healthy lifestyle, including smoking cessation,
moderate drinking, a balanced diet, exercise and weight loss could dramatically
reduce the growing burden of liver cancer and deaths due to liver disease,
according to a study presented last month at the
AASLD Liver Meeting.
years or decades, chronic hepatitis B or C infection, heavy alcohol
consumption, fatty liver disease and other causes can lead to liver cirrhosis,
hepatocellular carcinoma (HCC, the most common type of primary liver cancer)
and the need for a liver transplant. HCC is among the fastest-rising causes of
cancer-related death worldwide.
"Right now, there
are not yet any effective medications to reverse liver fibrosis or prevent HCC.
It is essential that we focus on controlling risk factors through primary
prevention," Dr Tracey Simon of Massachusetts General Hospital in
Boston said in an AASLD press release. "Lifestyle
modification represents a primary prevention effort that is likely to be a more
effective and feasible way to prevent HCC and liver-related mortality at the
Along with hepatitis B vaccination
and hepatitis C treatment, individual lifestyle changes have been shown to
reduce the risk of liver cancer and its complications. Dr Tracey Simon and colleagues conducted a study to
determine the overall impact of lifestyle on HCC incidence and liver-related mortality.
study looked at data from two prospective cohorts of US adults. The Nurses’
Health Study (NHS) enrolled more than 121,000 women in 1976. The Health
Professionals Follow-up Study (HPFS) enrolled over 51,000 men in 1986. Members
of both cohorts provided detailed clinical, lifestyle and dietary information
every two to four years.
analysis included 76,713 women in the NHS and 48,748 men in the HPFS who had
complete lifestyle data available in 1986; they were followed through 2012.
People who already had viral hepatitis, cirrhosis or liver cancer at study
entry were excluded.
researchers looked at five healthy lifestyle factors:
- Body mass index: normal weight, or a BMI of
24.9 or lower
- Physical activity: at least 150 minutes of
moderate to vigorous exercise each week
- Smoking: current non-smoker, including both
never-smokers and those who had quit
- Diet: a score in the upper 40% on the Alternate Healthy Eating Index 2010, which assesses diet quality.
- Alcohol: one or fewer drinks per day for women or two or fewer drinks
The researchers calculated population-attributable
risk, or the proportion of liver cancer cases and liver-related deaths that
could have been prevented if all participants adhered to a healthy lifestyle.
To assess whether their findings
were generalisable to the population as a whole – which may not be as healthy – they then
did a similar analysis based on a nationally representative sample of adults
from the 2009-2010 National
Health and Nutrition Examination Survey (NHANES).
pooled NHS and HPFS group, about two thirds were women, more than 90% were
white and the average age was approximately 52 years. As expected, people with
more healthy lifestyle factors were less likely to have diabetes, high blood
pressure or abnormal blood lipid levels.
individually, each lifestyle factor independently predicted a higher risk of
developing liver cancer. Smoking 15 or more cigarettes a day – less than a pack – was
associated with a rise in HCC risk. For alcohol use, risk rose even among those
who consumed just 5-15 grams per day (14 grams is generally considered a
standard drink, for example a bottle of beer, glass of wine or shot of
distilled spirits). Liver cancer cases decreased steadily as diet quality and
amount of exercise increased.
smoking was associated with a 27% reduction in HCC incidence, a healthy diet
reduced the risk by 17%, light or no drinking reduced incidence by 21%, a
healthy weight lowered the risk by 36% and a healthy level of exercise reduced incidence
by 35%. Looking at population-attributable risk, these factors could have
prevented 8%, 10%, 14%, 25% and 22% of liver cancer cases, respectively.
to liver-related mortality, meeting the healthy definition for each of the five
lifestyle factors reduced liver-related mortality by 31%, 19%, 37%, 48% and
54%, respectively. These factors could have prevented 16%, 8%, 20%, 37% and 35%
of deaths, the researchers calculated.
liver cancer and liver-related death, body mass index and exercise were the two
most important factors. Maintaining a healthy weight or exercising regularly
could have prevented 22 to 25% of new liver cancer cases and 35 to 37% of liver-related deaths.
Compared with individuals
with no healthy lifestyle factors, HCC risk decreased by 27% among those with
one factor, by 58% among those with two factors, by 81% among those with three
factors and by 92% among those with four or more factors.
The findings were similar
for liver-related death. Compared with those with no healthy lifestyle factors,
mortality decreased by 33% among those with one factor, by 66% among those with
two factors, by 74% among those with three factors and by 97% among those with
four or more factors.
For both HCC cases and
liver-related deaths, these patterns remained similar after adjusting for cases
of viral hepatitis or cirrhosis that arose during follow-up, Simon reported.
An exploratory analysis
of 1401 people who already had cirrhosis at baseline showed that they, too,
could still benefit. Those with one healthy lifestyle factor had a 17% lower
risk of liver-related death, those with two factors had a 33% lower risk and
those with three or more factors had a 47% reduction in relative risk.
Considering the lifestyle
factors in combination, having four or more healthy factors predicted an 88%
lower risk of developing liver cancer and a 91% reduction in liver-related
death. This combination could have prevented 82% of HCC cases and 90% of deaths,
the researchers calculated.
Having three healthy factors
was associated with a 46% lower risk of HCC and a 63% lower risk of
liver-related death. In other words, the triple combination could have
prevented 74% of HCC cases and 80% of deaths. Even having just two healthy
factors lowered the risk of HCC by 30% and mortality by 40%, preventing 45% of
liver cancer cases and 58% of liver-related deaths.
Looking at the NHANES cohort,
the researchers found that lifestyle had an even larger impact. In this general
population cohort, having four or more healthy lifestyle factors could have
prevented 89% of liver cancer cases and 94% of liver-related deaths.
underscore the enormous potential of primary prevention to reduce the growing
burden of HCC and liver-related mortality," the study authors concluded.