent of concurrent dietary intake.

Health effects of household air pollution related to biomass cook stoves in resource limited countries and its mitigation by improved cookstoves

BACKGROUND

Household air pollution (HAP) related to cooking is associated with significant global morbidity and mortality. An estimated three billion people worldwide are exposed to cooking related HAP caused by solid fuel combustion. This exposure is highest for the vulnerable population of women and children resulting in significant cumulative health effects.

METHODS

A literature review was conducted for health effects of household air pollution related to biomass cookstoves in resource limited countries and to evaluate the effect of improved cookstoves on these health effects. We searched PubMed, Embase and Cochrane Library. We conducted searches in January 2018 with a repeat in February 2020. We included only studies conducted in resource limited countries, published in English, irrespective of publication year and studies that examined the health effects of HAP and/or studied the effects of improved cookstove (IC). Two authors independently screened journal article titles, abstracts and full-text articles to identify those that included the following search term: biomass cookstoves and health risks. We also assessed the limitations of IC with barriers to their uptake.

RESULTS

Health effects associated with HAP mostly include increased blood pressure (BP), dyspnea, childhood pneumonia, lung cancer, low birthweight and cardiovascular diseases. Being a global problem with divergent environmental factors including wide variety of fuel used, housing condition, foods prepared, climatic condition and social factors; most solutions though efficient seems inadequate. Improved cookstove (IC) mitigates emissions and improves short term health, though few randomized long-term studies could substantiate its long-standing continuance and health benefits.

CONCLUSION

There is ample data about the health effects of HAP, with some benefit with IC intervention for elevated blood pressure, dyspnea symptoms, mutagenicity and cardiovascular diseases. IC does not have any benefit in pregnancy outcomes or children health.

Long-term exposure to outdoor and household air pollution and blood pressure in the Prospective Urban and Rural Epidemiological (PURE) study

Exposure to air pollution has been linked to elevated blood pressure (BP) and hypertension, but most research has focused on short-term (hours, days, or months) exposures at relatively low concentrations. We examined the associations between long-term (3-year average) concentrations of outdoor PM2.5 and household air pollution (HAP) from cooking with solid fuels with BP and hypertension in the Prospective Urban and Rural Epidemiology (PURE) study. Outdoor PM2.5 exposures were estimated at year of enrollment for 137,809 adults aged 35-70 years from 640 urban and rural communities in 21 countries using satellite and ground-based methods. Primary use of solid fuel for cooking was used as an indicator of HAP exposure, with analyses restricted to rural participants (n = 43,313) in 27 study centers in 10 countries. BP was measured following a standardized procedure and associations with air pollution examined with mixed-effect regression models, after adjustment for a comprehensive set of potential confounding factors. Baseline outdoor PM2.5 exposure ranged from 3 to 97 μg/m3 across study communities and was associated with an increased odds ratio (OR) of 1.04 (95% CI: 1.01, 1.07) for hypertension, per 10 μg/m3 increase in concentration. This association demonstrated non-linearity and was strongest for the fourth (PM2.5 > 62 μg/m3) compared to the first (PM2.5 < 14 μg/m3) quartiles (OR = 1.36, 95% CI: 1.10, 1.69). Similar non-linear patterns were observed for systolic BP (β = 2.15 mmHg, 95% CI: -0.59, 4.89) and diastolic BP (β = 1.35, 95% CI: -0.20, 2.89), while there was no overall increase in ORs across the full exposure distribution. Individuals who used solid fuels for cooking had lower BP measures compared to clean fuel users (e.g. 34% of solid fuels users compared to 42% of clean fuel users had hypertension), and even in fully adjusted models had slightly decreased odds of hypertension (OR = 0.93; 95% CI: 0.88, 0.99) and reductions in systolic (-0.51 mmHg; 95% CI: -0.99, -0.03) and diastolic (-0.46 mmHg; 95% CI: -0.75, -0.18) BP. In this large international multi-center study, chronic exposures to outdoor PM2.5 was associated with increased BP and hypertension while there were small inverse associations with HAP.

