Burning Issues

wood smoke lower birth rate
1: Environ Health Perspect 2002 Jan;110(1):109-14

Birth weight and exposure to kitchen wood smoke during pregnancy in rural Guatemala.

Boy E, Bruce N, Delgado H.

The Micronutrient Initiative, Ottawa, Ontario, Canada.

In this study, we aimed to establish whether domestic use of wood fuel is
associated with reduced birth weight, independent of key maternal, social, and
economic confounding factors. We studied 1,717 women and newborn children in
rural and urban communities in rural Guatemala. We identified subjects through
home births reported by traditional birth attendants in six rural districts
((italic)n(/italic) = 572) and all public hospital births in Quetzaltenango city
during the study period ((italic)n(/italic) = 1,145). All were seen within 72 hr
of delivery, and data were collected on the type of household fuel used, fire
type, and socioeconomic and other confounding factors. Smoking among women in
the study community was negligible. Children born to mothers habitually cooking
on open fires ((italic)n(/italic) = 861) had the lowest mean birth weight of
2,819 g [95% confidence interval (CI), 2,790-2,848]; those using a chimney stove
((italic)n(/italic) = 490) had an intermediate mean of 2,863 g (95% CI,
2,824-2,902); and those using the cleanest fuels (electricity or gas,
(italic)n(/italic) = 365) had the highest mean of 2,948 g (95% CI, 2,898-2,998)
((italic)p (/italic)< 0.0001). The percentage of low birth weights (< 500 g) in
these three groups was 19.9% (open fire), 16.8% (chimney stove), and 16.0%
(electricity/gas), (trend (italic)p(/italic) = 0.08). Confounding factors were
strongly associated with fuel type, but after adjustment wood users still had a
birth weight 63 g lower ((italic)p(/italic) = 0.05; 95% CI, 0.4-126). This is
the first report of an association between biofuel use and reduced birth weight
in a human population. Although there is potential for residual confounding
despite adjustment, the better-documented evidence on passive smoking and a
feasible mechanism through carbon monoxide exposure suggest this association may
be real. Because two-thirds of households in developing countries still rely on
biofuels and women of childbearing age perform most cooking tasks, the
attributable risk arising from this association, if confirmed, could be

PMID: 11781172 [PubMed - in process]


