Socioeconomic predictors of high allergen levels in homes in the greater Boston area

Influence of socioeconomic deprivation on the relation between air pollution and beta-agonist sales for asthma

BACKGROUND

Air pollution triggers asthma attacks hours to days after exposure. It remains unclear whether socioeconomic deprivation modulates these effects. Investigation of these interactions requires adequate statistical power, obtainable by using either a sufficient number of observations or very sensitive indicators of asthma attacks. Using a small-area temporal ecologic approach, we studied the short-term relations between ambient air pollution and sales of short-acting beta-agonist (SABA) drugs, a frequent and specific treatment for control of asthma attacks in children and young adults, and then tested the influence of deprivation on these relations.

METHODS

The study took place in Strasbourg, France in 2004. Health insurance funds provided data on 15,121 SABA sales for patients aged 0 to 39 years. Deprivation was estimated by small geographic areas using an index constructed from census data. Daily average ambient concentrations of particulate matter (particles with an aerodynamic diameter < 10 microm [PM(10)]), nitrogen dioxide (NO(2)), and ozone (O(3)) were modeled on a small-area level. Adjusted case-crossover models were used for statistical analysis.

RESULTS

Increased of 10 microg/m(3) in ambient PM(10), NO(2), and O(3) concentrations were associated, respectively, with increases of 7.5% (95% confidence interval [CI], 4 to 11.2%), 8.4% (95% CI, 5 to 11.9%), and 1% (95% CI, - 0.3 to 2.2%) in SABA sales. Deprivation had no influence on these relations.

CONCLUSION

The associations observed are consistent with those reported by studies focusing on SABA use. Similar studies in other settings should confirm whether the lack of interaction with deprivation is due to specific local conditions.

Housing and health: intersection of poverty and environmental exposures

The importance of adequate housing for the maintenance of health and well-being has long been a topic of scientific and public health policy discussion, but the links remain elusive. Here we explore the role of the residential environment in the etiology of illness (specifically asthma) and the persistence of socioeconomic health disparities. Housing conditions, shaped by social forces, affect exposure to physical and chemical "toxicants," thereby translating social adversities into individual illness and population health disparities. We discuss the mediating role of housing in determining health outcomes at multiple levels (social-structural, neighborhood, and individual family). To date, little attention has been paid by most environmental health scientists to the social-structural conditions underlying gross inequities in the distribution of toxic exposures, with even less attention to the processes whereby these social conditions may directly affect susceptibility to the toxic exposures themselves. This chapter goes beyond traditional medical and environmental science models to incorporate a range of social and physical determinants of environmental pollutions, illustrating how these conditions result in health and illness. We focus here on childhood asthma as an example of a serious public health problem that has been associated with low income, minority status, and characteristics of the home environment. We end the chapter with a discussion of the environmental justice movement and the role of housing as a potential agent of change and focus of interventions aimed to reduce the harmful effects of environmental pollutants.

Air pollution, asthma attacks, and socioeconomic deprivation: a small-area case-crossover study

With few exceptions, studies of short-term health effects of air pollution use pollutant concentrations that are averaged citywide as exposure indicators. They are thus prone to exposure misclassification and consequently to bias. Measurement of the relations between air pollution and health, generally and in specific populations, could be improved by employing more geographically precise exposure estimates. The authors investigated short-term relations between ambient air pollution estimated in small geographic areas (French census blocks) and asthma attacks in Strasbourg, France, in 2000-2005--in the general population and in populations with contrasting levels of socioeconomic deprivation. Emergency health-care networks provided data on 4,683 telephone calls made for asthma attacks. Deprivation was estimated using a block-level index constructed from census data. Hourly concentrations of particulate matter less than 10 microm in aerodynamic diameter (PM(10)), sulfur dioxide, nitrogen dioxide, and ozone were modeled by block with ADMS-Urban software. Adjusted case-crossover analyses showed that asthma calls were positively but not significantly associated with PM(10) (for a 10-microg x m(-3) increase, odds ratio (OR) = 1.035, 95% confidence interval (CI): 0.997, 1.075), sulfur dioxide (OR = 1.056, 95% CI: 0.979, 1.139), and nitrogen dioxide (OR = 1.025, 95% CI: 0.990, 1.062). No association was observed for ozone (OR = 0.998, 95% CI: 0.965, 1.032). Socioeconomic deprivation had no significant influence on these relations.

Allergen levels in inner city homes: baseline concentrations and evaluation of intervention effectiveness

Allergens in house dust are risk factors for asthma causation and exacerbation, and asthma interventions often focus on exposure reduction using methods that may not be sustainable over time in low-income communities. A randomized controlled trial with up to six home visits was used to evaluate the effectiveness of two interventions focused on reducing dust loading and allergen concentrations in 47 low-income inner-city households in Minneapolis, MN. The interventions, which included education and relatively inexpensive cleaning procedures, were developed using a community-based participatory consultation process with focus groups held in English, Somali, and Spanish to incorporate community feedback from participants into protocols and study design decisions. Change in levels of cat, cockroach, dust mite, and culturable fungi as well as overall dust loading were evaluated by measuring the difference in concentrations before and after the cleaning intervention, and mixed models were used to assess the effect of education and cleaning on baseline allergen levels during the final three home visits. The cleaning intervention significantly lowered dust loading in all households and culturable fungi levels in single family homes, reduced cat allergen concentrations in homes with cats, but had no significant effect on cockroach allergen levels. The cleaning intervention also modestly decreased the frequency of observed allergen concentrations above suggested health benchmarks for cat, cockroach, and fungi. The cleaning and education interventions had similar effects on baseline allergen levels measured during subsequent home visits; both interventions significantly reduced baseline levels of cat and fungal allergens observed in pre-cleaning samples, but had no significant effect on cockroach allergen levels. Overall, the cleaning intervention modestly reduced potential exposure to risk factors associated with asthma mortality and morbidity in a way that can be implemented by most homeowners or renters, independent of education, income, or the ability to speak English.

Pesticide loadings of select organophosphate and pyrethroid pesticides in urban public housing

We investigated the magnitude and distribution of pyrethroid and organophosphate pesticide loadings within public housing dwellings in Boston, Massachusetts and compared the results using various sampling methods. We collected dust matrices from living room and kitchen in 42 apartments and analyzed for eleven pyrethoids (e.g., permethrin and cyfluthrin) and two organophosphates (chlorpyrifos and diazinon) in house dust using GC/MS. Agreement between sampling methods were evaluated using Spearman correlations and Kappa statistics. Permethrin and chlorpyrifos were detected in kitchen floor wipes in all homes, followed in frequency of detects by diazinon (98%), cypermethrin (90%) and cyfluthrin (71%). At least six pesticides were detected in kitchen floor wipes in the majority of the homes (range 3-8). Positive and statistically significant correlations among dust matrices were observed between kitchen floor wipes and living room vacuum dust, including for diazinon (r=0.62) and cyfluthrin (r=0.69). Detection of several pesticides including banned or restricted use products in some public housing units, underscore the need for alternative pest management strategies that embrace the safe and judicious use of pest control products.

Survey of pest infestation, asthma, and allergy in low-income housing

Low-income housing often has multiple indoor health risks. Among them, pest infestation, pesticide use, and pest allergens are recognized as common risks which affect residents' health. Cockroach and rodent allergens are associated with morbidity and mortality of asthmatics. To characterize the levels of pest infestation, residents' attitudes toward pest control, and the relationships among cockroaches, mice, cockroach allergen level, asthma and allergy rate in public housing, we interviewed residents from 358 randomly selected apartments in Gary, Indiana and assessed the environmental conditions. Dust samples were collected from 101 apartment kitchen floors to analyze for cockroach allergen (Bla g 1 and Bla g 2) levels. Eighty one percent of the apartments were found infested by cockroaches, mice, ants, spiders, or flies. In the 101 apartments evaluated, 98% of the kitchen dust samples had detectable levels of Bla g 1 allergen (>or=0.4 U/g), 52% had >or=2 U/g, and 33% had >or=8 U/g of Bla g 1. Among the 1,173 residents, 13% and 9% had physician-diagnosed asthma and allergy, respectively. Existence of diagnosed asthmatic was positively correlated with mouse infestations.

Exposure to multiple indoor allergens in US homes and its relationship to asthma

BACKGROUND

The National Survey of Lead and Allergens in Housing was the first population-based study to measure indoor allergen levels in US homes.

OBJECTIVE

We characterized the overall burden to multiple allergens and examined whether increased allergen levels were associated with occupants' asthma status.

