Epidemiology

Glutathione is an antioxidant that mitigates oxidative stress in the lung. Acetaminophen results in a dose-dependent decrease in levels of glutathione in the lungs. Barr and colleagues in a prospective cohort study of 121,700 women in the Nurses' Health Study, examined the relationship between use of acetaminophen and the development of adult-onset asthma. Participants were queried about the frequency of acetaminophen use in 1990. Those who reported physician-diagnosed asthma on questionnaires completed in 1990–1996 and in 1998 were defined as new cases. During 352,719 person-years of follow-up, there were 346 new cases of asthma. Increasing frequency of acetaminophen use was positively associated with newly diagnosed asthma (p = 0.006). The authors suggested that the historical trends in analgesic use may be responsible, in part, for the population-level increases in asthma prevalence in the United States.

Asthma and obesity are both common problems in the United States, and epidemiologic data suggest that obesity may be a risk factor for asthma. In a report of an NHLBI workshop, Weiss and Shore summarized epidemiologic and pathophysiologic research linking obesity and asthma, and suggested future directions for research.

To determine the relationship between geohelminth infection, atopy, and symptoms of allergic disease, Cooper and coworkers  studied 4,433 schoolchildren from 71 schools in rural Ecuador. The prevalence of allergic symptoms was low (2.1% had recent wheeze), whereas the prevalence of skin-test reactivity was higher (18.2%). The presence of geohelminth infections was protective against allergen skin test reactivity (odds ratio, 0.62) and symptoms of exercise-induced wheeze (odds ratio, 0.59), but not against allergic rhinitis or atopic eczema. The prevalence of allergen skin-test reactivity was associated with intensity of infection with Ascaris lumbricoides (odds ratio, 0.82) and Trichuris trichiura (odds ratio, 0.67). There was no evidence of interactions between geohelminth infection and allergen skin-test reactivity on the risks of allergic symptoms. The authors conclude that geohelminth infections strongly protect against allergen skin-test reactivity, but do not strongly protect against allergic symptoms with the exception of exercise-induced wheeze. An editorial commentary by Britton  accompanies this article.

To determine the magnitude and predictors for hospital readmission for childhood asthma, Bloomberg and coworkers  analyzed data from 8,761 children who experienced 14,905 admissions for asthma. During the 10-year period, 30% of children were admitted more than once. A multivariate model revealed that African-American children with Medicaid or no insurance had a higher rate of readmission than did African-American children with commercial insurance or white (or other ethnicity) children regardless of insurance (risk ratio, 1.28). The probability of readmission increased from 30% after the first admission to 46% after a second admission and to 59% after a third admission. The authors conclude that prior admission is a more powerful predictor for readmission for childhood asthma than are ethnicity, insurance status, or their combination.

To determine whether parasitic infection decreases the risk of wheeze in young children, Dagoye and coworkers   did a nested case-control study based on data on 7,155 children aged 1 to 4 years living in urban and rural areas of Ethiopia. Infections with parasites was common: whipworm (Trichuris) (54%), roundworm (Ascaris) (38%), and hookworm (Ancylostoma spp.) (10%). Wheezing in the past year was more prevalent in urban children than in rural children (4.4% versus 2%), and was less prevalent in children infected with Ascaris (adjusted odds ratio, 0.5). A similar, although nonsignificant, association was found for hookworm (adjusted odds ratio, 0.6), but not for Trichuris. Skin sensitization with house dust mite (Dermatophagoides pteronyssinus) and cockroach (Blattella germanica) was more prevalent in rural than in urban children, and unrelated to wheeze. The authors conclude that Ascaris infection protects against wheeze in young Ethiopian children and that this effect is not mediated by inhibition of allergen sensitization.

Home dampness is associated with lower respiratory symptoms in children. To determine whether in-home fungal concentrations can predict lower respiratory illnesses (croup, pneumonia, bronchitis, and bronchiolitis) in the first year, Stark and coworkers  studied a prospective birth cohort of 499 children of parents with asthma/allergies. After controlling for sex, presence of water damage, presence of visible mold/mildew, a winter birth, breastfeeding, and exposure to other children (through siblings), multivariate analyses revealed significant associations between lower respiratory illnesses and high levels (more than 90th percentile) of airborne Penicillium (relative risk, 1.73), dust-borne Cladosporium (relative risk, 1.52), Zygomycetes (relative risk, 1.96), and Alternaria (relative risk, 1.51). On multivariate analysis, lower respiratory illnesses were associated with households that had any fungal level above the 90th percentile (relative risk, 1.86). The authors conclude that exposure to high levels of fungi in the home increase the risk of wheezing and nonwheezing lower respiratory illnesses during infancy.

