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Bioenergylists.orgThis article was downloaded by: [Clark, Maggie L.]On: 28 July 2009Access details: Access Details: [subscription number 913240046]Publisher Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK International Journal of Environmental Health ResearchPublication details, including instructions for authors and subscription information: Impact of improved cookstoves on indoor air pollution and adverse healtheffects among Honduran womenMaggie L. Clark a; Jennifer L. Peel a; James B. Burch b; Tracy L. Nelson a; Matthew M. Robinson a; StuartConway c; Annette M. Bachand a; Stephen J. Reynolds a a Environmental & Radiological Health Sciences, Colorado State University, Fort Collins, USA b University ofSouth Carolina, Columbia, SC, USA c Trees, Water & People, Fort Collins, CO, USA First Published on: 02 July 2009 To cite this Article Clark, Maggie L., Peel, Jennifer L., Burch, James B., Nelson, Tracy L., Robinson, Matthew M., Conway, Stuart,Bachand, Annette M. and Reynolds, Stephen J.(2009)'Impact of improved cookstoves on indoor air pollution and adverse healtheffects among Honduran women',International Journal of Environmental Health Research, To link to this Article: DOI: 10.1080/09603120902842705 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: This article may be used for research, teaching and private study purposes. Any substantial orsystematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply ordistribution in any form to anyone is expressly forbidden.
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International Journal of Environmental Health Research2009, 1–12, iFirst article Impact of improved cookstoves on indoor air pollution and adverse healtheﬀects among Honduran women Maggie L. Clarka*, Jennifer L. Peela, James B. Burchb, Tracy L. Nelsona,Matthew M. Robinsona, Stuart Conwayc, Annette M. Bachanda andStephen J. Reynoldsa aEnvironmental & Radiological Health Sciences, Colorado State University, Fort Collins, USA;bUniversity of South Carolina, Columbia, SC, USA; cTrees, Water & People, Fort Collins, CO,USA (Received 2 September 2008; ﬁnal version received 29 January 2009) Elevated indoor air pollution levels due to the burning of biomass in developingcountries are well established. Few studies have quantitatively assessed airpollution levels of improved cookstoves and examined these measures in relationto health eﬀects. We conducted a cross-sectional survey among 79 Honduranwomen cooking with traditional or improved cookstoves. Carbon monoxide andﬁne particulate matter (PM2.5) levels were assessed via indoor and personalmonitoring. Pulmonary function and respiratory symptoms were ascertained.
Finger-stick blood spot samples were collected to measure C-reactive protein(CRP) concentrations. The use of improved stoves was associated with 63% lowerlevels of personal PM2.5, 73% lower levels of indoor PM2.5, and 87% lower levelsof indoor carbon monoxide as compared to traditional stoves. Women usingtraditional stoves reported symptoms more frequently than those using improvedstoves. There was no evidence of associations between cookstove type or airquality measures with lung function or CRP.
Keywords: indoor air pollution; particulate matter; pulmonary function;respiratory symptoms; C-reactive protein Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 More than half of the world's population relies on biomass combustion to meet basicdomestic energy needs (Smith et al. 2004). Cooking in many developing countriesusually consists of burning solid fuels over open ﬁres or using traditional stoves thatusually emit high levels of pollutants. Improved stoves have been designed to burnfuel more eﬃciently and have usually incorporated a chimney or ﬂue for ventilationand have the potential to substantially reduce indoor air pollution exposures(Naeher et al. 2000; Ezzati and Kammen 2002; Smith 2002; Bruce et al. 2004).
However, evaluations of improved stoves are limited (Smith 2002). Biomass-derivedindoor air pollution in developing countries has been associated with increased risksof respiratory diseases (Bruce et al. 2000; Ezzati and Kammen 2002; Smith 2002;Schei et al. 2004; Smith et al. 2004; Naeher et al. 2005). Most studies have relied on *Corresponding author. Email: [email protected] ISSN 0960-3123 print/ISSN 1369-1619 onlineÓ 2009 Taylor & FrancisDOI: 10.1080/09603120902842705http://www.informaworld.com M.L. Clark et al.
proxies of exposure, such as type of stove (traditional or improved) or fuel and oftenlacked adjustment for potential confounders (Bruce et al. 1998; Smith 2002).