METHODS

This cross-sectional study surveyed a nationally representative sample of 831 housing units in 75 different locations throughout the United States. Information was collected by means of questionnaire and environmental assessment. Allergen concentrations in dust samples were assessed by using immunoassays. The following cutoff points were used to define increased allergen levels: 10 microg/g for Der p 1, Der f 1, and Can f 1; 8 microg/g for Fel d 1; 8 U/g for Bla g 1; 1.6 microg/g for mouse urinary protein; and 7 microg/g for Alternaria alternata antigens. Allergen burden was considered high when 4 or more allergens exceeded increased levels in any of the sampling locations.

RESULTS

Exposure to multiple allergens was common in US homes. Of the surveyed homes, 51.5% had at least 6 detectable allergens and 45.8% had at least 3 allergens exceeding increased levels. Race, income, housing type, absence of children, and presence of smokers, pets, cockroaches, rodents, and mold/moisture-related problems were independent predictors of high allergen burden. Among atopic subjects, high allergen burden increased the odds of having asthma symptoms (odds ratio, 1.81; 95% CI, 1.04-3.15).

CONCLUSION

Increased allergen levels in the home are associated with asthma symptoms in allergic individuals.

Longitudinal evaluation of allergen and culturable fungal concentrations in inner-city households

To characterize seasonal variation of three allergens (dust mite, cat, and cockroach) and total culturable fungi and to explore whether residential characteristics were associated with the concentrations of these agents, floor dust was collected from 47 inner-city homes in Minneapolis, Minnesota, over a 1-year period. A longitudinal analysis of allergen and fungal concentrations was carried out using mixed-effect models. Overall, relative humidity was a better predictor of allergen concentrations over time than indoor temperature. Seasonal variation of cat and cockroach allergens was negligible compared with the variability associated with residential characteristics such as race/ethnicity, family income, and the presence of cats. Fungal concentrations showed significant seasonal variation that outweighed the variability associated with residential characteristics. Less than 30% of the dust mite allergen and cockroach allergens concentrations were above limits of detection. Observed cockroach allergen concentrations were higher in Spanish- and Somali-speaking households than in English-speaking households, while English-speaking households had significantly higher cat allergen concentrations compared with the other language groups. The ratios of within-home to between-home variance for total culturable fungi, dust mite, cockroach, and cat allergen concentrations were 2.54, 1.91, 0.55, and 0.24, respectively. This ratio is used to predict the number of repeated measurements of each allergen required to robustly estimate long-term exposure estimates such that exposure misclassification bias is kept within acceptable limits. It is not clear whether repeated measurements of dust mite and cockroach allergens are required for long-term average exposure because of the large fraction of nondetects. It is concluded that a single measurement of cat allergen is a reasonable surrogate for long-term average exposure, since repeated measurements over time were highly correlated. Total culturable fungi will require greater than nine repeated measurements for robust assessment of long-term exposures because of low correlations in fungal measures over time.

Prevalence of indoor allergen exposures among New Orleans children with asthma

Studies of inner-city asthmatic children have shown significant regional variation in dust allergen exposures. The home environment of asthmatic children in the Gulf South region of the USA has not been characterized. This study describes indoor dust allergen levels in the homes of 86 asthmatic children in New Orleans and explores regional variability in dust allergen exposure. Data were used from baseline home visits of children in the New Orleans Healthy Homes Initiative. Interview, visual observation, and environmental dust sampling data of 86 children between 4 and 17 years of age were analyzed. Seventy-seven percent of households had moderate (>2.0-9.9 microg/g) or high (> or =10.0 microg/g) levels of either Der p 1 or Der f 1 dust mite allergen and 56.6% had moderate (>2.0-8.0 U/g) or high (>8.0 U/g) levels of cockroach allergen (Bla g 1). The prevalence of high (>10 microg/g) levels of dog (Can f 1) allergen was 26.5%, and few households (6.0%) had high cat allergen (Fel d 1) levels (>8.0 microg/g). Households with average humidity levels >50% were three times more likely to have elevated dust mite levels (odds ratio = 3.2; 95% confidence interval = 1.1, 9.3; p = 0.03). Home ownership and education level were inversely associated with cockroach and dust mite allergen levels, respectively. Our findings reinforce the evidence of regional variability in dust allergen exposure levels. Asthmatic children living in the Gulf South are exposed to multiple indoor allergen exposures and live in a highly allergenic environment.

Relationship between refraction and allergic conjunctivitis

PURPOSE

External allergens are the main causative factor in the pathogenesis of allergic diseases; however, little is known about internal factors such as the biometrical structure of the eye. We investigated the relationship between refractive error and allergic conjunctivitis in order to reveal possible insights into the pathogenesis in 1015 subjects.

METHODS

The patients were divided into four groups: contact lens wearers with allergic conjunctivitis (n=73), contact lens wearers without allergic conjunctivitis (n=59), non-contact lens wearers with allergic conjunctivitis (n=224), and non-contact lens wearers without allergic conjunctivitis (n=659). The spherical power, cylindrical power, corneal radius, and minimum and maximum corneal refractive powers were measured in all subjects.

RESULTS

In the non-contact lens wearers, the spherical equivalent and spherical power were significantly lower in patients with allergic conjunctivitis than in patients without allergic conjunctivitis (-3.01+/-3.83 D vs-1.36+/-3.08 D, P<0.0001, and -2.64+/-3.63 D vs-1.05+/-2.88 D, P<0.0001, respectively), while there was no significant difference in any of the parameters between the contact lens wearers with and without allergic conjunctivitis.

CONCLUSION

Refractive error may be a risk factor for allergic conjunctivitis.

Efficacy of integrated pest management in reducing cockroach allergen concentrations in urban public housing

The efficacy of residential interventions to reduce cockroach allergens in public housing developments was evaluated over months of follow-up. Repeated measurements were collected from 39 apartments, with longitudinal analyses used to evaluate changes over time. Bla g 1 kitchen concentrations were reduced 71% and bed concentrations 53% (86% and 70% for Bla g 2, respectively) by 6 months post-intervention, after which concentrations began to increase. Apartments with higher concentrations were usually in poorer condition and benefited most from pest management efforts. Intensive interventions can significantly reduce the allergen burden in public housing apartments, but intervention efforts must be sustained.

Mite and pet allergen exposure in hotels in Uberlândia, Midwestern Brazil

Mite allergens are involved in airway sensitization and allergic diseases. We evaluated the exposure to house dust-mite (Der p 1 and Der f 1) and pet (Fel d 1 and Can f 1) allergens in hotels in Uberlândia, Midwestern Brazil. A total of 140 dust samples were collected from bedding (n = 98) and carpet (n = 42) of bedrooms in 20 hotels enrolled for this study. Geometric mean (GM) levels of Der f 1 (11.30 microg/g of dust; 95% CI: 8.34-15.30 microg/g) were significantly higher than Der p 1 (0.15 microg/g of dust; 95% CI: 0.13-0.18 microg/g) in bedding dust samples (P < 0.001), regardless of the hotel classes. Der f 1 levels were significantly higher in bedding (11.30 microg/g of dust; 95% CI: 8.34-15.30 microg/g) than carpet (6.32 microg/g of dust; 95% CI: 4.31-9.26 microg/g) dust samples (P < 0.05). High levels of Der f 1 (>10 microg/g of dust) were found in 58%, 76%, and 69% of dust samples from Simple, Economical, and Tourist/Superior hotels, respectively, while GM levels of Fel d 1 (0.11 microg/g of dust; 95% CI: 0.09-0.14 microg/g) and Can f 1 (0.30 microg/g of dust; 95% CI: 0.20-0.44 microg/g) were relatively low. These results indicate that Der f 1 is the predominant allergen in hotels in Uberlândia, especially in bedding dust samples, regardless of the hotel classes and could represent an important risk factor for exacerbation of allergic symptoms in previously mite-sensitized guests.

PRACTICAL IMPLICATIONS

Mites and pets are important sources of indoor allergens. Most people spend the greatest part of their time indoors. Hotels can constitute an important allergen reservoir of the indoor environment and could represent an important risk for exacerbation of allergic symptoms in previously sensitized guests. Thus, hotels should also be included for planning indoor allergen avoidance as part of a global management strategy, especially in patients with respiratory allergy.

