Table 2.

Multivariate regression model

Variable	Likelihood ratio χ2	P value
Age	131·45	<0·001
Sex	0·29	0·590
Deprivation index	21·29	<0·001
Month	39·49	<0·001
Rural area	0·18	0·675
Water index	9·36	0·025
Age*Deprivation Index	6·80	0·033
Month*rural area	27·37	0·004