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Thomas Lumley

Publications and source records attributed to Thomas Lumley.

At least 37 records · Page 2Linked to original sources
PubMed2005

beta(2)-Adrenergic receptor polymorphisms and determinants of cardiovascular risk: the Cardiovascular Health Study.

BACKGROUND: Common Arg16Gly and Gln27Glu polymorphisms of the beta(2)-adrenergic receptor (beta(2)AR) have been associated with hypertension and coronary disease. This analysis of older adults in the Cardiovascular Health Study examined whether these polymorphisms were associated with blood pressure (BP), subclinical atherosclerosis, and, among treated hypertensive individuals, differences in coronary disease risk according to antihypertensive drug class. METHODS: Altogether, 5249 participants (4441 white and 808 African American, median follow-up time 10.2 years) were genotyped for both polymorphisms. Ankle-arm index (AAI), carotid intima-media thickness (IMT), and brachial flow-mediated dilation were measured cross-sectionally. All estimates were adjusted for ethnicity. RESULTS: Relative to Gln27 homozygotes, carrying the Glu27 allele was not associated with new-onset hypertension (hazard ratio [HR] = 1.01, 95% confidence interval [CI] = 0.87 to 1.16), BP control (odds ratio [OR] = 0.97, 95% CI = 0.89 to 1.06), AAI (mean difference 0.0042 +/- 0.0052), carotid IMT (mean difference 0.0044 +/- 0.02 mm), or brachial flow-mediated dilation (mean difference in baseline diameter -0.028 +/- 0.036 mm; the most marked of three measures). Among treated hypertensive individuals, coronary disease risk was similar in Glu27 carriers relative to Gln27 homozygotes in subgroups defined by use of beta-blockers (HR = 1.09, 95% CI = 0.64 to 1.87) or other antihypertensive medications (HR = 1.00, 95% CI = 0.78 to 1.28). Results were similar for the Arg16Gly polymorphism. CONCLUSIONS: The association of beta(2)AR genotype with coronary disease previously reported in this older adult population is not likely to be explained by BP levels, subclinical atherosclerosis, or antihypertensive treatment. Other measures of vascular response, gene-gene or gene-environment interactions, or characteristics developing earlier in life may mediate the association between beta(2)AR genotype and coronary disease and merit further research.

Black or African American↗
PubMed2005

Exposure and measurement contributions to estimates of acute air pollution effects.

Air pollution health effect studies are intended to estimate the effect of a pollutant on a health outcome. The definition of this effect depends upon the study design, disease model parameterization, and the type of analysis. Further limitations are imposed by the nature of exposure and our ability to measure it. We define a plausible exposure model for air pollutants that are relatively nonreactive and discuss how exposure varies. We discuss plausible disease models and show how their parameterizations are affected by different exposure partitions and by different study designs. We then discuss a measurement model conditional on ambient concentrations and incorporate this into the disease model. We use simulation studies to show the impact of a range of exposure model assumptions on estimation of the health effect in the ecologic time series design. This design only uses information from the time-varying ambient source exposure. When ambient and nonambient sources are independent, exposure variation due to nonambient source exposures behaves like Berkson measurement error and does not bias the effect estimates. Variation in the population attenuation of ambient concentrations over time does bias the estimates with the bias being either positive or negative depending upon the association of this parameter with ambient pollution. It is not realistic to substitute measured average personal exposures into time series studies because so much of the variation in personal exposures comes from nonambient sources that do not contribute information in the time series design. We conclude that general statements about the implications of measurement error need to be conditioned on the health effect study design and the health effect parameter to be estimated.

Air Pollutants↗
PubMed2005

Case-crossover analyses of air pollution exposure data: referent selection strategies and their implications for bias.

The case-crossover design has been widely used to study the association between short-term air pollution exposure and the risk of an acute adverse health event. The design uses cases only; for each individual case, exposure just before the event is compared with exposure at other control (or "referent") times. Time-invariant confounders are controlled by making within-subject comparisons. Even more important in the air pollution setting is that time-varying confounders can also be controlled by design by matching referents to the index time. The referent selection strategy is important for reasons in addition to control of confounding. The case-crossover design makes the implicit assumption that there is no trend in exposure across the referent times. In addition, the statistical method that is used-conditional logistic regression-is unbiased only with certain referent strategies. We review here the case-crossover literature in the air pollution context, focusing on key issues regarding referent selection. We conclude with a set of recommendations for choosing a referent strategy with air pollution exposure data. Specifically, we advocate the time-stratified approach to referent selection because it ensures unbiased conditional logistic regression estimates, avoids bias resulting from time trend in the exposure series, and can be tailored to match on specific time-varying confounders.

