ABSTRACT
Introduction:
In India, about 90% of the rural population relied upon biomass fuels like animal dung, crop residues and wood. Women generally being involved in cooking are at higher risk of developing respiratory diseases following use of unclean fuels. Objective: The objective of the study is to assess the association of respiratory morbidity with different fuels and the duration of exposure in the women residing in the rural area of Maharashtra.
Methodology:
A community-based cross-sectional study was conducted in field practice area of the Department of Community Medicine of Government Medical College in Maharashtra. Total of 994 eligible subjects were included in the study and data was collected using predesigned structured questionnaire. Abnormal pulmonary function of the study subjects was assessed by the measurement of peak expiratory flow rate (PEFR). Statistical tests such as ANOVA, bivariate and multivariate analysis were used.
Results:
Out of 994 subjects, 725 (72.9%) subjects were using only biomass fuel and 120 (12.1%) were using only LPG for domestic purposes. Lowest mean PEFR was seen in mixed fuel users, that is, 284.09 (SD ± 64.83), followed by biomass fuel users, that is, 287.88 (SD ± 61.47). Respiratory morbidity was seen in 369 (38.1%) subjects with maximum morbidity in biomass users, that is, 262 (p < 0.001). Occurrence of respiratory symptoms like dyspnoea, cough and rhinitis was significantly higher amongst the subjects using biomass fuel, with P < 0.001. Bivariate and multivariate analysis showed that use of biomass fuel, age above 60 years and EI more than 90 had higher odds of having respiratory morbidity.
Conclusion:
The risk of developing respiratory morbidities is high in subjects using biomass fuel. Also, the occurrence of such morbid conditions depends on the higher age and longer duration of exposure to biomass smoke.
Keywords: Biomass fuel, respiratory morbidity, rural, women
Introduction
The World Health Organization has estimated that indoor air pollution from solid fuel use is responsible for 2.6% of the total global burden of disease and between 1.5 and 2 million deaths each year, primarily due to acute lower respiratory infection in young children and chronic obstructive pulmonary disease in adult women.[1] In India, the 1991 National Census for the first time inquired about the cooking fuel used and revealed that about 90% of the rural population relied upon biomass fuels like animal dung, crop residues and wood. Nation-wide about 78% of the population relied upon the biomass fuels and 3% on coal.[2]
India, with 80% of households depending on traditional fuels, has the largest burden of disease amongst developing countries and contributes alone to 28% of the deaths due to indoor air pollution generated by use of unprocessed fuels.[3] In India, 34,000 deaths from chronic obstructive pulmonary disease (COPD) in women are attributed annually to household solid fuel use, making this the third leading risk factor amongst all risk factors contributing to the national burden of disease and exceeding the burden attributable to outdoor air pollution.[4]
Unclean fuels are still mainly in use in rural areas in developing countries. Commonly, these fuels are frequently used for a number of hours each day during times when people are present; they expose more individuals to interior air pollutants. It is undoubtedly true that the incidence of severe and critical illnesses would be decreased if physicians diagnose these respiratory morbidities at the primary care level. With this background, present study was planned to assess the association of respiratory morbidity with different fuels and the duration of exposure in the women residing in the rural area of Maharashtra.
Materials and Method
A community-based cross-sectional study was conducted in field practice area of the tertiary care hospital in rural Maharashtra. A house to house survey was done were subjects comprise of all women aged above 15 years involved in cooking, non-smokers and non-pregnant women and those who were resident of a village for more than 1 year. Women from the houses, which were locked during two consecutive visits made by the investigator and those who refused to participate in the study, were considered as non-respondents. According to the Census data, population of females who were resident of village was 2193. Excluding 41% of population upto 18 years of age and females not involved in cooking, the eligible subjects count comes to 994.[5] The study was approved by the Institutional Ethics Committee. Informed consent was obtained from all subjects.
Predesigned structured questionnaire was used to collected data including complete personal information, present complaints, past history and general household condition including type of fuel used for cooking, number of hours spent per day for cooking and number of years spent in cooking. Clinical examination included general examination along with systemic examination, weight with height measurement and body mass index using standard procedures. Bronchial asthma was diagnosed on the history of episodic cough with wheezing, presence of rhonchi and response to bronchodilators. Detail about respiratory diseases like chronic bronchitis were enquired by means of a standard questionnaire adopted from the British Medical Research Council (MRC).[6] Respiratory symptoms noted at the time of cooking were dry cough, dyspnoea in the absence of any clinical cardiopulmonary disease and nasal irritation. Exposure index was calculated by multiplying the number of hours spent in a day for cooking and the number of years of cooking.[7] Abnormal pulmonary function of the subjects was assessed by measurement of peak expiratory flow rate (PEFR) using Wright’s Peak Flow Meter. Three readings of PEFR were taken and highest of three readings was considered as a representative value.[8] Expected PEFR was calculated separately for each subject depending on the age in years (A) and height in centimeters (H) as given below.[7]
Expected PEFR = 3.310H – 1.865A – 81.0
Results
Total 994 subjects were studied, out of which 725 (72.9%) subjects were using only biomass fuel and 120 (12.1%) were using only LPG for cooking purposes. None of them were using kerosene as the only fuel for cooking. Statistical significance (p < 0.05) was observed between the mean PEFR of the subjects and fuels used for cooking with lowest in mixed fuel users, that is, 284.09 ± 64.83 and 287.88 ± 61.47 amongst biomass fuel users. Normal PEFR ranges were seen in subjects using cleaner fuel, that is, LPG [Table 1]. It was observed that almost all the subjects complained of watering of eyes during cooking (92%). Also approximately half of subjects using biomass had rhinitis and blurring of vision. Very few subjects using LPG or mixed fuel complained of these symptoms. The occurrence of all the symptoms was significantly higher amongst the subjects using biomass fuel, with P < 0.001 for all the symptoms [Table 2].