Research on the association between cookstove exposures and cardiovascular diseaseis limited. Assessing biomarkers of inﬂammation such as those commonly assessed inthe ambient air pollution literature (e.g. C-reactive protein [CRP]) (Seaton et al.
1999; Peters et al. 2001; Ruckerl et al. 2006), may help elucidate this relationship;however, studies may be limited by diﬃculty in collecting and handling bloodsamples in settings typical of developing countries. Collecting dried blood spots viaﬁnger-stick may provide a useful tool for examining this relationship (Parker andCubitt 1999; Mei et al. 2001; McDade et al. 2004).
We conducted a cross-sectional investigation to evaluate quantitative air pollution levels and health eﬀects, including symptoms and pulmonary function,associated with traditional and improved Justa stoves in Honduras. In addition, wemeasured CRP, a biomarker of inﬂammation and risk factor for cardiovasculardisease (Ridker 2001), in dried blood spots. This pilot study was conducted in part toidentify methodological issues and diﬃculties associated with cookstove exposureand health eﬀects research that may inﬂuence longitudinal and intervention studiesin developing country settings.
The data collection period was from June through August 2005. Fifty-nine non-smoking women who used cookstoves in enclosed or semi-enclosed kitchensparticipated from two Honduran communities: 30 from Santa Lucia and 29 fromSuyapa. An additional 20 women from Santa Lucia participated in an abbreviatedstudy protocol that did not include the quantitative air quality measurements.
Approximately half of the women cooked using traditional stoves (n ¼ 38) and halfusing improved stoves (n ¼ 41). Traditional stoves typically consisted of open ﬁre orpoorly designed combustion chambers and some included poorly functioningchimneys. The improved Justa stoves incorporated a chimney and an improvedcombustion chamber. All participants gave informed consent and the study wasapproved by the Institutional Review Board of Colorado State University (CSU).
Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 Exposure monitoring began around 8 am each morning and lasted for approximately eight hours. PM2.5 (particulate matter with an aerodynamic diameterof less than or equal to 2.5 mm) was assessed via 8-hour indoor and outdoormonitoring and 8-hour personal monitoring using PEM samplers (SKC Inc., PA)and 37 mm Teﬂon polytetraﬂouroethylene ﬁlters (2 mm pore size). Filters were pre-and post-weighed using a Mettler MT5 balance (Mettler-Toledo International, Inc.).
Carbon monoxide was assessed via 8-hour indoor monitoring and 20-min outdoormonitoring using a direct reading instrument (Q-TRAK Plus IAQ Monitor; TSIInc., MN, USA). The Q-TRAK was pre- and post-calibrated using zero air and35 ppm carbon monoxide gas cylinders (TSI Inc., MN). PM2.5 and carbon monoxideindoor sampling devices were collocated inside the kitchen at a height representativeof breathing zones. Personal PM2.5 was assessed by attaching the sampler to theparticipant's clothing nearest her breathing zone and placing the pump (Universal,SKC Inc., PA, USA) in a pack worn around her waist. Investigators assessed kitchenvolume, building materials, size of eave spaces and windows, and temperature.
Health endpoints were assessed at the end of the exposure monitoring period for each participant. Forced expiratory volume in one second (FEV1) and peak International Journal of Environmental Health Research expiratory ﬂow (PEF) were measured using the portable PiKo-1 peak ﬂow meter(Pulmonary Data Services, Inc., CO, USA) (Fonseca et al. 2005). CRP concentrationwas measured in dried blood spot samples. A ﬁnger-stick blood sample was collectedfrom each participating woman. The puncture site was cleansed with 70%isopropanol. Participants' ﬁngers were pricked with a sterile, disposable Tenderlett(ITC, NJ, USA) lancet with a 1.75 mm point. Drops of blood were spotted ontostandardized ﬁlter paper (903 Protein Saver Card, Schleicher & Schuell, NH, USA).