Dust mites: using data from an intervention study to suggest future research needs and directions

Dermatophagoides farinae (Der f 1; referred as Der f hereafter) and D. pteronyssinus (Der p 1; referred as Der p hereafter) are common allergy-causing mites found in homes worldwide. Mites are more prevalent in humid climates, but are rare or absent in drier climates. Levels of dust mite sensitivity have been reported between 48% and 63% for asthmatic children. Dose-response relations between levels of dust-mite exposure and sensitivity have been reported; yet, relatively high levels of dust mite sensitivity (50%-60%) have been found in populations exposed to concentrations below the proposed cut-point sensitization concentration of 2 microg dust mite per gram of dust. A meta-analysis of 49 trials involving 2733 patients found that interventions for dust mite-control did not result in any clinical benefit to mite-sensitive asthmatics. We assessed the impact of replacing old mattresses with dust-mite resistant mattresses on dust-mite levels, and to a more limited extent, on health outcomes. Replacement mattresses were provided to 44 asthmatic children residing in public housing in inner city Boston, Massachusetts. At baseline, we found concentrations to exceed the cut point of 2 microg g(-1) in only 9% of beds for Der p and 16% for Der f. Only 7% of beds for Der f and 5% for Der p exceeded 10 microg g(-1). Dust-mite allergy levels were high in these asthmatic children (54% for Der f and 62% for Der p) despite low baseline mattress levels. Our intervention reduced Der p (p = 0.026) and Der f (p < 0.001) below their low starting levels. Investigations are needed that (1) evaluate the reduction of dust-mite levels below the suggested cutpoints for sensitization and exacerbation; (2) assess the impact of reduction of multiple antigens; (3) assess exposure to dust mites outside of the home; and (4) test bundled interventions.

Exposure to dust mite allergen and endotoxin in early life and asthma and atopy in childhood

BACKGROUND

There has been no longitudinal study of the relation between concurrent exposure to dust mite allergen and endotoxin in early life and asthma and atopy at school age.

OBJECTIVES

To examine the relation between exposure to dust mite allergen and endotoxin at age 2 to 3 months and asthma, wheeze, and atopy in high-risk children.

METHODS

Birth cohort study of 440 children with parental history of atopy in the Boston metropolitan area.

RESULTS

In multivariate analyses, early exposure to high levels of dust mite allergen (> or =10 microg/g) was associated with increased risks of asthma at age 7 years (odds ratio [OR], 3.0; 95% CI, 1.1-7.9) and late-onset wheeze (OR, 5.0; 95% CI, 1.5-16.4). Exposure to endotoxin levels above the lowest quartile at age 2 to 3 months was associated with reduced odds of atopy at school age (OR, 0.5; 95% CI, 0.2-0.9). In contrast with its inverse association with atopy, endotoxin exposure in early life was associated with an increased risk of any wheeze between ages 1 and 7 years that did not change significantly with time (hazard ratio for each quartile increment in endotoxin levels, 1.23; 95% CI, 1.07-1.43).

CONCLUSION

Among children at risk of atopy, early exposure to high levels of dust mite allergen is associated with increased risks of asthma and late-onset wheeze. In these children, endotoxin exposure is associated with a reduced risk of atopy but an increased risk of wheeze.

CLINICAL IMPLICATIONS

Early endotoxin exposure may be a protective factor against atopy but a risk factor for wheeze in high-risk children.

Determinants of allergen concentrations in apartments of asthmatic children living in public housing

There is growing evidence linking poor housing conditions and respiratory diseases, including asthma. The association between housing conditions and asthma in the inner city has been attributed in part to cockroach and mouse infestation and the resulting allergen exposures. Multiple social and behavioral factors can influence environmental exposures and health conditions, necessitating a thorough examination of such factors. As part of the Healthy Public Housing Initiative, we evaluated the association between physical and household characteristics and pest-related allergen levels in three public housing developments in Boston, MA. We detected cockroach allergens (Bla g 1 and Bla g 2) in bedroom air, bed, and especially high concentrations in kitchen samples. In multivariate Tobit regressions controlling for development and season, clutter and lack of cleanliness in the apartment were associated with a tenfold increase in Bla g 1 concentration in the air, a sevenfold increase in Bla g 1 and an eightfold increase in Bla g 2 concentrations in the bed, and an 11-fold increase in Bla g 2 in the kitchen (p<0.05 for all). Holes in the wall/ceiling were associated with a six- to 11-fold increase in kitchen cockroach allergen concentrations (p<0.05). Occupancy in an apartment unit of 2 years or more was also associated with increased cockroach allergen concentrations. In contrast, there were low concentrations of mouse urinary protein in this population. In conclusion, these results suggest that interventions in these homes should focus on reducing cockroach allergen concentrations and that building-wide interventions should be supplemented with targeted efforts focused on high-risk units.

High prevalence of skin test positivity in severe or difficult-to-treat asthma

BACKGROUND

Skin tests are considered the gold standard for detecting allergen-specific immunoglobulin E (IgE) in the clinical setting and are an important tool for diagnosing and managing allergic asthma.

OBJECTIVE

To assess the prevalence of skin testing in patients > or = 12 years enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study.

METHODS

Patients were asked whether they had ever been skin tested and, if so, they were asked to provide the test results. Clinical characteristics were used to compare positive (ST+), negative (ST-), and skin test not done (STND) patients.

RESULTS

Of 2,985 patients eligible, 85.8% recalled being skin tested. Of those tested, 93.5% were positive (allergist 95.7%, pulmonologist 87.3%). A high proportion of Whites (93.5%) and non-Whites (94.0%) were ST+; however, more non-Whites had never been skin tested (21.7% vs. 12.3%, respectively; p < 0.0001). Total serum IgE was 104.6 IU/mL for ST+ patients, 87.1 IU/mL for STND patients, and 32.4 IU/mL for ST- patients. Age at asthma onset, duration of asthma, and the prevalence of atopic disorders and asthma triggers differentiated the ST+ from the ST- group. Disease severity appeared similar between the two groups. In general, values for STND patients were closer to the ST+ group, suggesting that those not tested would have been ST+ if administered a test.

CONCLUSIONS

The prevalence of ST+ patients was high in allergy and pulmonology practices, and in White and non-White patients. These data support the utility of a more complete allergic evaluation in severe asthmatics. Skin testing appears associated with disease pathophysiologies in asthma.

Predictors of cord blood IgE levels in children at risk for asthma and atopy

BACKGROUND

Increased cord blood IgE levels, in conjunction with a family history of atopy, are associated with the development of allergic diseases in children. However, little is known about predictors of cord blood IgE levels.

OBJECTIVE

Our objective was to identify predictors of cord blood IgE levels among infants at increased risk of atopy.

METHODS

Cord blood IgE levels were measured in 874 infants who were screened for participation in a birth cohort. Questionnaires were administered after birth of the infant, and maternal and cord blood was obtained for measurement of IgE levels. Logistic and tobit regression models were used to study the association between perinatal factors and cord blood IgE levels.

RESULTS

In multivariable models infant male sex, increased maternal total IgE level, maternal allergen sensitization, Hispanic ethnicity, and residence in low-income areas were associated with detectable or increased cord blood IgE levels, whereas increasing maternal age was associated with undetectable or lower cord blood IgE levels. Although maternal smoking during pregnancy was positively associated with cord blood IgE levels in univariable models, the effect did not persist after adjusting for potential confounders.

CONCLUSION

Maternal allergen sensitization, markers of socioeconomic disadvantage and race/ethnicity, maternal age, and infant sex might influence fetal production of IgE. We found no association of maternal parity, mode of delivery, gestational age, or season of birth with cord blood IgE levels.

CLINICAL IMPLICATIONS

The identification of these definable familial and environmental factors that predict cord blood IgE levels might help in the early detection of infants at risk for atopic disorders.

Asthma in Hispanics in the United States

The Hispanic population in the United States is diverse in many respects. Although there is marked variation in the prevalence, morbidity, and mortality of asthma among Hispanic subgroups in the United States, these differences are poorly understood. Future stu-dies of asthma should include large samples of Hispanic subgroups that are well characterized in terms of self-reported ethnicity, country of origin, place of birth, area of residence, and indicators of socioeconomic status. Because a significant proportion of Hispanics live in poverty, public health interventions aimed at improving access to health care and housing conditions would have a major impact on reducing asthma morbidity among Hispanics in the United States.

Ancestry-environment interactions and asthma risk among Puerto Ricans

BACKGROUND

Puerto Ricans, an admixed population of African, European, and Native American ancestries, have the highest asthma prevalence, morbidity, and mortality rates of any United States' population. Although socioeconomic status (SES) is negatively correlated with asthma incidence in most populations, no such relationship has been identified among Puerto Ricans. We hypothesized that, in this admixed population, the association between SES and asthma may interact with genetic ancestry.

METHODS

We analyzed 135 Puerto Rican subjects with asthma and 156 control subjects recruited from six different recruitment centers in Puerto Rico. Individual ancestry for each subject was estimated using 44 ancestry informative markers. SES was assigned using the census tracts' median family income. Analyses of SES were based on the SES of the clinic site from which the subjects were recruited and on a subset of individuals on whom home address-based SES was available.

RESULTS

In the two (independent) analyses, we found a significant interaction between SES, ancestry, and asthma disease status. At lower SES, European ancestry was associated with increased risk of asthma, whereas African ancestry was associated with decreased risk. The opposite was true for their higher SES counterparts.

