Table 2.

Prevalence rates of hospitalization due to pneumonia in comparison with the characteristics of older adults.

Variable	Category	Number	PR (%)	Variables	Category	Number	PR (%)
Frailty	Non-frail	1993	7.7	Household structure (living alone or with family)	Alone	784	14.9
	Pre-frail	3580	12.7		With spouse	3833	14.8
	Frail	1692	25.1		With children	579	13.6
IADL	0*	4483	11.4		With spouse and children	1220	14.8
	1	2352	15.3		In a three-generation household	1126	16.6
	≥ 2	1516	23.6		Others	1140	16.4
Physical strength	0	3701	11.1	Marital status	Married	6399	14.9
	1	2475	13.1		Widowed	1497	16.1
	≥ 2	2125	23.6		Divorced	397	13.9
Nutrition status	0	6498	12.2		Never married	217	11.1
	1	1777	22.0		Others	68	29.4
	2	223	38.6	Smoking status	Never smoked	4748	11.3
Oral function	0	3934	11.9		Quit smoking ≥ 5 years ago	2546	19.5
	1	2584	14.9		Quit smoking < 5 years ago	384	36.2
	≥ 2	1881	21.4		Smoking sometimes	155	19.4
Homeboundness	0	6733	12.2		Smoking almost every day	687	10.8
	1	1569	22.8	Population density	Metropolitan	2840	14.1
	2	249	41.4		Urban	2263	14.5
Cognitive function	0	5320	13.7		Semi-urban	926	14.9
	1	2284	16.0		Rural	2653	17.1
	≥ 2	883	21.2	Diabetes	No	7200	14.8
Depression status	0	4458	11.1		Yes	1178	19.2
	1	1453	14.3	Respiratory disease	No	6989	10.1
	≥ 2	2155	22.7		Yes	1389	42.1
Age groups	65–74	5020	10.4	Heart disease	No	7293	14.1
	≥ 75	3662	21.8		Yes	1085	24.3
Sex	Male	4402	19.3	Kidney/prostate gland disease	No	7608	14.7
	Female	4280	11.0		Yes	770	22.5
Educational attainment	> 6	76	32.9	Hematological/immune disease	No	8213	15.3
	6–9	2678	20.4		Yes	165	22.4
	10–12	3492	13.1	Pneumococcal vaccination	No	4296	10.5
	≥ 13	2296	11.8		Yes	4181	19.1
	The other	67	11.9
Equivalized income, million yen	< 0.5	357	15.1
	0.50–0.99	876	13.6
	1.00–1.99	2294	14.5
	2.00–3.99	2146	14.9
	≥ 4.00	930	13.9

*Numbers in IADL, physical strength, nutrition status, oral function, homebound, cognitive function, depressive mode are the numbers of the applicable KCL questions for the older adults.

PR prevalence rate, IADL instrumental activity of daily living, KCL Kihon checklist.