Relationship between household air pollution from biomass smoke exposure, and pulmonary dysfunction, oxidant-antioxidant imbalance and systemic inflammation in rural women and children in Nigeria

Exposure to cooking emissions in kitchens and chronic obstructive pulmonary disease in women: a population-based case-control study in Ouagadougou, Burkina Faso

Introduction

women exposed to smoke are three times more likely to suffer from chronic obstructive pulmonary disease than women who cook with clean fuels. The present study aims to compare the level of exposure to particulate matter (PM2.5), carbon monoxide (CO), and total volatile organic compounds (VOCs) inside kitchens, between women with chronic obstructive pulmonary disease (COPD) and healthy women, in Ouagadougou, Burkina Faso.

Methods

a pilot case-control study was conducted from January 7th to 25th, 2020, in 2 neighborhoods of Ouagadougou. Cases were women diagnosed with COPD and controls were women without COPD. The diagnosis of COPD was made on the basis of a standardized questionnaire administered and followed by a spirometry test. The sample comprised 9 cases and 9 controls. Exposure was assessed by using a multi-pollutant hand-held device, over a 24-hour period. Exposures of cases and controls were compared using the independent Student's t-test and in cases where the distribution was not normal, the Kruskal-Wallis test was used.

Results

the mean age was 59 ± 9.86 years in the cases group and 58.56 ± 7.45 years in the control group and there is no significant difference (p = 0.757). The mean concentrations of PM2.5 measured in the 2 groups were above the World Health Organization (WHO) recommended threshold of 15 µg/m3 for 24 h exposure. The mean PM2.5 concentration was 127.10 µg/m3 in the cases and 16.23 µg/m3 in the control group (p= 0.133). Concentrations of CO and VOCs were also higher in the kitchens of the cases than in those of the controls. However, no differences were statistically significant.

Conclusion

although no statistically significant differences were observed, pollutant concentrations were higher in the kitchens of women with COPD. In addition, PM2.5 levels measured in both groups exceeded WHO-recommended thresholds, underlining the need to reduce household exposure to pollutants. Further research is needed to better understand these impacts.

Air Pollution and Racial Disparities in Pregnancy Outcomes in the United States: A Systematic Review

BACKGROUND

Exposure to air pollutants and other environmental factors increases the risk of adverse pregnancy outcomes. There is growing evidence that adverse outcomes related to air pollution disproportionately affect racial and ethnic minorities. The objective of this paper is to explore the importance of race as a risk factor for air pollution-related poor pregnancy outcomes.

METHODS

Studies investigating the effects of exposure to air pollution on pregnancy outcomes by race were reviewed. A manual search was conducted to identify missing studies. Studies that did not compare pregnancy outcomes among two or more racial groups were excluded. Pregnancy outcomes included preterm births, small for gestational age, low birth weight, and stillbirths.

RESULTS

A total of 124 articles explored race and air pollution as risk factors for poor pregnancy outcome. Thirteen percent of these (n=16) specifically compared pregnancy outcomes among two or more racial groups. Findings across all reviewed articles showed more adverse pregnancy outcomes (preterm birth, small for gestational age, low birth weight, and stillbirths) related to exposure to air pollution among Blacks and Hispanics than among non-Hispanic Whites.

CONCLUSION

Evidence support our general understanding of the impact of air pollution on birth outcomes and, specifically, of disparities in exposure to air pollution and birth outcomes for infants born to Black and Hispanic mothers. The factors driving these disparities are multifactorial, mostly social, and economic factors. Reducing or eliminating these disparities require interventions at individual, community, state, and national level.

Personal exposure to household air pollution and lung function in rural Bangladesh: A population-based cross-sectional study

We assessed whether personal exposure to household air pollution [PM2.5 and black carbon (BC)] is associated with lung functions (FEV1, FVC, and their ratio) in non-smoking adults in rural Bangladesh. We measured personal exposure to PM2.5 using gravimetric analysis of PM2.5 mass and BC by reflectance measurement between April 2016 and June 2019. The average 24-hour PM2.5 and BC concentration was 141.0μgm-3 and 13.8μgm-3 for females, and 91.7 μgm-3 and 10.1 μgm-3 for males, respectively. A 1 μgm-3 increase in PM2.5 resulted in a 0.02 ml reduction in FEV1, 0.43 ml reduction in FVC, and 0.004% reduction in FEV1/FVC. We also found a similar inverse relationship between BC and lung functions (9.6 ml decrease in FEV1 and 18.5 ml decrease in FVC per 1μgm-3 increase in BC). A higher proportion of non-smoking biomass fuel users (50.1% of the females and 46.7% of the males) had restrictive patterns of lung function abnormalities, which need further exploration.

