乌鸦传媒

More than 80% of workers on the World Trade Center site following the 9/11 terrorist attack who later reported gastrointestinal (GI) symptoms actually suffered from toxin-associated fatty liver disease (TAFLD), according to a cohort study reported Thursday.

Among 243 recovery and cleanup workers at "Ground Zero" participating in the World Trade Center Health Program -- a government-funded project providing medical benefits to those working on the site in the weeks following the towers' collapse -- 195 (82.6%) showed hepatic steatosis index (HSI) scores greater than 36, reported Mishal Reja, MD, of Robert Wood Johnson University Hospital in Newark, New Jersey.

Reja said it was highly likely that these represent cases of TAFLD because of the individuals' previous exposures at the Ground Zero site.

The study was presented in an online press program organized by , which was to have started this weekend but was cancelled because of the COVID-19 pandemic.

These particular workers were referred to the program after reporting GI symptoms: predominantly gastroesophageal reflux, but also including dysphagia and general abdominal pain. Reja and colleagues suspected TAFLD would be highly prevalent in the group.

During his online presentation, Reja explained that building materials often contain endocrine-disrupting chemicals such as polycyclic aromatic hydrocarbons and vinyl chloride, which in turn have been linked in prior research to fatty liver disease, i.e., TAFLD. These compounds can easily be liberated during demolition work, for example. Massive quantities are known to have been released during the Trade Center buildings' collapse and subsequent debris removal.

Reja noted, too, that past studies of other occupational exposures to these substances showed "extremely high rates [of TAFLD] consistent with the rates we found in our study."

He added that TAFLD can be distinguished from ordinary non-alcoholic fatty liver disease in liver biopsies -- "they have different inflammatory markers" and a "different histological picture" -- but he also acknowledged that pathologists may disagree on particular biopsy samples for diagnosing TAFLD.

Ground Zero workers referred to Reja's clinic were assessed with the HSI, which combines body mass index, gender, diabetes mellitus presence, and the ratio of alanine to aspartate aminotransferase to generate a numeric score. Previous studies indicated a cutoff of 36 is 93.1% sensitive for fatty liver, his group noted.

The 82.6% prevalence of scores above 36 stands in contrast to estimates of 24%-45% in the general population, Reja noted.

DDW Chair Grace Elta, MD, of the University of Michigan in Ann Arbor, who served as discussant for the press program, said the prevalence of fatty liver in this group "seems extremely high," and asked how those individuals may have differed from those not meeting the HSI threshold.

Reja noted that obesity was strongly associated with fatty liver in the group (adjusted OR 3.26, 95% CI 2.24-5.50). Besides reflux disease, common comorbidities included hypertension (40%), chronic rhinosinusitis (67%), and obstructive sleep apnea (52%).

Also, the group with HSI scores greater than 36 were more likely than others in the cohort to show gastritis on endoscopy (68.9% vs 50.0%).

Reja concluded that the findings suggest that healthcare professionals -- primary care providers and gastroenterologists in particular -- be alert for fatty liver disease in Ground Zero workers. Routine liver function tests and/or hepatic ultrasound exams should be considered, he said.

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