Blood spots were dried overnight at room temperature in a horizontal position andthen stored in low gas-permeable zip-closure bags with desiccant packets andhumidity indicator cards (Hannon et al. 1997). Samples were frozen in Hondurasand transported to CSU where they were stored at 7808C.
The high-sensitivity CRP dried blood spot assay was modiﬁed from that of McDade et al. (2004) by utilizing a commercially available enzyme-linkedimmunosorbent assay (ELISA) kit (Virgo CRP Kit, Hemagen Diagnostics, Inc,Columbia MD, USA). The modiﬁcation, which was performed due to costconstraints and reagent availability at the time, included using a microplate withpre-coated anti-CRP in each well; all other procedures remained the same as inMcDade et al. (2004). We performed a small validation study of the modiﬁed driedblood spot CRP assay comparing CRP in plasma and dried blood spots from 40volunteers. In the validation study, dried blood CRP was consistently higher thanplasma CRP measured in the same person (regression equation: dried bloodCRP ¼ 5.91 [plasma CRP] þ 1.53; R2 ¼ 0.75).
A standardized respiratory symptoms and disease questionnaire developed and validated by the American Thoracic Society (Ferris 1978) was translated intoSpanish and administered to participants. Additionally, a study investigatormeasured each participant's height, weight, and waist circumference. The surveyalso collected demographic information, occupation, and information related toexposure (e.g. fuel type and time spent cooking) (Albalak et al. 2001) and outcome(e.g. medication and supplement use and recent illnesses).
All analyses were performed using the SAS statistical software (SAS 9.1, SAS Institute, Inc., Cary, NC, USA). Multiple linear regression was used to assess therelationship between cookstove type and air quality measures with lung function or Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 CRP concentrations. To meet assumptions of linear regression, the naturallogarithm transformation of CRP concentration was used. Multiple logisticregression was used to assess the relationship between cookstove exposures andair quality measures with symptoms. Cookstove exposures were assessed in separatemodels (personal 8-hour average PM2.5, indoor 8-hour average PM2.5, indoor 1-hourmaximum carbon monoxide, and stove type [traditional or improved]). All estimatesand conﬁdence intervals for PM2.5 and carbon monoxide concentrations wereexpressed for an interquartile range (IQR) increase of the pollutant. Models includedage (symptoms analyses); age and height (lung function analyses); and age, height,and waist circumference (CRP analyses). We also evaluated second-hand smokeexposure, education level, outdoor afternoon average temperature, and, in the CRPanalyses only, ﬁsh consumption, menopausal status, and the presence of a cold orsinus problem in the previous week as potential confounders.
Models were stratiﬁed by several variables in order to evaluate the heterogeneity of the estimates, including second-hand smoke exposure, outdoor concentrations ofPM2.5, village of residence, amount of time spent in the room with the ﬁre burning,outside average afternoon temperature, reported concern that stove smoke causes M.L. Clark et al.
health problems, years with the current stove, ventilation factors (in models withstove type; e.g. presence of kitchen windows, volume of kitchen), presence of a coldor sinus problem during the previous week (CRP analyses), history of smoking, andbronchodilator use (lung function models only).
A secondary analysis was performed in order to assess the relationship between cookstove type and air quality measures and percent predicted FEV1 (less than 80%vs. 80% or more) using logistic regression. Because standardized reference equationsfor Honduran women do not exist (to our knowledge), predicted FEV1 for eachparticipant was based on age and height-adjusted reference equations for Mexican-American women (Hankinson et al. 1999).