CONCLUSIONS

The observed interaction may help to explain the unique pattern of risk for asthma in Puerto Ricans and the lack of association with SES observed in previous studies when not accounting for varying proportions of ancestry.

Indoor environmental exposures among children with asthma seen in an urban emergency department

BACKGROUND

Current guidelines for asthma management emphasize the control of environmental irritants and allergens within the home. Understanding the prevalence of indoor home exposures within such a population may be important for any emergency department (ED) program that seeks to improve the quality of its asthma care and patient education.

OBJECTIVE

We sought to determine the prevalence of indoor home exposures in a cohort of children with moderate to severe asthma who were treated in an urban pediatric ED and to correlate these exposures with household income, prior asthma morbidity, health care utilization, and quality of life (QoL).

METHODS

We enrolled a cohort of children with chronic asthma who were 12 months through 17 years of age and who had at least one other unscheduled visit for asthma within the previous 6 months. Trained research assistants interviewed the children's parent or guardian regarding the prevalence of home exposures to environmental tobacco smoke (ETS) and common allergens. In addition, data were collected on each patient's prior asthma history, morbidity, health care utilization, medication use, and QoL.

RESULTS

Of the 488 eligible children enrolled, 60.0% were <6 years of age, 63.9% were male, 85.9% were black, 68.4% were publicly insured, and 51.8% had >3 ED visits in the previous 12 months. Home exposure to ETS and potential allergens was high. Exposure to cockroach allergen was significantly associated with household income. Coexistence of exposures was common: significantly more patients reporting ETS exposure also reported exposure to cockroach allergen and mold than those not reporting ETS exposure. Poorer QoL was significantly associated with cockroach exposure, although this effect was limited to those also exposed to ETS. Higher rates of unscheduled health care utilization and persistent asthma symptoms were not associated with exposures.

CONCLUSION

Additional investigation is necessary to clarify the role of exposure-avoidance measures as a component of ED-based interventions for asthma care.

National prevalence and exposure risk for cockroach allergen in U.S. households

We characterized the prevalence of cockroach allergen exposure in a nationally representative sample of U.S. homes and assessed risk factors for elevated concentrations.

DESIGN

We used data from the National Survey of Lead and Allergens in Housing, a population-based cross-sectional survey.

PARTICIPANTS

Participants were residents of 831 U.S. homes in the survey.

EVALUATIONS/MEASUREMENTS

We analyzed allergen, questionnaire, and observational data of 831 U.S. homes.

RESULTS

Cockroach allergen (Bla g 1) concentrations exceed 2.0 U/g, a level associated with allergic sensitization, in 11% of U.S. living room floors and 13% of kitchen floors. Concentrations exceed 8.0 U/g, a level associated with asthma morbidity, in 3% of living room floors and 10% of kitchen floors. Elevated concentrations were observed in high-rise apartments, urban settings, pre-1940 constructions, and households with incomes < $20,000. Odds of having concentrations > 8.0 U/g were greatest when roach problems were reported or observed and increased with the number of cockroaches observed and with indications of recent cockroach activity.

CONCLUSIONS

Household cockroach allergen exposure is characterized in a nationally representative context. The allergen is prevalent in many settings, at levels that may contribute to allergic sensitization and asthma morbidity.

RELEVANCE TO CLINICAL OR PROFESSIONAL PRACTICE

Likelihood of exposure can be assessed by consideration of demographic and household determinants.

Self-reported moisture or mildew in the homes of Head Start children with asthma is associated with greater asthma morbidity

This study used results from a cross-sectional survey of parents of 3- to 5-year-old children with asthma to assess the frequency of self-reported home environmental conditions that could contribute to worsening asthma and examined the relationship between these factors and the child's asthma morbidity. Participants were 149 parents drawn from the two largest agencies that provide subsidized preschool childcare services in East and Central Harlem, inner-city communities with high prevalence of asthma. The sample represented 77% of eligibles determined by a validated case-identification instrument. Data were collected on demographics, symptoms, medication use, Emergency Department visits and hospitalization, and environmental conditions in the home. One or more of these home environmental conditions were reported by 92% of participants. Controlling for other environmental conditions and demographics, associations were found between self-reported presence of moisture or mildew on ceilings, walls, or windows and higher frequency of hospitalizations for breathing-related problems (OR = 3.31; 95% CI 1.62-6.75), frequent episodes of wheezing (OR = 3.25; 95% CI 1.8-6.0), and higher frequency of night symptoms due to asthma (OR = 2.19; 95% CI 1.4-3.41). Having a carpet or rug in the child's bedroom or the living room was also associated with hospitalizations (OR = 3.23; 95% CI 1.53-6.8), and male gender was marginally associated with the frequency of night symptoms (OR = 1.51; 95% CI .95-2.4). Asthma is prevalent in the Head Start population, and exposure to home environmental conditions that may worsen asthma is common in the socially disadvantaged populations served by Head Start programs.

Association of housing disrepair indicators with cockroach and rodent infestations in a cohort of pregnant Latina women and their children

Health burdens associated with poor housing and indoor pest infestations are likely to affect young children in particular, who spend most of their time indoors at home. We completed environmental assessments in 644 homes of pregnant Latina women and their children living in the Salinas Valley, California. High residential densities were common, with 39% of homes housing > 1.5 persons per room. Housing disrepair was also common: 58% of homes had peeling paint, 43% had mold, 25% had water damage, and 11% had rotting wood. Evidence of cockroaches and rodents was present in 60% and 32% of homes, respectively. Compared with representative national survey data from the U.S. Department of Housing and Urban Development, homes in our sample were more likely to have rodents, peeling paint, leaks under sinks, and much higher residential densities. The odds of rodent infestations in homes increased in the presence of peeling paint [odds ratio (OR) 2.1; 95% confidence interval (CI), 1.5-3.1], water damage (OR 1.9; 95% CI, 1.2-2.7), and mold (OR 1.5; 95% CI, 1.0-2.1). The odds of cockroach infestation increased in the presence of peeling paint (OR 3.8; 95% CI, 2.7-5.6), water damage (OR 1.9; 95% CI, 1.2-2.9), or high residential density (OR 2.1; 95% CI, 1.2-3.8). Homes that were less clean than average were more prone to both types of infestations. Pesticides were stored or used in 51% of households, partly to control roach and rodent infestations. These data indicate that adverse housing conditions are common in this community and increase the likelihood of pest infestations and home pesticide use. Interventions to improve housing and promote children's health and safety in this population are needed.

Indoor air quality in two urban elementary schools--measurements of airborne fungi, carpet allergens, CO2, temperature, and relative humidity

This article presents measurements of biological contaminants in two elementary schools that serve inner city minority populations. One of the schools is an older building; the other is newer and was designed to minimize indoor air quality problems. Measurements were obtained for airborne fungi, carpet loadings of dust mite allergens, cockroach allergens, cat allergens, and carpet fungi. Carbon dioxide concentrations, temperature, and relative humidity were also measured. Each of these measurements was made in five classrooms in each school over three seasons--fall, winter, and spring. We compared the indoor environments at the two schools and examined the variability in measured parameters between and within schools and across seasons. A fixed-effects, nested analysis was performed to determine the effect of school, season, and room-within-school, as well as CO2, temperature and relative humidity. The levels of all measured parameters were comparable for the two schools. Carpet culturable fungal concentrations and cat allergen levels in the newer school started and remained higher than in the older school over the study period. Cockroach allergen levels in some areas were very high in the newer school and declined over the study period to levels lower than the older school. Dust mite allergen and culturable fungal concentrations in both schools were relatively low compared with benchmark values. The daily averages for temperature and relative humidity frequently did not meet ASHRAE guidelines in either school, which suggests that proper HVAC and general building operation and maintenance procedures are at least as important as proper design and construction for adequate indoor air quality. The results show that for fungi and cat allergens, the school environment can be an important exposure source for children.

Asthma in Hispanics

Hispanic individuals trace their ancestry to countries that were previously under Spanish rule, including Mexico, large parts of Central and South America, and some Caribbean islands. Most--but not all--Hispanics have variable proportions of European, Amerindian, and African ancestry. Hispanics are diverse with regard to many factors, including racial ancestry, country of origin, area of residence, socioeconomic status, education, and access to health care. Recent findings suggest that there is marked variation in the prevalence, morbidity, and mortality of asthma in Hispanics in the United States and in Hispanic America. The reasons for differences in asthma and asthma morbidity among and within Hispanic subgroups are poorly understood but are likely due to the interaction between yet-unidentified genetic variants and other factors, including environmental tobacco smoke exposure, obesity, allergen exposure, and availability of health care. Barriers to optimal management of asthma in Hispanics in the United States and in Hispanic America include inadequate access to health care, suboptimal use of antiinflammatory medications, and lack of reference values for spirometric measures of lung function in many subgroups (e.g., Puerto Ricans). Future studies of asthma in Hispanics should include large samples of subgroups that are well characterized with regard to self-reported ethnicity, country of origin, place of birth, area of residence, and indicators of socioeconomic status. Because Hispanics are disproportionately represented among the poor in the United States, implementation of adequate access to health care and social reforms (e.g., improving housing conditions) would likely have a major impact on reducing asthma morbidity in this population.

