Household fuel use and pulmonary tuberculosis in western Nepal: A case-control study.

BACKGROUND: Whether cooking with solid fuels, as occurs widely in developing countries, including Nepal, is a risk factor for pulmonary tuberculosis (PTB) is uncertain. Epidemiologic studies have produced variable results. This case-control study sought to resolve this issue with a large sample size and a population-based control group. METHODS: PTB cases (N = 581), aged 18-70 were recruited from diagnostic centers in Kaski and neighboring districts of Nepal. Population-based controls (N = 1226) were recruited. Persons who had previously been diagnosed with TB were excluded. Questionnaires were administered at participants' homes. RESULTS: Using liquefied petroleum gas (LPG) as the cookstove reference fuel, for women the odds ratio (OR) for having a primary cookstove that used wood was 0.21 (95% CI: 0.08,0.52); for men the corresponding OR was 0.80 (0.37, 1.74). For biogas, the OR for women was 0.24 (0.06,0.87) and for men, 1.41 (0.61, 3.23). CONCLUSIONS: The unexpected finding of a higher risk for women using LPG cookstoves, relative to wood or biogas-burning cookstoves, may be attributable to excluding persons with prior TB. A possible explanation is that emissions, such as ultrafine particles, formed during LPG combustion promote PTB manifestation in infected people who have not previously had PTB. The damage from the initial PTB leaves them susceptible to the PTB-promoting effects of smoke from wood fires. Further studies, excluding participants who have previously had TB are needed to confirm these findings. Use of exhaust hoods to the outdoors for all stoves, well-ventilated kitchens, and gas stoves raised above ground would reduce exposures.

Kitchen PM2.5 concentrations and child acute lower respiratory infection in Bhaktapur, Nepal: The importance of fuel type.

BACKGROUND: Globally, solid fuels are used by about 3 billion people for cooking and a smaller number use kerosene. These fuels have been associated with acute lower respiratory infection (ALRI) in children. Previous work in Bhaktapur, Nepal, showed comparable relationships of biomass and kerosene cooking fuels with ALRI in young children, compared to those using electricity for cooking. We examine the relationship of kitchen PM2.5 concentrations to ALRI in those households. METHODS: ALRI cases and age-matched controls were enrolled from a cohort of children 2-35 months old. 24-h PM2.5 was measured once in each participant's kitchen. The main analysis was carried out with conditional logistic regression, with PM2.5 measures specified both continuously and as quartiles. RESULTS: In the kitchens of 393 cases and 431 controls, quartiles of increasing PM2.5 concentration were associated with a monotonic increase in odds ratios (OR): 1.51 (95% CI: 1.00, 2.27), 2.22 (1.47, 3.34), 2.48 (1.63, 3.77), for the 3 highest exposure quartiles. The general kitchen concentration-response shape across all stoves was supralinear. There was evidence for increased risk with biomass stoves, but the slope for kerosene stoves was steeper, the highest quartile OR being 5.36 (1.35, 21.3). Evidence for increased risk was also found for gas stoves. CONCLUSION: Results support previous reports that biomass and kerosene cooking fuels are both ALRI risk factors, but suggests that PM2.5 from kerosene is more potent on a unit mass basis. Further studies with larger sample sizes and preferably using electricity as the baseline fuel are needed.

Lead in new paints in Nepal.

Samples from 75 paint products made by 21 domestic and foreign manufacturers were purchased from retail stores in five major cities in Nepal and tested for lead content. Information provided on product labels were noted. Samples were selected to be representative of the large number of brands and colors available in retail shops. Although a majority of the products purchased were manufactured in Nepal, paints from four additional countries were tested. Out of a total of 75 samples, 57 (76%) of the tested paints contained lead at concentrations greater than 90 ppm (ppm). Ninety-three percent of the paints that exceeded 90 ppm had levels in excess of 600 ppm. Lead concentrations in the tested paints ranged up to 200,000 ppm (20%) lead by weight and the median concentration was 5100 ppm. These results indicate that lead paint is commonly being sold for residential and other consumer applications in Nepal without any consumer warnings. Regulations are needed to specify the maximum concentration of lead allowed in paint products manufactured, imported, or distributed in the country to protect public health. Efforts must be made to get lead-containing paint products recalled from stores so that they are not used in homes, schools, and other child-occupied facilities.

Biomass stoves and lens opacity and cataract in Nepalese women.