The use of improved Justa stoves was associated with 63% lower levels of personalPM2.5, 73% lower levels of indoor PM2.5, and 87% lower levels of indoor carbonmonoxide levels compared to traditional stoves (Table 1). Only four women (5.1%)reported being previous cigarette smokers (all women reported being non-smokers atthe time of the study); however, 31.7% reported the presence of smokers in the house Population characteristics, air quality, and health endpoints among traditional and improved stove users (n ¼ 79).
stove users (n ¼ 38) Population characteristics: Mean (standard deviation [SD])Age (years) Body Mass Index (kg/m2) Waist circumference (cm) Education (years) Years with current stove Population characteristics: Frequency (percent)Second-hand smoke exposure Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 Air quality:* Mean (SD)PM2.5, personal (mg/m3; 8-hour average) PM2.5, indoor (mg/m3; 8-hour average) Carbon monoxide, indoor 1-hour max. (ppm) Self-reported symptoms: Frequency (percent)Cough Lung function and CRP:** Mean (SD)FEV1 (l) *Traditional stove sample sizes: n ¼ 28 for personal PM2.5, n ¼ 27 for indoor PM2.5, n ¼ 26 for carbonmonoxide; improved stove sample sizes: n ¼ 30 for personal PM2.5, n ¼ 30 for indoor PM2.5, n ¼ 28 for carbonmonoxide. **Lung function sample sizes: n ¼ 24 traditional stove and n ¼ 28 improved stove users; CRPsample sizes: n ¼ 35 traditional stove and n ¼ 36 improved stove users; geometric mean presented for CRP.
FEV1, forced expiratory volume in 1 sec; PEF, peak expiratory ﬂow; CRP, C-reactive protein.
International Journal of Environmental Health Research or kitchen. On average, traditional stove users were about 7 years younger, had theircurrent stove for 6.6 years longer, and were exposed to less second-hand smoke(26.3% vs. 36.6%) compared to improved stove users; body mass index, height, waistcircumference, and years of education were similar among the two groups (Table 1).
Adjusting for age and height, an IQR increase (106.1 mg/m3) of personal PM2.5 was associated with a 0.07 liter (95% conﬁdence interval (CI): 0.01–0.13) increase inFEV1 (Table 2). Associations of indoor PM2.5, carbon monoxide, and stove type(improved vs. traditional) with FEV1 (adjusted for age and height) were consistentwith null associations (Table 2). Associations of cookstove type and air qualitymeasures with PEF were similar to those for FEV1 (Table 2). Associations ofcookstove type and air quality measures with log-transformed CRP concentrations(adjusted for age, height, and waist circumference) were consistent with nullassociations (Table 3). Geometric mean CRP concentrations (adjusted for age,height, and waist circumference) for traditional and improved cookstove users were3.7 mg/l (95% CI: 2.3–5.8) and 4.7 mg/l (95% CI: 3.0–7.3), respectively.
Odds ratios (OR) for the associations of cookstove type and air quality measures with symptoms (adjusted for age) are presented in Table 4. Cooking with atraditional stove was associated with the usual presence of a cough (OR ¼ 7.99, 95%CI: 1.59–40.09), phlegm (OR ¼ 3.83, 95% CI: 0.86–17.14), headache during cooking(OR ¼ 5.59, 95% CI: 1.73–18.06), and shortness of breath (OR ¼ 2.33, 95% CI:0.83–6.57); the conﬁdence intervals were wide and some did not exclude a nullassociation. We did not observe evidence of an association between cookstove typeand nasal irritation (OR ¼ 0.92, 95% CI: 0.33–2.60). Associations of indoor PM2.5and carbon monoxide levels with symptoms, while weak, generally supported theresults for stove type (Table 4). Associations between personal PM2.5 and symptomswere consistent with null associations (Table 4).
Adjustment for additional variables (second-hand smoke exposure, education level, outdoor afternoon average temperature) did not substantially alter the results.
Results from stratiﬁed models, including reported exposure to second-hand smoke,did not provide evidence of heterogeneity across the strata.