Personal PM2.5 Elemental Components, Decline of Lung Function, and the Role of DNA Methylation on Inflammation-Related Genes in Older Adults: Results and Implications of the BAPE Study

Epidemiological evidence of the effects of PM_2.5 elements on lung function and DNA methylation is limited. We conducted a longitudinal panel study of 76 healthy older adults aged 60-69 years in Jinan, China, from September 2018 to January 2019. We periodically measured individual 72 h PM_2.5 and element concentrations, lung function, and DNA methylation levels of eight inflammation-related genes. We used linear mixed-effect models to investigate the effects of exposure to personal PM_2.5 elements on the lung function and DNA methylation. Mediation analysis was used to investigate the underlying effect mechanism. Negative changes in the ratio of forced expiratory volume in 1 s to forced vital capacity, ranging from -1.23% [95% confidence interval (CI): -2.11%, -0.35%] to -0.77% (95% CI: -1.49%, -0.04%), were significantly associated with interquartile range (IQR) increases in personal PM_2.5 at different lag periods (7-12, 13-24, 25-48, 0-24, 0-48, and 0-72 h). Arsenic (As), nickel, rubidium (Rb), selenium, and vanadium were significantly associated with at least three lung function parameters, and IQR increases in these elements led to 0.12-5.66% reductions in these parameters. PM_2.5 elements were significantly associated with DNA methylation levels. DNA methylation mediated 7.28-13.02% of the As- and Rb-related reduced lung function. The findings indicate that exposure to elements in personal PM_2.5 contributes to reduced lung function through DNA methylation.

Vitamin D intake modifies the association of household air pollution exposure with maternal disorders of pregnancy

To date, only three studies have investigated the association of household air pollution (HAP) exposure with pregnancy disorders. The ameliorating role of diet and nutrition in the association has never been explored. We conducted a cross-sectional study among 799 mothers who had recently given singleton birth in the Cape Coast Metropolis, Ghana. Structured questionnaire and semi-quantitative food frequency questionnaire were used to assess HAP exposure (from use of biomass fuels for cooking and garbage burning at home) and vitamin D (vitD) intake, respectively. Multivariable binary logistic regression was used to investigate the association between HAP exposure and pregnancy disorders. HAP exposure due to cooking with biomass fuels and garbage burning at home was associated with two fold (AOR = 2.15; 95% confidence interval [CI]: 1.05, 4.43) and six fold (AOR = 6.35; 95% CI: 2.43, 16.58) increased odds of hypertensive disorders of pregnancy (HDP). For gestational diabetes (GDM), the increased odds were two folds for both exposures but the 95% CI included the null value. Stove stacking was also associated with two folds increased odds of GDM (AOR = 1.83; 95% CI: 0.91, 3.68). In stratified analysis, the odds of HDP and GDM associated with biomass fuels use decreased with increasing vitD intake. All the interaction p values were, however, greater than 0.05. We provide the first evidence on the ameliorating role of vitD intake on the effect of HAP exposure on pregnancy disorders. In LMICs where solid fuel use and garbage burning at home is widespread, health workers should advise mothers during antenatal care visits to increase intake of vitamin D rich foods.

Prenatal and Postnatal Household Air Pollution Exposure and Infant Growth Trajectories: Evidence from a Rural Ghanaian Pregnancy Cohort

BACKGROUND

The exposure-response association between prenatal and postnatal household air pollution (HAP) and infant growth trajectories is unknown.

OBJECTIVES

To evaluate associations between prenatal and postnatal HAP exposure and stove interventions on growth trajectories over the first year of life.

METHODS

The Ghana Randomized Air Pollution and Health Study enrolled n=1,414 pregnant women at ≤24wk gestation from Kintampo, Ghana, and randomized them to liquefied petroleum gas (LPG), improved biomass, or open fire (control) stoves. We quantified HAP exposure by repeated, personal prenatal and postnatal carbon monoxide (CO) and, in a subset, fine particulate matter [PM with an aerodynamic diameter of ≤2.5μm (PM2.5)] assessments. Length, weight, mid-upper arm circumference (MUAC) and head circumference (HC) were measured at birth, 3, 6, 9, and 12 months; weight-for-age, length-for-age (LAZ), and weight-for-length z (WLZ)-scores were calculated. For each anthropometric measure, we employed latent class growth analysis to generate growth trajectories over the first year of life and assigned each child to a trajectory group. We then employed ordinal logistic regression to determine associations between HAP exposures and growth trajectory assignments. Associations with stove intervention arm were also considered.