Allergic rhinoconjunctivitis: epidemiology

Allergic rhinoconjunctivitis has been studied much less frequently than asthma using epidemiologic approaches. Population-based studies are difficult to conduct because of misclassification arising from the reliance on self-reported questionnaires that use terms such as allergic rhinitis or hay fever to establish the diagnosis. In addition, many epidemiologic studies focus on diagnostic skin testing or allergen-specific IgE antibodies (RASTs) as an objective outcome to assess for hay fever. These techniques are helpful but not perfect measures for predicting hay fever outcomes in epidemiologic studies. It is generally accepted, however, that allergic rhinoconjunctivitis is one of the most common of chronic diseases and is the most common atopic disorder. This article reviews the definition of allergic rhinoconjunctivitis, the epidemiology of this disorder from infancy into adulthood, and environmental risk factors for development of sensitization to certain allergens.

Does socio-demographic status influence the effect of pollens and molds on hospitalization for asthma? Results from a time-series study in 10 Canadian cities

PURPOSE

Social status influences asthma morbidity but the mechanisms are not well understood. To determine if sociodemographics influence the susceptibility to ambient aeroallergens, we determined the association between daily hospitalizations for asthma and daily concentrations of ambient pollens and molds in 10 large Canadian cities.

METHODS

Daily time-series analyses were performed and results were adjusted for day of the week, temperature, barometric pressure, relative humidity, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Results were then stratified by age, gender, and neighborhood family education and income.

RESULTS

There appeared to be age and gender interactions in the relation between aeroallergens and asthma. An increase in basidiomycetes equivalent to its mean value, about 300/m3, increased asthma admissions for younger males (under 13 years of age) by 9.3% (95% CI, 4.8%, 13.8%) vs. 4.2% (95% CI, - 0.1%, 8.5%) for older males. The reverse was true among females with increased effect in the older age group: 2.3% (95% CI, 1.2%, 5.8%) in those under 13 years vs. 7.1% (95% CI, 4.1%, 10.1%) for older females. Associations were seen between aeroallergens and asthma hospitalization in the lowest but not the highest education group.

CONCLUSIONS

Our results suggest that younger males and those within less educated families may be more vulnerable to aeroallergens as reflected by hospitalization for asthma.

Variation in total and specific IgE: effects of ethnicity and socioeconomic status

BACKGROUND

Asthma is common in minority and disadvantaged populations, whereas atopic disorders other than asthma appear to be less prevalent. It is unclear whether the same holds true for objective markers of sensitization.

OBJECTIVE

To determine the association of asthma, atopic disorders, and specific sensitization with race and socioeconomic factors.

METHODS

We analyzed total and specific IgE among 882 women (577 white, 169 black, and 136 Hispanic) who delivered a child at a large tertiary hospital in Boston, Mass, and who were screened for participation in a family and birth cohort study. Race/ethnicity and other characteristics were obtained from screening questionnaires. Addresses were geocoded, and 3 census-based geographic area socioeconomic variables were derived from block group information from the 1990 US Census.

RESULTS

Black and Hispanic women were more likely to come from areas with low socioeconomic indicators and were more likely to have asthma than white women. However, these women were less likely to have hay fever and eczema than their white counterparts. Compared with white women, black women had higher mean total IgE levels; had greater proportions of sensitization to indoor, outdoor, and fungal allergens; and were more than twice as likely to be sensitized to > or =3 aeroallergens.

CONCLUSION

The racial/ethnic disparities in atopic disorders may represent either underdiagnosis or underreporting and suggest that allergy testing may be underused in some populations. Differences in total IgE levels and specific allergen sensitization are likely a result of the complex interplay between exposures associated with socioeconomic disadvantage.

Implementing a pediatric asthma program: enabling self-care management through education

This article provides an overview of asthma prevalence among children, presents a summary of asthma triggers based on past research, outlines the essential components of a pediatric asthma home care model implemented by a large urban home health agency, and details the types of clinical documentation needed for care plan development and monitoring of asthma in the home.

The social and economic consequences of childhood asthma across the lifecourse: a systematic review

BACKGROUND

Asthma prevalence rates are high, and may be increasing in the Western world, particularly among children. The aim of this study was to evaluate the longer-term social and economic consequences of having asthma as a child and to determine whether adverse consequences are more severe for poorer children.

METHODS

Results from published and unpublished, quantitative and qualitative studies were synthesized narratively to examine the impact of childhood-onset asthma on school attendance, academic achievement and employment in adulthood. The question of whether the impact differed for different social groups was also examined.

FINDINGS

Twenty-nine good quality studies were identified, including in total 12 183 children with asthma or wheeze. Compared with asymptomatic children, those with asthma missed more days of school (additional absence as a result of asthma ranged from 2.1 to 14.8 days). Studies of academic achievement found that children with asthma performed as well as their healthy peers. The existing evidence on labour market performance is sparse, but there is an indication that people with asthma during childhood experience disadvantage in later employment. In an examination of consequences by social position, children with asthma from deprived areas were more likely to miss school than their more affluent peers, and minority ethnic children were also more likely to have poor school attendance. The only qualitative study suggested that children with asthma strove to participate fully in every aspect of their daily lives.

INTERPRETATION

Although asthma limits children's daily activities and affects their social activities, this research synthesis found little evidence of major, adverse long-term social and economic consequences in studies reviewed. Further longitudinal research using comparison groups is needed to fill key gaps in the existing evidence base.

Evaluating the needs of children with asthma in home care: the vital role of nurses as caregivers and educators

To date, few evaluations have examined issues specific to children's asthma management in their homes. This study examined the characteristics, risk factors, and needs of children with asthma, and the impact of home health nurses on improving parents'/family caregivers' knowledge about asthma triggers and management. The medical records of children, </=19 years, residing in New York City, who were admitted to home care with asthma in 1999 (n = 1,007) were reviewed retrospectively to collect a wide range of data. The majority of children with asthma in home care were </=5 years, male, racial/ethnic minorities, and hospital referred. Approximately one in four children with asthma suffered from additional comorbidities. Home environmental triggers included dust/dust mites, animal dander, mold, perfumes/detergents, and cigarette smoke. Notable psychosocial triggers were family tensions, physical activity, anxiety/stress, and friends/peer pressure. Most parents/family caregivers had inadequate knowledge about recognition of asthma attacks and its triggers and management. Discharge assessments suggested that home health nurses can help improve caregivers' knowledge about asthma management. Children with asthma in home care have diverse needs, receive few nurse home visits, and have parents/family caregivers in need of more intensive education on asthma symptom recognition and management.

Parental mental health, childhood psychiatric disorders, and asthma attacks in island Puerto Rican youth

OBJECTIVE

Previous research documents an association of poor parental mental health with asthma in children. This study aims to determine whether the associations between parental mental health problems and childhood asthma attacks persist after controlling for childhood anxiety and depression and other confounding factors.

DESIGN/METHODS

A community household sample of youth ages 4 to 17 years and their primary caregivers from the US Commonwealth of Puerto Rico was studied to determine the associations between parental mental health and childhood asthma attacks. Regression models that predicted asthma attacks in youth controlled for parental mental health problems, childhood anxiety and depression, zone of residence, and parents' age, education, and perception of poverty.

RESULTS

After adjusting for children's depressive and anxiety disorders as well as other important confounders, associations between parental depression, suicide attempts, ataque de nervios, and history of mental health treatment and asthma attacks in offspring, by parental report, persisted. Additionally, the frequency of parental mental health problems was associated with children's asthma attacks.

CONCLUSION

Parents with mental health problems were more likely to report histories of asthma attacks in their children compared with parents without mental health problems in Puerto Rico. These associations were not attributable to internalizing disorders in youth but persisted independent of childhood psychopathology and other confounding factors. Clinicians and researchers should recognize the relations between poor parental mental health and childhood asthma and explore the potential role of family psychosocial and behavioral factors related to the manifestation of the disease.

The influence of air conditioning, humidity, temperature and other household characteristics on mite allergen concentrations in the northeastern United States

BACKGROUND

Information about the influence of housing and occupant characteristics on mite allergen concentrations is crucial to determine which methods could be used to decrease exposure of susceptible subjects.