Multiple linear regression estimates and 95% conﬁdence intervals (CI) for the Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 association of air quality measures and cookstove type with forced expiratory volume in 1second (FEV1; liters) and peak expiratory ﬂow (PEF; liters/minute); associations adjusted forage and height.
Exposure measure* FEV1 Coeﬃcient (liters) 8-hour average personal PM2.5 (mg/m3) 8-hour average indoor PM2.5 (mg/m3) 1-hour maximum carbon monoxide (ppm) Stove type (traditional vs. improved) Exposure measure* PEF Coeﬃcient (l/min) 8-hour average personal PM2.5 (mg/m3) 8-hour average indoor PM2.5 (mg/m3) 1-hour maximum carbon monoxide (ppm) Stove type (traditional vs. improved) *Estimates for PM2.5 and carbon monoxide are per IQR increase: personal PM2.5 (106.1 mg/m3), indoorPM2.5 (572.3 mg/m3), and indoor carbon monoxide (4.62 ppm). PM2.5, particulate matter with anaerodynamic diameter of less than or equal to 2.5 mm.
M.L. Clark et al.
Multiple linear regression estimates and 95% conﬁdence intervals (CI) for the association of air quality measures and cookstove type with natural log transformedC-reactive protein concentrations (CRP; mg/l); associations adjusted for age, height, and waistcircumference.
Exposure measure* 8-hour average personal PM2.5 (mg/m3) 8-hour average indoor PM2.5 (mg/m3) 1-hour maximum carbon monoxide (ppm) Stove type (traditional vs. improved) *Estimates for PM2.5 and carbon monoxide are per IQR increase: personal PM2.5 (106.1 mg/m3), indoorPM2.5 (572.3 mg/m3), and indoor carbon monoxide (4.62 ppm). PM2.5, particulate matter with anaerodynamic diameter of less than or equal to 2.5 mm.
In this study of Honduran women, the use of improved Justa stoves was associatedwith 63% lower levels of personal PM2.5, 73% lower levels of indoor PM2.5, and87% lower levels of indoor carbon monoxide levels compared to traditional stoves.
Women using traditional stoves reported symptoms of cough, phlegm, wheeze,headache during cooking, and shortness of breath more frequently than those usingimproved stoves; results for indoor PM2.5 and carbon monoxide levels, while weak,generally supported the results for stove type. The results of this pilot study provideevidence of the potential impact on exposure and health of the improved Justa stovein this population. The results also demonstrate the need for continued evaluation ofimproved wood-burning stoves in order to justify costly intervention programs indeveloping countries. Additionally, this study, in conjunction with recent advancesin laboratory methods, illustrates the feasibility of using dried blood spot collectionin a developing country in order to evaluate biologic markers in environments withlimited resources.
In this study, we observed associations between stove type and self-reported symptoms which were supported by weaker associations between measured indoorair pollutants and self-reported symptoms. Previous studies have demonstrated that Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 women exposed to higher levels of indoor air pollution from the burning of biomassfuels are more likely to experience adverse symptoms (Smith et al. 2004; Regaladoet al. 2006), although not consistently (Riojas-Rodriguez et al. 2001). Inconsistentevidence of the relationship between cookstove exposures and reported symptomsmay arise because of discrepancies in the understanding of terms used to describesymptoms, particularly because rural areas of developing countries are oftencharacterized by low literacy and poor access to health care (Diaz et al. 2007;Thompson et al. 2007). Another potential limitation of the symptoms analyses is thepotential of reporting bias; that is, the knowledge of the adverse health eﬀects ofcookstoves could have inﬂuenced women with traditional stoves to report moresymptoms because of this knowledge. In this study, most women (76%) reportedthat they were concerned that the smoke from cookstoves could adversely aﬀect theirhealth. Ideally, we would have examined the association between exposure andhealth among women not expressing concern; however, due to limited sample size wewere unable to examine associations among these 19 women (24%).