RESULTS

Of the 1,306 live births, 1,144 had valid CO data and anthropometric variables measured at least once. Prenatal HAP exposure increased risk for lower length [CO odds ratio (OR)= 1.17, 95% CI: 1.01, 1.35 per 1-ppm increase; PM2.5 OR= 1.07, 95% CI: 1.02, 1.13 per 10-μg/m3 increase], lower LAZ z-score (CO OR= 1.15, 95% CI: 1.01, 1.32 per 1-ppm increase) and stunting (CO OR= 1.25, 95% CI: 1.08, 1.45) trajectories. Postnatal HAP exposure increased risk for smaller HC (CO OR= 1.09, 95% CI: 1.04, 1.13 per 1-ppm increase), smaller MUAC and lower WLZ-score (PM2.5 OR= 1.07, 95% CI: 1.00, 1.14 and OR= 1.09, 95% CI: 1.01, 1.19 per 10-μg/m3 increase, respectively) trajectories. Infants in the LPG arm had decreased odds of having smaller HC and MUAC trajectories as compared with those in the open fire stove arm (OR= 0.58, 95% CI: 0.37, 0.92 and OR= 0.45, 95% CI: 0.22, 0.90, respectively).

DISCUSSION

Higher early life HAP exposure (during pregnancy and through the first year of life) was associated with poorer infant growth trajectories among children in rural Ghana. A cleaner-burning stove intervention may have improved some growth trajectories. https://doi.org/10.1289/EHP8109.

Woodsmoke Extracts Cross-Link Proteins and Induce Cornified Envelope Formation without Stimulating Keratinocyte Terminal Differentiation

Air pollution poses a serious risk to human health. To help understand the contribution of smoke from wood burning to the harmfulness of air pollution toward the skin, we studied the effects of liquid smoke, aqueous extracts of wood smoke condensate, a commercially available food flavor additive, in cultured keratinocytes. We report that liquid smoke can react with and cross-link keratinocyte cellular proteins, leading to abnormal cross-linked envelope formation. Instead of inducing genes ordinarily involved in terminal differentiation, liquid smoke induced expression of genes associated with stress responses. When transglutaminase activity was inhibited, liquid smoke still promoted protein cross-linking and envelope formation in keratinocytes. This phenomenon likely results from oxidative stress and protein adducts from aldehydes as either preloading the cells with N-acetylcysteine or reducing the aldehyde content of liquid smoke decreased its ability to promote protein cross-linking and envelope formation. Finally, liquid smoke-induced envelopes were found to have elevated protein content, suggesting oxidative cross-linking and formation of protein adducts might impair barrier function by inducing abnormal incorporation of cellular proteins into envelopes. Since the cross-linked protein envelope provides structural stability to the stratum corneum and serves as a scaffold for the organization of the corneocyte lipid envelope (hydrophobic barrier to the environment), these findings provide new insight into the mechanism by which pro-oxidative air pollutants can impair epidermal function.

Acute changes in lung function following controlled exposure to cookstove air pollution in the subclinical tests of volunteers exposed to smoke (STOVES) study

Background: Exposure to household air pollution generated as a result of cooking and heating is a leading contributor to global disease. The effects of cookstove-generated air pollution on adult lung function, however, remain uncertain.Objectives: We investigated acute responses in lung function following controlled exposures to cookstove-generated air pollution.Methods: We recruited 48 healthy adult volunteers to undergo six two-hour treatments: a filtered-air control and emissions from five different stoves with fine particulate matter (PM_2.5) targets from 10 to 500 µg/m³. Spirometry was conducted prior to exposure and immediately, and three and 24 h post-exposure. Mixed-effect models were used to estimate differences in post-exposure lung function for stove treatments versus control.Results: Immediately post-exposure, lung function was lower compared to the control for the three highest PM_2.5-level stoves. The largest differences were for the fan rocket stove (target 250 µg/m³; forced vital capacity (FVC): -60 mL, 95% confidence interval (95% CI) -135, 15; forced expiratory volume (FEV₁): -51 mL, 95% CI -117, 16; mid-expiratory flow (FEF_25-75): -116 mL/s, 95% CI -239, 8). At 3 h post-exposure, lung function was lower compared to the control for all stove treatments; effects were of similar magnitude for all stoves. At 24 h post-exposure, results were consistent with a null association for FVC and FEV₁; FEF_25-75 was lower relative to the control for the gasifier, fan rocket, and three stone fire.Conclusions: Patterns suggesting short-term decreases in lung function follow from exposure to cookstove air pollution even for stove exposures with low PM_2.5 levels.

The Association of Cigarette Smoke Exposure with Lung Cellular Toxicity and Oxidative Stress: the Protective Role of Crocin

