It is well known that one-third of the poorest people in the world use biomass fuel for cooking and heating. It is a universally accepted fact that biomass fuel plays a significant role as a predisposing factor for tuberculosis, acute respiratory tract infections, and COPD, even in non-immune-suppressed (HIV sero-negative) individuals. As we all know, household cooking is primarily performed by women. So close association with biomass fuel and even longer duration make women more vulnerable to these RTI secondary RTI infections.

Aim: To study the effects of biomass fuel on the prevalence of RTI/tuberculosis in HIV-infected patients in Gujarat.

Material and Methods: In the present study, 961 HIV-infected patients with RTI, 300 HIV-infected patients without RRTI, and 300 HIV-uninfected patients with RTI were surveyed for use of biomass fuel or clean fuel.

Result

Conclusion: It had been surveyed, statistically analyzed, and found to be an even higher risk predisposing factor, mainly for tuberculosis and other acute respiratory tract infections in immune-suppressed HIV-seropositive patients. Here, biomass fuel had been evaluated as a risk factor in developing TB in HIV patients, and incidences of RTI in HIV sero-positive patients had been found in our study to be 2.3 times higher than those who were not suffering from HIV. Even among all these RTI patients who might acquire secondary RTI infections due to biomass fuel, 61.87% were found to be women. When only TB is considered in this study, it was found that 67.44% of women were observed to suffer from TB when compared with the same group of males. This increased exposure of women to TB and COPD in turn results in preterm delivery, which leads to the birth of low-birth weight babies if women are pregnant.

BMF refers to burned plant or animal material; wood, charcoal, dung, and crop residues account for more than one-half of domestic energy in most developing countries and for as much as 95% in lower-income countries [1]. Around 2.4 billion people rely on BMF as their main source of domestic energy for cooking, heating, and lighting [1,2] and a further 0.6 billion people use coal. The adverse health effects of indoor air pollution are often exacerbated by a lack of ventilation in homes using BMF and by the poor design of stoves that do not have flues or hoods to take smoke out of the living area. The combustion efficiency of BMF is also very low; thus, it yields relatively high levels of products of incomplete combustion, which are more damaging to health.

The polluting effect, efficiency, and cost of domestic fuel use are often construed as an ‘energy ladder’ [3]. Dried animal dung, scavenged twigs, and grass, which are cheap, inefficient, and pollute the most, are at the bottom of the ladder. Crop residues, wood, and charcoal are higher-level BMF, while kerosene, coal, and bottled or piped gas are the most efficient (non-BMF) combustible energy sources. Electricity is at the top of the energy ladder. The correlation of socioeconomic factors with the main fuel used is relatively close; however, most households use several fuels in different settings. Four factors that appear to be most relevant in a household's choice of fuel type are: (a) cost of fuel, stove type, and accessibility to fuels; (b) technical characteristics of stoves and cooking practices; (c) cultural preferences; and lastly, if at all, (d) the potential health impacts [4].

Inefficient burning of BMF on an open fire or traditional stove generates large amounts of particulate matter as well as carbon monoxide, hydrocarbons, oxygenated organics, free radicals, and chlorinated organics [5]. The particulate matter component of this smoke is classified according to its size, with inhalable material <10 μm in aerodynamic diameter referred to as PM₁₀. The 24-hour mean particulate matter levels set in the WHO guidelines for air quality are 50 μg/m³ for PM₁₀ and 25 μg/m³ for PM_2.5 [6], but in many parts of the developing world, the peak indoor concentration of PM₁₀ often exceeds 2000 μg/m³ [7,8]. Critically, there are age, gender, and socioeconomic differences in levels of exposure and the consequent health effects [9]. Exposure to BMF has been estimated to have caused 0.5% of all deaths and 0.4% of all disability-adjusted life years in South Africa in 2000 [10]. The adverse or bad effects of biomass fuel on human health are:

1. Respiratory illness in children
2. Nutritional deficiency in young children
3. Respiratory illness in adults
4. Interstitial lung diseases
5. Chronic obstructive lung diseases (COPD)
6. Tuberculosis
7. Lung cancer
8. Cardiovascular diseases
9. Cataract

The RTI are among the first opportunistic infections observed in HIV patients, and unlike HIV sero-negative persons, some of the RTI even cause permanent damage to the respiratory tract, thus affecting both the quality and quantity of their life. So, it is very important to prevent RTI in HIV patients by understanding the risk factors for RTI in them. In this study, we tried to understand the effect of biomass fuel (BMF) on opportunistic RTI in HIV patients.

Table 1: Occurrence of RTI among those reporting to ART Centre.

OR = 2.317 and 95% CI = 1.86 to 2.88

It can be seen that those who were detected as HIV+ had a 2.3 times higher chance of contracting a respiratory tract infection as compared to those detected as negative for HIV. The 95% confidence interval not including the null value (OR = 1) indicates the significant association between HIV status and the occurrence of RTI.

Globally, the total number of people living with HIV in 2012 was 35.3 million. In parts of the world where HIV infection is most common, BMF is the main energy source. In Malawi, for example, the incidence of HIV in pregnant women is 33%, and 70% of hospital admissions and >80% of households use BMF. However, the influence of BMF smoke on HIV-infected individuals has not been clarified.