Quantifying the Environmental Impacts of Cookstove Transitions: A Societal Exergy Analysis Based Model of Energy Consumption and Forest Stocks in Honduras

Unsustainable consumption of biofuels contributes to deforestation and climate change, while household air pollution from burning solid biofuels in homes results in millions of premature deaths globally every year. Honduras, like many low and medium Human Development Index countries, depends on primary solid biofuels for more than 30% of its primary energy supply (as of 2013). We conducted a societal exergy analysis and developed a forest stock model for Honduras for 1971–2013 and used the results to model an energy transition from traditional wood stoves to either improved efficiency wood cookstoves or modern fuel cookstoves (using Electricity or Liquefied petroleum gas) over the period 2013–2050. The exergy analysis and forest model enabled quantification of the environmental tradeoffs between the improved efficiency and fuel switching scenarios. We find that the continued reliance on wood within both the existing and improved wood cookstove scenarios would exhaust forest stocks by 2050, though improved efficiency could reduce national greenhouse gas emissions. Modern fuel cookstoves would reduce household air pollution, emissions, and deforestation. However, the best alternative to successfully reduce household air pollution, GHG emissions, and deforestation is a rapid switch to electric stoves with significant investment in renewable-based electricity.

Indoor air pollution concentrations and cardiometabolic health across four diverse settings in Peru: a cross-sectional study

BACKGROUND

Indoor air pollution is an important risk factor for health in low- and middle-income countries.

METHODS

We measured indoor fine particulate matter (PM2.5) and carbon monoxide (CO) concentrations in 617 houses across four settings with varying urbanisation, altitude, and biomass cookstove use in Peru, between 2010 and 2016. We assessed the associations between indoor pollutant concentrations and blood pressure (BP), exhaled carbon monoxide (eCO), C-reactive protein (CRP), and haemoglobin A1c (HbA1c) using multivariable linear regression among all participants and stratifying by use of biomass cookstoves.

RESULTS

We found high concentrations of indoor PM2.5 across all four settings (geometric mean ± geometric standard deviation of PM2.5 daily average in μg/m3): Lima 41.1 ± 1.3, Tumbes 35.8 ± 1.4, urban Puno 14.1 ± 1.7, and rural Puno 58.8 ± 3.1. High indoor CO concentrations were common in rural households (geometric mean ± geometric standard deviation of CO daily average in ppm): rural Puno 4.9 ± 4.3. Higher indoor PM2.5 was associated with having a higher systolic BP (1.51 mmHg per interquartile range (IQR) increase, 95% CI 0.16 to 2.86), a higher diastolic BP (1.39 mmHg higher DBP per IQR increase, 95% CI 0.52 to 2.25), and a higher eCO (2.05 ppm higher per IQR increase, 95% CI 0.52 to 3.57). When stratifying by biomass cookstove use, our results were consistent with effect measure modification in the association between PM2.5 and eCO: among biomass users eCO was 0.20 ppm higher per IQR increase in PM2.5 (95% CI - 2.05 to 2.46), and among non-biomass users eCO was 5.00 ppm higher per IQR increase in PM2.5 (95% CI 1.58 to 8.41). We did not find associations between indoor air concentrations and CRP or HbA1c outcomes.

CONCLUSIONS

Excessive indoor concentrations of PM2.5 are widespread in homes across varying levels of urbanisation, altitude, and biomass cookstove use in Peru and are associated with worse BP and higher eCO.

Mitigating the air pollution effect? The remarkable decline in the pollution-mortality relationship in Hong Kong

Using transboundary pollution from mainland China as an instrument, we show that air pollution leads to higher cardio-respiratory mortality in Hong Kong. However, the air pollution effect has dramatically decreased over the past two decades: before 2003, a 10-unit increase in the Air Pollution Index could lead to a 3.1% increase in monthly cardio-respiratory mortality, but this effect has declined to 0.5% using recent data and is no longer statistically significant. Exploratory analyses suggest that a well-functioning medical system and immediate access to emergency services can help mitigate the contemporaneous effects of pollution on mortality.

Association between biomass fuel use and risk of hypertension among Chinese older people: A cohort study

BACKGROUNDS

Previous studies linking biomass fuel use to hypertension have been inconsistent. We investigated the association between biomass fuel use and the risk of hypertension and blood pressure measures in older Chinese people.