OBJECTIVES

To identify housing and occupant characteristics that are associated with mite allergen concentrations in house dust collected from living rooms and mattresses.

METHODS

We collected dust samples from 750 homes in the northeastern US. The influence of various characteristics on concentrations of mite allergens (Der p 1 and Der f 1) was studied using multiple linear regression analysis.

RESULTS

Some characteristics, like absence of air conditioners, the presence of mold or mildew, and a lower temperature were consistently associated with higher concentrations of both mite allergens in dust from all sampling locations. However, none of these factors changed Der p 1 or Der f 1 concentrations by more than a factor of 2. People of white ethnic background had roughly two times higher mite allergen concentrations, while family income, family size, and education level only marginally influenced mite allergen concentrations.

CONCLUSIONS

Various housing characteristics have some influence on mite allergen concentrations, and could possibly be used to decrease exposure of susceptible subjects. However, only a limited percentage of the variation in mite allergen concentrations was explained by these characteristics.

Prediction of residential pet and cockroach allergen levels using questionnaire information

We assessed the accuracy of questionnaire reports of cat and dog ownership and presence of cockroaches in predicting measured allergen concentrations in house dust. We collected dust samples in the homes of 932 newborns living in New England. Dust samples were taken from the main living area and the infant's bedding. Allergen content of house dust was measured by enzyme-linked immunosorbent assays (ELISA) and related to questionnaire information on past and current cat and dog ownership and presence of cockroaches. Allergen levels were dichotomized using the limit of detection and the following cut points: 1.0 microg/g and 8.0 microg/g for cat, 2.0 microg/g and 10.0 microg/g for dog, and 2 U/g and 8 U/g for cockroach allergen. For the upper cut point, both specificity and sensitivity of questionnaire-reported cat and dog ownership and presence of cockroaches were high. For the limit of detection and lower cut point, specificity was high (> 80%), whereas sensitivity was low, particularly for current cat and dog ownership (21-60%). Taking pet ownership during the preceding 2 years into account increased the sensitivity by 10%, but it remained relatively poor. In conclusion, questionnaire-reported pet ownership and presence of cockroaches predicts allergen levels above the upper cut point but is a relatively poor measure of allergen exposure above the limit of detection and the lower cut point. Knowledge of past pet ownership can improve pet allergen exposure assessment by means of questionnaire. However, for epidemiologic purposes, measured concentrations of allergens are necessary.

Relationship between socioeconomic status and asthma: a longitudinal cohort study

BACKGROUND

There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors.

METHODS

We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models.

RESULTS

No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports.

CONCLUSIONS

Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding.

Ethnicity and skin test reactivity to aeroallergens among asthmatic children in Connecticut

OBJECTIVES

To examine the relationship between ethnicity and sensitization to allergens among children with asthma living in urban and suburban areas of Connecticut.

STUDY DESIGN

Cross-sectional study.

STUDY POPULATION

A total of 791 children with mild-to-severe asthma who received their medical care in the city of Hartford.

RESULTS

Puerto Rican ethnicity was associated with skin test reactivity (STR) to cockroach (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.7 to 6.4), STR to dust mite (OR, 1.7; 95% CI, 1.2 to 2.4), STR to mixed grass pollen (OR, 1.7; 95% CI, 1.1 to 2.7), and STR to mugwort/sage (OR, 2.4; 95% CI, 1.4 to 4.1). African-American ethnicity was associated with STR to four outdoor allergens (ie, mixed tree pollen [OR, 2.3; 95% CI, 1.3 to 3.9], mixed grass pollen [OR, 2.7; 95% CI, 1.6 to 4.8], mugwort/sage [OR, 3.1; 95% CI, 1.6 to 6.0], and ragweed [OR, 2.1; 95% CI, 1.2 to 3.8]). Among all children, STR to outdoor allergens was strongly associated with the extent of allergen sensitization. As an example, children sensitized to mixed grass pollen had 34.7 times higher odds of having at least four positive skin tests to other allergens than nonsensitized children (95% CI for OR, 15.6 to 77.0).

CONCLUSIONS

Our findings suggest that Puerto Rican ethnicity is associated with an increased risk of sensitization to indoor and outdoor allergens among children with asthma, and that allergy skin testing should be performed more often as part of the management of asthma in African-American children and in Puerto Rican children in the United States.

Elevated asthma and indoor environmental exposures among Puerto Rican children of East Harlem

OBJECTIVE

East Harlem in New York City, a community with a large Puerto Rican population, has among the highest rates of asthma hospitalizations and mortality in the United States, but it is not known if the high rates are related to the ethnic composition, environmental or community factors, or if the higher rates reflect differentials in access to appropriate asthma care. A survey was conducted to: (a) estimate the prevalence of current asthma by ethnicity among school-age children, (b) assess indoor environmental risk factors for childhood asthma, and (c) assess health care utilization and school absences associated with childhood asthma.

DESIGN

A cross-sectional survey of parents of elementary school children, using a self-administered questionnaire with a 12-month recall on asthma symptoms based on the International Study of Asthma and Allergies in Childhood.

SETTING

Two public elementary schools in East Harlem (n = 1615 students 5-12 years of age).

RESULTS

Among the 1319 respondents (response rate 82%), the prevalence for current asthma (doctor or nurse diagnosis at any time plus wheezing in the past 12 months) was 23%. Puerto Rican children had a prevalence of 35%. Puerto Rican children reported both higher symptomatic frequencies and higher rates of physician diagnosis. Living in a home where cockroaches, rats, or mice had been seen in the past month and with a dust-enhancing heating system also was associated with having asthma, regardless of ethnicity. Compared with other children with asthma, Puerto Rican children with asthma were more likely to live in homes where rats or mice had been seen in the past month. Regardless of ethnicity, children with more frequent, more severe asthma symptoms and incomplete asthma action plans were more likely to have visited the emergency department in the past year. Puerto Rican children were more likely to have missed school because of their asthma in the past year.

CONCLUSION

The prevalence of current asthma was significantly higher among Puerto Ricans, who had higher symptomatic frequency and greater diagnosis rates. Although all children with asthma in the East Harlem study appear to be sensitive to selected indoor environmental risk factors, only Puerto Rican children with asthma appear to be sensitive to the presence of rodents in their buildings. However, their higher school absence rate suggests problems with routine asthma management that could be addressed by improved medical management, programs to help parents manage their children's asthma, or school staff assistance with medications.

Cockroach allergen exposure and sensitization in suburban middle-class children with asthma

BACKGROUND

Exposure to cockroach allergen is prevalent in inner-city homes and is associated with an increased risk of cockroach sensitization.

OBJECTIVE

We sought to determine the prevalence of cockroach allergen exposure in suburban middle-class homes and to study its relationship to cockroach sensitization.

METHODS

Children with asthma, 6 to 17 years of age, were recruited from 3 pediatric practices located in counties surrounding Baltimore city and from 1 practice located within Baltimore city limits. Participants underwent skin prick testing and completed baseline questionnaires. In addition, their homes were inspected, and settled dust samples were collected for allergen analysis.

RESULTS

Forty-one percent of the total study population (n = 339) had kitchen Bla g 1 levels of greater than 1 U/g. Forty-nine percent were white, 53% had annual incomes of greater than US dollars 50000, and 48% of mothers had college degrees. Seventy-seven percent of the study population resided in a suburban or rural location, and 30% of kitchens in these homes had Bla g 1 levels of greater than 1 U/g. Among the suburban-rural subgroup, 21% were sensitized to cockroach compared with 35% of the city group. In multivariate analysis, exposure to kitchen Bla g 1 levels of greater than 1 U/g was associated with cockroach sensitization for both the total study population (odds ratio, 2.29; 95% CI, 1.28-4.11) and the suburban-rural subgroup (odds ratio, 2.37; 95% CI, 1.23-4.57).

CONCLUSIONS

Cockroach allergen exposure might be more common in suburban middle-class homes of asthmatic children than previously thought. Moreover, the data suggest that low-level cockroach exposure is a risk factor for cockroach sensitization.

