Table 2.

Impact of PM_2.5 weekly concentration on multiple sclerosis relapse, multivariate analysis.

Week	Variable	Odds ratio (confidence interval 95%)	P-value
Week 0	Ln of weekly PM2.5	1.08 (0.91;1.29)	0.399
	Weekly mean of dairy maximal temperature (1)	0.91 (0.79;1.04)	0.158
	Weekly flu like syndrome rate (1)	0.99 (0.87;1.12)	0.825
	Weekly pollen count (1)	0.99 (0.92;1.09)	0.995
	Holliday period (2)	0.76 (0.53;1.11)	0.154
Week−1	Ln of weekly PM2.5	1.03 (0.88;1.23)	0.730
	Weekly mean of dairy maximal temperature (1)	0.98 (0.84;1.13)	0.801
	Weekly flu like syndrome rate (1)	0.91 (0.80;1.04)	0.158
	Weekly pollen count (1)	0.95 (0.86;1.05)	0.354
	Holliday period (2)	0.39 (0.25;0.60)	0.001
Week−2	Ln of weekly PM2.5	0.97 (0.81;1.16)	0.748
	Weekly mean of dairy maximal temperature (1)	0.83 (0.72;0.95)	0.009
	Weekly flu like syndrome rate (1)	1.07 (0.94;1.23)	0.297
	Weekly pollen count (1)	0.91 (0.82;0.99)	0.036
	Holliday period (2)	0.75 (0.51;1.10)	0.136
Week-3	Ln of weekly PM2.5	1.21 (1.01;1.46)	0.039
	Weekly mean of dairy maximal temperature (1)	0.98 (0.86;1.13)	0.798
	Weekly flu like syndrome rate (1)	1.05 (0.92;1.20)	0.457
	Weekly pollen count (1)	0.94 (0.86;1.03)	0.189
	Holliday period (2)	0.82 (0.60;1.13)	0.227
Week-4	Ln of weekly PM2.5	0.93 (0.79;1.11)	0.443
	Weekly mean of dairy maximal temperature (1)	0.99 (0.86;1.15)	0.938
	Weekly flu like syndrome rate (1)	1.01 (0.88;1.15)	0.492
	Weekly pollen count (1)	0.99 (0.90;1.08)	0.739
	Holliday period (2)	0.92 (0.64;1.34)	0.652
Week-5	Ln of weekly PM2.5	0.87 (0.73;1.05)	0.150
	Weekly mean of dairy maximal temperature (1)	0.87 (0.75;1.00)	0.054
	Weekly flu like syndrome rate (1)	0.86 (0.75;0.99)	0.034
	Weekly pollen count (1)	0.99 (0.91;1.09)	0.868
	Holliday period (2)	0.72 (0.51;1.00)	0.055

(1) By increase of one quartile.

(2) Holidays: Christmas and summer holidays.

Bold values indicate p < 0.05.