METHODS

The prospective cohort study of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) included participants aged 65 years and older in 2011/2012 who were followed up until 2014 in 23 provinces in China. We explored the association between biomass fuel use and hypertension using the Cox proportional hazards model and examined the relationship of biomass fuel use with blood pressure measures using the generalized estimating equation. Additionally, we examined the effect of switching cooking fuels on hypertension during the follow-up.

RESULTS

Among 3754 participants who were without hypertension at baseline, the mean age was 86 years old, and 47.5% of participants were men. Reported use of biomass fuel for cooking (50.2%) was associated with a higher risk of hypertension (incidence rate (IR) per 100 person-years: 13.15 versus 12.99, hazard ratio (HR) = 1.15, 95% confidence interval (CI) = 1.01-1.31). Biomass fuel use was related to systolic blood pressure (SBP) (β 1.10 mmHg, 95% CI: 0.48-1.72), diastolic blood pressure (DBP) (β 1.02 mmHg, 95% CI: 0.61-1.43) and mean arterial pressure (MAP) (β 1.03 mmHg, 95% CI: 0.63-1.43) elevation. Compared with persistent clean fuel users, participants who reported switching from clean to biomass fuels for cooking had a noticeably higher risk of hypertension (IR per 100 person-years: 14.27 versus 12.81, HR 1.49, 95% CI: 1.16-1.90) and higher SBP (3.71 mmHg), DBP (2.44 mmHg) and MAP (2.86 mmHg). Interaction and stratified analyses showed greater effect estimates of SBP and MAP in the oldest oldpeople (≥85).

CONCLUSIONS

The use of biomass fuel for cooking was associated with greater hypertension risk, and the risk may be higher among those who switched from clean fuels to biomass fuels in the Chinese elderly population. Biomass fuel use was associated with a statistically significant but small absolute increase in blood pressure measures.

Design and Rationale of the HAPIN Study: A Multicountry Randomized Controlled Trial to Assess the Effect of Liquefied Petroleum Gas Stove and Continuous Fuel Distribution

BACKGROUND

Globally, nearly 3 billion people rely on solid fuels for cooking and heating, the vast majority residing in low- and middle-income countries (LMICs). The resulting household air pollution (HAP) is a leading environmental risk factor, accounting for an estimated 1.6 million premature deaths annually. Previous interventions of cleaner stoves have often failed to reduce exposure to levels that produce meaningful health improvements. There have been no multicountry field trials with liquefied petroleum gas (LPG) stoves, likely the cleanest scalable intervention.

OBJECTIVE

This paper describes the design and methods of an ongoing randomized controlled trial (RCT) of LPG stove and fuel distribution in 3,200 households in 4 LMICs (India, Guatemala, Peru, and Rwanda).

METHODS

We are enrolling 800 pregnant women at each of the 4 international research centers from households using biomass fuels. We are randomly assigning households to receive LPG stoves, an 18-month supply of free LPG, and behavioral reinforcements to the control arm. The mother is being followed along with her child until the child is 1 year old. Older adult women (40 to < 80   years of age) living in the same households are also enrolled and followed during the same period. Primary health outcomes are low birth weight, severe pneumonia incidence, stunting in the child, and high blood pressure (BP) in the older adult woman. Secondary health outcomes are also being assessed. We are assessing stove and fuel use, conducting repeated personal and kitchen exposure assessments of fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), carbon monoxide (CO), and black carbon (BC), and collecting dried blood spots (DBS) and urinary samples for biomarker analysis. Enrollment and data collection began in May 2018 and will continue through August 2021. The trial is registered with ClinicalTrials.gov (NCT02944682).

CONCLUSIONS

This study will provide evidence to inform national and global policies on scaling up LPG stove use among vulnerable populations. https://doi.org/10.1289/EHP6407.

