Non-alcoholic fatty liver disease is a growing cause of liver cancer and death in some regions of the world, an analysis of global reporting on liver disease shows. The findings were presented last month at the AASLD Liver Meeting in Boston.
James Paik and colleagues associated with the Betty and Guy Beatty Center for
Integrated Research, Inova Health System, Falls Church, Virginia, reviewed data
reported by the Global Burden of Disease study, to identify regional trends in
incidence of liver cancer and cirrhosis between 2012 and 2017.
They
compared changes in incidence and mortality related to liver cancer and
cirrhosis attributed to viral hepatitis, alcoholic liver disease and
non-alcoholic fatty liver disease (NAFLD). The investigators say theirs is the
first study to look at trends in illness and death due to NAFLD alongside viral
hepatitis and alcoholic liver disease.
The Global
Burden of Disease study, co-ordinated by the Institute of Health Metrics and
Evaluation at the University of Washington, Seattle, gathers data on 282
diseases and publishes estimates of the burden of disease – including the
incidence of illness and death – for 195 countries grouped into 21 regions. The
most recent report from the study was published in 2017.
Inova
Health investigators used the Global Burden of Disease data to estimate annual
changes in the incidence of liver cancer and deaths from liver cancer
attributable to hepatitis B, hepatitis C, alcoholic liver disease and NAFLD. They did the same for cirrhosis.
The study
investigators estimated that 2.2 million people died of liver-related causes in
2017 worldwide, 1.3 million of those from complications of cirrhosis and around
800,000 from liver cancer. Half of all deaths from liver-related causes
occurred in east Asia and one in five in south Asia (India, Pakistan, Nepal and
Bangladesh). The Middle East, north Africa and western sub-Saharan Africa
showed the next highest burdens.
One million
new cases of liver cancer and 5.2 million cases of cirrhosis were estimated to
have been diagnosed in 2017. Once again, the highest burden of cases was
concentrated in east Asia and south Asia.
Hepatitis B
was the largest cause of liver cancer death worldwide in 2017, accounting for
39% of deaths. Hepatitis C caused 29% of deaths from liver cancer. Alcoholic
liver disease accounted for 19% of deaths and NAFLD
for 9% of deaths. Hepatitis B and C and alcoholic liver disease each caused
around 30% of deaths from complications of cirrhosis.
Hepatitis B
caused more than half of liver cancer deaths in east Asia (53%).
Alcoholic
liver disease caused a higher proportion of liver-related deaths in western and central Europe (around 44%) than any other region of the world and alcoholic
liver disease caused 35 to 40% of liver-related deaths in eastern Europe, central
America, the Caribbean and Andean Latin America.
The study
showed that NAFLD is emerging as an important cause of liver disease and deaths
in many regions of the world, not just in high-income countries. At least 10%
of liver cancer and cirrhosis deaths were attributable to NAFLD in 10 of 21
global regions.
Thirteen
per cent of liver cancer deaths in south Asia in 2017 were attributed to NAFLD
and 7% in east Asia. In Andean Latin America (Bolivia, Ecuador and Peru), NAFLD
was linked to 17% of liver cancer deaths and 23% of cirrhosis deaths.
The
investigators also looked at annual changes in diagnoses and deaths from liver
cancer and cirrhosis. Whereas liver cancer incidence and deaths attributable to
all causes declined across all regions of sub-Saharan Africa between 2012 and
2017, the incidence of liver cancer and deaths from liver cancer increased by
between 1.4% and 2.5% per year in east Asia, tropical Latin America, south Asia
and Australasia, with the largest increases seen in liver cancers attributable
to NAFLD. Deaths due to liver cancer attributable to NAFLD increased by between
1.8% and 2.4% a year in five out of 21 regions.
Liver
cancers deaths due to hepatitis C, alcoholic liver disease and NAFLD increased
by more than 2% a year in eastern Europe, the region with the fastest rate of
growth in liver cancer deaths.
The
incidence of cirrhosis due to NAFLD also increased, by 2.7% a year in east Asia
and by 1 to 2% in a further eight out of 21 regions, including North America, south Asia and the Caribbean.
The
investigators say that although trends in liver cancer and cirrhosis related to
viral hepatitis in some regions of the world – notably sub-Saharan Africa and western Europe – are promising, trends in disease and death related to NAFLD
point to the need for national and global policies and programmes to address
the underlying causes and clinical diagnosis and management of NAFLD.