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. 2005 Jan 15;330(7483):120.
doi: 10.1136/bmj.38301.686030.63. Epub 2004 Dec 7.

Timing of birth and risk of multiple sclerosis: population based study

Cristen J Willer  1 , David A Dyment, A Dessa Sadovnick, Peter M Rothwell, T Jock Murray, George C Ebers; Canadian Collaborative Study Group
Affiliations
Free PMC article

Timing of birth and risk of multiple sclerosis: population based study

Cristen J Willer et al. BMJ. .
Free PMC article

Abstract

Objectives: To determine if risk of multiple sclerosis (MS) is associated with month of birth in countries in the northern hemisphere and if factors related to month of birth interact with genetic risk.

Design: Population based study with population and family based controls and a retrospective cohort identified from death certificates. A post hoc pooled analysis was carried out for large northern datasets including Sweden and Denmark.

Setting: 19 MS clinics in major cities across Canada (Canadian collaborative project on the genetic susceptibility to multiple sclerosis); incident cases of MS from a population based study in the Lothian and Border regions of Scotland; and death records from the UK Registrar General.

Populations: 17,874 Canadian patients and 11,502 British patients with multiple sclerosis.

Main outcome measure: Diagnosis of multiple sclerosis.

Results: In Canada (n = 17,874) significantly fewer patients with MS were born in November compared with controls from the population census and unaffected siblings. These observations were confirmed in a dataset of British patients (n = 11, 502), in which there was also an increase in the number of births in May. A pooled analysis of datasets from Canada, Great Britain, Denmark, and Sweden (n = 42,045) showed that significantly fewer (8.5%) people with MS were born in November and significantly more (9.1%) were born in May. For recent incident data, the effect of month of birth was most evident in Scotland, where MS prevalence is the highest.

Conclusions: Month of birth and risk of MS are associated, more so in familial cases, implying interactions between genes and environment that are related to climate. Such interactions may act during gestation or shortly after birth in individuals born in the northern countries studied.

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Figures

Fig 1
Fig 1
Pooled analysis of observed/expected births in people with multiple sclerosis in Canadian, British, Danish, and Swedish studies (n=42 045) with 95% confidence intervals
Fig 2
Fig 2
Odds ratios for people with multiple sclerosis being born in May/November among incident cases in northern hemisphere countries
See this image and copyright information in PMC

References

    1. Willer CJ, Dyment DA, Risch NJ, Sadovnick AD, Ebers GC. Twin concordance and sibling recurrence rates in multiple sclerosis. Proc Natl Acad Sci U S A 2003;100: 12877-82. - PMC - PubMed
    1. Ebers GC, Sadovnick AD, Risch NJ. A genetic basis for familial aggregation in multiple sclerosis. Canadian Collaborative Study Group. Nature 1995;377: 150-1. - PubMed
    1. Ebers G, Sadovnick A, Dyment D, Yee I, Willer C, Risch N, et al. A parent of origin effect in multiple sclerosis: observations in half siblings. Lancet 2004;363: 847-50. - PubMed
    1. Ebers GC, Yee IM, Sadovnick AD, Duquette P. Conjugal multiple sclerosis: population-based prevalence and recurrence risks in offspring. Canadian Collaborative Study Group. Ann Neurol 2000;48: 927-31. - PubMed
    1. McLeod JG, Hammond SR, Hallpike JF. Epidemiology of multiple sclerosis in Australia. With NSW and SA survey results. Med J Aust 1994;160: 117-22. - PubMed

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