THE US MIDLIFE MORTALITY CRISIS CONTINUES: EXCESS CAUSE-SPECIFIC MORTALITY DURING 2020.

COVID-19 prematurely ended many lives, particularly among the oldest Americans, but the pandemic also had an indirect effect on health and non-COVID mortality among the working-age population, who suffered the brunt of the economic consequences. This analysis investigates whether monthly excess mortality in the US during 2020 varied by age and cause of death. Based on national-level death counts and population estimates for 1999-2020, negative binomial regression models-fit separately by sex-were used to estimate monthly cause-specific excess mortality by age group during 2020. Among males, 71% non-COVID excess deaths occurred at working ages (25-64), but those ages accounted for only 36% of non-COVID excess deaths in females. The results revealed substantial numbers of excess deaths from external causes (particularly among males), heart disease, diabetes, Alzheimer's disease (particularly among women), and cerebrovascular disease. For males, the largest share of non-COVID excess deaths resulted from external causes, nearly 80% of which occurred at working ages. Although incorrectly classified COVID-19 deaths may explain some excess non-COVID mortality, misclassification is unlikely to explain the increase in external causes of mortality. Auxiliary analyses suggested that drug-related mortality may be driving the rise in external mortality, but drug overdoses were already increasing for a full year prior to the pandemic. The oldest Americans bore the brunt of COVID-19 mortality, but working-age Americans, particularly men, suffered substantial numbers of excess non-COVID deaths, most commonly from external causes and heart disease.