Michael Lenoir | PubMed Health

PubMed2006

Assessment of asthma control in a general population of asthmatics.

BACKGROUND: Asthma control is typically assessed by review of symptoms and measurement of airflow obstruction by clinic spirometry or outpatient peak flow. Recently the role of questionnaires to assess asthma control has been discussed. STUDY OBJECTIVE: To investigate the frequency of asthma control in the general population using the Asthma Control Test ([ACT], ACT is a trademark of QualityMetric, Lincoln RI) and force expiratory volume in one second (FEV1). RESEARCH DESIGN AND METHODS: Subjects with self-reported physician diagnosed asthma or use of asthma prescription medications attending community or sporting events were asked to complete the five-question ACT and to perform spirometry. Subjects with an ACT score of < or = 19 and/or an FEV1 of < 80% predicted were classified as having not well controlled (NWC) asthma. RESULTS: 2702 subjects completed both the ACT and spirometry. ACT scores < or = 19 were recorded in 27% and FEV1 < 80% predicted was noted in 26% of subjects evaluated. ACT and/or lung function was in the NWC range for 43% of subjects; 10% of subjects had both an ACT score < or = 19 and an FEV1 < 80% and 16-17% had either an ACT score < or = 19 or a FEV1 < 80%. CONCLUSION: A considerable portion (43%) of subjects with self-reported asthma in the general population was identified with NWC. In addition, the use of ACT and spirometry were equally effective methods to identify NWC asthma.

Adult↗

PubMed2005

Admixture-matched case-control study: a practical approach for genetic association studies in admixed populations.

Case-control genetic association studies in admixed populations are known to be susceptible to genetic confounding due to population stratification. The transmission/disequilibrium test (TDT) approach can avoid this problem. However, the TDT is expensive and impractical for late-onset diseases. Case-control study designs, in which, cases and controls are matched by admixture, can be an appealing and a suitable alternative for genetic association studies in admixed populations. In this study, we applied this matching strategy when recruiting our African American participants in the Study of African American, Asthma, Genes and Environments. Group admixture in this cohort consists of 83% African ancestry and 17% European ancestry, which was consistent with reports from other studies. By carrying out several complementary analyses, our results show that there is a substructure in the cohort, but that the admixture distributions are almost identical in cases and controls, and also in cases only. We performed association tests for asthma-related traits with ancestry, and only found that FEV(1), a measure for baseline pulmonary function, was associated with ancestry after adjusting for socio-economic and environmental risk factors (P=0.01). We did not observe an excess of type I error rate in our association tests for ancestry informative markers and asthma-related phenotypes when ancestry was not adjusted in the analyses. Furthermore, using the association tests between genetic variants in a known asthma candidate gene, beta(2) adrenergic receptor (beta(2)AR) and DeltaFEF(25-75), an asthma-related phenotype, as an example, we demonstrated population stratification was not a confounder in our genetic association. Our present work demonstrates that admixture-matched case-control strategies can efficiently control population stratification confounding in admixed populations.

Adolescent↗