Exposure to household air pollution from biomass cookstoves and self-reported symptoms among women in rural Honduras

Household air pollution from combustion of solid fuels is an important risk factor for morbidity and mortality, causing an estimated 2.6 million premature deaths globally in 2016. Self-reported health symptoms are a meaningful measure of quality of life, however, few studies have evaluated symptoms and quantitative measures of exposure to household air pollution. We assessed the cross-sectional association of self-reported symptoms and exposures to household air pollution among women in rural Honduras using stove type (traditional [n = 76]; cleaner-burning Justa [n = 74]) and 24-hour average personal and kitchen fine particulate matter (PM_2.5) concentrations. The odds of prevalent symptoms were higher among women using traditional stoves vs Justa stoves (e.g. headache: odds ratio = 2.23; 95% confidence interval = 1.13-4.39). Associations between symptoms and measured PM_2.5 were generally consistent with the null. These results add to the evidence suggesting reduced exposures and better health-related quality of life among women using cleaner-burning biomass stoves.

Biomass Fuel Use and Cardiac Function in Nepali Women

Background

Exposure to household air pollution (HAP) from cooking with biomass fuel affects billions of people. We hypothesized that HAP from woodsmoke, compared to other household fuels, was associated with adverse cardiovascular outcomes, of which there have been few studies.

Methods

A cross-sectional study was completed in 299 females aged 40-70 years in Kaski District, Nepal, during 2017-18. All participants underwent a standard 12-lead ECG, ankle and brachial systolic blood pressure measurement, and 2D color and Doppler echocardiography. Current stove type was confirmed by inspection. Blood pressure, height, and weight were measured using a standardized protocol. Hypertension was defined as ≥140/90 mmHg or prior diagnosis. Hemoglobin A1c (HbA1c) was obtained, with diabetes mellitus defined as a prior diagnosis or HbA1C ≥ 6.5%. We used adjusted linear and logistic multivariable regressions to examine the relationship of stove type with cardiac structure and function.

Results

The majority of women primarily used liquified petroleum gas (LPG) stoves (65%), while 12% used biogas, and 23% used wood-burning cook-stoves. Prevalence of major cardiovascular risk factors was 35% with hypertension, 19% with diabetes mellitus, and 15% current smokers. After adjustment, compared to LPG, wood stove use was associated with increased indexed left atrial volume (β = 3.15, 95% CI 1.22 to 5.09) and increased indexed left ventricular end diastolic volume (β = 7.97, 95% CI 3.11 to 12.83). There was no association between stove type and systemic hypertension, left ventricular mass, systolic dysfunction, diastolic dysfunction, pulmonary hypertension, abnormal ankle-brachial index, or clinically significant ECG abnormalities.

Conclusion

Biomass fuel use was associated with increased indexed left atrial volume and increased indexed left ventricular diastolic volume in Nepali women, suggesting subclinical adverse cardiac remodeling from HAP in this cross-sectional study. We did not find evidence of an association with hypertension or typical cardiac sequelae of hypertension. Future studies to confirm these results are needed.

Short-term effects of air pollution on blood pressure

Elevated blood pressure (BP) has been proposed as a possible pathophysiological mechanism linking exposure to ambient air pollution and the increased risk of cardiovascular mortality and morbidity. In this study, we investigated the hourly relationship between ambient air pollutants and BP. BP measurements were extracted from the electronic health record database of the Seoul National University Bundang Hospital from February 2015 to June 2017. A total of 98,577 individual BP measurements were matched to the hourly levels of air pollutants. A generalized additive model was constructed for hour lags of 0–8 of air pollutants adjusting for age, sex, meteorological variables, and time trend. Systolic BP was shown to be significantly lower at 2–4 hours and 3–5 hours after increased levels of SO₂ and CO, respectively (0.24 mmHg and 0.26 mmHg for an interquartile range, respectively). In contrast, O₃ and NO₂ were associated with significantly increased systolic BP at 3–5 lag hours and at 0–2 lag hours, respectively. BP elevation in association with O₃ and NO₂ was shown to be significantly greater in hypertensive patients than normotensive subjects. Our findings suggest that short-term exposure to air pollution may be associated with elevated BP.

Longitudinal evaluation of a household energy package on blood pressure, central hemodynamics, and arterial stiffness in China

BACKGROUND

Cardiovascular diseases are the leading contributors to disease burden in China and globally, and household air pollution exposure is associated with risk of cardiovascular disease.

