ReviewJournal of epidemiology and community health2002
Does a higher number of siblings protect against the development of allergy and asthma? A review.
Review in Journal of epidemiology and community health, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 88 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
88 citing papers in PubMed, 3 syntheses or guidelines pooled it, 321 citations in OpenAlex.
- A Pregnancy and Childhood Epigenetics Consortium (PACE) meta-analysis highlights potential relationships between birth order and neonatal blood DNA methylation.Communications biology · 2024Pooled it
- Is sibship composition a risk factor for childhood asthma? Systematic review and meta-analysis.World journal of pediatrics : WJP · 2023Pooled it
- Psychosocial Factors Affecting Parental Report of Symptoms in Children: A Systematic Review.Psychosomatic medicinePooled it
- Rising prevalence of asthma is sex-specific in a US farming population.The Journal of allergy and clinical immunology · 2011Trial
- Do We Have Any Environmental or Perinatal Factor Which May Predispose for Paediatric Airways Diseases? An Italian Population Prospective Study.Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery · 2026Article
- Evaluating the Impact of the COVID-19 Pandemic on Pediatric Asthma Incidence.The journal of allergy and clinical immunology. In practice · 2025Review
- The Effect of Environmental Factors, Health Behaviors, and Psychosocial Aspects on Allergic Diseases in Korean Adolescents.Medicina (Kaunas, Lithuania) · 2025Article
- Does having siblings really protect against childhood atopic diseases? A total population and within-family analysis.European journal of epidemiology · 2024Article
- Differences between parents' and paediatricians' perceptions of mild respiratory infections in childhood: contrast study.Frontiers in public health · 2024Article
- Birthing parent adverse childhood experiences and risk of atopic diseases in 5-year-old children.Frontiers in allergy · 2024Article
- Environmental exposures associated with atopy in a rural community in Gwanda district, Zimbabwe: a cross-sectional study.Frontiers in public health · 2024Article
- Epithelial Barrier Theory: The Role of Exposome, Microbiome, and Barrier Function in Allergic Diseases.Allergy, asthma & immunology research · 2023Review
- Early-life and health behaviour influences on lung function in early adulthood.The European respiratory journal · 2023Article
- Associations of only-child status with health outcomes and risky behaviors in Korean middle- and high-school students: An outcome-wide analysis.Preventive medicine reports · 2023Article
- Exposure to isocyanates predicts atopic dermatitis prevalence and disrupts therapeutic pathways in commensal bacteria.Science advances · 2023Article
- The Exposome Applied: A Step toward Defining the Totality of Environmental Exposures in Asthma.American journal of respiratory and critical care medicine · 2022Article
- Article
- The developing airway and gut microbiota in early life is influenced by age of older siblings.Microbiome · 2022Article
- Sex Differences in the Association of Sibship Size and Position in Sibship with Lipid Profile during Adolescence: A Cross-Sectional Study.International journal of endocrinology · 2022Article
- The hygiene hypothesis for allergy - conception and evolution.Frontiers in allergy · 2022Article
28 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
2 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
STUDY
objectiveTo review the "protective" effects of having a higher number of siblings for the risk of atopic eczema, asthma wheezing, hay fever, and allergic sensitisation.
methodReview of the literature (Medline since 1965 and references). MAIN
results53 different studies were identified. For eczema, 9 of 11 studies reported an inverse relation with number of siblings; for asthma and wheezing, 21 of 31 reported the inverse association; for hay fever, all 17 studies showed the effect; for allergic sensitisation or immunoglobulin E reactivity 14 of 16 studies supported the "protective" effect of a higher number of siblings. The studies emphasise a "theory" that is based exclusively on epidemiological associations.
conclusionsResearch has not yet answered the question of which causal factors explain the sibling effect. Causal factors must meet two criteria; they must vary with sibship size and they must protect against atopic manifestations. The prevailing "hygiene hypothesis" failed to explain the findings adequately. Alternative explanations include in utero programming or endocrine explanatory models. The epidemiology research into siblings and atopic disorders has entered an intellectually challenging phase. Possessing sufficient knowledge about the causal factors might prevent at least 30% of all cases of asthma, eczema, and hay fever.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.