Cooking outdoors or with cleaner fuels does not increase malarial risk in children under 5 years: a cross-sectional study of 17 sub-Saharan African countries

Katherine E Woolley; Suzanne E Bartington; Francis D Pope; Sheila M Greenfield; Lucy S Tusting; Malcolm J Price; G Neil Thomas

doi:10.1186/s12936-022-04152-3

Cooking outdoors or with cleaner fuels does not increase malarial risk in children under 5 years: a cross-sectional study of 17 sub-Saharan African countries

Katherine E Woolley, Suzanne E Bartington, Francis D Pope, Sheila M Greenfield, Lucy S Tusting, Malcolm J Price, G Neil Thomas

Research output: Contribution to journal › Article › peer-review

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Abstract

BACKGROUND: Smoke from solid biomass cooking is often stated to reduce household mosquito levels and, therefore, malarial transmission. However, household air pollution (HAP) from solid biomass cooking is estimated to be responsible for 1.67 times more deaths in children aged under 5 years compared to malaria globally. This cross-sectional study investigates the association between malaria and (i) cleaner fuel usage; (ii) wood compared to charcoal fuel; and, (iii) household cooking location, among children aged under 5 years in sub-Saharan Africa (SSA).

METHODS: Population-based data was obtained from Demographic and Health Surveys (DHS) for 85,263 children within 17 malaria-endemic sub-Saharan countries who were who were tested for malaria with a malarial rapid diagnostic test (RDT) or microscopy. To assess the independent association between malarial diagnosis (positive, negative), fuel type and cooking location (outdoor, indoor, attached to house), multivariable logistic regression was used, controlling for individual, household and contextual confounding factors.

RESULTS: Household use of solid biomass fuels and kerosene cooking fuels was associated with a 57% increase in the odds ratio of malarial infection after adjusting for confounding factors (RDT adjusted odds ratio (AOR):1.57 [1.30-1.91]; Microscopy AOR: 1.58 [1.23-2.04]) compared to cooking with cleaner fuels. A similar effect was observed when comparing wood to charcoal among solid biomass fuel users (RDT AOR: 1.77 [1.54-2.04]; Microscopy AOR: 1.21 [1.08-1.37]). Cooking in a separate building was associated with a 26% reduction in the odds of malarial infection (RDT AOR: 0.74 [0.66-0.83]; Microscopy AOR: 0.75 [0.67-0.84]) compared to indoor cooking; however no association was observed with outdoor cooking. Similar effects were observed within a sub-analysis of malarial mesoendemic areas only.

CONCLUSION: Cleaner fuels and outdoor cooking practices associated with reduced smoke exposure were not observed to have an adverse effect upon malarial infection among children under 5 years in SSA. Further mixed-methods research will be required to further strengthen the evidence base concerning this risk paradigm and to support appropriate public health messaging in this context.

Original language	English
Article number	133
Number of pages	15
Journal	Malaria Journal
Volume	21
Issue number	1
DOIs	https://doi.org/10.1186/s12936-022-04152-3
Publication status	Published - 27 Apr 2022

Bibliographical note

Funding Information:
KEW is funded by a University of Birmingham Global Challenges Scholarship. MJP is supported by the NIHR Birmingham Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

This cross-sectional study uses publicly available survey data for 17 malarial-endemic SSA countries with available malarial data (Fig. ), obtained from the DHS program supported by the United States Agency for International Development (USAID) within the last 10 years (2010–2020). The DHS undertakes full surveys every 5 years, and intermediate Malaria Indicators Surveys (MIS) []; only some of the full DHS survey modules undertake malarial testing. For those DHS surveys including malaria modules, malarial testing is undertaken by trained fieldworkers on a sub-sample of eligible children aged 6–59 months using a malarial rapid diagnostic test (RDT) []. A two-stage stratified sampling technique was employed to obtain a representative population-based sample, with residential households randomly selected. Eligible households included those with an ever-married (married, widowed or divorced) woman aged between 15 and 49 years and resident the night before the survey. Ethical approval for data collection was gained from the relevant government authority [], and authorization for data access was provided by the DHS.

Publisher Copyright:
© 2022, The Author(s).

Keywords

Air Pollution, Indoor/adverse effects
Charcoal/analysis
Child
Child, Preschool
Cooking/methods
Cross-Sectional Studies
Humans
Malaria/epidemiology
Smoke/adverse effects
Malaria
Children under 5 years
Household air pollution
Biomass
Sub-Saharan Africa
Low and middle-income country

ASJC Scopus subject areas

Infectious Diseases
Parasitology

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1186/s12936-022-04152-3Licence: Creative Commons: Attribution (CC BY)

WoolleyK2022CookingFinal published version, 1.01 MBLicence: Creative Commons: Attribution (CC BY)

