Successful techniques for retention of study participants in an inner-city population.

The purpose of this work was to describe methods of retaining participants in studies of inner-city populations, including the timing and intensity of contacts; and to describe the characteristics of participants who did not complete all follow-up interviews and/or return all peak flow diaries in the National Cooperative Inner-City Asthma Study. A cohort study design was used involving hospital emergency rooms and community clinics in seven major urban areas. Participants included 1337 4- to 9-year-old asthmatic children and their caretakers. Nearly 89% of participants completed 3-, 6-, and 9-month follow-up interviews. The 15% of participants who completed a baseline interview on the weekends were significantly more likely to complete follow-up interviews on a weekend. The percent of follow-up interviews conducted in person increased over time from 5% to 8%. The percent of participants with complete follow-up increased as the number of contact names increased (86% with zero contacts, 91% with two contracts; p = 0.03, test for trend). Participants who required at least four phone calls to complete the 3- and 6-month assessment were significantly more likely to be black, have higher participant stress, and have a smoker in the household (p < 0.05). Multiple logistic regression suggests that higher social support and lower parental stress were both predictors of completed interviews. Within our study sample of inner-city minority participants with asthmatic children, only a small proportion of participants missed any follow-up interviews. Increased caretaker stress, decreased social support, and inability to provide several alternate contacts were all predictive of retention problems. Having a flexible staff, computer tracking, and face-to-face recruitment appear essential to achieving nearly complete follow-up within a population historically difficult to follow.

Design and methods of the National Cooperative Inner-City Asthma Study.

The National Cooperative Inner-City Asthma Study (NCICAS) was established to identify and then intervene on those factors which are related to asthma morbidity among children in the inner-city. This paper describes the design and methods of the broad-based initial Phase I epidemiologic investigation. Eight research centers enrolled 1,528 children, 4 to 9 years of age, from English- or Spanish-speaking families, all of whom resided in major metropolitan inner-city areas. The protocol included an eligibility assessment and an extensive baseline visit, during which symptom data, such as wheezing, lost sleep, changes in activities of daily living, inpatient admissions, and emergency department and clinic visits were collected. A comprehensive medical history for each child was taken and adherence to the medical regimen was assessed. Access, as well as barriers, to the medical system were addressed by a series of questions including the location, availability, and consistency of treatment for asthma attacks, follow-up care, and primary care. The psychological health of the caretaker and of the child was also measured. Asthma knowledge of the child and caretaker was determined. Sensitization to allergens was assessed by skin-prick allergen testing and exposure to cigarette smoke and the home environment were assessed by questionnaire. For more than a third of the families, in-home visits were conducted with dust sample allergen collection and documentation of the home environment, such as the presence of pets and evidence of smoking, mildew, and roaches. Urine specimens were collected to measure passive smoke exposure by cotinine assays, blood samples were drawn for banking, and children age 6 to 9 years were given spirometric lung function assessment. At 3, 6 and 9 months following the baseline assessment, telephone interviews were conducted to ask about the child's symptoms, unscheduled emergency department or clinic visits, and hospitalizations. At this time, peak flow measurements with 2-week diary symptom records were collected.

The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma.

BACKGROUND: It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust. METHODS: From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period. RESULTS: Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen. CONCLUSIONS: The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.