Table 3

Confounders included in the different models with the following abbreviations: S: penalized spline (* k = 30, otherwise k = 10), Poly: Polynomial with order in brackets, L: linear term, X: dummies, D: by design.

Trend

Temperature

Temperature difference

Relative humidity

Air pressure

Weekday

Holiday

Population decrease

Augsburg

Poisson Regression : Final

S

-

L

-

-

X

-

-

Poisson Regression : Remove

S

-

-

-

-

-

-

-

Poisson Regression : Add

S

S

L

L

-

X

-

-

Case-crossover

D

-

L

-

-

D

-

-

Extended Cox Regression

L

-

L

-

-

X

-

-

Barcelona

Poisson Regression : Final

S

L

-

-

-

X

-

X

Poisson Regression : Remove

S

-

-

-

-

-

-

X

Poisson Regression : Add

S

L

L

-

-

X

-

X

Case-crossover

D

L

-

-

-

D

-

X

Extended Cox Regression

L

L

-

-

-

X

-

X

Helsinki

Poisson Regression : Final

S

L

L

L

-

X

-

-

Poisson Regression : Remove

S

-

L

L

-

X

-

-

Poisson Regression : Add

S

S

S

L

-

X

-

-

Case-crossover

D

L

L

L

-

D

-

-

Extended Cox Regression

L

L

L

L

-

X

-

-

Rome

Poisson Regression : Final

S*

S

-

L

-

X

X

X

Poisson Regression : Remove

S*

L

-

L

-

X

-

-

Poisson Regression : Add

S*

S

-

S

-

X

X

X

Case-crossover

D

S

-

L

-

D

X

X

Extended Cox Regression

L

Poly(2)

-

L

-

X

X

X

Stockholm

Poisson Regression : Final

S

L

-

S

L

X

-

X

Poisson Regression : Remove

S

-

-

S

L

X

-

X

Poisson Regression : Add

S

L

L

S

L

X

-

X

Case-crossover

D

L

-

S

L

D

-

X

Extended Cox Regression

L

L

-

Poly(2)

L

X

-

X

Peters et al. Epidemiologic Perspectives & Innovations 2006 3:10   doi:10.1186/1742-5573-3-10