OBJECTIVES

We evaluated whether subclinical cardiovascular outcomes in adult Chinese women would improve after distribution of an energy package comprised of a semi-gasifier cookstove, water heater, chimney, and supply of processed biomass fuel.

METHODS

We enrolled 204 households (n = 205 women) from 12 villages into a controlled before- and after-intervention study on cardiovascular health and air pollution in Sichuan Province. The intervention was distributed to 124 households during a government-sponsored rural energy demonstration program. The remaining 80 households received the package 18 months later at the end of the study, forming a comparison group. One woman from each household had their blood pressure (BP), central hemodynamics, and arterial stiffness measured along with exposures to air pollution and demographic and household characteristics, on up to five visits. We used a difference-in-differences mixed-effects regression approach with Bayesian inference to assess the impact of the energy package on sub-clinical cardiovascular outcomes.

RESULTS

Women who did not receive the energy package had greater mean decreases in brachial systolic (-4.1 mmHg, 95% credible interval (95%CIe) -7.3, -0.9) and diastolic BP (-2.0 mmHg, 95%CIe -3.6, -0.5) compared with women who received the package (systolic: -2.7, 95%CIe -5.0, -0.4; diastolic: -0.3, 95%CIe -1.4, 0.8) resulting in slightly positive but not statistically significant difference-in-differences effect estimates of 1.3 mmHg (95%CIe -2.5, 5.2) and 1.7 mmHg (95%CIe -0.3, 3.6), respectively. Similar trends were found for central BP, central pulse pressure, and arterial stiffness. Air pollution exposures decreased on average for both treatment groups, with a greater range of reductions among women who did not receive the package (with package: -30% to -50%; without package: +2% to -69%), likely as a result of increased use of gas fuel and electric stoves among this group. Outdoor air quality changed very little over time.

CONCLUSIONS

Gasifier stoves have been widely promoted as the next generation of 'clean-cooking' technologies, however their effectiveness in improving health in real-world settings should be carefully evaluated and communicated before scaling up their implementation.

Coronary heart disease, hypertension and use of biomass fuel among women: comparative cross-sectional study

OBJECTIVES

To explore the associations of hypertension and coronary heart disease (CHD) with use of biomass fuel for cooking.

DESIGN

Comparative cross-sectional study.

SETTING

Rural villages in Sindh, Pakistan.

PARTICIPANTS

Women aged ≥40 years who had used biomass fuel for cooking for at least the last year (n=436), and a comparison group (n=414) who had cooked only with non-biomass fuel during the last year were recruited through door-to-door visits. None of those who were invited to take part declined.

PRIMARY AND SECONDARY OUTCOME MEASURES

Hypertension was determined from blood pressure measurements and use of medication. CHD was assessed by three measures: history of angina (Rose angina questionnaire), previous history of 'heart attack', and definite or probable changes of CHD on ECG. Potentially confounding risk factors were ascertained by questionnaire and anthropometry. Associations of hypertension and CHD with use of biomass and other risk factors were assessed by logistic regression, and summarised by ORs with 95% CIs.

RESULTS

After adjustment for potential confounders, there was no association of hypertension (OR: 1.0, 95% CI 0.8 to 1.4) angina (OR: 1.0, 95% CI 0.8 to 1.4), heart attack (OR: 1.2, 95% 0.7 to 2.2) or ECG changes of CHD (OR: 0.8, 95% CI 0.6 to 1.2) with current use of biomass for cooking. Nor were any associations apparent when analyses were restricted to long-term (≥10 years) users and non-users of biomass fuel.

CONCLUSIONS

A linked air monitoring study indicated substantially higher airborne concentrations of fine particulate matter in kitchens where biomass was used for cooking. It is possible that associations with CHD and hypertension were missed because most of the comparison group had used biomass for cooking at some time in the past, and risk remains elevated for many years after last exposure.

Acute Effects on Blood Pressure Following Controlled Exposure to Cookstove Air Pollution in the STOVES Study

Background

Exposure to air pollution from solid fuel used in residential cookstoves is considered a leading environmental risk factor for disease globally, but evidence for this relationship is largely extrapolated from literature on smoking, secondhand smoke, and ambient fine particulate matter (PM_2.5).

