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Month of birth and level of insolation as risk factors for multiple sclerosis in Poland

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Many studies have shown that people born in the spring are at a higher risk of developing multiple sclerosis (MS). This may be associated with lower levels of sun exposure, and consequently, lower levels of vitamin D3 during pregnancy. However, these relationships have not been verified thus far in any countries in Central Europe.

Objective: The aim of our study was to determine the frequency distribution of births for each calendar month in patients suffering from MS in Poland.

Methods: We analyzed data for 2574 patients diagnosed with MS (1758 women, 816 men) living in Poland for an extended period. We added corrections resulting from the frequency distribution of births for the years in which the patients were born. We applied the Hewitt test for seasonality with Rogerson modification for 3-, 4-, or 6-month pulses or periods. Moreover, we examined the average number hours of sunshine in every month of the year.

Results: The rank-sums for successive 3- and 4-month segments indicated the period from September to December and from October to December as having a significantly lower incidence (p = 0.027 and p = 0.054, respectively). We did not find a correlation between with hours of sunshine in the first trimester of pregnancy, the child’s birth month, and the child developing MS.

Conclusions: We were able to confirm a seasonal variation in the risk of MS in Poland. However, these findings did not correlate with hours of sunshine during the first trimester of pregnancy.

No MeSH data available.


Location of the MS units included in the study (in brackets number of patients).
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pone.0175156.g001: Location of the MS units included in the study (in brackets number of patients).

Mentions: This study was conducted among patients with MS according to the criteria of Poser and McDonald [10,11]. We obtained cases registered in the MS units in Zabrze and Rzeszów (south of Poland), and Bydgoszcz, Szczecin, and Białystok (north of the country) (Fig 1). The latitudinal extent between cities was from 50.04° to 53.43° N. Information on insolation was obtained from the Institute of Meteorology and Water Management (a national research and development unit). Data were analyzed separately for individual months from 1962 to 1986, which corresponds to the mean age of the study group ± standard deviation. The approval of the Bioethics Committee of Pomeranian Medical University was obtained. We used the anonymized registry data. The clinical information was collected after written informed consent. The information collected did not cause harm to patients.


Month of birth and level of insolation as risk factors for multiple sclerosis in Poland
Location of the MS units included in the study (in brackets number of patients).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383232&req=5

pone.0175156.g001: Location of the MS units included in the study (in brackets number of patients).
Mentions: This study was conducted among patients with MS according to the criteria of Poser and McDonald [10,11]. We obtained cases registered in the MS units in Zabrze and Rzeszów (south of Poland), and Bydgoszcz, Szczecin, and Białystok (north of the country) (Fig 1). The latitudinal extent between cities was from 50.04° to 53.43° N. Information on insolation was obtained from the Institute of Meteorology and Water Management (a national research and development unit). Data were analyzed separately for individual months from 1962 to 1986, which corresponds to the mean age of the study group ± standard deviation. The approval of the Bioethics Committee of Pomeranian Medical University was obtained. We used the anonymized registry data. The clinical information was collected after written informed consent. The information collected did not cause harm to patients.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Many studies have shown that people born in the spring are at a higher risk of developing multiple sclerosis (MS). This may be associated with lower levels of sun exposure, and consequently, lower levels of vitamin D3 during pregnancy. However, these relationships have not been verified thus far in any countries in Central Europe.

Objective: The aim of our study was to determine the frequency distribution of births for each calendar month in patients suffering from MS in Poland.

Methods: We analyzed data for 2574 patients diagnosed with MS (1758 women, 816 men) living in Poland for an extended period. We added corrections resulting from the frequency distribution of births for the years in which the patients were born. We applied the Hewitt test for seasonality with Rogerson modification for 3-, 4-, or 6-month pulses or periods. Moreover, we examined the average number hours of sunshine in every month of the year.

Results: The rank-sums for successive 3- and 4-month segments indicated the period from September to December and from October to December as having a significantly lower incidence (p = 0.027 and p = 0.054, respectively). We did not find a correlation between with hours of sunshine in the first trimester of pregnancy, the child’s birth month, and the child developing MS.

Conclusions: We were able to confirm a seasonal variation in the risk of MS in Poland. However, these findings did not correlate with hours of sunshine during the first trimester of pregnancy.

No MeSH data available.