Table 1.
Relation of mean PEFR of subjects with type of fuel used
| Types of fuel | No. of subjects | Mean PEFR | P |
|---|---|---|---|
| Biomass Fuel | 725 | 287.88±61.47 |
F statistics 3.40 ANOVA P=0.03 |
| LPG | 120 | 302.41±60.58 | |
| Mixed Fuel | 149 | 284.09±64.83 |
Table 2.
Distribution of study subjects according to various symptoms in relation with fuel used
| Symptoms during cooking | Type of Fuel | Total No (%) | Chi-square and P | ||
|---|---|---|---|---|---|
|
| |||||
| Biomass No (%) | LPG No (%) | Mixed No (%) | |||
| Dyspnoea | 274 (27.6) | 20 (2.0) | 25 (2.5) | 319 (32.1) | 39.947 P<0.001 |
| Cough | 382 (38.4) | 40 (4.0) | 56 (5.6) | 478 (48.0) | 23.200, P<0.001 |
| Rhinitis | 529 (53.2) | 60 (6.0) | 127 (12.8) | 716 (72.0) | 42.120, P<0.001 |
| Blurring of Vision | 510 (51.3) | 60 (6.0) | 65 (6.5) | 685 (63.8) | 49.649, P<0.001 |
| Watering of Eyes | 685 (68.5) | 80 (8.0) | 149 (15.0) | 914 (91.9) | 122.986, P<0.001 |
| Headache | 379 (38.1) | 40 (4.0) | 37 (3.7) | 456 (45.8) | 46.136, P<0.001 |
Bivariate analysis was done using chisquare and multivariate analysis using multiple logistic regression [Table 3]. Respiratory morbidity was seen in 369 (38.1%) subjects with maximum morbidity in subjects using biomass, that is, 262 (p < 0.001). About 16% subjects above 60 years of age had respiratory morbidity with P value < 0.001. Significant respiratory morbidity (18.1%) was seen in subjects having exposure index more than 90 hours-years (p < 0.001). It was observed that as the exposure index increases, the probability of respiratory morbidity increases (p < 0.001). Multivariate analysis showed that use of biomass fuel (OR: 1.2), age above 60 years (OR: 154.06) and EI more than 90 (OR: 13.49) had higher odds of having respiratory morbidity.
Table 3.
Distribution of subjects according to types of fuel, age group and exposure index in relation with respiratory morbidity
| Variables | No. of subjects with respiratory morbidity | Total No. (%) | Bivariate analysis (Chi-square and P) | Multivariate analysis (OR P) | |
|---|---|---|---|---|---|
|
| |||||
| Present (%) | Absent (%) | ||||
| I Types of Fuel Used | |||||
| Biomass | 262 (26.3) | 463 (46.6) | 725 (72.9) | 13.983, P<0.001* | 1.2 P<0.05 |
| LPG | 40 (4.0) | 80 (8.1) | 120 (12.1) | 1 | |
| Mixed | 77 (7.8) | 72 (7.2) | 149 (15.0) | 0.3 P>0.05 | |
| Total | 379 (38.1) | 615 (61.9) | 994 (100) | ||
| II Age Groups (Years) | |||||
| 15-30 | 100 (10.1) | 259 (26.1) | 359 (36.2%) | 278.719, P<0.001* | 1 |
| 31-45 | 60 (6.0) | 277 (27.9) | 337 (33.9%) | 2.07 P<0.05 | |
| 46-60 | 59 (5.9) | 59 (5.9) | 118 (11.8%) | 9.78 P<0.05 | |
| >60 | 160 (16.1) | 20 (2.0) | 180 (18.1%) | 154.06 P<0.05 | |
| Total | 379 (38.1) | 615 (61.9) | 994 (100%) | ||
| III Exposure Index | |||||
| <30 | 40 (4.0) | 159 (16.0) | 199 (20.0) | 106.745, P<0.001* | 1 |
| 31-60 | 80 (8.0) | 219 (22.0) | 299 (30.1) | 9.46 P<005 | |
| 61-90 | 79 (7.9) | 119 (12.0) | 198 (19.9) | 12.86 P<0.05 | |
| >90 | 180 (18.1) | 118 (11.9) | 298 (30.0) | 13.49 P<0.05 | |
| Total | 379 (38.1) | 615 (61.9) | 994 (100) | ||
Discussion
India is predominantly a rural country. Availability of fuel resources and its affordability is still subjective. Various other factors for choice of fuel are domestic needs of energy, sustainability of alternate source, cultural and economic aspects, etc., The preponderance of the biomass fuel was higher in study area, mainly due to low socioeconomic conditions and its easy availability. LPG using families were less due to its higher cost and also its occasional unserviceability. Also, non-availability of kerosene as well as its cost was the reasons that none of subjects used kerosene as the only fuel source. Mishra V analysed the data of National Family Health Survey I (NFHS) 1992–93 and NFHS-II (1998-99) and reported percentage of population in rural area using biomass fuels for cooking as 93.1% and 57.6%, respectively, whereas population using cleaner fuels as 6.9% and 15.4%, respectively.[9,10] The findings were in accordance with results of many studies.[11,12,13,14] Previous literature supports the fact that usage of cleaner fuels for cooking has increased in past few years but not in required proportion. Current study findings differ with the results of James BS et al.[15] where 67.2% used mixed fuels and only 5.3% used biomass.