Cite this

@article{994b5c59cf8f4ee1aa20c9a1eeb6c085,

title = "Cooking outdoors or with cleaner fuels does not increase malarial risk in children under 5 years: a cross-sectional study of 17 sub-Saharan African countries",

abstract = "BACKGROUND: Smoke from solid biomass cooking is often stated to reduce household mosquito levels and, therefore, malarial transmission. However, household air pollution (HAP) from solid biomass cooking is estimated to be responsible for 1.67 times more deaths in children aged under 5 years compared to malaria globally. This cross-sectional study investigates the association between malaria and (i) cleaner fuel usage; (ii) wood compared to charcoal fuel; and, (iii) household cooking location, among children aged under 5 years in sub-Saharan Africa (SSA).METHODS: Population-based data was obtained from Demographic and Health Surveys (DHS) for 85,263 children within 17 malaria-endemic sub-Saharan countries who were who were tested for malaria with a malarial rapid diagnostic test (RDT) or microscopy. To assess the independent association between malarial diagnosis (positive, negative), fuel type and cooking location (outdoor, indoor, attached to house), multivariable logistic regression was used, controlling for individual, household and contextual confounding factors.RESULTS: Household use of solid biomass fuels and kerosene cooking fuels was associated with a 57% increase in the odds ratio of malarial infection after adjusting for confounding factors (RDT adjusted odds ratio (AOR):1.57 [1.30-1.91]; Microscopy AOR: 1.58 [1.23-2.04]) compared to cooking with cleaner fuels. A similar effect was observed when comparing wood to charcoal among solid biomass fuel users (RDT AOR: 1.77 [1.54-2.04]; Microscopy AOR: 1.21 [1.08-1.37]). Cooking in a separate building was associated with a 26% reduction in the odds of malarial infection (RDT AOR: 0.74 [0.66-0.83]; Microscopy AOR: 0.75 [0.67-0.84]) compared to indoor cooking; however no association was observed with outdoor cooking. Similar effects were observed within a sub-analysis of malarial mesoendemic areas only.CONCLUSION: Cleaner fuels and outdoor cooking practices associated with reduced smoke exposure were not observed to have an adverse effect upon malarial infection among children under 5 years in SSA. Further mixed-methods research will be required to further strengthen the evidence base concerning this risk paradigm and to support appropriate public health messaging in this context.",

keywords = "Air Pollution, Indoor/adverse effects, Charcoal/analysis, Child, Child, Preschool, Cooking/methods, Cross-Sectional Studies, Humans, Malaria/epidemiology, Smoke/adverse effects, Malaria, Children under 5 years, Household air pollution, Biomass, Sub-Saharan Africa, Low and middle-income country",

author = "Woolley, {Katherine E} and Bartington, {Suzanne E} and Pope, {Francis D} and Greenfield, {Sheila M} and Tusting, {Lucy S} and Price, {Malcolm J} and Thomas, {G Neil}",

note = "Funding Information: KEW is funded by a University of Birmingham Global Challenges Scholarship. MJP is supported by the NIHR Birmingham Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. This cross-sectional study uses publicly available survey data for 17 malarial-endemic SSA countries with available malarial data (Fig. ), obtained from the DHS program supported by the United States Agency for International Development (USAID) within the last 10 years (2010–2020). The DHS undertakes full surveys every 5 years, and intermediate Malaria Indicators Surveys (MIS) []; only some of the full DHS survey modules undertake malarial testing. For those DHS surveys including malaria modules, malarial testing is undertaken by trained fieldworkers on a sub-sample of eligible children aged 6–59 months using a malarial rapid diagnostic test (RDT) []. A two-stage stratified sampling technique was employed to obtain a representative population-based sample, with residential households randomly selected. Eligible households included those with an ever-married (married, widowed or divorced) woman aged between 15 and 49 years and resident the night before the survey. Ethical approval for data collection was gained from the relevant government authority [], and authorization for data access was provided by the DHS. Publisher Copyright: {\textcopyright} 2022, The Author(s).",

year = "2022",

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day = "27",

doi = "10.1186/s12936-022-04152-3",

language = "English",

volume = "21",

journal = "Malaria Journal",

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number = "1",

}

TY - JOUR

T1 - Cooking outdoors or with cleaner fuels does not increase malarial risk in children under 5 years

T2 - a cross-sectional study of 17 sub-Saharan African countries

AU - Woolley, Katherine E

AU - Bartington, Suzanne E

AU - Pope, Francis D

AU - Greenfield, Sheila M

AU - Tusting, Lucy S

AU - Price, Malcolm J

AU - Thomas, G Neil

N1 - Funding Information: KEW is funded by a University of Birmingham Global Challenges Scholarship. MJP is supported by the NIHR Birmingham Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. This cross-sectional study uses publicly available survey data for 17 malarial-endemic SSA countries with available malarial data (Fig. ), obtained from the DHS program supported by the United States Agency for International Development (USAID) within the last 10 years (2010–2020). The DHS undertakes full surveys every 5 years, and intermediate Malaria Indicators Surveys (MIS) []; only some of the full DHS survey modules undertake malarial testing. For those DHS surveys including malaria modules, malarial testing is undertaken by trained fieldworkers on a sub-sample of eligible children aged 6–59 months using a malarial rapid diagnostic test (RDT) []. A two-stage stratified sampling technique was employed to obtain a representative population-based sample, with residential households randomly selected. Eligible households included those with an ever-married (married, widowed or divorced) woman aged between 15 and 49 years and resident the night before the survey. Ethical approval for data collection was gained from the relevant government authority [], and authorization for data access was provided by the DHS. Publisher Copyright: © 2022, The Author(s).

