Background

Asthma affects over 20 million people in the United States, where the prevalence of asthma increased by ~75% from 1980 to 1996. Puerto Ricans have the highest prevalence, morbidity, and mortality from asthma of all ethnic groups in the U.S. Although asthma is a major problem among Puerto Ricans, little is known about the relative contributions of genetic, environmental, and behavioral factors to asthma in this population. Obesity, a common problem in Puerto Ricans, has been associated with asthma in non-Puerto Rican populations but the mechanisms underlying this association are unclear. Although candidate genes for obesity have been identified through genome-wide studies of association and linkage, no study has tested for association between variants in those genes and asthma in Puerto Ricans. Exposure to indoor allergens (e.g., dog, cat, cockroach) is associated with asthma phenotypes in non-Puerto Ricans. However, little is known about the patterns of allergen exposure and the relation between indoor allergen exposure and the development and severity of asthma and atopy in Puerto Ricans. Low levels of vitamin D were associated with asthma and its intermediate phenotypes in a recent study of children followed from birth until age 5 years. Polymorphisms in the vitamin D receptor gene (VDR) have been associated with immune-related diseases, and both the receptor and vitamin D itself are important in T-cell differentiation. Although variants in VDR have been associated with asthma in European-American children, variants in genes in the vitamin D metabolism pathway have not been tested for association with asthma in Puerto Ricans. Findings from studies in Puerto Rico and in U.S. cities with large Puerto Rican populations suggest that Puerto Ricans are exposed to high levels of violence and suffer more emotional distress than other ethnic groups in response to violence exposure. Although stress has been associated with asthma morbidity in non-Puerto Rican children, little is known about the impact of stress and violence on asthma and asthma morbidity in Puerto Rican children. No study has examined the relation between variants in genes that regulate stress responses and asthma in Puerto Ricans.


AIMS

  • Aim 1: Develop a data set containing 700 Puerto Rican children, as follows: 350 Puerto Rican children (ages 6 to 14 years) with asthma (cases) and 350 Puerto Rican children (ages 6 to 14 years) without asthma (controls)

  • Aim 2: Test for association between single nucleotide polymorphisms (SNPs) in 20 positional candidate genes and a) asthma (in all subjects), b) lung function phenotypes (airway responsiveness, FEV1, FEV1/FVC, and bronchodilator responsiveness) and atopy phenotypes (skin test reactivity to allergens, serum total and allergen-specific IgE, and eosinophil count) separately in cases and in control subjects, and c) asthma severity in cases.

  • Aim 3:Examine whether a) parental report of exposure to pets (dogs and/or cats) in early life is associated with reduced risks of asthma (in all subjects) and atopy, b) current exposure to indoor allergens (dust mite, cockroach, dog, cat, mouse, and rat) is associated with increased severity and abnormal lung function phenotypes in cases, and with atopy phenotypes separately in cases and in controls.

  • Aim 4:Test whether low vitamin D levels are associated with increased risks of asthma (in all subjects), atopy (separately in cases and in control subjects), and abnormal lung function phenotypes and increased disease severity in cases.

  • Aim 5:Examine whether increased body mass index (BMI) is associated with increased risks of asthma (in all subjects), atopy (separately in cases and controls), and both abnormal lung function phenotypes and disease severity (in cases).

  • Aim 6:Test whether increased levels of stress and violence are associated with increased risks of asthma (in all subjects), atopy (separately in cases and controls), and both abnormal lung function phenotypes and disease severity (in cases).

  • Aim 7:. Examine interactions between exposure to SNPs in selected candidate genes and each of the environmental/lifestyle factors.
 

Funding Acknowledgement

NIH: R01 HL079966 Genes, Allergens, and Asthma in Puerto Rican Children. RCMII: Clinical Research Center



Investigators

 

Publications

  • None with this dataset
 

Presentations

 

Questionnaires

  • Modified version of the QUESTIONNAIRE ON CHARACTERISTICS OF THE HOUSEHOLD. It obtains information from parents about characteristics of their household, sun exposure and parental responses to stress.

  • Modified version of the RESPIRATORY HEALTH QUESTIONNAIRE . It obtains information from parents about their child’s respiratory and general health, family history of respiratory and allergic diseases.

  • Modified semi-quantitative FOOD FREQUENCY QUESTIONNAIRE (FFQ) developed in Puerto Rico (W. Rivera) to obtain information about the child’s diet and consumption of supplemental medicine.

  • CHILD EXPOSURE TO STRESS AND VIOLENCE QUESTIONNAIRE. Assesses exposure to violence and responses to stress in children over 9 years old.

  • CENTER FOR EPIDEMIOLOGICAL STUDY-DEPRESSION (CES-D).
 

Other Measures

  • Pulmonary Function Testing
  • Blood collection for DNA extraction (20 ml); measurement of serum total and allergen-specific immunoglobulin E, vitamin D, and cytokines (15 ml); and eosinophil count (3 ml).
  • Assessment of anthropometric measures (BMI, waist-to-hip ratio, mid-upper arm circumference, and skinfold thickness)
  • Assessment of airway responsiveness to methacholine
  • Skin test reactivity to 16 aeroallergens
  • Collection of household dust samples