Salzer J, Svenningsson A, Sundström P
Department of Neurology, Umeå University Hospital, Umeå, Sweden.
Acta Neurol Scand. 2010 Jan;121(1):20-3. doi: 10.1111/j.1600-0404.2009.01181.x. Epub 2009 Nov 23.
To estimate the risk of multiple sclerosis (MS) by month of birth in Sweden.
Cases (n = 9361) were obtained from the Swedish MS Registry. All births in Sweden 1900-2007 served as controls (n = 12,116,853). The risk of MS was analyzed for each month of birth separately compared with birth during the other 11 months.
More (11%) cases with MS than expected were born in June. Fewer (8% and 10%) cases with MS than expected were born in December and January (non-significant after correction for multiple analyses). More (5%) cases with MS than expected were born in February-July as compared with August-January.
This study supports previous results suggesting an association between the risk of MS and the season of birth. Decreased exposure to sun in the winter leading to low vitamin D levels during pregnancy is a possible explanation that needs further research.
评估瑞典不同出生月份患多发性硬化症（MS）的风险。
病例（n = 9361）来自瑞典MS登记处。1900年至2007年瑞典所有出生人口作为对照（n = 12,116,853）。将每个出生月份患MS的风险分别与其他11个月份的出生情况进行比较分析。
6月份出生的MS病例比预期更多（11%）。12月份和1月份出生的MS病例比预期更少（分别为8%和10%，经多重分析校正后无统计学意义）。与8月至1月相比，2月至7月出生的MS病例比预期更多（5%）。
本研究支持先前的结果，提示MS风险与出生季节之间存在关联。冬季日照减少导致孕期维生素D水平降低是一个可能的解释，需要进一步研究。