PY - 2022/4/27

Y1 - 2022/4/27

N2 - BACKGROUND: Smoke from solid biomass cooking is often stated to reduce household mosquito levels and, therefore, malarial transmission. However, household air pollution (HAP) from solid biomass cooking is estimated to be responsible for 1.67 times more deaths in children aged under 5 years compared to malaria globally. This cross-sectional study investigates the association between malaria and (i) cleaner fuel usage; (ii) wood compared to charcoal fuel; and, (iii) household cooking location, among children aged under 5 years in sub-Saharan Africa (SSA).METHODS: Population-based data was obtained from Demographic and Health Surveys (DHS) for 85,263 children within 17 malaria-endemic sub-Saharan countries who were who were tested for malaria with a malarial rapid diagnostic test (RDT) or microscopy. To assess the independent association between malarial diagnosis (positive, negative), fuel type and cooking location (outdoor, indoor, attached to house), multivariable logistic regression was used, controlling for individual, household and contextual confounding factors.RESULTS: Household use of solid biomass fuels and kerosene cooking fuels was associated with a 57% increase in the odds ratio of malarial infection after adjusting for confounding factors (RDT adjusted odds ratio (AOR):1.57 [1.30-1.91]; Microscopy AOR: 1.58 [1.23-2.04]) compared to cooking with cleaner fuels. A similar effect was observed when comparing wood to charcoal among solid biomass fuel users (RDT AOR: 1.77 [1.54-2.04]; Microscopy AOR: 1.21 [1.08-1.37]). Cooking in a separate building was associated with a 26% reduction in the odds of malarial infection (RDT AOR: 0.74 [0.66-0.83]; Microscopy AOR: 0.75 [0.67-0.84]) compared to indoor cooking; however no association was observed with outdoor cooking. Similar effects were observed within a sub-analysis of malarial mesoendemic areas only.CONCLUSION: Cleaner fuels and outdoor cooking practices associated with reduced smoke exposure were not observed to have an adverse effect upon malarial infection among children under 5 years in SSA. Further mixed-methods research will be required to further strengthen the evidence base concerning this risk paradigm and to support appropriate public health messaging in this context.

AB - BACKGROUND: Smoke from solid biomass cooking is often stated to reduce household mosquito levels and, therefore, malarial transmission. However, household air pollution (HAP) from solid biomass cooking is estimated to be responsible for 1.67 times more deaths in children aged under 5 years compared to malaria globally. This cross-sectional study investigates the association between malaria and (i) cleaner fuel usage; (ii) wood compared to charcoal fuel; and, (iii) household cooking location, among children aged under 5 years in sub-Saharan Africa (SSA).METHODS: Population-based data was obtained from Demographic and Health Surveys (DHS) for 85,263 children within 17 malaria-endemic sub-Saharan countries who were who were tested for malaria with a malarial rapid diagnostic test (RDT) or microscopy. To assess the independent association between malarial diagnosis (positive, negative), fuel type and cooking location (outdoor, indoor, attached to house), multivariable logistic regression was used, controlling for individual, household and contextual confounding factors.RESULTS: Household use of solid biomass fuels and kerosene cooking fuels was associated with a 57% increase in the odds ratio of malarial infection after adjusting for confounding factors (RDT adjusted odds ratio (AOR):1.57 [1.30-1.91]; Microscopy AOR: 1.58 [1.23-2.04]) compared to cooking with cleaner fuels. A similar effect was observed when comparing wood to charcoal among solid biomass fuel users (RDT AOR: 1.77 [1.54-2.04]; Microscopy AOR: 1.21 [1.08-1.37]). Cooking in a separate building was associated with a 26% reduction in the odds of malarial infection (RDT AOR: 0.74 [0.66-0.83]; Microscopy AOR: 0.75 [0.67-0.84]) compared to indoor cooking; however no association was observed with outdoor cooking. Similar effects were observed within a sub-analysis of malarial mesoendemic areas only.CONCLUSION: Cleaner fuels and outdoor cooking practices associated with reduced smoke exposure were not observed to have an adverse effect upon malarial infection among children under 5 years in SSA. Further mixed-methods research will be required to further strengthen the evidence base concerning this risk paradigm and to support appropriate public health messaging in this context.

KW - Air Pollution, Indoor/adverse effects

KW - Charcoal/analysis

KW - Child

KW - Child, Preschool

KW - Cooking/methods

KW - Cross-Sectional Studies

KW - Humans

KW - Malaria/epidemiology

KW - Smoke/adverse effects

KW - Malaria

KW - Children under 5 years

KW - Household air pollution

KW - Biomass

KW - Sub-Saharan Africa

KW - Low and middle-income country

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U2 - 10.1186/s12936-022-04152-3

DO - 10.1186/s12936-022-04152-3

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C2 - 35477567

SN - 1475-2875

VL - 21

JO - Malaria Journal

JF - Malaria Journal

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