The most important effect of HIV infection in Africa is that it causes increased bacterial infections, pneumonia, and TB. HIV infection is associated with mild airway obstruction and loss of gas transfer, with severe impairment occurring in the presence of Pneumocystis jiroveci infection [11]. HIV is also associated with the accelerated development of COPD [12], and it is likely, although not proven, that HIV infection is a significant contributor to airway disease in much of the adult population of Africa. Since both BMF use and HIV are associated with an increase in the incidence of pneumonia [13,14], and as particulate matter exposure and HIV result in increased pulmonary inflammation [15-17], it is possible that by causing pulmonary inflammation, the two major risk factors for pneumonia in African adults (HIV and BMF smoke) may actually demonstrate previously unrecognized synergy.

Evidence exists that implicates exposure to BMF smoke in adverse effects on different birth outcomes [18]. There is a published association between low birth weight, intrauterine growth retardation, perinatal mortality, and air pollution [19-21]. A study from Guatemala identified an association between birth weight and the type of fuel used. The use of an open fire produced average PM10 levels of 1000 μg/m3. The babies of mothers using open wood fires were on average 63 g lighter compared with babies born to mothers using cleaner fuels [22]. A similar (slightly larger) effect has also been reported in Zimbabwe [23]. The model in the figure below attempts to explain how BMF may fit into a multifactorial explanation of low birth weight.

Tuberculosis is the second most common cause of death globally in adults attributable to a single infectious agent (WHO, 1998). Tuberculosis remains the leading cause of death due to infection in India, which bears nearly 30% of the global tuberculosis burden [24]. Each year, 2 million people in India develop tuberculosis, and nearly 500 000 die from it, averaging more than 1000 TB deaths a day (WHO, 2000). India has the largest pool of people infected with tuberculosis (Mycobacterium tuberculosis), with an annual incidence of 1.98 million, the largest number in any one country and accounting for a fifth of the global burden of TB. It is estimated that more than half of India’s adult population is infected with the tuberculosis bacterium, Mycobacterium tuberculosis. Once a person is infected, any condition that weakens the immune system can trigger the development of active tuberculosis. Typically, 5–10% of these infected people eventually become ill with active tuberculosis (ATS 1990). However, this percentage may be higher in the case of India because of the ubiquity of the tuberculosis bacillus, high population density, and poor socioeconomic and health conditions. Approximately 500,000 people die from tuberculosis each year in India. In recent years, the growth of drug-resistant tuberculosis and the rapid spread of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) have contributed to the resurgence of tuberculosis in India and in other parts of the world (Raviglione MC, 1995; Piot P, 1997; Kochi A, 1994; WHO, 1992; Sawert H, 1996). NFHS recorded an overall active tuberculosis prevalence rate of 467 per 100,000 persons (IIPS, 1992), slightly higher than other estimates of the active (sputum-positive) disease rate in India, which mostly range between 400 and 450 per 100,000 persons (WHO, 1992). Tuberculosis is a social disease with medical aspects, and it has been described as a barometer of social welfare. As the women spent much more time in proximity to biomass fuel for cooking, they were found to be at higher risk of acquiring secondary RTI and TB than men staying in the same home.

Table 2: Comparison of Risk of acquiring TB between TB patients from HIV sero-positive patients from T group and HIV/TB negative patients from C2.

In our present study, biomass fuel was found to be a statistically significant predisposing factor for TB, with a p value found to be 0.5 in females and 0.10 in males. It was found to be less significant when compared between TB patients in group C1 and non-TB patients in group C2 (Table 2).

The reason seems to be very simple and well understood: in our society, mostly women are supposed to cook food, so spending much more time in close proximity to sources of biomass fuel while cooking food for the family, even though she might be even HIV-seropositive,. While males of the same family with sero-positivity to HIV spend most of their time either out of home or away from the sources of biomass fuel, So naturally, people acquire less bad effects from biomass fuel, and that is why the chances of acquiring TB due to the bad effects of biomass fuel were found to be very low when compared with the same group of males.

Whether cooking has been done outside of the home or even in a well-ventilated home, the chances of a bad effect of biomass fuel always remain higher due to the close proximity and longer duration of time for women to the biomass fuel sources than for men, who very rarely contribute to cooking the food. So, my present study proved that HIV-positive women are at higher risk of acquiring secondary RTI, COPD, and TB than HIV-positive male patients due to indoor biomass fuel. If such HIV-positive women are pregnant, it may lead to preterm delivery and low-birth-weight babies.

Indoor air pollution from BMF disproportionately affects women and children and is the cause of significant global mortality and morbidity in even normal HIV-negative women. Here, our study proved that HIV-positive people have a 2.3-fold higher risk of contracting respiratory tract infections as compared to those who are not suffering from HIV. Even among all these RTI patients who might acquire secondary RTI infections due to biomass fuel, 61.87% were found to be women. When only TB is considered in this study, it was found that 67.44% of women were observed to suffer from TB when compared with the same group of males. This is a neglected area of global disease that affects a large proportion of the world's population.

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