Prevalence of Asthma and Chronic Respiratory Symptoms Among Alaska Native Children

Toby C. Lewis, MD, MPH; James W. Stout, MD, MPH; Patricia Martinez, MD, MPH; Barbara Morray, RN, MS; Lisa C. White, MPH; Susan R. Heckbert, MD, PhD; Gregory J. Redding, MD, FCCP

Disclosures

CHEST. 2004;125(5) 

In This Article

Abstract and Introduction

Study Objectives: To quantify the prevalence and impact of chronic respiratory symptoms among predominantly Alaska Native (AN)/American Indian (AI) middle school students.
Design: School-based prevalence assessment using the International Study of Asthma and Allergy in Children survey, with supplemental video material and added questions about productive cough, exposure to tobacco smoke, and the functional impact of symptoms.
Setting: The Yukon-Kuskokwim delta region of western Alaska.
Participants: A total of 466 children in the sixth to ninth grades, 81% of whom are AN/AI (377 children).
Interventions: No study intervention.
Results: Among the 377 AN/AI children, 40% reported one of the following three categories of chronic respiratory disease: physician-diagnosed asthma, 7.4%; asthma-like symptoms (ALS) without an asthma diagnosis, 11.4%; and chronic productive cough (CPC) without asthma diagnosis or symptoms, 21.5%. Symptom prevalence differed substantially between the largest town in the region and rural villages. After an adjustment for demographic factors, exposure to environmental tobacco smoke, active tobacco smoking, and self-report of atopy, village residents were 63% less likely to have ALS (p = 0.009), and had a twofold greater risk of CPC (p < 0.001) compared to children living in the town. Children with respiratory symptoms experienced sleep disturbances and accessed clinic visits for respiratory problems more often than did asymptomatic children.
Conclusions: Chronic respiratory symptoms are very common among AN children. CPC is an important nonasthmatic respiratory condition in this population. The differing patterns of respiratory illness within this region may help to elucidate the specific risk factors for asthma and chronic bronchitis in children.

Asthma is the most common chronic disease of childhood, affecting at least 5 million children in the United States and causing significant morbidity among children of all ages.[1–3] Worldwide, the prevalence of asthma among children has increased steadily during the last 2 decades.[4] Considerable evidence[5–8] indicates that regional variation exists in the prevalence of asthma and in the relative importance of risk factors. Understanding these variations is important both for local health-care endeavors and also for gaining insight into the epidemiology of asthma.

The prevalence and severity of asthma among Alaska Native (AN) and American Indian (AI) children has been incompletely described. In the United States, urban ANs and AIs have been identified as high-risk populations due to significantly lower general health indexes than whites.[9,10] Some studies[11] have suggested comparable rates of asthma in AN/AI children and the general US population. In contrast, asthma mortality among AI adults has been reported to be negligible.[12] Even so, asthma may be an emerging problem as the increase in hospitalization rates for asthma among AN/AI children has paralleled the increase described for white children.[10,13,14]

Information regarding the prevalence of asthma and its functional impact among AN children is both timely and important. Clarifying the disease burden among the AN/AI population is a priority of the National Institutes of Health.[15] Many culturally specific asthma interventions targeting African-American and Hispanic children have been initiated.[16,17,18,19] Yet, it is unclear whether similar culturally specific interventions focused on AI/AN children are warranted.

Children from the Yukon-Kuskokwim (YK) delta region of southwestern Alaska are predominantly Yup'ik Eskimo. Culturally,[20] linguistically,[20] and by relatedness of genetic markers,[21] AN residents of the YK delta are more similar to other coastal Eskimo (also called Inuit) populations in northeastern Siberia and northern Canada than to inland ANs/AIs. The YK delta is 258,000 square kilometers of subarctic tundra that contain one large town, Bethel, which serves as the hub of local commerce and health care. The population is approximately 25,000, with 5,600 people living in Bethel and the remaining 75% of the population living in rural villages.[22]

Several factors that are highly prevalent in the region may predispose Yup'ik children to acquire asthma, including crowded housing conditions, low income levels, and frequent exposure to environmental tobacco and wood-burning stove emission.[10,22–24] Children from the YK delta also experience extremely high rates of acute lower respiratory tract infections, which may contribute to the development of chronic airway disease, particularly in AN/AI children.[24–34] Yup'ik children also have high rates of postinfectious bronchiectasis.[35,36]

The YK delta also has characteristics that may protect children from acquiring asthma. Exposure to concentrated industrial or motor vehicle emissions is rare. Exposure to allergens is thought to be uncommon, given the subarctic climate.[29] Unlike many urban poor populations, AN children have access to an integrated health-care system, which initially was established by the Indian Health Service and is maintained by a native corporation.

This study seeks to define the prevalence of diagnosed asthma and chronic respiratory symptoms associated with asthma and chronic bronchitis among middle school students in the YK delta region of Alaska. It examines the significance of these conditions by describing the severity and functional impact of the symptoms and explores potential risk factors for chronic respiratory symptoms among AN/AI students.

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