Acute Disease↗
PubMed2005

Weight loss, muscle strength, and angiotensin-converting enzyme inhibitors in older adults with congestive heart failure or hypertension.

OBJECTIVES: To determine whether angiotensin-converting enzyme (ACE) inhibitor use may be associated with weight maintenance and sustained muscle strength (measured by grip strength) in older adults. DESIGN: Data from the Cardiovascular Health Study (CHS), a community-based prospective cohort study of 5,888 older adults, were used. SETTING: Subjects were recruited from four U.S. sites beginning in 1989; this analysis included data through 2001. PARTICIPANTS: CHS participants with congestive heart failure (CHF) or treated hypertension. MEASUREMENTS: The exposure, current ACE inhibitor use, was ascertained by medication inventory at annual clinic visits; the outcomes were weight change and grip-strength change during the following year. Multivariate linear regression was used, accounting for correlations between observations on the same participant over time. RESULTS: The average annual weight change was -0.38 kg in 2,834 participants (14,443 person-years) with treated hypertension and -0.62 kg in 342 participants (980 person-years) with CHF. ACE inhibitor use was associated with less annual weight loss after adjustment for potential confounders: a difference of 0.17 kg (95% confidence interval (CI)=0.05-0.29) in those with treated hypertension and 0.29 kg (95% CI=-0.25-0.83) in those with CHF. There was no evidence of association between ACE inhibitor use and grip-strength change. CONCLUSION: ACE inhibitor use may be associated with weight maintenance, but not maintenance of muscle strength, in older adults with treated hypertension.

Aged↗
PubMed2005

Pulmonary effects of indoor- and outdoor-generated particles in children with asthma.

Most particulate matter (PM) health effects studies use outdoor (ambient) PM as a surrogate for personal exposure. However, people spend most of their time indoors exposed to a combination of indoor-generated particles and ambient particles that have infiltrated. Thus, it is important to investigate the differential health effects of indoor- and ambient-generated particles. We combined our recently adapted recursive model and a predictive model for estimating infiltration efficiency to separate personal exposure (E) to PM2.5 (PM with aerodynamic diameter < or = 2.5 microm) into its indoor-generated (Eig) and ambient-generated (Eag) components for 19 children with asthma. We then compared Eig and Eag to changes in exhaled nitric oxide (eNO), a marker of airway inflammation. Based on the recursive model with a sample size of eight children, Eag was marginally associated with increases in eNO [5.6 ppb per 10-microg/m3 increase in PM2.5; 95% confidence interval (CI), -0.6 to 11.9; p = 0.08]. Eig was not associated with eNO (-0.19 ppb change per 10 microg/m3). Our predictive model allowed us to estimate Eag and Eig for all 19 children. For those combined estimates, only Eag was significantly associated with an increase in eNO (Eag: 5.0 ppb per 10-microg/m3 increase in PM2.5; 95% CI, 0.3 to 9.7; p = 0.04; Eig: 3.3 ppb per 10-microg/m3 increase in PM2.5; 95% CI, -1.1 to 7.7; p = 0.15). Effects were seen only in children who were not using corticosteroid therapy. We conclude that the ambient-generated component of PM2.5 exposure is consistently associated with increases in eNO and the indoor-generated component is less strongly associated with eNO.

Adolescent↗
PubMed2005

Exhaled nitric oxide in children with asthma and short-term PM2.5 exposure in Seattle.

