Contributions
Abstract: P334
Type: Poster
Abstract Category: Clinical aspects of MS - 5 Epidemiology
Background: Previous studies have shown that the risk of multiple sclerosis (MS) is associated to season of birth with a higher proportion of MS patients being born in spring. However, this relationship has recently been questioned and may be due to confounding factors.
Objective: Our aim was to assess the influence from season or month of birth on the risk of developing MS in Sweden and Iceland.
Methods: Information about month of birth, gender and phenotype of MS for patients born 1940-1996 were retrieved from the Swedish MS registry (SMSR), and their place of birth were retrieved from The Swedish Total Population Registry (TPR). The corresponding information was retrieved from medical journals of Icelandic MS patients born 1981-1996. The control groups consisted of every person born in Sweden 1940-1996, their gender and county of birth (TPR), and in Iceland all persons born between 1981-1996 and their gender (Statistics Iceland). We calculated the expected number of MS patients born during each season and in every month and compared it with the observed number. Adjustments were made for gender, birth year and county of birth.
Results: We included 12020 Swedish and 108 Icelandic MS patients in the analyses. There was no significant difference between expected and observed MS births related to season or month of birth in Sweden or Iceland. Adjustments were made for birth year and birth place. However, similar results were obtained even without such adjustments. No significant differences were found in subgroup analyses including data of latitude of birth, gender, clinical phenotype and early MS onset ≤30 years.
Conclusion: Our results don't support the previously reported association between season or month of birth and MS risk.
Disclosure:
Ólöf Eliasdóttir has received unconditional research grants from Biogen and Novartis. The study was even funded by the Swedish Neuroförbundet, NHR Stockholm and Edit Jacobsson foundation
Jan Lycke has received travel support and/or lecture honoraria from Biogen, Novartis, Teva and Genzyme/SanofiAventis; has served on scientific advisory boards for Almirall, Teva, Biogen, Novartis and Genzyme/SanofiAventis; serves on the editorial board of the Acta Neurologica Scandinavica; has received unconditional research grants from Biogen, Novartis and Teva.
Abstract: P334
Type: Poster
Abstract Category: Clinical aspects of MS - 5 Epidemiology
Background: Previous studies have shown that the risk of multiple sclerosis (MS) is associated to season of birth with a higher proportion of MS patients being born in spring. However, this relationship has recently been questioned and may be due to confounding factors.
Objective: Our aim was to assess the influence from season or month of birth on the risk of developing MS in Sweden and Iceland.
Methods: Information about month of birth, gender and phenotype of MS for patients born 1940-1996 were retrieved from the Swedish MS registry (SMSR), and their place of birth were retrieved from The Swedish Total Population Registry (TPR). The corresponding information was retrieved from medical journals of Icelandic MS patients born 1981-1996. The control groups consisted of every person born in Sweden 1940-1996, their gender and county of birth (TPR), and in Iceland all persons born between 1981-1996 and their gender (Statistics Iceland). We calculated the expected number of MS patients born during each season and in every month and compared it with the observed number. Adjustments were made for gender, birth year and county of birth.
Results: We included 12020 Swedish and 108 Icelandic MS patients in the analyses. There was no significant difference between expected and observed MS births related to season or month of birth in Sweden or Iceland. Adjustments were made for birth year and birth place. However, similar results were obtained even without such adjustments. No significant differences were found in subgroup analyses including data of latitude of birth, gender, clinical phenotype and early MS onset ≤30 years.
Conclusion: Our results don't support the previously reported association between season or month of birth and MS risk.
Disclosure:
Ólöf Eliasdóttir has received unconditional research grants from Biogen and Novartis. The study was even funded by the Swedish Neuroförbundet, NHR Stockholm and Edit Jacobsson foundation
Jan Lycke has received travel support and/or lecture honoraria from Biogen, Novartis, Teva and Genzyme/SanofiAventis; has served on scientific advisory boards for Almirall, Teva, Biogen, Novartis and Genzyme/SanofiAventis; serves on the editorial board of the Acta Neurologica Scandinavica; has received unconditional research grants from Biogen, Novartis and Teva.