Fatty liver disease is now recognized as a significant cause of liver problems, including cirrhosis and liver failure. In this condition, fat deposits in the liver may form over time. Fatty liver disease is linked with a variety of conditions such as obesity, diabetes and high cholesterol levels. There are 2 types of fatty liver disease: once caused by alcohol (alcoholic liver disease) and one not related to alcohol (nonalcoholic fatty liver disease, or NAFLD).
The potential association between NAFLD and thyroid function has remained controversial. A possible link between this condition and thyroid disease has been an area of study. Recent studies have emerged suggesting that individuals with NAFLD have an increased incidence of hypothyroidism, which leads to a wide range of metabolic complications. This study was performed to assess the relationships between TSH levels and NAFLD and whether having thyroid disease increases the risk of developing NAFLD.
THE FULL ARTICLE TITLE
Fan H et al 2022 Thyroid stimulating hormone levels are associated with genetically predicted nonalcoholic fatty liver disease, J Clin Endocrinol Metab. Epub 2022 Jun 28. PMID: 35763044.
SUMMARY OF THE STUDY
This study reviewed medical charts of over 14,000 patients. The age of the participants ranged from 20 to 74 years. Those included in the study had an ultrasound of their abdomen as well as thyroid blood work tested (TSH, T4). The authors used genetic data from a large database to look for possible connections. In addition, statistical methods were utilized to look at a possible association. This analysis included 1801 patients with NAFLD and 6185 healthy patients without liver disease.
It was found that TSH levels were related to NAFLD to a certain extent. Patients who did not have NAFLD typically had lower TSH and higher T4 levels. The data suggested that NAFLD caused an increase in TSH levels while TSH levels did not significantly change the risk of NAFLD.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study is one of the few that have looked at the link of NAFLD with thyroid diseases. It suggests that there may be a link of increased TSH levels and NAFLD. However, further studies will be needed to investigate this link further to determine whether thyroid disease is in fact a risk factor for fatty liver disease.
— Vibhavasu Sharma, MD, FACE
ABBREVIATIONS & DEFINITIONS
TSH: thyroid stimulating hormone — produced by the pituitary gland that regulates thyroid function; also the best screening test to determine if the thyroid is functioning normally.
Fatty liver disease: liver diseases including cirrhosis caused by deposits of fat in the liver. This can be caused by alcohol (alcoholic fatty liver disease) or not related to alcohol (nonalcoholic fatty liver disease, NAFLD). NAFLD can be seen in patients with diabetes and/or obesity.