1: Environ Health Perspect 2001 Jun;109 Suppl 3:405-9
Air pollution and blood markers of cardiovascular risk.
Schwartz J.
Environmental Epidemiology Program, Department of Environmental Health, Harvard
School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA.
Recent studies have linked air pollution to tens of thousands of premature
cardiovascular deaths per year. The mechanisms of such associations remain
unclear. In this study we examine the association between blood markers of
cardiovascular risk and air pollution in a national sample of the U.S.
population. Air pollution concentrations were merged to subjects in the Third
National Health and Nutrition Examination Survey (NHANES III) in the United
States, and the association with fibrinogen levels and counts of platelets and
white blood cells were examined. The subjects in NHANES III are a representative
sample of the U.S. population. Regressions controlled for age, race, sex, body
mass index, current smoking, and number of cigarettes per day. The complex
survey design was dealt with using mixed models with a random sampling site
effect. In single-pollutant models, PM(10) (particulate matter with a mass
median aerodynamic diameter less than 10 microm) was associated with all three
outcomes (p< 0.05): Sulfur dioxide (SO(2)) was significantly associated only
with white cell counts, nitrogen dioxide (NO(2)) with platelet counts and
fibrinogen, and ozone with none of the outcomes. In two-pollutant models, PM(10)
remained a significant predictor of white cell counts controlling for SO(2) but
not vice versa. PM(10) was marginally significant in a model for platelet counts
with NO(2), and the sign of the NO(2) coefficient was reversed. These results
were stable with control for indoor exposures (wood stoves, environmental
tobacco smoke, gas stoves, fireplaces), dietary risk factors (saturated fat,
alcohol, caffeine intake, n-3 fatty acids), and serum cholesterol. The magnitude
of the effects are modest [e.g., 13 microg/dL fibrinogen for an interquartile
range (IQR) change in PM(subscript)10(/subscript), 95% confidence interval (CI)
4.6-22.1 mg/dL]. However, the odds ratio of being in the top 10% of fibrinogen
for the same IQR change was 1.77 (95% CI 1.26-2.49). These effects provide
considerable biologic plausibility to the mortality studies. PM(10), but not
gaseous air pollutants, is associated with blood markers of cardiovascular risk,
and this may explain epidemiologic associations with early deaths.
PMID: 11427390 [PubMed - indexed for MEDLINE]
1: Tesfaigzi Y, Singh SP, Foster JE, Kubatko J, Barr EB, Fine PM, McDonald JD,
Hahn FF, Mauderly JL.
Health Effects of Subchronic Exposure to Low Levels of Wood Smoke in Rats.
Toxicol Sci. 2002 Jan;65(1):115-125.
PMID: 11752691 [PubMed - as supplied by publisher]
2: Schwartz J.
Air pollution and blood markers of cardiovascular risk.
Environ Health Perspect. 2001 Jun;109 Suppl 3:405-9.
PMID: 11427390 [PubMed - indexed for MEDLINE]
3: Sheppard L, Levy D, Checkoway H.
Correcting for the effects of location and atmospheric conditions on air
pollution exposures in a case-crossover study.
J Expo Anal Environ Epidemiol. 2001 Mar-Apr;11(2):86-96.
PMID: 11409009 [PubMed - indexed for MEDLINE]
4: Kinney PL, Lippmann M.
Respiratory effects of seasonal exposures to ozone and particles.
Arch Environ Health. 2000 May-Jun;55(3):210-6.
PMID: 10908105 [PubMed - indexed for MEDLINE]
5: Mishra VK, Retherford RD, Smith KR.
Biomass cooking fuels and prevalence of tuberculosis in India.
Int J Infect Dis. 1999 Spring;3(3):119-29.
PMID: 10460922 [PubMed - indexed for MEDLINE]
6: Xu X, Niu T, Christiani DC, Weiss ST, Chen C, Zhou Y, Fang Z, Jiang Z, Liang
W, Zhang F.
Occupational and Environmental Risk Factors for Asthma in Rural Communities in
Int J Occup Environ Health. 1996 Jul;2(3):172-176.
PMID: 9933871 [PubMed - as supplied by publisher]
7: Betchley C, Koenig JQ, van Belle G, Checkoway H, Reinhardt T.
Pulmonary function and respiratory symptoms in forest firefighters.
Am J Ind Med. 1997 May;31(5):503-9.
PMID: 9099351 [PubMed - indexed for MEDLINE]
8: Ellegard A.
Cooking fuel smoke and respiratory symptoms among women in low-income areas in
Environ Health Perspect. 1996 Sep;104(9):980-5.
PMID: 8899378 [PubMed - indexed for MEDLINE]
9: Gharaibeh NS.
Effects of indoor air pollution on lung function of primary school children in
Ann Trop Paediatr. 1996 Jun;16(2):97-102.
PMID: 8790672 [PubMed - indexed for MEDLINE]
10: Larson TV, Koenig JQ.
Wood smoke: emissions and noncancer respiratory effects.
Annu Rev Public Health. 1994;15:133-56. Review.
PMID: 8054078 [PubMed - indexed for MEDLINE]
11: Gold DR.
Indoor air pollution.
Clin Chest Med. 1992 Jun;13(2):215-29. Review.
PMID: 1511550 [PubMed - indexed for MEDLINE]
12: Henry CJ, Fishbein L, Meggs WJ, Ashford NA, Schulte PA, Anderson H, Osborne
JS, Sepkovic DW.
Approaches for assessing health risks from complex mixtures in indoor air: a
panel overview.
Environ Health Perspect. 1991 Nov;95:135-43. Review.
PMID: 1821367 [PubMed - indexed for MEDLINE]
13: Dales RE, Burnett R, Zwanenburg H.
Adverse health effects among adults exposed to home dampness and molds.
Am Rev Respir Dis. 1991 Mar;143(3):505-9.
PMID: 2001058 [PubMed - indexed for MEDLINE]
14: Festy B, Petit-Coviaux F, Le Moullec Y.
[Current data on atmospheric pollutions]
Ann Pharm Fr. 1991;49(1):1-17. French.
PMID: 1867457 [PubMed - indexed for MEDLINE]
15: Pierson WE, Koenig JQ, Bardana EJ Jr.
Potential adverse health effects of wood smoke.
West J Med. 1989 Sep;151(3):339-42. Review.
PMID: 2686171 [PubMed - indexed for MEDLINE]
16: Boleij JS, Brunekreef B.
Domestic pollution as a factor causing respiratory health effects.
Chest. 1989 Sep;96(3 Suppl):368S-372S. Review. No abstract available.
PMID: 2670478 [PubMed - indexed for MEDLINE]
17: Englert N.
[Indoor air pollutants and their effects on human health]
Offentl Gesundheitswes. 1989 Aug-Sep;51(8-9):409-13. Review. German.
PMID: 2531320 [PubMed - indexed for MEDLINE]
18: Koenig JQ.
Indoor and outdoor pollutants and the upper respiratory tract.
J Allergy Clin Immunol. 1988 May;81(5 Pt 2):1055-9. Review.
PMID: 3286732 [PubMed - indexed for MEDLINE]
19: Samet JM, Marbury MC, Spengler JD.
Health effects and sources of indoor air pollution. Part I.
Am Rev Respir Dis. 1987 Dec;136(6):1486-508. Review.
PMID: 3318602 [PubMed - indexed for MEDLINE]
20: Samet JM, Marbury MC, Spengler JD.
Respiratory effects of indoor air pollution.
J Allergy Clin Immunol. 1987 May;79(5):685-700.
PMID: 3571762 [PubMed - indexed for MEDLINE]