Our results examining cookstove type and measured air pollution do not support the hypothesis that improved stoves result in better lung function. In similar studies, International Journal of Environmental Health Research Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 M.L. Clark et al.
associations between biomass exposures and lung function have been weak andvariable (Reddy et al. 2004; Regalado et al. 2006; Rinne et al. 2006; Diaz et al. 2007).
Explanations for the lack of consistent associations despite elevated exposures areunknown (Regalado et al. 2006). It is possible that biomass smoke has no or littleimpact on lung function or that women chronically exposed to biomass smoke havedeveloped reduced susceptibility (Regalado et al. 2006). Furthermore, the mostsusceptible time frame may be during childhood when all of the women likelyexperienced similarly high exposures due to the use of traditional stoves as children(USEPA 1992; Rinne et al. 2006). In addition, air pollution levels measured for theimproved stove users (mean personal PM2.5 ¼ 73.6 mg/m3; mean indoor PM2.5 266.3 mg/m3, mean indoor 1-hour maximum carbon monoxide ¼ 1.8 ppm), while lower than the traditional stove users, are still relatively high, which may limit theability to detect health diﬀerences among the women if a threshold exists. The indoorPM2.5 levels observed in this study are similar to those observed for other improvedbiomass stoves, including wood- and dung-burning cookstoves in India (Chengappaet al. 2007; Dutta et al. 2007), wood-burning cookstoves in Mexico (Masera et al.
2007), and wood-burning cookstoves in Guatemala (Naeher et al. 2000; Albalaket al. 2001; McCracken et al. 2007). In addition, Cynthia et al. (2008) suggest that therelationship between reductions in kitchen concentrations and reductions in personalconcentrations are not consistent and may diﬀer based on stove type. In this study,personal carbon monoxide concentrations were not assessed which may limitinterpretation of results if carbon monoxide is the health-damaging pollutant and ifchanges in indoor carbon monoxide do not reﬂect changes in personal carbonmonoxide. However, PM2.5 was the primary pollutant of interest and personalconcentrations of this pollutant were assessed for each participant. Finally, our useof education level as an indicator of socioeconomic status may have resulted inresidual confounding. Studies in Guatemala have examined more culturally-appropriate indicators of socio-economic status not available in this study, includingan asset index incorporating the possession of a radio, a television, and/or a bicycle,as well as owning pigs or cattle (Bruce et al. 1998; Dı´az et al. 2007; McCracken et al.
Personal PM2.5 levels were associated with FEV1 in the direction opposite to that Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 hypothesized (i.e. increased levels of personal PM2.5 were associated with improvedlung function). The increases in lung function observed when exposures increased arelikely not clinically meaningful. Because changes in FEV1 are diﬃcult to interpret,values are typically compared to a predicted level within a population. While to ourknowledge reference values are not available for Honduran women, in our secondaryanalyses using Mexican-American reference values for FEV1, the results did notprovide evidence of an association for cookstove type or air pollution measures.
Increasing age was associated with decrements in lung function and increasing heightwas associated with increases in lung function, as would be expected (Hankinsonet al. 1999); therefore, some conﬁdence can be placed in the lung function values. Theunexpected result for personal PM2.5 and FEV1 may partially be explained by theinability of a cross-sectional study design to determine temporality of exposure anddisease. It is possible that women already experiencing the most adverse healtheﬀects were the women who received improved stoves. The women in this study wereselected to receive the improved stoves by a local non-proﬁt organization, and we donot have any information regarding why women were selected to receive new stoves.
Women with improved stoves were on average 7.2 years older than women using International Journal of Environmental Health Research traditional stoves. Because improved stoves had been disseminated an average of 2.4years prior to the study, the total lifetime use of traditional stoves may have actuallybeen longer for the improved stove user group.