To determine the association between day care attendance in the first year of life and asthma and wheezing over the first 6 years of life, Celedon and coworkers  followed from birth 453 children with and without a maternal history of asthma. Day care in the first year of life was inversely associated with eczema (odds ratio, 0.3). Day care attendance in the first year of life was associated with a decreased risk of asthma (odds ratio, 0.3) and recurrent wheezing (odds ratio, 0.3) at 6 years of age, and with a decreased risk of wheezing after 4 years of age among children without a maternal history of asthma. Among children with a maternal history of asthma, day care in early life did not have a protective effect on asthma or recurrent wheezing at 6 years of age, but was instead associated with an increased risk of wheezing in the first 6 years of life. The authors conclude that a maternal history of asthma influences the relationship between day care–related exposure and childhood asthma.

In a cohort of children with asthma from 12 Southern California communities, McConnell and coworkers  investigated the relationship between bronchitic symptoms and ambient particulate matter, particulate elemental and organic carbon, nitrogen dioxide, and other gaseous pollutants. Symptoms (assessed by questionnaire every year between 1996 and 1999) were associated with yearly variability of particulate matter with aerodynamic diameter less than 2.5 µm (odds ratio, 1.41), nitrogen dioxide (odds ratio, 1.07), organic carbon (odds ratio, 1.41), nitrogen dioxide (odds ratio, 1.07), and ozone (odds ratio, 1.06). The within-community associations were stronger in magnitude than the between-community associations. The effects of yearly variation of organic carbon and nitrogen dioxide were only modestly reduced after adjusting for other pollutants. The effects of all other pollutants were reduced after adjusting for organic carbon and nitrogen dioxide. The authors conclude that previous cross-sectional studies may have underestimated the effects of organic carbon and nitrogen dioxide on chronic bronchitic symptoms in children with asthma.

To describe the natural history of atopic and wheezy disorders, Rhodes and coworkers  enrolled 100 subjects at birth on the basis that at least one parent had atopy. Sixty-three percent of the subjects were studied at 22 years of age. The annual prevalence of both wheeze and bronchial hyperresponsiveness to histamine increased with age, and 25% of adults had asthma. Remission of wheeze was common in children younger than 5 years, but wheeze was likely to persist if it was present at 11 years. Of adults with asthma, 60% developed sensitivity to common allergens by 2 years of age and displayed bronchial hyperreactivity by 11 years of age. The authors conclude that adults with asthma can begin to wheeze at any age, but they tend to sensitize early and display bronchial hyperreactivity by 11 years of age.

To determine the role of indoor allergen sensitization and exposure as a cause of morbidity in women with asthma, Lewis and coworkers  studied 458 women from Boston (140 of whom had asthma) over a 4-year period. Women with asthma who had elevated levels of specific IgE to cat or cockroach allergens reported greater morbidity in the preceding year if high levels of a relevant allergen were found in dust samples from the home. Women with asthma sensitized to cat allergen and with concentrations of greater than 8 µg per gram in the home samples were more likely to have used glucocorticoids (odds ratio, 2.7) and to have wheezed without a cold (odds ratio, 6.8). Women sensitized to cockroach and exposed to cockroaches were at least three times more likely to have used glucocorticoids and to have visited an emergency room. The authors conclude that cockroach and cat allergens contribute to asthma morbidity in sensitized women.

To determine the interrelationship between current and past infection with Ascaris lumbricoides and asthma and atopy, Palmer and coworkers  studied a cross-sectional sample of 2,164 children between the ages of 8 and 18 years from rural China. The prevalence of either a history or positive stool examination for Ascaris was 24.5%. Independently of other factors, infection with Ascaris was associated with increased risk of asthma (odds ratio, 1.85), increased number of skin tests positive to aeroallergens (odds ratio, 1.25), and an increased slope of the dose–response to methacholine. The authors conclude that infection with Ascaris lumbricoides is associated with an increased risk of childhood asthma, increased airway hyperresponsiveness, and sensitization to common aeroallergens.

To determine the relationship between exposure to microbial load during pregnancy and the development of allergic disease, McKeever and coworkers  analyzed data from a birth cohort of 24,690 children. Exposure to antibiotics in utero was associated with an increased risk of asthma in a dose-related manner. Compared with no antibiotics, more than two courses of antibiotics was associated with increased risk of asthma (hazard ratio, 1.68), eczema (hazard ratio, 1.17), and hay fever (hazard ratio, 1.56). Exposure to a range of infections in utero was associated with a small increased risk of developing allergic disease. The presence of an older sibling had a strong protective effect on the incidence of allergy. The authors conclude that exposure to antibiotics in utero is associated with a dose-related increase in the risk of allergic disease in children.