The objective of this study was to evaluate associations between short-term (hourly) exposures to particulate matter with aerodynamic diameters < 2.5 microm (PM2.5) and the fractional concentration of nitric oxide in exhaled breath (FE(NO) in children with asthma participating in an intensive panel study in Seattle, Washington. The exposure data were collected with tapered element oscillation microbalance (TEOM) PM2.5 monitors operated by the local air agency at three sites in the Seattle area. FE(NO) is a marker of airway inflammation and is elevated in individuals with asthma. Previously, we reported that offline measurements of FE(NO) are associated with 24-hr average PM2.5 in a panel of 19 children with asthma in Seattle. In the present study using the same children, we used a polynomial distributed lag model to assess the association between hourly lags in PM2.5 exposure and FE(NO) levels. Our model controlled for age, ambient NO levels, temperature, relative humidity, and modification by use of inhaled corticosteroids. We found that FE(NO) was associated with hourly averages of PM2.5 up to 10-12 hr after exposure. The sum of the coefficients for the lag times associated with PM2.5 in the distributed lag model was 7.0 ppm FE(NO). The single-lag-model FE(NO) effect was 6.9 [95% confidence interval (CI), 3.4 to 10.6 ppb] for a 1-hr lag, 6.3 (95% CI, 2.6 to 9.9 ppb ) for a 4-hr lag, and 0.5 (95% CI, -1.1 to 2.1 ppb) for an 8-hr lag. These data provide new information concerning the lag structure between PM2.5 exposure and a respiratory health outcome in children with asthma.

Age Factors↗
PubMed2005

An open source environment for the statistical evaluation of outbreak detection methods.

We describe the design and initial steps to implementation of a computational framework for evaluating outbreak detection methods. The framework will include components for combining simulated and historical data to create artificial outbreaks and components that implement various outbreak detection algorithms. The first algorithms to be implemented are the three Cumulative Sums (cusum) methods described in the CDC Early Aberration Reporting System.

Algorithms↗
PubMed2004

Esterified estrogens and conjugated equine estrogens and the risk of venous thrombosis.

CONTEXT: Clinical trial evidence indicates that estrogen therapy with or without progestins increases venous thrombotic risk. The findings from these trials, which used oral conjugated equine estrogens, may not be generalizable to other estrogen compounds. OBJECTIVE: To compare risk of venous thrombosis among esterified estrogen users, conjugated equine estrogen users, and nonusers. DESIGN, SETTING, AND PARTICIPANTS: This population-based, case-control study was conducted at a large health maintenance organization in Washington State. Cases were perimenopausal and postmenopausal women aged 30 to 89 years who sustained a first venous thrombosis between January 1995 and December 2001 and controls were matched on age, hypertension status, and calendar year. MAIN OUTCOME MEASURE: Risk of first venous thrombosis in relation to current use of esterified or conjugated equine estrogens, with or without concomitant progestin. Current use was defined as use at thrombotic event for cases and a comparable reference date for controls. RESULTS: Five hundred eighty-six incident venous thrombosis cases and 2268 controls were identified. Compared with women not currently using hormones, current users of esterified estrogen had no increase in venous thrombotic risk (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.69-1.22). In contrast, women currently taking conjugated equine estrogen had an elevated risk (OR, 1.65; 95% CI, 1.24-2.19). When analyses were restricted to estrogen users, current users of conjugated equine estrogen had a higher risk than current users of esterified estrogen (OR, 1.78; 95% CI, 1.11-2.84). Among conjugated equine estrogen users, increasing daily dose was associated with increased risk (trend P value = .02). Among all estrogen users, concomitant progestin use was associated with increased risk compared with use of estrogen alone (OR, 1.60; 95% CI, 1.13-2.26). CONCLUSION: Our finding that conjugated equine estrogen but not esterified estrogen was associated with venous thrombotic risk needs to be replicated and may have implications for the choice of hormones in perimenopausal and postmenopausal women.

Adult↗
PubMed2004

Survival associated with two sets of diagnostic criteria for congestive heart failure.

Congestive heart failure (CHF) definitions vary across epidemiologic studies. The Framingham Heart Study criteria include CHF signs and symptoms assessed by a physician panel. In the Cardiovascular Health Study, a committee of physicians adjudicated CHF diagnoses, confirmed by signs, symptoms, clinical tests, and/or medical therapy. The authors used data from the Cardiovascular Health Study, a population-based cohort study of 5,888 elderly US adults, to compare CHF incidence and survival patterns following onset of CHF as defined by Framingham and/or Cardiovascular Health Study criteria. They constructed an inception cohort of nonfatal, hospitalized CHF patients. Of 875 participants who had qualifying CHF hospitalizations between 1989 and 2000, 54% experienced a first CHF event that fulfilled both sets of diagnostic criteria (concordant), 31% fulfilled only the Framingham criteria (Framingham only), and 15% fulfilled only the Cardiovascular Health Study criteria (Cardiovascular Health Study only). No significant survival difference was found between the Framingham-only group (hazard ratio = 0.87, 95% confidence interval: 0.71, 1.07) or the Cardiovascular Health Study-only group (hazard ratio = 0.89, 95% confidence interval: 0.68, 1.15) and the concordant group (referent). Compared with Cardiovascular Health Study central adjudication, Framingham criteria for CHF identified a larger group of participants with incident CHF, but all-cause mortality rates were similar across these diagnostic classifications.