Cigarette smoke (CS) contains many free radicals and toxic chemicals. Nuclear erythroid-related factor-2 (Nrf2) is a transcriptional regulator of several phase II antioxidant genes, including glutamate-cysteine ligase (GCL). In this study, it was hypothesized that Crocin may mediate antioxidant signaling pathway to protect human lung epithelial cells against CS-mediated toxicity and oxidative stress via inducing glutathione (GSH) biosynthesis and activation of Nrf2 pathway. Alveolar epithelial cells (A549) were exposed to 1, 2.5 and 5% cigarette smoke extracts (CSE) with or without Crocin (500 μM). After 48 h exposure, the cytotoxicity, oxidant/antioxidant parameters and the Nrf2 pathway modification were assayed. Treatment of A549 cells with all concentrations of CSE dose dependently decreased cell viability, antioxidant levels, GCL and Nrf2 gene expression, which was associated with increased production of reactive oxygen species. Crocin not only restored CSE-depleted GSH levels by enhancing GCL expression via activation of Nrf2 but also quenched the CSE-generation and release of reactive oxygen species. Crocin attenuated CSE-mediated Nrf2 modifications, thereby inducing its nuclear accumulation associated with GCL gene transcription leading to enhanced GSH levels. By inducing GSH synthesis, Crocin attenuates CSE-mediated GSH depletion and protects cells against CSE-induced oxidative stress via Nrf2 pathway. These results may have implications in dietary modulation of natural antioxidants in treatment of pulmonary diseases.

Environmental Health Research in Africa: Important Progress and Promising Opportunities

The World Health Organization in 2016 estimated that over 20% of the global disease burden and deaths were attributed to modifiable environmental factors. However, data clearly characterizing the impact of environmental exposures and health endpoints in African populations is limited. To describe recent progress and identify important research gaps, we reviewed literature on environmental health research in African populations over the last decade, as well as research incorporating both genomic and environmental factors. We queried PubMed for peer-reviewed research articles, reviews, or books examining environmental exposures and health outcomes in human populations in Africa. Searches utilized medical subheading (MeSH) terms for environmental exposure categories listed in the March 2018 US National Report on Human Exposure to Environmental Chemicals, which includes chemicals with worldwide distributions. Our search strategy retrieved 540 relevant publications, with studies evaluating health impacts of ambient air pollution (n=105), indoor air pollution (n = 166), heavy metals (n = 130), pesticides (n = 95), dietary mold (n = 61), indoor mold (n = 9), per- and polyfluoroalkyl substances (PFASs, n = 0), electronic waste (n = 9), environmental phenols (n = 4), flame retardants (n = 8), and phthalates (n = 3), where publications could belong to more than one exposure category. Only 23 publications characterized both environmental and genomic risk factors. Cardiovascular and respiratory health endpoints impacted by air pollution were comparable to observations in other countries. Air pollution exposures unique to Africa and some other resource limited settings were dust and specific occupational exposures. Literature describing harmful health effects of metals, pesticides, and dietary mold represented a context unique to Africa. Studies of exposures to phthalates, PFASs, phenols, and flame retardants were very limited. These results underscore the need for further focus on current and emerging environmental and chemical health risks as well as better integration of genomic and environmental factors in African research studies. Environmental exposures with distinct routes of exposure, unique co-exposures and co-morbidities, combined with the extensive genomic diversity in Africa may lead to the identification of novel mechanisms underlying complex disease and promising potential for translation to global public health.

Keep the cat, change the care pathway: A transformational approach to managing Fel d 1, the major cat allergen

Background

Allergies to cats are the most common animal‐origin allergy, and affect approximately 1 in 5 adults worldwide. The prevalence of allergy to furry animals has been increasing, and allergy to cats is a major risk factor for the development of asthma and rhinitis. The diagnosis of cat allergy is now well established. The exact significance of component‐resolved diagnosis in the diagnosis of cat allergy remains to be fully understood. Allergen avoidance is effective but often has a psychologic impact. Allergen immunotherapy is not well demonstrated. There is a need for innovative approaches to better manage cat allergens. Next‐generation care pathways for asthma and rhinitis will define the place of cat allergen avoidance.

Methods and Results

This manuscript, based on content presented at the European Academy of Allergy and Clinical Immunology Congress 2019, provides information on the prevalence and impact of cat allergies and the molecular biology of Fel d 1, the major cat allergen.

Discussion

The authors present the scientific basis of a novel care pathway that utilizes anti‐Fel d 1 IgY antibodies to safely and effectively neutralize Fel d 1 after its production by the cat but before human exposure.

Conclusion

Efficacy of a feline diet with an egg product ingredient containing anti‐Fel d 1 IgY antibodies was demonstrated in vitro, ex vivo, and in vivo, and further validated by a pilot exposure study involving cat‐allergic human participants.

Brief Report: Systemic Inflammation, Immune Activation, and Impaired Lung Function Among People Living With HIV in Rural Uganda

BACKGROUND

Although both chronic lung disease and HIV are inflammatory diseases common in sub-Saharan Africa, the relationship between systemic inflammation and lung function among people living with HIV (PLWH) in sub-Saharan Africa is not well described.

METHODS

We measured lung function (using spirometry) and serum high sensitivity C-reactive protein, interleukin 6 (IL-6), soluble CD14 (sCD14), and soluble CD163 (sCD163) in 125 PLWH on stable antiretroviral therapy (ART) and 109 age- and sex-similar HIV-uninfected control subjects in rural Uganda. We modeled the relationship between lung function and systemic inflammation using linear regression, stratified by HIV serostatus, controlled for age, sex, height, tobacco, and biomass exposure.

