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 Table of Contents  
Year : 2017  |  Volume : 2  |  Issue : 2  |  Page : 55-59

Association of adverse neonatal outcome with biomass fuel use

1 Department of Occupational Medicine, Regional Occupational Health Centre (Eastern), Kolkata, West Bengal, India
2 Department of Occupational Medicine, All Institute of Hygiene and Public Health, Kolkata, West Bengal, India
3 Department of Obstetrics and Gynaecology, Calcutta Medical College, Kolkata, West Bengal, India

Date of Submission22-Feb-2017
Date of Acceptance11-Apr-2017
Date of Web Publication30-Jun-2017

Correspondence Address:
Asim Saha
Department of Occupational Medicine, Regional Occupational Health Centre (Eastern), DP Block, Sector V, Salt Lake City, Kolkata - 700 091, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ed.ed_3_17

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Background: Evidence has emerged which suggests that indoor air pollution resulting from biomass fuel combustion in developing countries may, apart from chronic bronchitis, chronic obstructive pulmonary disease, and lung cancer, also increase the risk of asthma, middle ear infection in children, and tuberculosis, nasopharyngeal and laryngeal cancer, and cataract in adults. Significant findings, although through fewer studies, are being observed recently regarding the association of low birth weight, neonatal mortality with biomass fuel use. Biomass provides 32% of all the primary energy use in India at present, which may bring significant adverse impacts on human health. In this backdrop, the present study was initiated to explore the effect of biomass fuel use on adverse neonatal outcome.
Methods: This hospital-based prospective study was carried out during March 2014–December 2015 in Medical College and Hospital, Kolkata, India. This study included 609 subjects and compared adverse neonatal outcome with normal outcome in relation to fuel use characteristics.
Results: This study observed that low birth weight, lesser head circumference, neonatal death, less developed genitalia, and need to stay at nursery was more frequent with mothers using biomass fuel. Significantly increased risk of “low birth weight” (risk ratio [RR] 1.78, 95% confidence interval [CI]; 1.11–3.64) and “need of newborn to stay in neonatal care unit” (RR 1.82, 95% CI; 1.08–4.06) was observed in biomass fuel users after adjusting for age of mother, type of residence, age at marriage, and hemoglobin level of the mother at last trimester.
Conclusions: This study observed a significant association between biomass fuel use and adverse neonatal outcomes such as low birth weight and stay in neonatal care unit. Observation of the study not only highlighted the need of a proper preventive measure in the form of an intervention device but also pointed out the fact that elevating the level of education among women may suitably contribute in effective control of the problem.

Keywords: Biomass fuel, low birth weight, neonatal outcome

How to cite this article:
Saha A, Atul A, Hira S, Naskar N N, Lahiri T K. Association of adverse neonatal outcome with biomass fuel use. Environ Dis 2017;2:55-9

How to cite this URL:
Saha A, Atul A, Hira S, Naskar N N, Lahiri T K. Association of adverse neonatal outcome with biomass fuel use. Environ Dis [serial online] 2017 [cited 2022 Dec 10];2:55-9. Available from: http://www.environmentmed.org/text.asp?2017/2/2/55/209264

