Chest Email Content Delivery
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Guest Access | Sign In via User Name/Password
First published online on April 5, 2007
Chest, doi:10.1378/chest.06-2818
A more recent version of this article appeared on June 1, 2007
This Article
Right arrow Full Text (PDF) Free
Right arrow All Versions of this Article:
chest.06-2818v1
131/6/1747    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Goldberg, S.
Right arrow Articles by Picard, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Goldberg, S.
Right arrow Articles by Picard, E.

Asthma prevalence, family size and birth order

Shmuel Goldberg, MD1; Eran Israeli, MD2,3; Shepard Schwartz, MD4; Tzippora Shochat, M.Sc3; Gabriel Izbicki, MD5; Ori Toker-Maimon, MD4; Eyal Klement, DVM3 and Elie Picard, MD1

1From the Departments of Pediatric Pulmonology 2Department of Medicine, Hebrew University- Hadassah Medical Center, Jerusalem, Israel and 3IDF Medical Corps 4Pediatrics 5Institute of Pulmonology, Shaare Zedek Medical Center, Jerusalem, Israel; Faculty of Health Sciences, Ben-Gurion University of the Negev, Beersheva, Israel, and from

sgoldberg{at}szmc.org.il

Abstract

BackgroundAsthma prevalence may be reduced in large families. The hygiene hypothesis suggests that older siblings protect their younger siblings from asthma through a modulating effect on the yet maturing immune system. If the hygiene hypothesis is correct, asthma prevalence should be inversely related to birth order.

The objective of this study was to examine the relationship between asthma prevalence, family size and birth order.

MethodsThe medical records of 531,116 Israeli conscripts were reviewed. Association between number of children in the family and prevalence of asthma, and between birth order and prevalence of asthma was assessed. Odds ratios for asthma by birth order and family size, adjusted for each other, were calculated.

ResultsAsthma was diagnosed in 26,833 males (8.6%) and in 15,079 females (6.9%). Asthma prevalence was inversely related to the number of children in the family (p <0.001). Among subjects who were the only child in the family, prevalence of asthma was 7.3%. The prevalence increased to 8.95% among subjects from families with three siblings, and then progressively decreased as the number of siblings increased, and reached a trough of 0.58% in conscripts from families of 15-20 siblings. Asthma prevalence was similar for all birth orders.

ConclusionsIn families with 4 or more children, asthma prevalence is inversely related to the number of children in the family. Asthma prevalence is similar for all birth orders. The similar asthma prevalence for all birth orders challenges the hygiene hypothesis as the mechanism for the decreased asthma prevalence in large families.

Key Words: Asthma • Epidemiology • Pediatrics






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2007 by the American College of Chest Physicians.