The “Metabolic Syndrome”, defined by the International Diabetes Federation as the presence of central obesity (or increased waist circumference) plus any two of the four following conditions: insulin resistance, high blood levels of triglycerides (fat), low levels of HDL (High Density Lipoprotein, or the “good” cholesterol), or high blood pressure, is a true disease epidemic in Western countries.
The Metabolic Syndrome is caused by overeating foods high in fat and sugar and inadequate physical activity, which lead to obesity, Type II diabetes, hyperlipidemia, and hypertension. There is probably a genetic component involved as well, but anyone who is obese is at high risk. If unchecked, heart disease, fatty liver disease, and all of the complications associated with diabetes inevitably progress to threaten the lives of all those with this syndrome.
Non Alcoholic Fatty Liver Disease (NAFLD) is the hepatic (liver cell) manifestation of the Metabolic Syndrome and is the most common cause of chronic liver injury in the Western world. NAFLD can progress to Non Alcoholic Steato-Hepatitis (NASH), which is a chronic inflammation of the liver leading to cell death, fibrosis, and cirrhosis. NASH is becoming the most common cause of end stage liver disease requiring liver transplantation.
NAFLD and NASH
General Population: 20-30% 2-3%
Morbidly Obese: 90% 37%
General Pediatric: 3%
Obese Pediatric: 53%
Type II Diabetics: 70%
As you can see from this table, up to 30% of the general population (in Western countries) has fatty liver disease, or accumulation of fat droplets within the cells of the liver). A smaller, but not insignificant, portion of the general population has NASH. In morbidly obese people (defined as a Body Mass Index of 35 kg/m2 or greater), NAFLD and NASH are far more prevalent (90% and 37%, respectively). Quite concerning is the childhood obesity problem, with 3% of all children and 53% of obese children having fatty livers. 70% of those with Type II Diabetes (by far the most common type) have NAFLD. Although these data are from Western countries, the problem is global. The World Health Organization estimates that over one billion people are overweight (BMI>25), of whom 300 million are obese (BMI>30).
People with NAFLD or NASH have an increased risk of developing liver cancer (Hepatocellular Carcinoma or “HCC”). Independent associations of liver cancer and diabetes or heart disease that have been reported in the scientific literature can be explained by the fact that most with the Metabolic Syndrome also have fatty liver disease.
Currently, the management of fatty liver disease involves dietary restriction and modification of the types of food eaten as well as increased exercise. For the Metaboloc Syndrome, medicines exist to treat cholesterol and lipid levels, high blood pressure, and diabetes. But for NAFLD, no highly effective medical treatment exists yet. Investigational drugs (that are nowhere near being ready for general use in humans) include the antioxidants silymarin and nitro-aspirin.
Interfering with the endocannabinoid system (yes, the molecules naturally produced in our bodies that interact with marijuana) by receptor blockade (CB-1&2) may help NAFLD.
But for advanced disease when behavioral modifications are not effective, bariatric surgery is the accepted treatment in appropriate candidates.
The good news is that fatty livers can become normal again when appropriate measures are taken. If NAFLD progresses to NASH, however, the process is unlikely to reverse with our current therapies, even surgery. Although the best way to definitively diagnose NAFLD and NASH is to perform a liver biopsy, we and others are actively investigating noninvasive means of assessing fatty liver disease in order to decrease the frequency of biopsies and to gauge response to therapeutic interventions.
The best medicine is preventive medicine. So watch what you eat, how much you eat, and get some exercise (even a gentle stroll can significantly help and water aerobics are great for those with physical limitations). Easier said than done, but it is certainly possible. As much as I enjoy operating, I would prefer that you take care of yourself as best you can so that I won’t have to perform a liver transplant or liver cancer resection on you!