To characterize the burden of asthma in the United States, Fuhlbrigge and coworkers  did a telephone survey of 42,022 households to identify adults with asthma or parents of children with asthma. The burden consisted of three components: short-term burden (4-week recall); long-term burden (1-year recall); and functional impact (limitation of activity). Only 10.7% of individuals with asthma were classified as having mild intermittent asthma; 77.3% were classified as having moderate to severe persistent asthma. The discordance in type and distribution of symptoms of asthma among individuals demonstrates that an exact estimate of asthma burden depends on how a classification is operated. The authors conclude that the burden of asthma on health and functioning of the U.S. population is substantial, and that most patients have persistent asthma rather than mild intermittent asthma.

Citations 1-10 of 10 total displayed.

Obesity and Asthma: Directions for Research

Scott T. Weiss and Stephanie Shore
Am. J. Respir. Crit. Care Med. 169: 963 -968. First published online as doi:10.1164/rccm.200303-403WS [Full text]  

Prospective Study of Acetaminophen Use and Newly Diagnosed Asthma among Women

R. Graham Barr, Catherine C. Wentowski, Gary C. Curhan, Samuel C. Somers, Meir J. Stampfer, Joel Schwartz, Frank E. Speizer, and Carlos A. Camargo, Jr.
Am. J. Respir. Crit. Care Med. 169: 836 -841. First published online as doi:10.1164/rccm.200304-596OC [Abstract] [Full text]  

Lower Bronchodilator Responsiveness in Puerto Rican than in Mexican Subjects with Asthma

Esteban González Burchard, Pedro C. Avila, Sylvette Nazario, Jesus Casal, Alfonso Torres, Jose R. Rodriguez-Santana, Monica Toscano, Jody Senter Sylvia, MariaElena Alioto, Michael Salazar, Ivan Gomez, Joanne K. Fagan, Jorge Salas, Craig Lilly, Henry Matallana, Elad Ziv, Richard Castro, Moises Selman, Rocio Chapela, Dean Sheppard, Scott T. Weiss, Jean G. Ford, Homer A. Boushey, William Rodriguez-Cintron, Jeffrey M. Drazen, and Edwin K. Silverman
Am. J. Respir. Crit. Care Med. 169: 386 -392. First published online as doi:10.1164/rccm.200309-1293OC [Abstract] [Full text]  

Prospective Study of Air Pollution and Bronchitic Symptoms in Children with Asthma

Rob McConnell, Kiros Berhane, Frank Gilliland, Jassy Molitor, Duncan Thomas, Fred Lurmann, Edward Avol, W. James Gauderman, and John M. Peters
Am. J. Respir. Crit. Care Med. 168: 790 -797. First published online as doi:10.1164/rccm.200304-466OC [Abstract] [Full text]  

Parasites, Allergy, and Asthma

John Britton
Am. J. Respir. Crit. Care Med. 168: 266-267. [Full text]  

Allergic Symptoms, Atopy, and Geohelminth Infections in a Rural Area of Ecuador

Philip J. Cooper, Martha E. Chico, Martin Bland, George E. Griffin, and Thomas B. Nutman
Am. J. Respir. Crit. Care Med. 168: 313 -317. First published online as doi:10.1164/rccm.200211-1320OC [Abstract] [Full text]  

Fungal Levels in the Home and Lower Respiratory Tract Illnesses in the First Year of Life

Paul C. Stark, Harriet A. Burge, Louise M. Ryan, Donald K. Milton, and Diane R. Gold
Am. J. Respir. Crit. Care Med. 168: 232 -237. First published online as doi:10.1164/rccm.200207-730OC [Abstract] [Full text]  

Wheezing, Allergy, and Parasite Infection in Children in Urban and Rural Ethiopia

Damtew Dagoye, Zegaye Bekele, Kifle Woldemichael, Hailu Nida, Meselech Yimam, Andy Hall, Andrea J. Venn, John R. Britton, Richard Hubbard, and Sarah A. Lewis
Am. J. Respir. Crit. Care Med. 167: 1369 -1373. First published online as doi:10.1164/rccm.200210-1204OC [Abstract] [Full text]  

Day Care Attendance in Early Life, Maternal History of Asthma, and Asthma at the Age of 6 Years

Juan C. Celedón, Rosalind J. Wright, Augusto A. Litonjua, Diane Sredl, Louise Ryan, Scott T. Weiss, and Diane R. Gold
Am. J. Respir. Crit. Care Med. 167: 1239 -1243. First published online as doi:10.1164/rccm.200209-1063OC [Abstract] [Full text]  

Hospital Readmissions for Childhood Asthma: A 10-Year Metropolitan Study

Gordon R. Bloomberg, Kathryn M. Trinkaus, Edwin B. Fisher, Jr., Judith R. Musick, and Robert C. Strunk
Am. J. Respir. Crit. Care Med. 167: 1068-1076. [Abstract] [Full text]