PURPOSE: Cataract is the most prevalent cause of blindness in Nepal. Several epidemiologic studies have associated cataracts with use of biomass cookstoves. These studies, however, have had limitations, including potential control selection bias and limited adjustment for possible confounding. This study, in Pokhara City, in an area of Nepal where biomass cookstoves are widely used without direct venting of the smoke to the outdoors, focuses on preclinical measures of opacity while avoiding selection bias and taking into account comprehensive data on potential confounding factors. METHODS: Using a cross-sectional study design, severity of lenticular damage, judged on the LOCS (Lens Opacities Classification System) III scales, was investigated in women (n = 143), aged 20 to 65 years, without previously diagnosed cataract. Linear and logistic regression analyses were used to examine the relationships with stove type and length of use. Clinically significant cataract, used in the logistic regression models, was defined as a LOCS III score ≥2. RESULTS: Using gas cookstoves as the reference group, logistic regression analysis for nuclear cataract showed evidence of relationships with stove type: for biomass stoves, the odds ratio was 2.58 (95% confidence interval, 1.22 to 5.46); and for kerosene stoves, the odds ratio was 5.18 (95% confidence interval, 0.88 to 30.38). Similar results were found for nuclear color (LOCS III score ≥2), but no association was found with cortical cataracts. Supporting a relationship between biomass stoves and nuclear cataract was a trend with years of exposure to biomass cookstoves (p = 0.01). Linear regression analyses did not show clear evidence of an association between lenticular damage and stove types. Biomass fuel used for heating was not associated with any form of opacity. CONCLUSIONS: This study provides support for associations of biomass and kerosene cookstoves with nuclear opacity and change in nuclear color. The novel associations with kerosene cookstove use deserve further investigation.

Prevalence and determinants of hypertension in underrepresented indigenous populations of Nepal.

Indigenous populations residing in low- and middle-income countries (LMICs) are highly underrepresented in medicine and public health research. Specifically, data on non-communicable diseases (NCDs) from indigenous populations remains scarce. Despite the increasing burden of NCDs in the Himalayan region, their prevalence in many indigenous populations remains understudied. The nationally representative public health surveys often do not include the indigenous communities, especially those that reside in rural areas or exist in small numbers. This observational cross-sectional survey study aimed to assess the prevalence of three NCD risk factors namely obesity, hypertension, and tachycardia and identify dietary and lifestyle variables associated with them across underrepresented indigenous populations of Nepal. A total of 311 individuals (53.3% women, 46.7% men) with mean age 43±15 years from 12 indigenous Nepali communities residing in rural (47.9%) or semi-urban (52.1%) areas volunteered to participate in this study. Univariate tests and multivariable logistic regressions were used to analyze the survey data. The mean systolic and diastolic blood pressures were 121.3±19.5 mmHg and 81.3±11.8 mmHg respectively. Overall, the prevalence of obesity and tachycardia was low (0.64% and 3.22%, respectively) but hypertension was prevalent at 23.8%. Hypertension was not significantly different across populations, but it was associated with age, BMI, and tobacco use, and collectively, these variables explained 13.9% variation in hypertension prevalence. Although we were unable to detect direct associations between individual determinants of hypertension identified in non-indigenous Nepalis, such as education levels, alcohol consumption, and smoking in this study, having one or more determinants increased the odds of hypertension in the indigenous participants. Furthermore, ~14% of the hypertensive individuals had none of the universally identified hypertension risk factors. The lack of association between previously identified risk factors for hypertension in these individuals indicates that the additional determinants of hypertension remain to be identified in indigenous Nepali populations.

Review: Lead exposure in battery manufacturing and recycling in developing countries and among children in nearby communities.

The battery industry is the largest consumer of lead, using an estimated 80% of the global lead production. The industry is also rapidly expanding in emerging market countries. A review of published literature on exposures from lead-acid battery manufacturing and recycling plants in developing countries was conducted. The review included studies from 37 countries published from 1993 to 2010 and excluded facilities in developed countries, such as the United States and those in Western Europe, except for providing comparisons to reported findings. The average worker blood lead level (BLL) in developing countries was 47 µg/dL in battery manufacturing plants and 64 µg/dL in recycling facilities. Airborne lead concentrations reported in battery plants in developing countries averaged 367 µg/m3, which is 7-fold greater than the U.S. Occupational Safety and Health Administration's 50 µg/m3 permissible exposure limit. The geometric mean BLL of children residing near battery plants in developing countries was 19 µg/dL, which is about 13-fold greater than the levels observed among children in the United States. The blood lead and airborne lead exposure concentrations for battery workers were substantially higher in developing countries than in the United States. This disparity may worsen due to rapid growth in lead-acid battery manufacturing and recycling operations worldwide. Given the lack of regulatory and enforcement capacity in most developing countries, third-party certification programs may be the only viable option to improve conditions.