RESULTS

Half of subjects [46% (107/234)] were women, and the median age was 52 years (interquartile range: 48-55). Most PLWH [92% (115/125)] were virologically suppressed on first-line ART. Median CD4 count was 472 cells/mm. In multivariable linear regression models stratified by HIV serostatus, an interquartile range increase in IL-6 and sCD163 were each inversely associated with lung function (mL, 95% confidence interval) among PLWH [IL-6: forced expiratory volume in 1 second (FEV1) -18.1 (-29.1 to -7.1), forced vital capacity (FVC) -17.1 (-28.2 to -5.9); sCD163: FVC -14.3 (-26.9 to -1.7)]. High sensitivity C-reactive protein (>3 vs. <1 mg/L) was inversely associated with lung function among both PLWH and HIV-uninfected control subjects [PLWH: FEV1 -39.3 (-61.7 to -16.9), FVC -44.0 (-48.4 to -6.4); HIV-uninfected: FEV1 -37.9 (-63.2 to -12.6), FVC -58.0 (-88.4 to -27.5)]. sCD14 was not associated with lung function, and all interaction terms were insignificant.

CONCLUSIONS

Macrophage activation and systemic inflammation are associated with lower lung function among PLWH on stable ART in rural Uganda. Future work should focus on underlying mechanisms and public health implications.

Household Air Pollution, Levels of Micronutrients and Heavy Metals in Cord and Maternal Blood, and Pregnancy Outcomes

Cooking with kerosene emits toxic pollutants that may impact pregnancy outcomes. Sixty-eight women in their first trimester of pregnancy, kerosene users (n = 42) and liquefied natural gas (LNG) users (n = 26), were followed until birth. Maternal and cord blood were collected immediately after birth. Levels of micronutrients and heavy metals were quantified. Pregnancy outcomes (gestation age (GA), birth weight (BW), and chest and head circumference) were also measured. Mean (± standard deviation (SD)) age of mothers in kerosene and LNG groups were similar (p = 0.734). Mean (±SD) BW of newborns of LNG users was significantly higher compared to newborns of kerosene users (3.43 ± 0.32 vs. 3.02 ± 0.43, p < 0.001). Mean GA (in weeks) was similar between the two groups (p = 0.532). Women in the kerosene group had significantly higher cord blood levels of zinc, lead, mercury, iodine and vitamin B6 and lower levels of folic acid compared to LNG users (p < 0.05). Newborns of kerosene users had reduced levels of zinc, lead, mercury, iodine, vitamins B6 and B12, folic acid, and homocysteine compared with LNG users (p < 0.05). Also, cooking with kerosene was significantly associated with reduced birth weight after adjusting for potential confounders (β ± standard error (SE) = −0.326 ± 0.155; p = 0.040). Smoke from kerosene stove was associated with reduced birth weight and micronutrients imbalance in mothers and newborns.

Indoor air pollution in rural north-east India: Elemental compositions, changes in haematological indices, oxidative stress and health risks

Chronic smoke exposure, emitted by biomass fuel burning leads to many diseases, which are originated due to oxidative stress. The present study investigated the levels of PM_2.5, PM₁₀ and PM_2.5 bound trace metals released during cooking with fuelwood and subsequent changes in haematological parameters along with oxidative stress in rural tribal women of northeast India exposed to wood smoke. The levels of PM_2.5, PM₁₀ and trace metals associated with PM_2.5 (nickel, cobalt, manganese, zinc, cadmium, lead and copper) were measured. In addition, blood samples were analyzed for concentrations of different blood related parameters (haemoglobin, platelet count, red blood cells and white blood cells) and levels of antioxidants (reduced glutathione, superoxide dismutase, and catalase). Plasma malondialdehyde (MDA) was measured as a biomarker of lipid peroxidation. Health risk assessment was done to assess the potential risk posed by inhalation of fine particles emitted from cooking with fuel wood. Levels of both PM_2.5 and PM₁₀ were higher in wood users compared to LPG users during cooking period (644.4 ± 368.3 µg/m³ vs 50 ± 23.8 µg/m³; 915 ± 441.3 µg/m³ vs 83.3 ± 33 µg/m³) and it exceeded the permissible limits of WHO. Levels of trace metals during the cooking period in fuel wood users were significantly higher than LPG users (p = 0.01). After controlling possible confounders, both platelet count and white blood cells (WBC) had a significant positive association with PM_2.5and PM₁₀. Similarly, haemoglobin had a negative association with both PM_2.5 and PM₁₀. Depleted levels of antioxidant enzymes and increase in lipid peroxidation (MDA) suggest a close association with pollutants released from wood smoke, indicating oxidative stress in women who used fuelwood for cooking. The total hazard quotient (HQ) of 0.11 was within the acceptable limit (i.e., 1.0). The total excess lifetime cancer risk (ELCR) was 5.4 × 10^-6 which is five times higher than the acceptable limit of 1.0 × 10^-6. Individual carcinogenic risk of Ni (2.3 × 10^-6) and Cd (3.1 × 10^-6) were also higher compared to acceptable limit. These results indicate that tribal women cooking with wood are at greater risk of developing cancer and also give support to the positive association between wood smoke and oxidative stress.

