Study / Trial Background

We propose to conduct a scientifically valid, descriptive survey to measure the prevalence and levels of lead in dust, soil, and paint, and the prevalence and levels of various indoor allergens in floor and bedding dust in the nation's housing stock. The survey strategy is a population-based, multi-stage area probability sample designed to represent all 50 states. The survey will include approximately 1000 homes in at least 100 primary sampling units (PSU, a metropolitan area or cluster of counties). Residents of candidate participant housing units (HUs) will initially be contacted by a letter to introduce and provide a brief explanation of the study. 

NIEHS in conjunction with the Department of Housing and Urban Development (HUD) Office of Lead Hazard Control sponsored a study entitled the National Survey of Lead and Allergens in Housing (NSLAH). This study provided information to enable HUD and NIEHS scientists to assess the magnitude of the American public's exposure to household indoor allergens. NIEHS conducted the NSLAH in light of recent studies which suggested that cumulative exposure to indoor allergens can increase a person's risk for developing allergic disease and asthma. 

NIEHS is using the allergen data from the NSLAH to: 

  • estimate indoor allergen exposures of the general population 
  • assess the magnitude of levels of indoor allergens in the United States housing stock 
  • evaluate differences in population exposure to allergens based on factors such as region/geography, ethnicity, socioeconomic status, and housing type. 

This study provides important indoor allergen exposure data and seeks to examine the complex relationship between allergic sensitization to indoor allergens and asthma development. 

The questionnaire used in the survey is available as a PDF file: 

National Survey of Lead Hazards and Allergens in Housing: Resident Questionnaire (197KB)

A detailed list of the 75 Population Sampling Units (PSUs) and Strata used in the survey is also available as a PDF file: 

Eligibility Criteria

  • Ages Eligible for Study: 18–65 years
  • Genders Eligible for Study: All
  • Accepts Healthy Volunteers: No
  • The target population for the Survey is the national housing stock of approximately 95 million housing units.
  • The decision to include or exclude a subset is usually based on such factors as relevancy to the study objectives, availability of data from other sources, and effort required to obtain the study data.
  • None of the possible housing type exclusion or oversampling proposals are based upon gender, race, ethnic, cultural, or biological factors.
  • Housing built after 1977.
  • Housing units in multi-family buildings.
  • Manufactured housing units, i.e., mobile homes and trailers.

Principal Investigator

Darryl C. Zeldin, M.D.
Darryl C. Zeldin, M.D.
Scientific Director and Principal Investigator
Tel 984-287-3641
[email protected]
P.O. Box 12233
Mail Drop A2-05
Durham, NC 27709