Methods and Results

We conducted a controlled human‐exposure study (STOVES [the Subclinical Tests on Volunteers Exposed to Smoke] Study) to investigate acute responses in blood pressure following exposure to air pollution emissions from cookstove technologies. Forty‐eight healthy adults received 2‐hour exposures to 5 cookstove treatments (three stone fire, rocket elbow, fan rocket elbow, gasifier, and liquefied petroleum gas), spanning PM_2.5 concentrations from 10 to 500 μg/m³, and a filtered air control (0 μg/m³). Thirty minutes after exposure, systolic pressure was lower for the three stone fire treatment (500 μg/m³PM_2.5) compared with the control (−2.3 mm Hg; 95% CI, −4.5 to −0.1) and suggestively lower for the gasifier (35 μg/m³PM_2.5; −1.8 mm Hg; 95% CI, −4.0 to 0.4). No differences were observed at 3 hours after exposure; however, at 24 hours after exposure, mean systolic pressure was 2 to 3 mm Hg higher for all treatments compared with control except for the rocket elbow stove. No differences were observed in diastolic pressure for any time point or treatment.

Conclusions

Short‐term exposure to air pollution from cookstoves can elicit an increase in systolic pressure within 24 hours. This response occurred across a range of stove types and PM_2.5 concentrations, raising concern that even low‐level exposures to cookstove air pollution may pose adverse cardiovascular effects.

Study protocol for a stepped-wedge randomized cookstove intervention in rural Honduras: household air pollution and cardiometabolic health

BACKGROUND

Growing evidence links household air pollution exposure from biomass-burning cookstoves to cardiometabolic disease risk. Few randomized controlled interventions of cookstoves (biomass or otherwise) have quantitatively characterized changes in exposure and indicators of cardiometabolic health, a growing and understudied burden in low- and middle-income countries (LMICs). Ideally, the solution is to transition households to clean cooking, such as with electric or liquefied petroleum gas stoves; however, those unable to afford or to access these options will continue to burn biomass for the foreseeable future. Wood-burning cookstove designs such as the Justa (incorporating an engineered combustion zone and chimney) have the potential to substantially reduce air pollution exposures. Previous cookstove intervention studies have been limited by stove types that did not substantially reduce exposures and/or by low cookstove adoption and sustained use, and few studies have incorporated community-engaged approaches to enhance the intervention.

METHODS/DESIGN

We conducted an individual-level, stepped-wedge randomized controlled trial with the Justa cookstove intervention in rural Honduras. We enrolled 230 female primary cooks who were not pregnant, non-smoking, aged 24-59 years old, and used traditional wood-burning cookstoves at baseline. A community advisory board guided survey development and communication with participants, including recruitment and retention strategies. Over a 3-year study period, participants completed 6 study visits approximately 6 months apart. Half of the women received the Justa after visit 2 and half after visit 4. At each visit, we measured 24-h gravimetric personal and kitchen fine particulate matter (PM2.5) concentrations, qualitative and quantitative cookstove use and adoption metrics, and indicators of cardiometabolic health. The primary health endpoints were blood pressure, C-reactive protein, and glycated hemoglobin. Overall study goals are to explore barriers and enablers of new cookstove adoption and sustained use, compare health endpoints by assigned cookstove type, and explore the exposure-response associations between PM2.5 and indicators of cardiometabolic health.

DISCUSSION

This trial, utilizing an economically feasible, community-vetted cookstove and evaluating endpoints relevant for the major causes of morbidity and mortality in LMICs, will provide critical information for household air pollution stakeholders globally.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02658383 , posted January 18, 2016, field work completed May 2018. Official title, "Community-Based Participatory Research: A Tool to Advance Cookstove Interventions." Principal Investigator Maggie L. Clark, Ph.D. Last update posted July 12, 2018.