Aged↗
PubMed2004

Time trends in the use of beta-blockers and other pharmacotherapies in older adults with congestive heart failure.

BACKGROUND: Evidence supporting pharmacotherapy of congestive heart failure (CHF) has grown substantially over the past decade and includes large, placebo-controlled trials with mortality end points. We describe beta-blocker and other medication temporal treatment trends of CHF in the Cardiovascular Health Study, a community-based cohort study of 5888 adults > or =65 years of age. METHODS: Prescription medication data were collected from hospital discharge summaries for incident CHF events and at in-study annual clinic visits for prevalent CHF cases from 1989 to 2000. Change in use of agents over time was estimated by using generalized estimating equations while adjusting for potential confounding factors of age, sex, race, and cardiovascular and pulmonary comorbidities. RESULTS: Among 1033 incident CHF events, beta-blocker use after diagnosis increased an average of 2.4 percentage points annually (95% CI, 1.5 to 3.4 points) from 1989 to 2000. The increasing trend was consistent throughout follow-up. Among participants with coronary disease and/or hypertension and among those with low ejection fractions (<45%), beta-blocker use remained flat from 1989 to 1994 and increased 4.7 points annually (2.5 to 6.9) and 10.0 points annually (6.1 to 13.8), respectively, from 1995 to 2000. Among participants without coronary disease or hypertension, there was no overall increase in use. Use of renin-angiotensin system inhibitors increased 2.3 points annually (1.0 to 3.5), digoxin use decreased 2.4 points annually (-3.6 to -1.1), and loop diuretic use remained flat between 1989 and 2000. In general, treatment trends were similar for prevalent CHF. CONCLUSIONS: Treatment of CHF has changed gradually in the 1990s and may in part reflect the influence of CHF clinical trial evidence.

Adrenergic beta-Antagonists↗
PubMed2004

The association between lipid levels and the risks of incident myocardial infarction, stroke, and total mortality: The Cardiovascular Health Study.

OBJECTIVES: To assess the association between lipid levels and cardiovascular events in older adults. DESIGN: A prospective population-based study. SETTING: Four field centers in U.S. communities. PARTICIPANTS: A total of 5,201 adults aged 65 and older living in U.S. communities, plus a recruitment of 687 African Americans 3 years later. MEASUREMENTS: Fasting lipid measures included low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, and triglycerides. RESULTS: At baseline, 1,954 men and 2,931 women were at risk for an incident myocardial infarction (MI) or stroke. During an average 7.5-year follow-up, 436 subjects had a coronary event, 332 had an ischemic stroke, 104 a hemorrhagic stroke, and 1,096 died. After adjustment, lipid measures were not major predictors of the outcomes of MI, ischemic stroke, hemorrhagic stroke, and total mortality. For total cholesterol and LDL-C, the associations with MI and ischemic stroke were only marginally significant. HDL-C was inversely associated with MI risk (hazard ratio=0.85 per standard deviation of 15.7 mg/dL, 95% confidence interval=0.76-0.96). For the outcome of ischemic stroke, high levels of HDL-C were associated with a decreased risk in men but not women. Lipid measures were generally only weakly associated with the risks of hemorrhagic stroke or total mortality. CONCLUSION: In this population-based study of older adults, most lipid measures were weakly associated with cardiovascular events. The association between low HDL-C and increased MI risk was nonetheless strong and consistent.

Black or African American↗
PubMed2003

Health outcomes associated with various antihypertensive therapies used as first-line agents: a network meta-analysis.