Lower PEFR ranges were mainly seen in subjects using biomass fuel and mixed fuel users (p < 0.05). These results were in line with various studies with statistical significance (p < 0.05).[11,16,17,18] Absorption and accumulation of toxins from the biomass was responsible for various symptoms. Approximately half of subjects using biomass had rhinitis and blurring of vision. Very few subjects using LPG or mixed fuel complained of these symptoms. The occurrence of all the symptoms was significantly higher amongst the subjects using biomass fuel, with P < 0.001. The reason for all the symptoms was the harmful smoke emission from the biomass fuels. These findings were in line with other studies.[17,19,20] A study in rural Kenya reported increased coughing, wheezing, eye problems and headaches amongst women using wood as fuel with P < 0.05.[21]
Respiratory morbidity was reported in 38.1% subjects being highest in subjects using biomass fuel. A significant negative correlation of respiratory morbidity with EI suggested a greater decline on lung function amongst women exposed for longer duration of time. On comparing participants with normal and abnormal PEFR, it was seen that the use of biomass fuel (OR 1.2; P < 0.05) increasing age (OR 154; P < 0.05) and higher EI (OR 13.49; P < 0.05) increased the odds of having an abnormal PEFR. Lower prevalence was seen in younger participants. Majority of the studies were in compliance and showed significant association between the age and respiratory morbidity (p < 0.05).[7,13,22,23]
In the current study, we observed a lower lung function in participants exposed to biomass fuel compared to LPG users and results were similar to other studies.[11,16,17,18] Exposure to air pollutants causes constriction of the airway smooth muscles and irritation of the mucous glands, leading to wheezing and overproduction of sputum. The inhalation of these hazardous fumes causes constriction in the respiratory airway, causing lung inflammation and excessive mucous secretion, and finally resulting in airway remodelling. India’s NFHS III (2005-2006) data indicated that adult women using biomass and solid fuels have a significantly higher risk of asthma than those using cleaner fuels (OR: 1.26; 95%CI: 1.06-1.49; P =0.010).[24] Strong association between the respiratory morbidity with the exposure index (p < 0.001) with odds of 13.49 in EI above 90 was shown in present study. These findings were in accordance with other studies.[18,25] A cohort study showed that compared to that of participants using clean fuels for cooking, PEF of participants using solid fuels were decreased by 3.5 l/min per two years over a four-year follow-up.[23] Deterioration of pulmonary functions is primarily due to long term exposure to biomass smoke sitting near fire place which is inadequately ventilated.
Assessment of respiratory involvement in women using unclear fuels has lost the track due to occurrence of newer health issues. But burden of respiratory illnesses due to use of unclean fuels for domestic purpose along with exposure to various environment and manmade pollutants need attention. In order to diagnose these respiratory morbidities at an early stage, it is therefore necessary to assess the respiratory functioning periodically by the physicians at the primary care level mainly in rural areas. Use of cleaner fuels and reducing exposure duration can definitely alter the disease progression in women involved in domestic works. Along with all, government commitment for the continuous supply of cleaner fuels like LPG cylinders is must.
Conclusion
Current study shows that biomass fuel is still used for domestic purpose mainly in rural areas. Use of cleaner fuels for domestic purpose in study area is still very low compared to the state average. Risk of developing respiratory and other morbidities was high in women using biomass fuel for cooking and the occurrence of such morbid conditions depends on longer duration of exposure to biomass smoke. Easy availability of cleaner fuels in rural areas could definitely reduce incidence of various respiratory morbidities.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgements
We would like to acknowledge all the women participants in our research work.
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