Health Effects of Indoor Air Pollution

Exposure to indoor-generated air pollution causes a large number of deaths and cases of disease. These effects are found, largely, in developing countries where people, especially women and young children, are exposed to high concentrations of smoke produced by biomass burning for cooking. Approximately 3 million deaths occur each year. In developed countries, the problem is much less acute: accidental exposure to high concentrations of carbon monoxide is the main cause of death. It should be remembered, however, that much of people's exposure to pollutants generated outdoors occurs in the indoor environment. Indoor exposure to particulate matter has the same effects as outdoor exposure: the cardiovascular system is most affected, with deaths being due to ischaemic heart disease and stroke. Exposure to particulate matter may also contribute to the development of chronic obstructive pulmonary disease (COPD). Exposure to high concentrations of nitrogen dioxide, although perhaps not having a great effect on measures of lung function, may contribute to the development of emphysema and reduce the resistance of the body to bacterial and viral infections. Lung cancer, due to exposure to carcinogens in wood smoke, also occurs. Efforts to reduce levels of indoor air pollution in developing countries, for example by providing flued cooking stoves, have been shown to reduce the prevalence of disease.

Implementation of clean cookstove interventions and its effects on blood pressure in low-income and middle-income countries: systematic review

OBJECTIVE

A review of the implementation outcomes of clean cookstove use, and its effects on blood pressure (BP) in low-income and middle-income countries (LMICs).

DESIGN

Systematic review of studies that reported the effect of clean cookstove use on BP among women, and implementation science outcomes in LMICs.

DATA SOURCES

We searched PubMed, Embase, INSPEC, Scielo, Cochrane Library, Global Health and Web of Science PLUS. We conducted searches in November 2017 with a repeat in May 2018. We did not restrict article publication date.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included only studies conducted in LMICs, published in English, regardless of publication year and studies that examined the use of improved or clean cookstove intervention on BP. Two authors independently screened journal article titles, abstracts and full-text articles to identify those that included the following search terms: high BP, hypertension and or household air pollution, LMICs, cookstove and implementation outcomes.

RESULTS

Of the 461 non-duplicate articles identified, three randomised controlled trials (RCTs) (in Nigeria, Guatemala and Ghana) and two studies of pre-post design (in Bolivia and Nicaragua) met eligibility criteria. These articles evaluated the effect of cookstove use on BP in women. Two of the three RCTs reported a mean reduction in diastolic BP of -2.8 mm Hg (-5.0, -0.6; p=0.01) for the Nigerian study; -3.0 mm Hg; (-5.7, -0.4; p=0.02) for the Guatemalan study; while the study conducted in Ghana reported a non-significant change in BP. The pre-post studies reported a significant reduction in mean systolic BP of -5.5 mm Hg; (p=0.01) for the Bolivian study, and -5.9 mm Hg (-11.3, -0.4; p=0.05) for the Nicaraguan study. Implementation science outcomes were reported in all five studies (three reported feasibility, one reported adoption and one reported feasibility and adoption of cookstove interventions).

CONCLUSION

Although this review demonstrated that there is limited evidence on the implementation of clean cookstove use in LMICs, the effects of clean cookstove on BP were significant for both systolic and diastolic BP among women. Future studies should consider standardised reporting of implementation outcomes.

Indoor air pollution exposure effects on lung and cardiovascular health in the High Himalayas, Nepal: An observational study

BACKGROUND

Exposure to indoor biomass fuel smoke is associated with increased morbidity and mortality. The aim of this study is to evaluate the association between exposure to indoor biomass burning and early pulmonary and cardiovascular damage.

METHODS

The indoor levels of particulate matter (PM) [PM₁₀, PM_2.5] and black carbon (BC) were monitored in 32 houses in a Himalayan village. Seventy-eight subjects were submitted to spirometry and cardiovascular evaluation [carotid to femoral pulse wave velocity (PWV) and echocardiography].

RESULTS

Peak indoor BC concentration up to 100 μg m^-3 and PM₁₀ - PM_2.5 up to 1945-592 μg m^-3 were measured. We found a non-reversible bronchial obstruction in 18% of subjects ≥40 yr; mean forced expiratory flow between 25% and 75% of the forced vital capacity (FEF_25-75) <80% in 54% of subjects, suggestive of early respiratory impairment, significantly and inversely related to age. Average BC was correlated with right ventricular-right atrium gradient (R = 0.449,p = .002), total peripheral resistances (TPR) (R = 0.313,p = .029) and PWV (R = 0.589,p < .0001) especially in subjects >30 yr. In multiple variable analysis, BC remained an independent predictor of PWV (β = 0.556,p = .001), and TPR (β = 0.366;p = .018).

