Free full text: http://onlinelibrary.wiley.com/doi/10.1111/cei.12077/full
Early-life hygiene-related factors affect risk of central nervous system demyelination and asthma differentially
A-M Hughes,* R M Lucas,* A J McMichael,* T Dwyer,† M P Pender,¶ I Mei,†† B V Taylor,†† P Valery,** C Chapman,§ A Coulthard,¶ K Dear,* T J Kilpatrick,‡ D Williams,‡‡ and A-L Ponsonby†
Clin Exp Immunol. Jun 2013; 172(3): 466–474.
Published online Apr 18, 2013. doi: 10.1111/cei.12077
PMCID: PMC3646446
ABSTRACT
The increasing prevalence of immune-related diseases, including multiple sclerosis, may be partly explained by reduced microbial burden during childhood.
Within a multi-centre case–control study population, we examined:
(i) the co-morbid immune diseases profile of adults with a first clinical diagnosis of central nervous system demyelination (FCD)
and
(ii) sibship structure in relation to an autoimmune (FCD) and an allergic (asthma) disease.
FCD cases (n = 282) were aged 18–59 years; controls (n = 558) were matched on age, sex and region.
Measures include: history of doctor-diagnosed asthma; sibling profile (number; dates of birth); and regular childcare attendance.
FCD cases did not differ from controls with regard to personal or family history of allergy, but had a greater likelihood of chronic fatigue syndrome [odds ratio (OR) = 3·11; 95% confidence interval (CI) 1·11, 8·71].
Having any younger siblings showed reduced odds of FCD (OR = 0·68; 95% CI: 0·49, 0·95) but not asthma (OR = 1·47; 95% CI: 0·91, 2·38).
In contrast, an increasing number of older siblings was associated with reduced risk of asthma (P trend = 0·04) but not FCD (P trend = 0·66).
Allergies were not over-represented among people presenting with FCD.
Sibship characteristics influence both FCD and asthma risk but the underlying mechanisms differ, possibly due to the timing of the putative ‘sibling effect’.