A hierarchical model for estimating the exposure-response curve by combining multiple studies of acute lower respiratory infections in children and household fine particulate matter air pollution.

Adverse health effects of household air pollution, including acute lower respiratory infections (ALRIs), pose a major health burden around the world, particularly in settings where indoor combustion stoves are used for cooking. Individual studies have limited exposure ranges and sample sizes, while pooling studies together can improve statistical power. METHODS: We present hierarchical models for estimating long-term exposure concentrations and estimating a common exposure-response curve. The exposure concentration model combines temporally sparse, clustered longitudinal observations to estimate household-specific long-term average concentrations. The exposure-response model provides a flexible, semiparametric estimate of the exposure-response relationship while accommodating heterogeneous clustered data from multiple studies. We apply these models to three studies of fine particulate matter (PM2.5) and ALRIs in children in Nepal: a case-control study in Bhaktapur, a stepped-wedge trial in Sarlahi, and a parallel trial in Sarlahi. For each study, we estimate household-level long-term PM2.5 concentrations. We apply the exposure-response model separately to each study and jointly to the pooled data. RESULTS: The estimated long-term PM2.5 concentrations were lower for households using electric and gas fuel sources compared with households using biomass fuel. The exposure-response curve shows an estimated ALRI odds ratio of 3.39 (95% credible interval = 1.89, 6.10) comparing PM2.5 concentrations of 50 and 150 µg/m3 and a flattening of the curve for higher concentrations. CONCLUSIONS: These flexible models can accommodate additional studies and be applied to other exposures and outcomes. The studies from Nepal provides evidence of a nonlinear exposure-response curve that flattens at higher concentrations.

Acute bacterial conjunctivitis - antibiotic susceptibility and resistance to commercially available topical antibiotics in Nepal.

INTRODUCTION: There is a shifting trend in susceptibility and resistance of the bacteria towards available antibiotics in the last decade. Therefore, periodic studies to monitor the emerging trends in antibiotic susceptibility and resistance are crucial in guiding antibiotic selection. OBJECTIVES: The aim of this study was to determine the most common pathogens causing bacterial conjunctivitis, and to find the in vitro susceptibility and resistance of these pathogens to commercially available topical antibiotic eye drops in Nepal. SUBJECTS AND METHODS: Conjunctival smears and antibiotic sensitivity tests were performed for 308 patients presenting to the Eye Care Center, Padma Nursing Home, Pokhara, Nepal from 11th December 1012 to 4th October 2013 with clinical signs and symptoms of acute infective conjunctivitisin in a hospital based cross-sectional study. Antibiotic sensitivity tests were performed for thirteen commercially available topical antibiotics- Chloroamphenicol, Moxifloxacin, Ofloxacin, Ciprofloxacin, Gentamycin, Tobramycin, Neomycin, Bacitracin, Polymyxin-B, Methicillin, Cephazoline, Amikacin and Vancomycin. RESULTS: Acute infective conjunctivitis and viral conjunctivitis was more common in adults and in males. Bacterial conjunctivitis was present in about one third (32.47% to 36.04%) of the patients with acute infective conjunctivitis, and it was more common in children. Bacteria were highly sensitive (93-98%) to most commercially available antibiotics but significant resistance was found against three antibiotics-Bacitracin (9.0%), Neomycin (16.0%) and Polymyxin-B (24.0%). MRSA infection was found in 7.0% of the bacterial isolates. Rest of antibiotics, showed variable resistance (14.3% to 100.0%). All cases of Ophthalmia neonatorum were bacterial. CONCLUSION: The best commercially available antibiotic for bacterial conjunctivitis was Moxifloxacin.

Case-control study of indoor cooking smoke exposure and cataract in Nepal and India.

