NEW YORK (Reuters Health) – The patterns of chronic liver disease (CLD) and cirrhosis and their underlying causes differ by ethnicity, according to results from the Multiethnic Cohort (MEC).
“We were surprised that the nonalcoholic fatty liver disease (NAFLD) prevalence in Japanese Americans is as high as (if not slightly higher than) in Latinos,” Dr. Veronica Wendy Setiawan from Keck School of Medicine University of Southern California, Los Angeles, California told Reuters Health by email. “NAFLD was also found to be the second most common cause of CLD in African Americans. This is important as African Americans are thought to have less prevalence of the disease compared to others.”
Previous studies have revealed racial/ethnic differences in the prevalence of CLD and cirrhosis in the U.S., but the data are limited and restricted to a few ethnic/racial populations.
Dr. Setiawan and colleagues analyzed the prevalence of CLD and cirrhosis, and underlying etiology, in five ethnic groups: African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites.
Among the 5783 cases of CLD identified, 51.7% had NAFLD, 20.7% had alcoholic liver disease (ALD), 8.6% had hepatitis C virus (HCV), 3.1% had hepatitis B virus (HBV), 2.9% had both HCV and HBV, and 6.5% were classified as cryptogenic. The remainder of the cases were due to other causes, according to the July 17th Hepatology online report.
The prevalence of CLD was highest among Japanese Americans (6.9%) and Latinos (6.7%) and was lower among whites (4.1%) and among African Americans and Native Hawaiians (3.9% each).
NAFLD was most prevalent among Japanese Americans (4.4%), followed by Latinos (3.1%), Native Hawaiians (2.3%), whites (1.7%), and African Americans (1.5%).
ALD was most prevalent among Latinos (1.6%), followed by whites (1.2%), African Americans (1.0%), Native Hawaiians (0.9%), and Japanese Americans (0.8%).
Overall, NAFLD was the most common cause of CLD without cirrhosis and CLD with cirrhosis.
CLD without cirrhosis due to NAFLD was highest in Japanese Americans and Native Hawaiians, whereas CLD without cirrhosis due to ALD was highest in African Americans.
NAFLD was the most common cause of cirrhosis in Japanese Americans, Native Hawaiians, and Latinos. ALD was the most common cause of cirrhosis in whites. HCV and NAFLD were the most common causes of cirrhosis in African Americans.
“Given that NAFLD has become the most common cause of CLD, our findings underscore the need to implement improved screening, diagnostic, and management approaches for this growing NAFLD epidemic,” Dr. Setiawan said. “The most common causes of NAFLD are obesity, diabetes, and high cholesterol — these factors can be avoided and treated.”
“Historically certain ethnic groups (i.e., Latinos) are known to be more susceptible to NAFLD, but these new data show that NALFD is an important cause of CLD in all ethnicities,” she concluded. “Most NAFLD are harmless, but just like any CLD, they can progress to cirrhosis and liver failure.”
“Physicians should find out what has led to NAFLD in each patient and stage the disease properly, especially in those at risk of progression to cirrhosis,” Dr. Setiawan said.
Dr. Jody C. Olson from The University of Kansas in Kansas City, who recently reviewed gastrointestinal issues in liver disease, told Reuters Health, “The findings of this study highlight the importance of screening for liver disease in these traditionally understudied patient groups which may allow for early intervention prior to the onset of cirrhosis. Given the high prevalence of NAFLD in certain ethnic populations increased vigilance for recognition is warranted.”
“Liver disease will remain a major source of significant morbidity and mortality for years to come,” he said. “The monumental progress in treating hepatitis C in recent years is attenuated by the dramatic increase in NAFLD. Furthermore, the prevalence of NAFLD is high in traditionally understudied patient populations, and these patients are often at higher risk for impaired access to the healthcare system thus compounding the overall effect of liver disease in these groups.”
“Both this study and the previous work by Asrani et al. demonstrate that the true prevalence of liver disease is underestimated,” Dr. Olson added. “It is critically important that non-liver disease specialists are up to date in appropriate screening and referral recommendations to ensure that liver disease is recognized early and appropriate care initiated.”