Faculty Collaboration Database

Combining individual- and group-level exposure information: child carbon monoxide in the Guatemala woodstove randomized control trial. Epidemiology 2009 Jan;20(1):127-36

Date

12/06/2008

Pubmed ID

19057384

DOI

10.1097/EDE.0b013e31818ef327

Scopus ID

2-s2.0-67651108828 (requires institutional sign-in at Scopus site)   64 Citations

Abstract

BACKGROUND: Epidemiology frequently relies on surrogates of long-term exposures, often either individual-level short-term measurements or group-level based on long-term characteristics of subjects and their environment. Whereas individual-level measures are often imprecise due to within-subject variability, group-level measures tend to be inaccurate due to residual between-subject variability within groups. Rather than choose between these error-prone estimates, we borrow strength from each by use of mixed-model prediction and we compare the predictive validity.

METHODS: We compared alternative measures of long-term exposure to carbon monoxide (CO) among children in the RESPIRE woodstove randomized control trial during years 2003 and 2004. The main study included 1932 repeated 48-hour-average personal CO measures among 509 children from 0-18 months of age. We used a validation study with additional CO measures among a random subsample of 70 of the children to compare the predictive validity of individual-level estimates (based on observed short-term exposures), group-level estimates (based on stove type and other residential characteristics), and mixed-model predictions that combine these 2 sources of information.

RESULTS: The estimated error variance for mixed-model prediction was 63% lower than the individual-level measure based on the exposure data and 58% lower than the corresponding group-level measure.

CONCLUSIONS: When both individual- and group-level estimates are available but imperfect, mixed-model prediction may provide substantially better measures of long-term exposure, potentially increasing the sensitivity of epidemiologic studies to underlying causal relations.

Author List

McCracken JP, Schwartz J, Bruce N, Mittleman M, Ryan LM, Smith KR

Author

Lawrence M. Ryan MD Emeritus Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Air Pollution, Indoor
Carbon Monoxide
Cooking
Epidemiologic Methods
Female
Guatemala
Humans
Incineration
Infant
Infant, Newborn
Male
Models, Theoretical
Validation Studies as Topic
Young Adult