1: Toxicol Sci 2002 Jan;65(1):115-125
Health Effects of Subchronic Exposure to Low Levels of Wood Smoke in Rats.
Tesfaigzi Y, Singh SP, Foster JE, Kubatko J, Barr EB, Fine PM, McDonald JD, Hahn
FF, Mauderly JL.
Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque,
New Mexico 87108 and California Institute of Technology, Pasadena, California
Wood smoke is a significant source of air pollution in many parts of the United
States, and epidemiological data suggest a causal relationship between elevated
wood smoke levels and health effects. The present study was designed to provide
information on the potential respiratory health responses to subchronic wood
smoke exposures in a Native American community in New Mexico. Therefore, this
study used the same type of wood under similar burning conditions and wood smoke
particle concentrations to mimic the conditions observed in this community.
Brown Norway rats were exposed 3 h/day, 5 days/week for 4 or 12 weeks to air as
control, or to 1 or 10 mg/m(3) concentrations of wood smoke particles from pinus
edulis. The wood smoke consisted of fine particles (< 1 &mgr;m) that formed
larger chains and aggregates having a size distribution of 63-74% in the <
1-&mgr;m fraction and 26-37% in the > 1-&mgr;m fraction. The particle-bound
material was primarily composed of carbon, and the majority of identified
organic compounds consisted of sugar and lignin derivatives. Pulmonary function,
specifically carbon monoxide-diffusing capacity and pulmonary resistance, was
somewhat affected in the high-exposure group. Mild chronic inflammation and
squamous metaplasia were observed in the larynx of the exposed groups. The
severity of alveolar macrophage hyperplasia and pigmentation increased with
smoke concentration and length of exposure, and the alveolar septae were
slightly thickened. The content of mucous cells lining the airways changed from
Periodic Acid Schiff- to Alcian Blue-positive material in the low-exposure group
after 90 days. Together, these observations suggest that exposure to wood smoke
caused minor but significant changes in Brown Norway rats. Further studies are
needed to establish whether exposure to wood smoke exacerbates asthmalike
symptoms that resemble those described for children living in homes using wood
stoves for heating and cooking.
PMID: 11752691 [PubMed - as supplied by publisher]