The role of environmental exposure to non-cigarette smoke in lung disease

Chronic exposure to household indoor smoke and outdoor air pollution is a major contributor to global morbidity and mortality. The majority of these deaths occur in low and middle-income countries. Children, women, the elderly and people with underlying chronic conditions are most affected. In addition to reduced lung function, children exposed to biomass smoke have an increased risk of developing lower respiratory tract infections and asthma-related symptoms. In adults, chronic exposure to biomass smoke, ambient air pollution, and opportunistic exposure to fumes and dust are associated with an increased risk of developing chronic bronchitis, chronic obstructive pulmonary disease (COPD), lung cancer and respiratory infections, including tuberculosis. Here, we review the evidence of prevalence of COPD in people exposed to non-cigarette smoke. We highlight mechanisms that are likely involved in biomass-smoke exposure-related COPD and other lung diseases. Finally, we summarize the potential preventive and therapeutic strategies for management of COPD induced by non-cigarette smoke exposure.

Household fuel use and biomarkers of inflammation and respiratory illness among rural South African Women

Though literature suggests a positive association between use of biomass fuel for cooking and inflammation, few studies among women in rural South Africa exist. We included 415 women from the South African Study of Women and Babies (SOWB), recruited from 2010 to 2011. We obtained demographics, general medical history and usual source of cooking fuel (wood, electricity) via baseline questionnaire. A nurse obtained height, weight, blood pressure, and blood samples. We measured plasma concentrations of a suite of inflammatory markers (e.g., interleukins, tumor necrosis factor-α, C-reactive protein). We assessed associations between cooking fuel and biomarkers of inflammation and respiratory symptoms/illness using crude and adjusted linear and logistic regression models. We found little evidence of an association between fuel-use and biomarkers of inflammation, pre-hypertension/hypertension, or respiratory illnesses. Though imprecise, we found 41% (95% confidence interval (CI) = 0.72-2.77) higher odds of self-reported wheezing/chest tightness among wood-users compared with electricity-users. Though studies among other populations report positive findings between biomass fuel use and inflammation, it is possible that women in the present study experience lower exposures to household air pollution given the cleaner burning nature of wood compared with other biomass fuels (e.g., coal, dung).

Evidence of Biomass Smoke Exposure as a Causative Factor for the Development of COPD

Chronic obstructive pulmonary disease (COPD) is a progressive disease of the lungs characterised by chronic inflammation, obstruction of airways, and destruction of the parenchyma (emphysema). These changes gradually impair lung function and prevent normal breathing. In 2002, COPD was the fifth leading cause of death, and is estimated by the World Health Organisation (WHO) to become the third by 2020. Cigarette smokers are thought to be the most at risk of developing COPD. However, recent studies have shown that people with life-long exposure to biomass smoke are also at high risk of developing COPD. Most common in developing countries, biomass fuels such as wood and coal are used for cooking and heating indoors on a daily basis. Women and children have the highest amounts of exposures and are therefore more likely to develop the disease. Despite epidemiological studies providing evidence of the causative relationship between biomass smoke and COPD, there are still limited mechanistic studies on how biomass smoke causes, and contributes to the progression of COPD. This review will focus upon why biomass fuels are used, and their relationship to COPD. It will also suggest methodological approaches to model biomass exposure in vitro and in vivo.

Pulmonary function and respiratory health of rural farmers and artisanal and small scale gold miners in Ghana

The recent increase in artisanal and small scale gold mining (ASGM) worldwide has elicited a number of public health concerns for miners and mining communities, including respiratory health. The two primary inhalational exposures of concern are crystalline silica expected to be present in gold ore and smoke from biomass fuels used in cooking. Here, measurements of pulmonary function and of respiratory symptoms were performed in an ASGM community, Kejetia, and a comparison agricultural community, Gorogo, in the Upper East Region of Ghana in May-July 2011. Of 172 participants, 159 performed spirometry, yielding 119 and 95 valid measurements for FEV₁ and FVC, respectively. Percent predicted FEV₁, FVC and FEV₁/FVC, which were lower than predicted for a healthy population, were not significantly different between Kejetia and Gorogo or by mining status in Kejetia. Abnormal lung function was elevated for predicted FEV₁ (15.0%) and FEV₁/FVC (22.0%) beyond an expected five percent in healthy populations. This first examination of pulmonary function in an ASGM community in Ghana (and possibly worldwide) did not show an obvious relationship between mining involvement and lung function abnormality, but did show associations between the use of biomass fuels, adverse respiratory symptoms, and reduced pulmonary function in both populations. A number of factors including age differences between the populations and the required lag time after silica exposure for the onset of respiratory disease may have affected results. Additional research is needed with larger sample sizes and with more detailed questionnaires to further assess the impact of multiple stressors on respiratory health in ASGM communities.

