Methods: Data were extracted on KPH patients enrolled from 2005-2013. Pathogenic pulmonary NTM isolates were identified, and zip codes geocoded and linked to environmental and socioeconomic data. Spatial scan tests were run to estimate relative risks (RR) for NTM clusters, and maps generated using ArcGIS. Regression models adjusted for sex, age and KPH population size estimated adjusted odds ratios (aOR) and 95% confidence intervals (CI) for factors associated with NTM.
Results: Of 286,322 KPH patients, 378 (0.13%) had pulmonary NTM. Prevalence was highest on Oahu (153 cases/100,000 persons), followed by Maui (91 cases/100,000 persons), and the Big Island (84 cases/100,000 persons); no cases were from Kauai. A cluster of Mycobacterium avium complex was identified near Honolulu (RR=1.9, p=0.0002) and of M. abscessus in eastern Oahu (RR=2.3, p=0.06) (Fig. 1). NTM clusters had greater proportions of Asian residents (p<0.0001), and fewer white and Hawaiian/Pacific Islander residents (p<0.0001); no environmental associations were detected. After controlling for demographic factors, NTM cases remained more likely to be from Oahu (aOR=1.5, 95% CI=1.2-1.9) and less likely to live on Maui (aOR=0.7, 95% CI=0.5-0.9).
Conclusion: Spatial variations in NTM risk were detected in Hawaii, with the highest prevalence on Oahu. However, within Oahu, only demographic factors—and not climatic variables—were predictive of high-risk areas. Race/ethnicity is a surrogate for both genetic and behavioral/cultural factors which may affect exposure. While differences in environmental exposure levels may vary by or within island, these data suggest that in Hawaii, host factors are more important determinants of disease risk.
Y. Daida, None
J. Honda, None
K. N. Olivier, None
A. Zelazny, None
S. Honda, None
D. R. Prevots, None
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