1: J Expo Anal Environ Epidemiol 2001 Mar-Apr;11(2):86-96
Correcting for the effects of location and atmospheric conditions on air
pollution exposures in a case-crossover study.
Sheppard L, Levy D, Checkoway H.
Department of Biostatistics and Environmental Health, University of Washington,
Seattle, Washington 98195-7232, USA. sheppard@biostat.washington.edu
A limitation of most air pollution health effects studies is that they rely on
monitoring data averaged over one or more ambient monitors to represent daily
air pollution exposures for individuals. Such data analyses therefore implicitly
require the assumption of a homogeneous spatial distribution for particulate
matter (PM). This assumption may be suspected in the Pacific Northwest because
of its hilly topography and local variations in wood burning. To examine the
bias from substituting regional PM (i.e., the average of three ambient monitor
measurements) for individual PM exposure, we conducted an exposure substudy to
identify the influence of location factors, specifically urban versus suburban
classification and topographic features ("upstream" versus "downstream"), on
local ambient measurements. Using nephelometer measurements collected over 1
year in four locations, we developed regression models to predict local PM as a
function of regional PM, atmospheric stagnation, temperature, and location. We
found a significant interaction between atmospheric stagnation and topography,
with the most upstream site having reduced PM levels on high stagnation days
after controlling for regional PM. We also found a significant interaction with
temperature at one downstream site thought to be heavily exposed to wood smoke
in the winter. These results are consistent with the physics of surface
radiation inversions. The interactions reordered the index versus referent
exposures in a case-crossover analysis of out-of-hospital primary cardiac arrest
for subjects living in specific locations, but did not meaningfully change the
associations with PM from the analysis using regional PM as the exposure. The
lack of change in these results may be due to limitations in the data used to
correct the exposure estimates or to the absence of a PM effect among persons
without prior heart disease who experienced a primary cardiac arrest.
PMID: 11409009 [PubMed - indexed for MEDLINE]

1: Arch Environ Health 2000 May-Jun;55(3):210-6
Respiratory effects of seasonal exposures to ozone and particles.
Kinney PL, Lippmann M.
Division of Environmental Health Sciences, Columbia School of Public Health, New
York, New York 10032-4206, USA.
Whereas human respiratory effects of brief ozone exposures are well documented,
much less is known about the human health effects of mid- to long-term
exposures. The authors' objective in this study was to determine whether lung
function or respiratory symptom changes would occur over the course of a summer
season among healthy young adults working outdoors in the presence of ozone. The
authors studied 72 sophomore cadets from the U.S. Military Academy at West
Point, New York, 21 of whom attended special summer training in Fort Dix, New
Jersey, an area characterized by elevated ozone levels; the remaining cadets
attended training in areas with moderate ozone levels (i.e., Fort Benning,
Georgia; Fort Leonard Wood, Missouri; and Fort Sill, Oklahoma). The authors
hypothesized that adverse respiratory outcomes, if any, would be more pronounced
in the group exposed to higher ozone levels. Spirometry was performed and
respiratory symptoms were assessed-both before and after the summer-in a clinic
at West Point. Time spent outdoors during summer training averaged 11 hr/d. Both
mean and peak ozone levels were higher at Fort Dix than at the three remaining
sites. Regional levels of sulfur dioxide and particulate matter less than 10
microm in aerodynamic diameter were relatively low during the study. However,
all cadets reported frequent exposure to dust, exhaust, and smoke in the course
of their training. Averaged across all subjects, there was a statistically
significant drop in forced expiratory volume in 1 sec of 44 ml (p = .035) over
the summer. There were also significant increases in reports of cough, chest
tightness, and sore throat at the follow-up clinic visit. A larger mean forced
expiratory volume in 1 sec decline was observed at Fort Dix, where ozone
exposures were the highest. The results of this study demonstrated a seasonal
decline in respiratory function among healthy young adults working outdoors in
the presence of ozone and particulate matter.
PMID: 10908105 [PubMed - indexed for MEDLINE]