  Introduction Top

Large numbers of people are exposed on a daily basis to harmful emissions and other health risks from biomass and coal burning. Exposure to indoor air pollution from the combustion of traditional biomass fuels (wood, charcoal, animal dung, and crop wastes) and coal is a significant public health hazard, predominantly affecting poor rural and urban communities in developing countries.[1] The majority of those exposed are women, who are normally responsible for food preparation and cooking, and infants/young children who are usually with their mothers near the cooking area.[2] There is consistent evidence that exposure to biomass smoke is associated with increased risk of a range of common and serious diseases of both children and adults. Acute lower respiratory infections in childhood (particularly pneumonia),[3] chronic bronchitis, and chronic obstructive pulmonary disease (particularly among women)[4] are well associated. Evidence also suggest that such exposures markedly increases the risk of lung cancer, particularly in women.[5],[6] With regard to ocular morbidity also, there is increasing evidence that biofuel pollution causes eye irritation as well as cataract.[7] Deteriorated pulmonary function has also been found to be associated with similar fuel use.[8] Some studies have claimed (although not confirmed) association between biofuel use and increased risk of tuberculosis.[9] In recent years, newer evidence has emerged which suggest that indoor air pollution in developing countries may also increase the risk of other important health problems such as low birth weight, neonatal mortality, etc.[10],[11] although this evidence is more tentative, being based on fewer studies. A need is also felt for more studies to address these issues, clarify causal connections, and identify effective approaches to reduce the burden.[11] As far as, biomass fuel use in India is concerned, the country produces about 400–500 million tons of biomass per year and biomass provides 32% of all the primary energy use in the country at present.[12] Biomass fuel consists of firewood, dung cakes, agricultural crop residues such as straw, grass, and shrubs, etc., Together with coal and kerosene, they supply 75% of the domestic energy in India.[13] According to the World Health Organization, an estimated 58% of the Indian population depended on solid fuels for domestic use in 2010.[14] In this backdrop, the present study was planned to understand the effect of fuel use on adverse neonatal outcome by comparing adverse outcome with normal outcome in relation to fuel use characteristics in a prospective manner.

  Methods Top

Location and time of the study

This hospital-based prospective epidemiological study on neonatal outcome of biofuel use was carried out in the outpatient department of a hospital to explore the hypothesis. We conducted the study during March 2014–December 2015 in Medical College and Hospital, Kolkata, India. This hospital is located in a central place of Kolkata city. It has about 1000 inpatient care beds, and outpatient department caters about 3000 attendees daily. Our study was conducted on obstetrics outpatient department of the hospital. As far as, attendees are concerned, this hospital caters a big geographical area which covers both rural and urban localities. This study was approved by the Institutional Scientific Advisory Committee and Institutional Ethics Committee.


This study has been a comparative study where exposed and unexposed groups were selected and followed up till the eventual outcome results with the objective of comparing adverse outcome and normal outcome in relation to fuel use characteristics. In our study, we found that our subjects were users of wood, cattle dung, coal, kerosene, and liquefied petroleum gas (LPG), either alone or in combination. While categorizing, we initially classified wood and cattle dung users as biomass fuel users. Coal, kerosene, and LPG users were treated as separate groups. Subsequently, to evaluate the effects of fuel use, the exposed group was constituted by biomass fuel users (alone or in combination with coal/kerosene) and the LPG users constituted the unexposed group. Subjects with known cause of adverse neonatal/perinatal outcome (maternal known health problems such as hypertension, diabetes, malnutrition, etc.), subjects with eventful pregnancy (bleeding, infection, etc.) that may contribute to adverse neonatal outcome and occupational exposure of the mother from methylmercury, polychlorinated biphenyls, and polychlorinated dibenzofurans were excluded from this study.

Sample size was calculated in the principles of prospective cohort study. Presuming risk ratio (RR) of 1.5 and unexposed with outcome as 20%, restricting alpha error to <5% and power of study to 80%, required sample size came out to be 332 exposed and 221 unexposed subjects (1.5:1). We recruited the subjects of this study from the outpatient department of a hospital. While selecting the subjects for this study, 2 days of every week (from 6 days, Sunday being holiday) was first selected randomly on which days the subjects were selected. Subsequently, every “n”th attendee (coming for the first visit of antenatal check-up) on the selected days was recruited (n is a random number selected between 1 and 10). We set our target at 250 unexposed subjects or 350 exposed subjects whichever achieved earlier provided the required number is also achieved in the other category. First, we achieved the target of 350 exposed subjects; however, the number of 250 unexposed was not reached by that time. Hence, we continued till we reach 250 unexposed subjects and in the process, the number of exposed subjects reached 381. However, we did not include 13 unexposed subjects and 9 exposed subjects in the analysis due to lack of complete information. Hence, a total of 631 subjects were enrolled for the study; however, final analysis included 609 subjects for which proper follow-up could be done, and complete information could be achieved.