In this study, estimates of the associations between cookstove type and air quality measures with CRP were consistent with null associations. Studies havereported associations between ambient air pollution exposures and increased CRPconcentrations (Seaton et al. 1999; Peters et al. 2001; Ruckerl et al. 2006), althoughnot consistently (Diez Roux et al. 2006). CRP is an indicator of systemicinﬂammation, and elevated concentrations have been associated with risk ofcardiovascular disease (Ridker 2001). Few studies have assessed the relationshipbetween biomass burning exposures and cardiovascular health in developingcountries. The use of improved stoves versus traditional open ﬁres was associatedwith reductions in systolic and diastolic blood pressure in Guatemala (McCrackenet al. 2007). Ray et al. (2006) reported increased activation of platelets andformations of platelet leukocyte complexes among biomass users compared to liquidpetroleum gas users in India. In addition, Barregard et al. (2006) reported smallexposure-related increases in inﬂammatory mediators, such as Serum Amyloid Aand Factor VIIIc, and a 10% increase in CRP levels three hours after controlledexposure to wood smoke compared to the same amount of time following clean airexposure.
One goal of this study was to measure CRP as an indicator of chronic inﬂammation due to long-term biomass smoke exposures (Macy et al. 1997; Daneshet al. 2004; McDade 2006); however, it is possible that the CRP concentrations wereinﬂuenced by acute exposures. Results from our validation study indicated that driedblood CRP was consistently higher than plasma CRP measured in the same person(regression equation: dried blood CRP ¼ 5.91 [plasma CRP] þ 1.53; R2 ¼ 0.75).
Therefore, dried blood CRP concentrations measured among the Honduranparticipants (ranging from 0.02 to 41.0 mg/l) were reasonably consistent withplasma CRP concentrations less than 10 mg/l, indicating that these women had notlikely experienced acute infection or injury prior to sample collection.
Despite the documented high exposures, estimates concerning the health eﬀects of biomass burning have considerable uncertainty (Zhang and Smith 2003). Few Downloaded By: [Clark, Maggie L.] At: 22:20 28 July 2009 studies have quantitatively assessed personal and indoor air pollution levels relatedto improved cookstoves and examined these measures in relation to health eﬀects,particularly cardiovascular health eﬀects. Continued evaluations of exposurereductions and health improvements are needed in order to encourage and justifythe use and dissemination of improved wood-burning stoves, especially in parts ofthe world where wood is the preferred or necessary cooking fuel. It is likely that theglobal burden of disease due to indoor air pollution from biomass burning will beeven greater once the cardiovascular disease health impacts are more clearlyunderstood (Smith 2002). Assay methods have now been validated for a largenumber of markers of systemic inﬂammation in dried blood spots (Mei et al. 2001;McDade et al. 2004; Skogstrand et al. 2005), including markers that may be betterindicators of cardiovascular and pulmonary health than CRP. With furtherreﬁnement, the minimally invasive use of dried blood spots could provide a viablealternative to venipuncture blood collection; several community-based studies havedemonstrated it to be a convenient and reliable means to blood collection, storage,and transportation (Worthman and Stallings 1997; Cook et al. 1998; Erhardt et al.
2002; McDade et al. 2004; McDade et al. 2007). This ﬁeld method could prove to be M.L. Clark et al.
a useful tool for evaluating multiple biological markers, including DNA (Steinberget al. 2002), to further elucidate the relationship between indoor air pollution andcardiovascular and respiratory health eﬀects in developing countries (Parker andCubitt 1999; Mei et al. 2001; McDade et al. 2004).
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Redalyc. patrones de autoatención y automedicación entre la población estudiantil universitaria de la ciudad de puebla . elementos: ciencia y cultura
Elementos: ciencia y culturaBenemérita Universidad Autónoma de PueblaISSN: 0187-9073 MÉXICO Enrique Soto Pérez de Celis / Yolanda Roa Nava PATRONES DE AUTOATENCIÓN Y AUTOMEDICACIÓN ENTRE LA POBLACIÓN ESTUDIANTIL UNIVERSITARIA DE LA CIUDAD DE PUEBLA Elementos: ciencia y cultura, octubre-diciembre, año/vol. 11, número 055-056 Benemérita Universidad Autónoma de Puebla