1: Int J Infect Dis 1999 Spring;3(3):119-29
Biomass cooking fuels and prevalence of tuberculosis in India.
Mishra VK, Retherford RD, Smith KR.
Population and Health Studies, East-West Center, Honolulu, Hawaii 96848-1601,
USA. mishra@hawaii.edu
OBJECTIVES: To examine the relation between use of biomass cooking fuels (wood
or dung) and prevalence of active tuberculosis in India. METHODS: The analysis
is based on 260,162 persons age 20 and over in India's 1992-93 National Family
Health Survey. Logistic regression is used to estimate the effects of biomass
fuel use on prevalence of active tuberculosis, as reported by household heads,
after controlling for a number of potentially confounding variables. RESULTS:
Persons living in households that primarily use biomass for cooking fuel have
substantially higher prevalence of active tuberculosis than persons living in
households that use cleaner fuels (odds ratio [OR] = 3.56; 95% confidence
interval [CI] = 2.82-4. 50). This effect is reduced somewhat when availability
of a separate kitchen, house type, indoor crowding, age, gender, urban or rural
residence, education, religion, caste or tribe, and geographic region are
statistically controlled (OR = 2.58; 95% CI = 1.98-3.37). Fuel type also has a
large effect when the analysis is done separately for men (OR = 2.46; 95% CI =
1.79-3.39) and women (OR = 2. 74; 95% CI = 1.86-4.05) and separately for urban
areas (OR = 2.29; 95% CI = 1.61-3.23) and rural areas (OR = 2.65; 95% CI =
1.74-4.03). The analysis also indicates that, among persons age 20 years and
over, 51% of the prevalence of active tuberculosis is attributable to cooking
smoke. CONCLUSIONS: Results strongly suggest that use of biomass fuels for
cooking substantially increases the risk of tuberculosis in India.
PMID: 10460922 [PubMed - indexed for MEDLINE]

1: Am J Ind Med 1997 May;31(5):503-9
Pulmonary function and respiratory symptoms in forest firefighters.
Betchley C, Koenig JQ, van Belle G, Checkoway H, Reinhardt T.
Department of Environmental Health, University of Washington, Seattle
98195-7234, USA.
This study evaluated effects on respiratory health of forest firefighters
exposed to high concentrations of smoke during their work shift. This is the
first study of cross-shift respiratory effects in forest firefighters conducted
on the job. Spirometric measurements and self-administered questionnaire data
were collected before and after the 1992 firefighting season. Seventy-six (76)
subjects were studied for cross-shift and 53 for cross-season analysis. On
average, the cross-season data were collected 77.7 days after the last
occupational smoke exposure. The cross-shift analysis identified significant
mean individual declines in FVC. FEV1, and FEF25 75. The preshift to midshift
decreases were 0.089 L, 0.190 L, and 0.439 I/sec. respectively, with preshift to
postshift declines of 0.065 L, 0.150 L, and 0.496 L/sec. Mean individual
declines for FVC, FEV1 and FEF25 75 of 0.033 L, 0.104 L, and 0.275 I/sec.
respectively, also were noted in the cross-season analysis. The FEV1 changed
significantly (p < 0.05). The use of wood for indoor heat also was associated
with the declines in FEV1. Although annual lung function changes for a small
subset (n = 10) indicated reversibility of effect, this study suggests a concern
for potential adverse respiratory effects in forest firefighters.
PMID: 9099351 [PubMed - indexed for MEDLINE]

1: Environ Health Perspect 1996 Sep;104(9):980-5
Cooking fuel smoke and respiratory symptoms among women in low-income areas in
Ellegard A.
University of Goteborg, Department for Human Ectology, Goteborg, Sweden.

The association between exposure to air pollution from cooking fuels and health
aspects was studied in Maputo. Mozambique. Almost 1200 randomly selected women
residing in the suburbs of Maputo were interviewed and 218 were monitored for
air pollution. The fuels most commonly used were wood, charcoal, electricity,
and liquified petroleum gas (LPG). Wood users were exposed to significantly
higher levels of particulate pollution during cooking time (1200 micrograms/m3)
than charcoal users (540 micrograms/m3) and users of modern fuels (LPG and
electricity) (200-380 micrograms/m3). Wood users were found to have
significantly more cough symptoms than other groups. This association remained
significant when controlling for a large number of environmental variables.
There was no difference in cough symptoms between charcoal users and users of
modern fuels. Other respiratory symptoms such as dyspnea, wheezing, and
inhalation and exhalation difficulties were not associated with wood use.
Reducing wood use would likely improve acute respiratory health effects in wood
users and possibly improve the ambient air pollution conditions in Maputo. To
reduce the health impact of wood smoke exposure, it appears that the least
costly and quickest method would be to encourage charcoal use to a greater
extent, although high carbon monoxide levels would have to be addressed. Turning
to modern fuels is beyond the means of most these households in the short term
and could not be shown to be more effective.

PMID: 8899378 [PubMed - indexed for MEDLINE]


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