Data collection

Every subject (pregnant woman) included in this study was interviewed with an interviewer-administered questionnaire for personal, occupational, fuel use, and morbidity details. All the subjects (mother and child as a unit) were examined clinically to obtain basic health status details, detect obvious abnormality if any. Questionnaire was suitably designed to collect information regarding exposure to fuel per day and also regarding years of exposure. Information regarding ventilation of the cooking area was also collected. The information regarding ventilation status was categorized (separate kitchen, cooking in the living room, and cooking in open area) on the basis of collected information. Occupation of pregnant woman, smoking status of husband, etc., were also taken into consideration. So far, as nutritional status of the mother is concerned, two objective parameters were examined in all the subjects; hemoglobin level (gm percentage) in the last trimester and body mass index.

Statistical analysis

Initially, a descriptive analysis was carried out to obtain basic details of the study parameters. Afterward, analysis of variance was used to ascertain the differences among different comparison groups in relation to different study parameters. Finally, the subjects with and without adverse neonatal outcome were compared with reference to their fuel use, taking care of the possible confounders. The analysis was done using SPSS software (SPSS Inc, Chicago, USA). Logistic regression technique was applied to obtain the contribution of fuel use toward adverse neonatal outcome, irrespective of the effect of the possible confounders. Variables such as different fuels (yes, no), smoking (ever smoker, never smoker), education of the subject (up to primary standard, higher than that), kitchen type (separate kitchen, cooking in the living room and cooking in open area) were taken as categorical variables. Other variables such as age (years) and hemoglobin level (gram percent) were taken as continuous variables. In our analysis, we accommodated fuel types together with possible confounding variables in the logistic regression model as covariates to estimate the effect of fuel variables, adjusting for the effects of other variables. Adverse neonatal outcome (birth weight <2.5 kg, head circumference <35 cm, death in first 4 weeks of life, deficient reflex, less developed genitalia, and stay at neonatal care unit) were included as outcome variable.

  Results Top

Pregnant mothers

This study observed the details of childbirth and newborns and analyzed the association of these details with the characteristics of the parents, especially the fuel use nature of the family. Mean age of the mothers was 23.1 ± 3.5 years, majority (55.5%) was in the age group of 21–30 years. Sixty-five percent of them had normal body mass index and mean height and weight of the subjects was 157.4 ± 6.8 cm and 51.7 ± 9.9 kg, respectively. The majority of the subjects were only primary level educated (54%). A large number of families had kachcha type of residence (76.8%). About 21% had open kitchen and 34% cooked in living rooms. Husbands of 35.1% subjects were smokers. Mean age at their marriage was 19.8 ± 2.7 years. About 80% availed regular prenatal visit, and 61% had regular intake of iron-folate. While analyzing the distribution of these characteristics according to fuel use characters of the study subjects, no significant difference was observed between biomass fuel users and LPG users. So far, as cooking fuel use characteristics are concerned, 44.7% families used biomass fuel (either wood or wood and dung in combination). Kerosene and coal (used in combination with biomass fuel) were used by 8.7% and 10.8% families, respectively. Wood and cow-dung (alone or in combination) were used by 51.8% and 61.1% subjects, respectively. LPG was used by 38.9% families [Table 1].
Table 1: Fuel use characteristics of study population

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On analysis of childbirth details and also the details of the newborn, it was observed that term delivery took place in about 80.8% of incidents. Neonatal death took place in 29 cases. Birth weight was <2.5 kg in about 45% of newborns. However, mean birth weight was found as 2.53 ± 0.62 kg while considering all the births. The mean head circumference was 33.06 ± 1.7 cm. The presence of deep sole crease was observed in 81.9% newborns, however, less developed genitalia was seen in 36.2% births. Sucking and grasping reflex was found satisfactory in about 93% and 85% newborns, respectively. Stay at nursery was needed in case of 9.4% newborns.

