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DALLAS, April 14, 2022 — About one in four adults worldwide are estimated to have liver disease which is a risk factor for heart disease, according to a new scientific statement from the American Heart Association released today. in the Association’s peer-reviewed journal. Arteriosclerosis, thrombosis and vascular biology. The disease, called non-alcoholic fatty liver disease (NAFLD), occurs when abnormally large amounts of fat build up in the liver, sometimes leading to inflammation and scarring. The prevalence of NAFLD is an estimate, taking into account the difficulties in diagnosing the disease, which are detailed in the statement.
A scientific statement from the American Heart Association is an expert analysis of current research and may inform future guidelines. Professional gastroenterology organizations have previously issued statements about the disease, however, they focus on liver toxicity (including scarring, cirrhosis, and liver cancer) rather than heart disease risk. This is the Association’s first statement on NAFLD.
“Non-alcoholic fatty liver disease (NAFLD) is a common condition that is often hidden or missed in routine medical care. Knowing about the disease and treating it early is important because it is a risk factor for chronic liver injury and cardiovascular disease,” said P. Barton Duell, MD, FAHA, Editorial Board Chair of the declaration and professor of medicine at the Knight. Cardiovascular Institute and Division of Endocrinology, Diabetes, and Clinical Nutrition at Oregon Health and Science University in Portland, Oregon.
There are two types of NAFLD: one when only fat is present in the liver (called non-alcoholic fatty liver disease), and the other when inflammation and scarring are also present (called non-alcoholic steatohepatitis, or NASH). . Excessive alcohol consumption can cause similar fat deposition and liver dysfunction, so the term NAFLD is used to differentiate disease caused by excessive alcohol consumption from disease without alcohol as the underlying cause.
NAFLD can go undiagnosed for years, so the statement emphasizes the need for awareness and surveillance for NAFLD, access to improved screening tools and treatment, and highlights highlighted lifestyle changes to help prevent and treat the disorder.
NAFLD increases the risk of heart disease
Heart disease is the leading cause of death for people with NAFLD. The diseases share many of the same risk factors, including metabolic syndrome (high blood sugar and triglycerides, increased abdominal fat, and high blood pressure); Type 2 diabetes; impaired glucose tolerance (prediabetes); and obesity. However, people with NAFLD are at a higher risk of heart disease than people who have the same risk factors for heart disease without liver disease.
NAFLD can sometimes be prevented
NAFLD is often preventable by maintaining a healthy body weight, exercising regularly, eating a heart-healthy diet, and managing conditions such as type 2 diabetes and high triglyceride levels (a type of fat) in the blood. Genetic factors also play a role in whether a person develops NAFLD and whether it leads to NASH, cirrhosis, or liver cancer.
“Although healthy living can help many people avoid NAFLD, some can develop NAFLD despite their best efforts,” Duell said. “At the other end of the spectrum, some people may have a genetic makeup that protects them from developing NAFLD despite obesity, type 2 diabetes, metabolic syndrome, poor dietary habits, or physical inactivity.”
NAFLD can go undiagnosed for years
Most people with NAFLD go undiagnosed, creating a barrier to optimal medical management, the statement said. The initial stages of NAFLD usually have no symptoms and people feel fine, and routine blood tests may not show liver abnormalities. Often, elevated liver enzymes in the blood, a possible sign of NAFLD, can be mistakenly attributed to a side effect of medications or recent alcohol consumption. Also, the absence of elevated liver enzyme levels does not rule out NAFLD or NASH.
According to the statement, a specialized ultrasound that measures liver elasticity, fat and stiffness (resulting from scarring) in the liver can detect NAFLD. This type of liver scan is a noninvasive way to help diagnose and monitor treatment for NAFLD and NASH, but it is underused. Liver biopsy is the definitive test for diagnosis of more advanced stages of NAFLD, however, it is invasive and expensive.
“Lack of awareness of the high prevalence of NAFLD contributes to underdiagnosis,” Duell said. “People with risk factors for NAFLD warrant more careful screening.”
If diagnosed in time, liver damage can be reversible
“Some of the good news about managing NAFLD is that healthy eating, regular exercise, and weight loss or prevention of weight gain are all valuable interventions for improving the health of most people. between us whether or not we have NAFLD,” Duell said.
Lifestyle changes are the cornerstone of treatment for early NAFLD. Dietary recommendations include reducing fat intake, limiting consumption of simple sugars, and choosing vegetables and whole grains that are higher in fiber. A Mediterranean-style diet is the only specific diet recommended by a consortium of professional groups for the treatment of NAFLD and NASH. Avoidance of alcohol is encouraged because even light alcohol consumption can worsen NAFLD and interfere with the healing ability of the liver.
Consulting a dietitian can help people with NAFLD plan and maintain a healthy diet and lose weight, if needed. The statement cites research showing that losing 10% of body weight significantly reduces liver fat and improves fibrosis, with lower levels of improvement with at least 5% body weight loss. Research also supports 20-30 minutes of physical activity daily to reduce liver fat and improve insulin sensitivity even in the absence of weight loss.
Medication may be needed to treat type 2 diabetes, lower cholesterol, or reduce weight. Bariatric surgery may be appropriate for some people because the resulting marked weight loss can be an effective intervention for NAFLD. Optimal care may also involve seeing a lipid specialist, endocrinologist, or gastroenterologist.
This scientific statement was prepared by the volunteer writing group on behalf of the American Heart Association Council on Atherosclerosis, Thrombosis, and Vascular Biology; the Hypertension Council; the Council on the Kidney in Cardiovascular Diseases; the Council on Lifestyle and Cardiometabolic Health; and the Peripheral Vascular Disease Council. Scientific statements from the American Heart Association promote greater awareness of cardiovascular disease and stroke and help facilitate informed healthcare decisions. Scientific statements describe what is currently known about a subject and areas that require further research. Although scientific statements can inform the development of guidelines, they do not make treatment recommendations. The American Heart Association guidelines provide the Association’s official clinical practice recommendations.
Co-authors are Vice President Francine Welty, MD; Michael Miller, MD; Alan Chait, MD; Gmerice Hammond, MD, MPH; Zahid Ahmad, MD; David E. Cohen, MD, Ph.D.; Jay D. Horton, MD; Gregg S. Pressman, MD; Peter P. Toth, MD, Ph.D. The authors’ disclosures are listed in the manuscript.
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About the American Heart Association
The American Heart Association is an unrelenting force for a world of longer, healthier lives. We are committed to equitable health in all communities. Through collaboration with many organizations and millions of volunteers, we fund innovative research, advocate for public health and share vital resources. The Dallas-based organization has been a leading source of health information for nearly a century. Join us on heart.org, Facebook, Twitter or by calling 1-800-AHA-USA1.
Arteriosclerosis Thrombosis and vascular biology