CONTEXT: Establishing relative benefit or harm from specific antihypertensive agents is limited by the complex array of studies that compare treatments. Network meta-analysis combines direct and indirect evidence to better define risk or benefit. OBJECTIVE: To summarize the available clinical trial evidence concerning the safety and efficacy of various antihypertensive therapies used as first-line agents and evaluated in terms of major cardiovascular disease end points and all-cause mortality. DATA SOURCES AND STUDY SELECTION: We used previous meta-analyses, MEDLINE searches, and journal reviews from January 1995 through December 2002. We identified long-term randomized controlled trials that assessed major cardiovascular disease end points as an outcome. Eligible studies included both those with placebo-treated or untreated controls and those with actively treated controls. DATA EXTRACTION: Network meta-analysis was used to combine direct within-trial between-drug comparisons with indirect evidence from the other trials. The indirect comparisons, which preserve the within-trial randomized findings, were constructed from trials that had one treatment in common. DATA SYNTHESIS: Data were combined from 42 clinical trials that included 192 478 patients randomized to 7 major treatment strategies, including placebo. For all outcomes, low-dose diuretics were superior to placebo: coronary heart disease (CHD; RR, 0.79; 95% confidence interval [CI], 0.69-0.92); congestive heart failure (CHF; RR, 0.51; 95% CI, 0.42-0.62); stroke (RR, 0.71; 0.63-0.81); cardiovascular disease events (RR, 0.76; 95% CI, 0.69-0.83); cardiovascular disease mortality (RR, 0.81; 95% CI, 0.73-0.92); and total mortality (RR, 0.90; 95% CI, 0.84-0.96). None of the first-line treatment strategies-beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers (CCBs), alpha-blockers, and angiotensin receptor blockers-was significantly better than low-dose diuretics for any outcome. Compared with CCBs, low-dose diuretics were associated with reduced risks of cardiovascular disease events (RR, 0.94; 95% CI, 0.89-1.00) and CHF (RR, 0.74; 95% CI, 0.67-0.81). Compared with ACE inhibitors, low-dose diuretics were associated with reduced risks of CHF (RR, 0.88; 95% CI, 0.80-0.96), cardiovascular disease events (RR, 0.94; 95% CI, 0.89-1.00), and stroke (RR, 0.86; 0.77-0.97). Compared with beta-blockers, low-dose diuretics were associated with a reduced risk of cardiovascular disease events (RR, 0.89; 95% CI, 0.80-0.98). Compared with alpha-blockers, low-dose diuretics were associated with reduced risks of CHF (RR, 0.51; 95% CI, 0.43-0.60) and cardiovascular disease events (RR, 0.84; 95% CI, 0.75-0.93). Blood pressure changes were similar between comparison treatments. CONCLUSIONS: Low-dose diuretics are the most effective first-line treatment for preventing the occurrence of cardiovascular disease morbidity and mortality. Clinical practice and treatment guidelines should reflect this evidence, and future trials should use low-dose diuretics as the standard for clinically useful comparisons.

Humans↗
PubMed2003

Beta2-adrenergic receptor polymorphisms and risk of incident cardiovascular events in the elderly.

BACKGROUND: Genetic polymorphisms at codons 16 and 27 of the beta2-adrenergic receptor have been associated with altered response to sympathetic stimulation. We examined these polymorphisms in relation to cardiovascular event risk in the Cardiovascular Health Study. METHODS AND RESULTS: A total of 808 black and 4441 white participants (mean age, 73 years) were genotyped for the Arg16Gly and Gln27Glu polymorphisms of the beta2-adrenergic receptor. There were 702 incident coronary events, 438 ischemic strokes, and 1136 combined cardiovascular events during 7 to 10 years of follow-up. Allele frequencies differed by race but not by age or hypertension status. Glu27 carriers had a lower risk of coronary events than Gln27 homozygotes (hazard ratio, 0.82; 95% CI, 0.70 to 0.95), and there was a suggestion of decreased risk among Gly16 carriers compared with Arg16 homozygotes (hazard ratio, 0.88; 95% CI, 0.72 to 1.07). There was no association of beta2-adrenergic receptor genotype with ischemic stroke or combined cardiovascular events. CONCLUSIONS: The Glu27 allele of the beta2-adrenergic receptor was associated with a lower risk of incident coronary events in this elderly population.

Aged↗
PubMed2003

Association of alcohol-related laws with deaths due to motor vehicle and motorcycle crashes in the United States, 1980-1997.

