Table S1. Deaths and mortality associated with population aging between 1990 and 2019 in four selected countries based on the three decomposition methods.*.

Country	Number of old adults aged ≥65				Proportion of old adults aged ≥65 (%)				Deaths/mortality related to aging†
	1990	2019	Change		1990	2019	Change		Method Ⅰ	Method Ⅱ§	Method Ⅲ
* To properly compare three decomposition methods, we followed the basic guideline that a valid method should reflect the impact of population aging in a reasonable direction. Specifically, a valid decomposition method should generate an increase (decrease) in aging-associated health outcome counts or rates as the population ages (gets younger), according to common logic that older adults typically have higher all-cause mortality and morbidity rates than children and younger adults. † Methods Ⅰ and Ⅱ respectively denote the commonly used number-based and rate-based decomposition methods (1,5,6). Method Ⅲ represents the new decomposition method; § Decomposed results of methods Ⅰ and III are reported in the number of deaths, and decomposed results of method II are reported as mortality per 100,000 persons; ¶ The decomposed deaths of method I was 0.18 for Nauru due to the small population size and was therefore rounded to zero.
Afghanistan	560,091	784,021	223,930		4.9	2.1	−2.8		−77,227	−315	20,800
China	65,625,721	178,348,576	112,722,855		5.5	12.5	7.0		6,529,541	504	6,429,286
Nauru	188	168	−20		1.8	1.6	−0.2		0¶	2	−3
Niue	203	186	−17		8.7	11.1	2.4		5	237	−2