“…After screening for valid data, 92 counties across 10 states and the District of Columbia were left for the current study. Following the definition by the National Vital Statistics System (NVSS), opioid-related death is defined as the following multiple cause of death codes including opium, heroin, natural and semisynthetic opioids, methadone, synthetic opioids other than methadone or other and unspecified narcotics (T40.0, T40.1, T40.2, T40.3, T40.4, T40.6) among the cases with the following underlying causes of death including unintentional, suicide, homicide, or undetermined intent death (Hedegaard, Warner, & Miniño, 2017;Hedegaard, Miniño, & Warner, 2020). The same crude rates of opioid-death between two counties should be viewed differently if those counties have significantly contrasting structures of age-graded population (Bachhuber, Saloner, Cunningham, & Barry, 2014;Wilson et al, 2020).…”