Biomass smoke exposure as an occupational risk: cross-sectional study of respiratory health of women working as street cooks in Nigeria

OBJECTIVE

Little is known about respiratory health of women who are occupationally exposed to biomass smoke outside their homes. This study reports the exposure and respiratory health of street cooks in Ile-Ife, Nigeria.

METHODS

We assessed exposure to biomass smoke by questionnaire in 188 street cooks and 197 control women and by personal diffusive samplers to quantify volatile organic compounds (VOCs) in a subsample of the women. Respiratory symptoms were assessed by a standardised questionnaire, and pulmonary function was assessed by spirometry before and after bronchodilation. Regression analysis was conducted to compare the outcome between the two groups.

RESULTS

The study included 188 women (median age 40, IQR 30-50 years) who had worked as street cooks for a median of 7 years (IQR 3-15 years) and 197 control women with similar demographics. Benzene concentration in passive samplers worn by the street cooks was significantly higher compared with controls (median (IQR) 119.3 (82.7-343.7) µg/m³ vs 0.0 (0.0-51.2) µg/m³, p<0.001). The odds of reported respiratory symptoms were significantly higher among the street cooks than controls: cough (adjusted OR 4.4, 95% CI 2.2 to 8.5) and phlegm (adjusted OR 3.9, 95% CI 1.5 to 7.3). The street cooks also had higher odd of airway obstruction as measured by forced expiratory volume in 1 s/forced vital capacity <0.7: 11% 3% (adjusted OR of 3.3 (95% CI 1.3 to 8.7)).

CONCLUSIONS

This study provides evidence of adverse respiratory effects among street cooks using biomass fuels.

Effect of a clean stove intervention on inflammatory biomarkers in pregnant women in Ibadan, Nigeria: A randomized controlled study

BACKGROUND

Exposure to household air pollution (HAP) has been linked to systemic inflammation. We determined the impact of transition from traditional firewood/kerosene stove to bioethanol-burning stove on inflammatory biomarkers in pregnant Nigerian women.

METHODS

Women (n=324), cooking with kerosene/firewood, were recruited during their first trimester of pregnancy from June 2013-October 2015 and were randomly allocated to either control (n=162) or intervention (n=162) group using web-based randomization. Controls continued to use their own firewood/kerosene stove, while intervention participants received bioethanol CleanCook stoves. Serum concentrations of retinol-binding protein (RBP), malondialdehyde (MDA), tumor necrosis factor alpha (TNF)-α, interleukin (IL)-6, and IL-8 were measured by ELISA.

RESULTS

After excluding 53 women (loss of follow-up, untimely biomarker assessments, incorrect dates of enrollment), data from 271 women were included in analysis. Mean (SD) change in RBP, MDA, TNF-α, IL-6, and IL-8 between baseline and third trimester was -2.16 (4.47), -19.6 (46.4), 3.72 (37.2), 0.51 (14.4), and 13.2 (197), respectively, in intervention and -2.25 (4.30), -24.6 (43.6), 7.17 (32.6), -1.79, (11.4), and 31.3 (296) in control groups. None of these changes differed significantly between the two treatment arms. However, changes from baseline in TNF-α levels were significantly different between intervention and control groups in subset of women (n=99) using firewood before trial (-7.03 [32.9] vs. +12.4 [33.6]; 95% CI for group difference: -35.4 to -3.4, p=0.018).

CONCLUSIONS

Decrease in TNF-α concentration from baseline to third trimesters in intervention group women could indicate reduced cardiovascular stress and prothrombotic effects from decreased HAP. Our findings suggest that ethanol-burning stoves may mitigate cardiovascular health risks.

A Systematic Review of Innate Immunomodulatory Effects of Household Air Pollution Secondary to the Burning of Biomass Fuels

BACKGROUND

Household air pollution (HAP)-associated acute lower respiratory infections cause 455,000 deaths and a loss of 39.1 million disability-adjusted life years annually. The immunomodulatory mechanisms of HAP are poorly understood.

OBJECTIVES

The aim of this study was to conduct a systematic review of all studies examining the mechanisms underlying the relationship between HAP secondary to solid fuel exposure and acute lower respiratory tract infection to evaluate current available evidence, identify gaps in knowledge, and propose future research priorities.