CONCLUSIONS

Indoor pollution exposure is associated to early pulmonary and cardiovascular damages, more evident for longer duration and higher intensity exposure.

Household air pollution from biomass-burning cookstoves and metabolic syndrome, blood lipid concentrations, and waist circumference in Honduran women: A cross-sectional study

BACKGROUND

Household air pollution from cooking with solid fuels affects nearly 3 billion people worldwide and is responsible for an estimated 2.5 million premature deaths and 77 million disability-adjusted life years annually. Investigating the effect of household air pollution on indicators of cardiometabolic disease, such as metabolic syndrome, can help clarify the pathways between this widespread exposure and cardiovascular diseases, which are increasing in low- and middle-income countries.

METHODS

Our cross-sectional study of 150 women in rural Honduras (76 with traditional stoves and 74 with cleaner-burning Justa stoves) explored the effect of household air pollution exposure on cardiovascular disease risk factors. Household air pollution was measured by stove type and 24-h average kitchen and personal fine particulate matter [PM_2.5] mass and black carbon concentrations. Health endpoints included non-fasting total cholesterol, high-density lipoprotein, calculated low-density lipoprotein, triglycerides, waist circumference to indicate abdominal obesity, and presence of metabolic syndrome (defined by current modified international guidelines: waist circumference ≥ 80 cm plus any two of the following: triglycerides > 200 mg/dL, HDL < 50 mg/dL, systolic blood pressure ≥ 130 mmHg, diastolic blood pressure ≥ 85 mmHg, or glycated hemoglobin > 5.6%).

RESULTS

Forty percent of women met the criteria for metabolic syndrome. The prevalence ratio [PR] for metabolic syndrome (versus normal) per interquartile range increase in kitchen PM_2.5 and kitchen black carbon was 1.16 (95% confidence interval [CI]: 1.01-1.34) per 312 μg/m³ increase in PM_2.5, and 1.07 (95% CI: 1.03-1.12) per 73 μg/m³ increase in black carbon. There is suggestive evidence of a stronger effect in women ≥ 40 years of age compared to women < 40 (p-value for interaction = 0.12 for personal PM_2.5). There was no evidence of associations between all other exposure metrics and health endpoints.

CONCLUSIONS

The prevalence of metabolic syndrome among our study population was high compared to global estimates. We observed a suggestive effect between metabolic syndrome and exposure to household air pollution. These results for metabolic syndrome may be driven by specific syndrome components, such as blood pressure. Longitudinal research with repeated health and exposure measures is needed to better understand the link between household air pollution and indicators of cardiometabolic disease risk.

Exposure to household air pollution from biomass cookstoves and blood pressure among women in rural Honduras: A cross-sectional study

Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed cross-sectional associations of 24-hour mean concentrations of personal and kitchen fine particulate matter (PM_2.5 ), black carbon (BC), and stove type with blood pressure, adjusting for confounders, among 147 women using traditional or cleaner-burning Justa stoves in Honduras. We investigated effect modification by age and body mass index. Traditional stove users had mean (standard deviation) personal and kitchen 24-hour PM_2.5 concentrations of 126 μg/m³ (77) and 360 μg/m³ (374), while Justa stove users' exposures were 66 μg/m³ (38) and 137 μg/m³ (194), respectively. BC concentrations were similarly lower among Justa stove users. Adjusted mean systolic blood pressure was 2.5 mm Hg higher (95% CI, 0.7-4.3) per unit increase in natural log-transformed kitchen PM_2.5 concentration; results were stronger among women of 40 years or older (5.2 mm Hg increase, 95% CI, 2.3-8.1). Adjusted odds of borderline high and high blood pressure (categorized) were also elevated (odds ratio = 1.5, 95% CI, 1.0-2.3). Some results included null values and are suggestive. Results suggest that reduced household air pollution, even when concentrations exceed air quality guidelines, may help lower cardiovascular disease risk, particularly among older subgroups.