LOS ANGELES-Alcohol-associated liver disease (ALD) became the most common factor in liver transplants in the United States,  recent research shows.

Of over 32,000 liver transplants studied, the proportion of liver transplants for ALD increased from 24.2 percent in 2012 to 36.7 percent in 2016, according to a study from the University of California-San Francisco published Tuesday.  One reason is that the six-month sobriety requirement was no longer regarded as a mandatory principle. "Shortening the mandated period of alcohol abstinence would be anticipated to allow more patients with ALD to survive until  liver transplant," the research indicated.

   The "six-month rule" used to be a gold standard in the United States and required that "patients with alcoholic liver disease should be sober at least for six months before they are considered for liver transplant," said ABC News. But the research team found that U.S. transplant centers never took it as an ablsolute policy in real practice, and even set their own ones.

The mandated abstinence period was also weakened by paperwork from medical scholars, in which they promote early liver transplants for ALD patients.

Although the U.S. medical community was under increasing openness towards shortening abstinence, researchers were still concerned about the late death rate after a transplant as well as regional disparities among ALD patients, calling for further studies

on long-term outcomes.