METHODS

We conducted and report on studies in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In all, 133 articles were fully reviewed and main characteristics were detailed, namely study design and outcome, including in vivo versus in vitro and pollutants analyzed. Thirty-six studies were included in a nonexhaustive review of the innate immune system effects of ambient air pollution, traffic-related air pollution, or wood smoke exposure of developed country origin. Seventeen studies investigated the effects of HAP-associated solid fuel (biomass or coal smoke) exposure on airway inflammation and innate immune system function.

RESULTS

Particulate matter may modulate the innate immune system and increase susceptibility to infection through a) alveolar macrophage-driven inflammation, recruitment of neutrophils, and disruption of barrier defenses; b) alterations in alveolar macrophage phagocytosis and intracellular killing; and c) increased susceptibility to infection via upregulation of receptors involved in pathogen invasion.

CONCLUSIONS

HAP secondary to the burning of biomass fuels alters innate immunity, predisposing children to acute lower respiratory tract infections. Data from biomass exposure in developing countries are scarce. Further study is needed to define the inflammatory response, alterations in phagocytic function, and upregulation of receptors important in bacterial and viral binding. These studies have important public health implications and may lead to the design of interventions to improve the health of billions of people daily.

Pathogenic mechanisms in chronic obstructive pulmonary disease due to biomass smoke exposure

Chronic obstructive pulmonary disease (COPD) mortality and morbidity have increased significantly worldwide in recent decades. Although cigarette smoke is still considered the main risk factor for the development of the disease, estimates suggest that between 25% and 33% of COPD patients are non-smokers. Among the factors that may increase the risk of developing COPD, biomass smoke has been proposed as one of the most important, affecting especially women and children in developing countries. Despite the epidemiological evidence linking exposure to biomass smoke with adverse health effects, the specific cellular and molecular mechanisms by which this pollutant can be harmful for the respiratory and cardiovascular systems remain unclear. In this article we review the main pathogenic mechanisms proposed to date that make biomass smoke one of the major risk factors for COPD.

Respiratory risks from household air pollution in low and middle income countries

A third of the world's population uses solid fuel derived from plant material (biomass) or coal for cooking, heating, or lighting. These fuels are smoky, often used in an open fire or simple stove with incomplete combustion, and result in a large amount of household air pollution when smoke is poorly vented. Air pollution is the biggest environmental cause of death worldwide, with household air pollution accounting for about 3·5-4 million deaths every year. Women and children living in severe poverty have the greatest exposures to household air pollution. In this Commission, we review evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases. Respiratory infections (comprising both upper and lower respiratory tract infections with viruses, bacteria, and mycobacteria) have all been associated with exposure to household air pollution. Respiratory tract cancers, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal burning and further data are needed about other solid fuels. Chronic lung diseases, including chronic obstructive pulmonary disease and bronchiectasis in women, are associated with solid fuel use for cooking, and the damaging effects of exposure to household air pollution in early life on lung development are yet to be fully described. We also review appropriate ways to measure exposure to household air pollution, as well as study design issues and potential effective interventions to prevent these disease burdens. Measurement of household air pollution needs individual, rather than fixed in place, monitoring because exposure varies by age, gender, location, and household role. Women and children are particularly susceptible to the toxic effects of pollution and are exposed to the highest concentrations. Interventions should target these high-risk groups and be of sufficient quality to make the air clean. To make clean energy available to all people is the long-term goal, with an intermediate solution being to make available energy that is clean enough to have a health impact.

Relationships between Plasma Micronutrients, Serum IgE, and Skin Test Reactivity and Asthma among School Children in Rural Southwest Nigeria

Objective. Increasing prevalence of asthma has been attributed to changes in lifestyle and environmental exposures. We conducted a case-control study to investigate the relationship between serum micronutrients and asthma in rural school children in Nigeria. Methods. We administered questionnaires to 1,562 children to identify children with asthma. Serum concentration levels of 12 micronutrients were determined in asthma cases (N = 37) and controls (N = 30). Allergy skin prick test and spirometry were also performed. Results. Plasma levels of the following micronutrients were significantly different between cases and controls: calcium (7.48 ± 2.16 versus 8.29 ± 1.62 mg/dL; P = 0.04), manganese (44.1 ± 11.5 versus 49.3 ± 7.9 mg/L; P = 0.01), selenium (76.1 ± 14.9 versus 63.3 ± 26.8 μg/L; P = 0.02), and albumin (3.45 ± 0.90 versus 3.91 ± 0.99 g/dL; P = 0.04). Plasma concentrations of iron and selenium were positively correlated with lung function, r = 0.43 (P < 0.05 in each case) while manganese serum concentration was negatively correlated with asthma (r = −0.44; P < 0.05). Conclusions. Children with asthma had reduced levels of plasma manganese, calcium, and albumin but raised level of selenium. The protective or risk effects of these micronutrients on asthma warrant further investigation.