Biomass fuel use and neonatal effects

When biomass fuel users were compared with other fuel users in relation to the childbirth characteristics, it was observed that low birth weight, lesser head circumference, neonatal death, less developed genitalia, deficient reflexes, and need to stay at nursery was more frequent with mothers using biomass fuel although the difference was not statistically significant.

Mean birth weight and head circumference values when compared between biomass fuel use and other fuel use were found to be lower in biomass fuel users. Lower values were also found with smoker status of husband, lower age at marriage, and kutcha type of residence. These differences were mostly nonsignificant on statistical analysis. However, birth weight was found to be significantly lower among biomass fuel users. On multivariate analysis [Table 2], significantly increased risk of “low birth weight” (RR 1.78, 95% confidence interval [CI]; 1.11–3.64) and “need of newborn to stay in neonatal care unit” (RR 1.82, 95% CI; 1.08–4.06) in the form of calculated RR was observed in biomass fuel users after adjusting for age of mother, type of kitchen, age at marriage, smoking of husband, education of mother, cooking hour-years, and hemoglobin level of the mother at the last trimester. The lower education level of mother was also observed to be a near significant contributor (RR 2.6, 95% CI; 0.91–6.25) of adverse neonatal outcome.
Table 2: Relationship of neonatal characteristics with biomass fuel use (multivariate analysis)

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  Discussions Top

Recent studies conducted in China [15] and India [16] found significant association between biomass fuel use and low birth weight. Contemporary studies also reported increased risk of preeclampsia/eclampsia among biomass fuel using population.[17] In the backdrop of increasing evidence of adverse health effects of biomass smoke, importance of identification of more and more modifiable associated risk factors is being felt, different intervention devices are being tested for its efficacy.[18],[19] This present study has included and analyzed 609 episodes of neonatal/perinatal outcome. This study found neonatal outcomes such as low birth weight and need of newborn to stay in nursery are more associated with biomass fuel use. This study also observed that factors such as lower education level of mother might also have contributed to such findings.

This study, however, had some limitations also. Analysis of adverse outcome according to the duration of fuel use may have provided more information on the contribution of fuel use to adverse outcomes. However, it was ensured that all the subjects included in the final analysis had exposure of at least 10 cooking hour-years. Analysis of adverse outcomes, taking into account more contributing factors could have made the study more valid. Economics influences the choice and quantity of fuel use. Studies have already shown that energy-poverty nexus exists and biomass fuel use is sometimes dependent on low household income.[20],[21] Poverty is a close associate of less education level, and many adverse health outcomes are directly/indirectly associated. This remains a confounding effect in elucidating the effect of biomass use on morbidity. The inclusion of a large number of variables during analysis in the logistic regression model may have been another limitation of our study. With a larger sample size, effects of individual fuels, as well as effects of all possible fuel combinations could have been studied. The hospital-based study design also contained its own inherent bias. Selection of a proper cohort of subjects from multiple localities through a community-based study design could have made the findings of this study more generalizable.

Air pollution from solid fuel use in all developing countries including India has been suggested to have a serious impact on health.[22] Biomass fuel attributes for 5%–6% of the national burden of disease.[23] Considering the magnitude of the problem, it is evident that government initiatives in this regard and awareness among common people are important. In our study, we found that 68% of subjects were unaware about adverse health effect of such fuel use and 79% of them did not know that some modification of their cooking arrangement can be made for their health benefit. In India, government programs are there to develop and deploy biomass cookstoves for providing cleaner cooking energy solution.[24] This effort can mitigate drudgery of women and children as well as can benefit by reducing emission. Our study highlights the fact that strengthening the implementation of such government initiatives supplemented with the awareness generation efforts among women can very well lessen the morbidity among poor mother and children and reduce national burden of disease.

  Conclusions Top

This study observed significant association between biomass fuel use and adverse neonatal outcomes such as low birth weight and stay in neonatal care unit. The findings highlighted in this study have important implications from preventive policy point of view, especially in economically backward countries. The present study has not only highlighted the need of a proper preventive measure in the form of an intervention device but also pointed out the fact that elevating the level of education among women may suitably contribute in effective control of the problem.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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