The US longevity gap is becoming a chasm. For decades, life expectancy in the States has lagged behind wealthy nations like Japan, Switzerland and Australia, with Americans consistently dying younger than their peers abroad. Now, a landmark “population autopsy” analyzing more than 63 million deaths has identified two key factors fueling shorter lifespans nationwide, as experts warn the trend is only getting worse. In the study , researchers compared the US to 17 peer nations and found that