Table 2

Observed:expected MS cases by month of birth.

Observed:expected MS births (ratio (95% CI); significance)
AnalysisJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
All studies (n=151 978)0.96 (0.92 to 1.01)0.98 (0.94 to 1.01)0.99 (0.95 to 1.03)1.05 (1.00 to 1.11) p=0.051.05 (0.98 to 1.13)1.05 (0.93 to 1.19)1.03 (0.98 to 1.08)1.01 (0.98 to 1.05)0.98 (0.95 to 1.01)0.95 (0.91 to 1.00) p=0.040.92 (0.86 to 0.98) p=0.010.98 (0.96 to 1.01)
Population conservative (n=140 474)0.95 (0.91 to 1.00) p=0.070.98 (0.04 to 1.02)0.99 (0.95 to 1.04)1.05 (0.99 to 1.12) p=0.081.03 (0.98 to 1.09)1.05 (0.91 to 1.02)1.02 (0.97 to 1.08)1.01 (0.98 to 1.05)0.98 (0.95 to 1.02)0.96 (0.91 to 1.01)0.93 (0.87 to 1.00) p=0.040.98 (0.93 to 1.03)
Geographically conservative (n=89 059)0.95 (0.88 to 1.02)1.01 (0.96 to 1.06)0.99 (0.94 to 1.04)1.08 (1.03 to 1.12) p=0.0011.11 (1.03 to 1.21) p=0.0071.06 (1.00 to 1.13) p=0.051.01 (0.97 to 1.06)0.99 (0.94 to 1.04)0.96 (0.92 to 1.01)0.94 (0.89 to 0.98) p=0.0060.89 (0.82 to 0.96) p=0.0040.97 (0.90 to 1.04)
Overall conservative (n=78 488)0.93 (0.86 to 1.01)1.01 (0.96 to 1.06)0.99 (0.93 to 1.06)1.08 (1.02 to 1.13) p=0.0041.09 (1.03 to 1.14) p=0.0021.06 (0.99 to 1.14)1.00 (0.96 to 1.05)0.99 (0.94 to 1.05)0.97 (0.92 to 1.01)0.95 (0.90 to 1.00) p=0.030.90 (0.82 to 0.99) p=0.030.99 (0.93 to 1.06)
  • p values are given for significant results in bold, and for borderline significant results (not bold).

  • MS, multiple sclerosis.