How Accurately Do Young Adults Recall Childhood Pets? A Validation Study
How Accurately Do Young Adults Recall Childhood Pets? A Validation Study
Charlotte Nicholas
Ganesa Wegienka
Suzanne Havstad
Dennis Ownby
Christine Cole Johnson
Edward Zoratti
American Journal of Epidemiology ª The Author 2009. Published by the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: . Epidemiologic research shows that pets influence human health, demonstrating both protective and deleterious health risks; therefore, valid definitions of pet exposure would enhance research. The authors determined how well young adults aged 18 years report their early childhood pets. Subjects in an established birth cohort from Detroit, Michigan, born in 1987-1989 (n ¼ 820) were asked a series of questions about pets in the home during their first 6 years of life. Pet recall was compared with annual prospectively collected parental report from 12-18 years prior. Exposure to cats was correctly reported on average 86.3% of the time (95% confidence interval: 85.0, 87.5) and dogs 79.2% (95% confidence interval: 77.7, 80.6) of the time (P < 0.01). Cats and dogs were more likely to be underreported than overreported, from as few as 1.8-fold to as many as 8.3-fold (P < 0.05). Reporting differed by sex of the respondent and current pet ownership. No differences were found in reporting by those who experienced allergy symptoms near dogs or cats. Findings suggest good reliability of young adult pet reporting for ages 0-6 years but that childhood pet exposure may need to be assessed separately depending on the participant's sex and the outcome of interest. animals, domestic; asthma; cats; cohort studies; dogs; hypersensitivity; mental recall; validation studies Correspondence to Charlotte Nicholas, 1 Ford Place, 3E, Detroit, MI 48202 (e-mail: ).
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Epidemiologic research suggests that pet exposure may
influence human health starting in utero and continuing into
adulthood (1–9). Several large birth-cohort studies
investigating early-life factors related to allergic disorders have
particularly focused on the role of pets (1–3). Pets have
exhibited both protective and deleterious associations with
human health, and investigations into the effects of pet
exposure on health will likely continue.
Although a number of birth cohort studies have obtained
prospectively collected pet data (1–3), in numerous studies
exposure history is based on participant recall (4–7). In
many such studies, childhood pet ownership (i.e., number
of cats and/or dogs) is based on self-report without
additional measures to verify or ensure accuracy of the report,
potentially leading to bias and conflicting results. There is
little evidence in the literature to quantify the accuracy of
self-report of this important information for epidemiologic
investigations (8). Our goal in these analyses was to
determine the accuracy of self-reported early childhood pet
exposure by participants aged 18 years in a birth cohort study
by comparing their reports with prospective data on
household pets collected from their parents by annual
questionnaires during the participants’ first 6 years of life.
MATERIALS AND METHODS
Subject recruitment and selection
The methodology for the Childhood Allergy Study has
been fully described elsewhere (9). In summary, pregnant
women aged 18 years or older from a geographically defined
area of metropolitan Detroit, Michigan, who belonged to
a health maintenance organization affiliated with the Henry
Ford Health System and had an estimated date of
confinement between April 15, 1987, and August 31, 1989, were
eligible for the study. Study enrollment included providing
written informed consent, completing a predelivery
interview, and having cord blood collected at delivery. Women
were asked to complete annual telephone questionnaires on
the anniversary of their child’s birth until (and including) the
child’s sixth birthday. Answers to questions on
environmental exposures, including household pets, were obtained in
these yearly interviews in addition to information on the
child’s allergic and nonallergic disease outcomes. Upon
conclusion of the Childhood Allergy Study, 835 families
remained eligible for enrollment in follow-up studies.
Recently, we contacted this original Childhood Allergy
Study cohort of 835 children to obtain updated health
information through age 18 years. After their 18th birthday, teens
were contacted to complete 1) a telephone-administered
interview and 2) a clinical evaluation.
Of the 835 teens eligible when the Childhood Allergy
Study ended, 15 withdrew from the study or otherwise
became ineligible prior to the follow-up at age 18 years. Of the
remaining 820 teens, 48 were unable to be evaluated (40
could not be contacted, 3 were enlisted in the military, 3 had
medical conditions precluding them from a personal
interview, and 2 were incarcerated), leaving 772 teens eligible to
participate. Of the 772 teens eligible, 670 (86.8%)
consented to study enrollment. The (...truncated)