Cohort profile: the Korean National Health Examination Baseline (KNHEB) cohort for longitudinal health monitoring in South Korea

Table 2 Health screening attrition rate by year

Screening Period¹⁾	Number of participants, A²⁾	Number of deaths, B	Number of participants lost to follow-up, C	Attrition rate, C/A (%)
Baseline (2002–2003)	8,916,544	19,213	-	-
2004–2005	8,897,331	64,457	214,084	2.4
2006–2007	8,832,874	78,063	103,424	1.2
2008–2009	8,754,811	88,389	97,793	1.2
2010–2011	8,666,422	99,071	125,519	1.5
2012–2013	8,567,351	109,789	169,923	2.1
2014–2015	8,457,562	118,217	234,160	3.0
2016–2017	8,339,345	128,571	512,284	6.9
2002–2017	8,916,544	705,770	1,457,187	16.3

¹⁾ Since the National Health Screening is conducted biennially, except for manual labourers, the attrition rate is calculated in two-year intervals.who
²⁾ The number of individuals eligible for follow-up, excluding those who died (B) or were lost to follow-up (C) in the previous period

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