Table 2

Estimates of relative risks and 95% CI from Poisson regression modelling of P&I rates overall and by age categories for demographic (models 1–3), socioeconomic (models 4–6) and for all variables combined (model 7)

		Children–elderly person interactions		Socioeconomic status
		Youth dependencyratio	Proportion of live-in grandparents who care for their grandchildren	Below US median income county	Gini index
Model 1	All	0.84 (0.48, 1.48)
	65–74 years	1.04 (0.58, 1.86)
	75–84 years	0.81 (0.46, 1.28)
	85+ years	0.66 (0.90, 1.17)
Model 2	All		1.62 (1.25, 2.12)***
	65–74 years		1.67 (1.27, 2.21)***
	75–84 years		1.50 (1.14, 1.97)**
	85+ years		1.41 (1.06, 1.88)*
Model 3	All	0.93 (0.54, 1.60)	1.62 (1.25, 2.11)***
	65–74 years	1.16 (0.66, 2.03)	1.68 (1.28, 2.20)***
	75–84 years	0.88 (0.51, 1.52)	1.49 (1.14, 1.96)**
	85+ years	0.70 (0.40, 1.22)	1.40 (1.06, 1.84)*
Model 4	All			1.19 (1.11, 1.28)***
	65–74 years			1.23 (1.14, 1.32)***
	75–84 years			1.16 (1.08, 1.25)***
	85+ years			1.13 (1.05, 1.23)**
Model 5	All				1.14 (1.03, 1.26)**
	65–74 years				1.21 (1.08, 1.35)***
	75–84 years				1.10 (0.99, 1.23)
	85+ years				1.08 (0.97, 1.20)
Model 6	All			1.20 (1.09, 1.31)***	0.98 (0.87, 1.11)
	65–74 years			1.21 (1.11, 1.32)***	1.03 (0.90, 1.18)
	75–84 years			1.18 (1.08, 1.29)***	0.96 (0.84, 1.09)
	85+ years			1.15 (1.05, 1.27)**	0.96 (0.84, 1.10)
Model 7	All	1.04 (0.61, 1.77)	1.48 (1.11, 1.96)**	1.18 (1.08, 1.30)***	0.97 (0.86, 1.09)
	65–74 years	1.36 (0.79, 2.36)	1.48 (1.16, 1.98)**	1.20 (1.09, 1.32)***	1.02 (0.90, 1.16)
	75–84 years	0.95 (0.55, 1.62)	1.38 (1.03, 1.85)*	1.17 (1.07, 1.28)**	0.95 (0.84, 1.07)
	85+ years	0.74 (0.43, 1.28)	1.31 (0.97, 1.78)	1.14 (1.03, 1.26)*	0.95 (0.83, 1.07)

* p<0.05; **p<0.01; ***p<0.001.
All models controlled for log of population density, spatial location and seasonal variability.
P&I, pneumonia and influenza.