Comparison of multiple environmental factors for asthmatic children in public housing

Nine families of a public housing development in Boston were enrolled in a pilot asthma intervention program designed to gather dense environmental data and generate hypotheses about the relative importance of different contaminants and the viability of interventions. Despite formidable challenges working with this inner-city population, the project team succeeded in gaining active support for the project by forming a partnership with a community-based organization and by building positive relationships between the field team and the residents. Families were provided with physical interventions such as air filters, industrial cleaning and mattress covers to each apartment. Indoor temperature was high and relative humidity low during winter. Insulation of exposed steam pipes did not lower temperature. Cockroach, mouse and pet antigen levels were variable and frequently high in settled dust. Viable fungal spore levels were variable and high in some apartments. Dust-mite allergen levels were below the level of concern. Industrial cleaning led to transient reduction in mouse and cockroach antigen burden. Mattress and pillow covers lowered dust-mite antigen in bedrooms, but not living rooms. Nitrogen dioxide (NO2) levels exceeded ambient concentrations due to use of gas stoves and concentrations of particulate matter with aerodynamic diameter <2.5 microm (PM2.5) were above ambient levels because of smoking. Air filtering systems did not reduce PM levels. Several volatile organic compounds (VOCs) were above adverse risk concentrations. We hypothesize that our findings are consistent with a multifactorial model for exacerbation of asthma in this population and that no single problem dominates.

The importance of population susceptibility for air pollution risk assessment: a case study of power plants near Washington, DC

In evaluating risks from air pollution, health impact assessments often focus on the magnitude of the impacts without explicitly considering the distribution of impacts across subpopulations. In this study, we constructed a model to estimate the magnitude and distribution of health benefits associated with emission controls at five older power plants in the Washington, DC, area. We used the CALPUFF atmospheric dispersion model to determine the primary and secondary fine-particulate-matter (< 2.5 micro m in aerodynamic diameter) concentration reductions associated with the hypothetical application of "Best Available Control Technology" to the selected power plants. We combined these concentration reductions with concentration-response functions for mortality and selected morbidity outcomes, using a conventional approach as well as considering susceptible subpopulations. Incorporating susceptibility had a minimal effect on total benefits, with central estimates of approximately 240 fewer premature deaths, 60 fewer cardiovascular hospital admissions (CHA), and 160 fewer pediatric asthma emergency room visits (ERV) per year. However, because individuals with lower education appear to have both higher background mortality rates and higher relative risks for air-pollution-related mortality, stratifying by educational attainment implies that 51% of the mortality benefits accrue among the 25% of the population with less than high school education. Similarly, diabetics and African Americans bear disproportionate shares of the CHA and ERV benefits, respectively. Although our ability to characterize subpopulations is constrained by the available information, our analysis demonstrates that incorporation of susceptibility information significantly affects demographic and geographic patterns of health benefits and enhances our understanding of individuals likely to benefit from emission controls.

Exposure to cat allergen, maternal history of asthma, and wheezing in first 5 years of life

We looked for an association between early exposure to pets and asthma and wheezing in children whose mothers or fathers did or did not have a history of asthma. We followed up 448 children, who had at least one parent with a history of atopy, from birth to 5 years. Among children whose mothers had no history of asthma, exposure to a cat or a Fel d 1 concentration of at least 8 microg/g at the age of 2-3 months was associated with a reduced risk of wheezing between the ages of 1 and 5 years. However, among children whose mothers did have a history of asthma, such exposures were associated with an increased risk of wheezing at or after the age of 3 years. There was no association between wheezing and exposure to dog or dog allergen, and the father's allergy status had no effect on the relation between childhood wheezing and cat exposure.

Hay fever and asthma in relation to markers of infection in the United States

BACKGROUND

The hygiene hypothesis proposes that declining exposure to infections is implicated in the rising trend of allergy and asthma.

OBJECTIVE

We sought to test this hypothesis by examining the relationship of hay fever, asthma, and atopic sensitization with markers of infection in a large general population sample of the United States.

METHODS

We analyzed the data of 33,994 US residents recorded in a public database of a nationally representative cross-sectional survey (Third National Health and Nutrition Examination Survey, 1988-1994). The variables examined were sociodemographic information, lifetime diagnosis and age at first diagnosis of hay fever or asthma, current skin sensitization to 9 airborne allergens and peanut, and current serology for Toxoplasma gondii, herpes simplex viruses type 1 and 2, and hepatitis A, B, and C viruses.

RESULTS

Hay fever (adjusted odds ratio, 0.27; 95% CI, 0.18-0.41; P <.001) and asthma (adjusted odds ratio, 0.45; 95% CI, 0.31-0.66; P <.001) were less frequent in subjects seropositive for hepatitis A virus (HAV), T gondii, and herpes simplex virus 1 versus seronegative subjects after adjusting for age, sex, race, urban residence, census region, family size, income, and education. Skin sensitization to peanut and to all the airborne allergens examined, except for cockroach, was less frequent among HAV-seropositive versus HAV-seronegative subjects younger than 40 years of age. The prevalence of hay fever and asthma diagnosed at or before 18 years of age in HAV-seronegative subjects increased progressively from 2.7% (95% CI, 0.7%-4.7%) and 0.4% (95% CI, 0.1%-1.6%), respectively, in cohorts born before 1920 to 8.5% (95% CI, 7.3%-9.7%) and 5.8% (95% CI, 4.8%-6.8%), respectively, in cohorts born in the 1960s, whereas they remained constant at around 2% in all cohorts of HAV-seropositive subjects.

CONCLUSION

In the United States serologic evidence of acquisition of certain infections, mainly food-borne and orofecal infection, is associated with a lower probability of having hay fever and asthma. Third National Health and Nutrition Examination Survey data support the hypothesis that hygiene is a major factor contributing to the increase in hay fever, asthma, and atopic sensitization in westernized countries.

Influence of family income on hospital visits for asthma among Canadian school children

BACKGROUND

A study was undertaken to investigate the mechanisms by which socioeconomic status may influence asthma morbidity in Canada.

METHODS

A total of 2968 schoolchildren aged 5-19 years with reported asthma were divided into three family income ranges. Hospital visits and risk factors for asthma, ascertained by questionnaire, were compared between the three groups.

RESULTS

The mean (SE) annual period prevalence of a hospital visit was 25.0 (3.1)% among schoolchildren with household incomes of less than $20 000 Canadian compared with 16.0 (1.3)% among those with incomes of more than $60 000 (p<0.05). Students with asthma from lower income households were more likely to be younger and exposed to environmental tobacco smoke and cats, and their parents were more likely to have a lower educational attainment and be unmarried (p<0.05). Across all income groups, younger age, lower parental education, having unmarried parents, and regular exposure to environmental tobacco smoke were each associated with an increase in risk of a hospital visit (p<0.05). No increased risk was detected due to sex, having pets, and not taking dust control measures. Although not statistically significant at p<0.05, there may have been an interactive effect between income and susceptibility to environmental tobacco smoke. In the lower income group those children who were regularly exposed to second hand smoke had a 79% higher risk of a hospital visit compared with a 45% higher risk in the higher income group. In a logistic regression model the association between income and hospital visit was no longer significant after adjusting for differences in reported exposure to passive smoking.

CONCLUSION

Socially disadvantaged Canadian schoolchildren have increased asthma morbidity. Exposure to cigarette smoke appears to be one important explanation for this observation.

Unraveling the ecology of risks for early childhood asthma among ethnically diverse families in the southwest

OBJECTIVES

We describe the prevalence of asthma risk factors within racial/ethnic and language groups of infants participating in an intervention study for reducing chronic asthma.

METHODS

Low-income children aged 9 to 24 months with 3 or more episodes of wheezing illness were enrolled. Baseline information included family and medical histories, allergic status, environmental exposures, emotional environment, and caregiver psychosocial resources.

RESULTS

Racial/ethnic and language groups-European Americans, African Americans, high-acculturated Hispanics, and low-acculturated Hispanics-showed different patterns of risk factors for childhood asthma, with low-acculturated Hispanics showing the most distinctive pattern.

CONCLUSIONS

Patterns of covariation of biological and psychosocial risk factors for childhood asthma were associated with racial/ethnic and language status among urban, low-income children.

The Seattle-King County healthy homes project: implementation of a comprehensive approach to improving indoor environmental quality for low-income children with asthma

Pediatric asthma is a growing public health issue, disproportionately affecting low-income people and people of color. Exposure to indoor asthma triggers plays an important role in the development and exacerbation of asthma. We describe the implementation of the Seattle-King County Healthy Homes Project, a randomized, controlled trial of an outreach/education intervention to improve asthma-related health status by reducing exposure to allergens and irritants in the home. We randomly assigned 274 low-income children with asthma ages 4-12 to either a high- or a low-intensity group. In the high-intensity group, community health workers called Community Home Environmental Specialists (CHES) conducted initial home environmental assessments, provided individualized action plans, and made additional visits over a 12-month period to provide education and social support, encouragement of participant actions, provision of materials to reduce exposures (including bedding encasements), assistance with roach and rodent eradication, and advocacy for improved housing conditions. Members of the low-intensity group received the initial assessment, home action plan, limited education during the assessment visit, and bedding encasements. We describe the recruitment and training of CHES and challenges they faced and explain the assessment and exposure reduction protocols addressing dust mites, mold, tobacco smoke, pets, cockroaches, rodents, dust, moisture, and toxic or hazardous chemicals. We also discuss the gap between the practices recommended in the literature and what is feasible in the home. We accomplished home interventions and participants found the project very useful. The project was limited in resolving structural housing quality issues that contributed to exposure to indoor triggers.