The authors compared US motor vehicle and motorcycle mortality rates during periods when each of several alcohol-related laws were in effect with mortality rates during other periods. During the period 1980-1997, there were 792,184 deaths due to motor vehicle crashes and 63,052 deaths due to motorcycle crashes. An estimated 26% and 49% of these fatalities, respectively, were attributable to alcohol use. The incidence of alcohol-related mortality in motor vehicle crashes was lower when laws specifying a blood alcohol concentration of 0.08 g/dl per se (laws stating that it is a criminal offense to drive with a blood alcohol concentration above the state's legal limit) were in effect (adjusted rate ratio (RR) = 0.86, 95% confidence interval (CI): 0.83, 0.88). For motorcycle deaths, the adjusted rate ratio was 0.87 (95% CI: 0.79, 0.95). The incidence of alcohol-related mortality in motor vehicle crashes was also lower during periods when two other types of laws were in effect: zero tolerance laws (adjusted RR = 0.88, 95% CI: 0.86, 0.90) and administrative license revocation laws (adjusted RR = 0.95, 95% CI: 0.93, 0.98). Overall motorcycle mortality was lower when administrative license revocation laws were in effect (adjusted RR = 0.95, 95% CI: 0.92, 0.98).

Accidents, Traffic↗
PubMed2003

Angiotensinogen Met235Thr polymorphism, angiotensin-converting enzyme inhibitor therapy, and the risk of nonfatal stroke or myocardial infarction in hypertensive patients.

UNLABELLED: The ThrThr genotype of the angiotensinogen (AGT) Met235Thr polymorphism has been associated with elevated AGT levels, hypertension, increased heart disease risk, and improved blood pressure (BP) response to angiotensin-converting enzyme (ACE) inhibitors. We hypothesized that risk of stroke or myocardial infarction (MI) associated with ACE inhibitor use varies by AGT genotype, with a larger protective effect of ACE inhibitors in individuals with the ThrThr genotype than individuals who are carriers of the Met allele. METHODS: We conducted a population-based case-control study. Participants were health maintenance organization members aged 30 to 79 years with treated hypertension. Those who survived incident stroke (n = 116) or MI (n = 208) during the study period were designated as cases. Control subjects (n = 717) were randomly sampled and frequency-matched to MI cases on age, sex, and calendar year. Health history, medication use, and AGT genotype were assessed. RESULTS: ThrThr genotype was present in 21% of stroke cases, 26% of MI cases, and 19% of control subjects. Compared with nonuse, ACE inhibitor use was associated with lower stroke risk among Thr homozygotes (odds ratio [OR] = 0.37, 95% CI = 0.14 to 0.99) than among Met carriers (OR = 1.4, 95% CI = 0.88 to 2.4; P for interaction =.02). Compared with nonuse, ACE inhibitor use was associated with similar MI risk among Thr homozygotes (OR = 0.90, 95% CI = 0.62 to 1.3) and among Met carriers (OR = 1.2, 95% CI = 0.60 to 2.5; P for interaction = 0.5). CONCLUSIONS: In this hypertensive population, the association of ACE inhibitor use with risk of nonfatal stroke varied by genotype. The protective association between ACE inhibitor use and nonfatal stroke risk among individuals with ThrThr genotype was not observed for nonfatal MI.

Adult↗
PubMed2003

Effects of ambient air pollution on symptom severity and medication use in children with asthma.

BACKGROUND: Exposure to air pollutants has been investigated as a possible cause of asthma attacks in children. OBJECTIVE: To investigate the short-term effects of air pollutants on a panel of 133 children with asthma who enrolled in the Childhood Asthma Management Program. METHODS: During screening, the children completed daily diary cards for an average of 58 days to indicate their medication use and asthma severity. We used ordinal logistic regression to compare the odds of a more serious relative to a less serious asthma attack, and we used a Poisson model to analyze medication use. In both analyses we accommodate dependence in the data and different periods of observation for study subjects. RESULTS: Our results indicate that a 10-microg/m3 increase in particulate matter less than or equal to 2.5 microm (PM2.5) lagged 1 day was associated with a 1.20 times increased odds of having a more serious asthma attack [95% confidence interval (CI), 1.05 to 1.37] and a 1.08-fold increase in medication use (95% CI, 1.01 to 1.15). A 10-microg/m3 increase in particulate matter less than or equal to 10 microm (PM10) increased the odds of a more serious asthma attack (odds ratio = 1.12; 95% CI, 1.04 to 1.22) and also increased medication use (relative risk = 1.05; 95% CI, 1.00 to 1.09). CONCLUSIONS: Increases in PM2.5 and PM10 are significantly associated with an increased risk of more severe asthma attacks and medication use in Seattle area children with asthma. We also found associations with carbon monoxide, but we believe that carbon monoxide is a marker for exposure to combustion byproducts.

Adolescent↗