Observed number of people in Canada with multiple sclerosis (MS) compared with expected number, according to month of birth
|
|
|
People with MS (n=17 874)
|
|
|
|
Month
|
All births (1926-70) (n=13 675 451)
|
Observed No of births
|
Expected No of births
|
Observed/expected births (95% CI)
|
Month specific  2 test of association
|
P value
|
Jan
|
1 096 651
|
1425
|
1433
|
0.99 (0.94 to 1.05)
|
0.05
|
0.82
|
Feb
|
1 032 882
|
1369
|
1350
|
1.02 (0.96 to 1.07)
|
0.29
|
0.59
|
Mar
|
1 187 630
|
1533
|
1552
|
0.99 (0.93 to 1.04)
|
0.26
|
0.61
|
Apr
|
1 168 350
|
1532
|
1527
|
1.00 (0.95 to 1.06)
|
0.02
|
0.89
|
May
|
1 238 935
|
1675
|
1619
|
1.04 (0.99 to 1.09)
|
2.10
|
0.15
|
Jun
|
1 202 046
|
1512
|
1571
|
0.96 (0.91 to 1.01)
|
2.43
|
0.12
|
Jul
|
1 193 942
|
1608
|
1561
|
1.03 (0.98 to 1.08)
|
1.58
|
0.21
|
Aug
|
1 156 480
|
1553
|
1512
|
1.03 (0.98 to 1.08)
|
1.24
|
0.27
|
Sept
|
1 157 627
|
1525
|
1513
|
1.01 (0.96 to 1.06)
|
0.10
|
0.75
|
Oct
|
1 114 282
|
1455
|
1456
|
1.00 (0.95 to 1.05)
|
0.00
|
0.97
|
Nov
|
1 050 758
|
1257
|
1373
|
0.91 (0.85 to 0.97)
|
10.67
|
0.0011
|
Dec
|
1 075 868
|
1430
|
1406
|
1.02 (0.96 to 1.07)
|
0.44
|
0.51
|
|
* P=0.013 after Bonferroni correction for multiple comparisons.