The role of indoor allergen sensitization and exposure in causing morbidity in women with asthma

Longitudinal evidence that indoor allergen exposure causes morbidity in sensitized individuals with asthma is scarce. We evaluated the association of allergen sensitization and home exposure to short- and long-term morbidity in 140 women with asthma and to asthma prevalence in 458 women from metropolitan Boston. Cockroach (Blattella germanica), dust mite (Dermatophagoides farinae), and cat (Felis domesticus) allergens in home dust samples, and specific immunoglobulin E antibodies were measured at outset, and doctor-diagnosed asthma and markers of asthma morbidity were ascertained by questionnaire during a 4-year follow-up. Cat- and cockroach-sensitive (immunoglobulin E immunocap [Cap] class > or = 1) women with asthma reported greater morbidity in the past year at the start, and during follow-up, if high levels of the relevant allergen were found. Women with asthma sensitized to cat allergen and with concentrations at 8 microg/g or greater were more likely to have used steroid (adjusted odds ratio [95% confidence interval] 2.7 [1.2-6.2]) and wheezed without a cold (odds ratio 6.8 [3.3- 14.0]) during follow-up. Those sensitized and exposed to cockroach (Bla g 1 or 2 > or = 2 U/g) were at least three times more likely to have used steroid and to have attended a hospital emergency room; the size of the effect upon steroid use was maintained, but the precision was reduced and the 95% confidence interval included one (p = 0.07), with adjustment for race and poverty. We conclude that cockroach and cat allergens may contribute to asthma morbidity in sensitized women.

Dust mite, cockroach, cat, and dog allergen concentrations in homes of asthmatic children in the northeastern United States: impact of socioeconomic factors and population density

Home exposures to aeroallergens are an important environmental factor in allergic sensitization and in the development and exacerbation of asthma. We assessed variations in home concentrations of dust mite, cockroach, cat, and dog allergens in dust collected in the main living areas of asthmatics' homes by family income, mother's education, dwelling type, population density, household population density, and ethnicity in Connecticut and south-central Massachusetts. Dust samples were collected at the time of home interview in 999 homes as part of an ongoing longitudinal birth cohort study of 1,002 infants and their asthmatic siblings. The analysis employed lower and upper cut points for group 1 dust mite (> or = 2.0 microg/g and > or = 10 microg/g), cockroach (> or = 1.0 U/g and > or = 4.0 U/g), cat (> or = 1.0 microg/g and > or = 8.0 ug/g), and dog (> or = 2.0 microg/g and > or = 10.0 microg/g) allergens. Subject residences were geocoded to assess population density from the U.S. Census, and multiple logistic regression was used to control for confounding. The portion of homes at the lower cut point for dust mite, cockroach, cat, and dog allergens were 46.9%, 24.9%, 42.2%, and 35.6%, respectively; the upper cut point for each of the allergens was reached in 22.4%, 13.4%, 21.0%, and 22.9% of the homes, respectively. In all, 86.0% of the homes had at least one allergen at the lower cut point, and 58.0% had at least one allergen at the upper cut point. Forty-nine percent of the homes had two or more allergens at the lower cut point, and 19.7% had two or more allergens at the upper cut point. Higher education of the mother, higher household income, living in a single-family home in a less densely populated area with fewer people per room, and being a white household were associated with elevated dust mite, cat, and dog allergens and low cockroach allergen. In contrast, low income, living in a multifamily home in a high population density area with a higher occupancy rate per room, and being a Hispanic or black household were associated with elevated cockroach allergens and low concentrations of dust mite, cat, and dog allergens. Although the presence of an individual allergen is more likely associated with one or more socioeconomic or ethnic factors, most homes typically have multiple allergen burdens in excess of concentrations thought to be associated with sensitization and exacerbation of asthma. Mite and cockroach allergens have distinct and opposite associations with socioeconomic factors and population density.

Different slopes for different folks: socioeconomic and racial/ethnic disparities in asthma and hay fever among 173,859 U.S. men and women

Although allergic diseases such as asthma and hay fever are a major cause of morbidity in industrialized countries, most studies have focused on patterns of prevalence among children and adolescents, with relatively few studies on variations in prevalence by race/ethnicity and socioeconomic position among adults. Our study examined racial/ethnic and socioeconomic patterns in the prevalence of asthma overall, asthma with hay fever, asthma without hay fever, and hay fever overall, in a population of 173,859 women and men in a large prepaid health plan in northern California. Using education as a measure of socioeconomic position, we found evidence of a positive gradient for asthma with hay fever with increasing level of education but an inverse gradient for asthma without hay fever. Hay fever was also strongly associated with education. Compared with their White counterparts, Black women and men were more likely to report asthma without hay fever, and Black women were less likely to have asthma with hay fever. Asian men were also more likely to report asthma with hay fever, and Asian women and men were much more likely to have hay fever. Racial/ethnic disparities in prevalence of allergic diseases were largely independent of education. We discuss implications for understanding these social inequalities in allergic disease risk in relation to possible differences in exposure to allergens and determinants of immunologic susceptibility and suggest directions for future research.

Deteriorated housing contributes to high cockroach allergen levels in inner-city households

The high prevalence of childhood asthma in low-income, inner-city populations is not fully understood but has been at least partly attributed to the disproportionate exposures associated with socioeconomic disadvantage. The contribution of indoor allergens to asthma is well documented, but links between socioeconomic disadvantage and indoor allergen levels are not clear. We investigated levels of cockroach allergens (Bla g 2) in a sample of 132 Dominican or African American low-income households with young children in northern Manhattan in New York City (40% were receiving public assistance) to determine whether the distribution of allergens is a function of housing deterioration. Deterioration was measured by the presence and number of physical housing problems (holes in the ceilings and walls, water damage, etc.). More than 50% of the sample had two or more types of housing dilapidation, and 67% of the sample reported cockroach sightings in their homes. Samples of dust were collected from kitchen and bedroom surfaces. We hypothesized that the greater the dilapidation, the higher the allergen levels, independent of income, sociocultural factors, and pest-control methods. In addition, we hypothesized that the homes of families characterized by frequent moves (23.5%) would have higher allergen levels than more stable families. Results showed significant positive associations between housing deterioration and allergen levels in kitchens, after adjusting for income and ethnicity, with independent effects of residential stability (p< 0.05). Bedroom allergen levels were associated with housing instability (p < 0.01) and ethnicity (p< 0.01). Findings demonstrated that indoor household allergen levels are related to degree of household disrepair, after adjusting for individual family attributes, suggesting that social-structural aspects of housing may be appropriate targets for public health interventions designed to reduce allergen exposure.

Sociodemographic correlates of indoor allergen sensitivity among United States children

BACKGROUND

Exposure to indoor allergens is associated with asthma morbidity. Nationally, asthma morbidity disproportionately affects socially disadvantaged populations, but it is unclear whether exposure to indoor allergens follows a similar pattern.

OBJECTIVE

We sought to examine the national prevalences and demographic correlates of sensitivity to indoor allergens related to asthma.

METHODS

Analysis of a cross-sectional survey of a representative sample of 4164 United States children aged 6 to 16 years who participated in allergen testing in the Third National Health and Nutrition Examination Survey from 1988 to 1994 was performed. The main outcome measures were sensitivity reactions to cockroach, dust mite, cat, and Alternaria alternata, as measured via skin prick testing.

RESULTS

Multivariate models, including sex, age, race-ethnicity, education, poverty, family history, region of country, housing age, crowding, and urban residence, revealed significant racial-ethnic disparities in sensitivity. Compared with white children, African American children had higher odds ratios (ORs) of cockroach or dust mite sensitivity (cockroach OR, 2.5 [95% CI, 1.9-3.2]; dust mite OR, 1.3 [95% CI, 1.0-1.7]), as did Mexican American children (cockroach OR, 1.9 [95% CI, 1.3-2.8]; dust mite OR, 1.6 [95% CI, 1.2-2.2]). African American children also had significantly higher odds of sensitivity to A alternata (OR, 2.1 [95% CI, 1.5-2.8]).

CONCLUSIONS

African American and Mexican American children are substantially more likely than white children to be sensitized to allergens important in asthma. Differences in indoor allergen sensitivity are consistent with racial differences in asthma morbidity. Along with other data, these findings suggest that racial disparities in housing, community, or both environmental factors play a role in determining national patterns of asthma morbidity.