BACKGROUND: The prevalence of cataract is higher in developing countries, and in both developed and developing countries more females than males are blind from cataracts. Three epidemiological studies have associated indoor cooking with solid fuels (e.g. wood or dung) and cataract or blindness. However, associations in these studies may have been caused by unmeasured confounding. METHODS: A hospital-based case-control study was conducted on the Nepal-India border. Cases (n = 206) were women patients, aged 35-75 years with confirmed cataracts. Controls (n = 203), frequency matched by age, were patients attending the refractive error clinic at the same hospital. A standardized questionnaire was administered to all participants. Logistic regression analysis involved adjustment for age, literacy, residential area, ventilation, type of lighting, incense use, and working outside. RESULTS: Compared with using a clean-burning-fuel stove (biogas, LPG, or kerosene), the adjusted odds ratio (OR) for using a flued solid-fuel stove was 1.23 [95% confidence interval (CI) 0.44-3.42], whereas use of an unflued solid-fuel stove had an OR of 1.90 (95% CI 1.00-3.61). Lack of kitchen ventilation was an independent risk factor for cataract (OR 1.96; 95% CI 1.25-3.07). CONCLUSION: This study provides confirmatory evidence that use of solid fuel in unflued indoor stoves is associated with increased risk of cataract in women who do the cooking. The association is not likely to be due to bias, including confounding, and strengthens the findings of three previous studies. Replacing unflued stoves with flued stoves would greatly reduce this risk, although cooking with cleaner-burning fuels would be the best option.

Acute lower respiratory infection in childhood and household fuel use in Bhaktapur, Nepal.

BACKGROUND: Globally, solid fuels are used by about 3 billion people for cooking. These fuels have been associated with many health effects, including acute lower respiratory infection (ALRI) in young children. Nepal has a high prevalence of use of biomass for cooking and heating. OBJECTIVE: This case-control study was conducted among a population in the Bhaktapur municipality, Nepal, to investigate the relationship of cookfuel type to ALRI in young children. METHODS: Cases with ALRI and age-matched controls were enrolled from an open cohort of children 2-35 months old, under active monthly surveillance for ALRI. A questionnaire was used to obtain information on family characteristics, including household cooking and heating appliances and fuels. The main analysis was carried out using conditional logistic regression. Population-attributable fractions (PAF) for stove types were calculated. RESULTS: A total of 917 children (452 cases and 465 controls) were recruited into the study. Relative to use of electricity for cooking, ALRI was increased in association with any use of biomass stoves [odds ratio (OR) = 1.93; 95% CI: 1.24, 2.98], kerosene stoves (OR = 1.87; 95% CI: 1.24, 2.83), and gas stoves (OR = 1.62; 95% CI: 1.05, 2.50). Use of wood, kerosene, or coal heating was also associated with ALRI (OR = 1.45; 95% CI: 0.97, 2.14), compared with no heating or electricity or gas heating. PAFs for ALRI were 18.0% (95% CI: 8.1, 26.9%) and 18.7% (95% CI: 8.4%-27.8%), for biomass and kerosene stoves, respectively. CONCLUSIONS: The study supports previous reports indicating that use of biomass as a household fuel is a risk factor for ALRI, and provides new evidence that use of kerosene for cooking may also be a risk factor for ALRI in young children.

Tuberculosis and indoor biomass and kerosene use in Nepal: a case-control study.

BACKGROUND: In Nepal, tuberculosis (TB) is a major problem. Worldwide, six previous epidemiologic studies have investigated whether indoor cooking with biomass fuel such as wood or agricultural wastes is associated with TB with inconsistent results. OBJECTIVES: Using detailed information on potential confounders, we investigated the associations between TB and the use of biomass and kerosene fuels. METHODS: A hospital-based case-control study was conducted in Pokhara, Nepal. Cases (n = 125) were women, 20-65 years old, with a confirmed diagnosis of TB. Age-matched controls (n = 250) were female patients without TB. Detailed exposure histories were collected with a standardized questionnaire. RESULTS: Compared with using a clean-burning fuel stove (liquefied petroleum gas, biogas), the adjusted odds ratio (OR) for using a biomass-fuel stove was 1.21 [95% confidence interval (CI), 0.48-3.05], whereas use of a kerosene-fuel stove had an OR of 3.36 (95% CI, 1.01-11.22). The OR for use of biomass fuel for heating was 3.45 (95% CI, 1.44-8.27) and for use of kerosene lamps for lighting was 9.43 (95% CI, 1.45-61.32). CONCLUSIONS: This study provides evidence that the use of indoor biomass fuel, particularly as a source of heating, is associated with TB in women. It also provides the first evidence that using kerosene stoves and wick lamps is associated with TB. These associations require confirmation in other studies. If using kerosene lamps is a risk factor for TB, it would provide strong justification for promoting clean lighting sources, such as solar lamps.