NAFLD, diabetes, and other endocrine diseases: clinical implications. Book Chapter

Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent and burdensome liver disease that has been overlooked by endocrinologists. NAFLD affects up to 70-80% of patients with type 2 diabetes (T2DM) and up to 30-40% of adult patients with type 1 diabetes. Compelling evidence indicates that the coexistence of NAFLD and diabetes mellitus increases the risk of developing not only the more severe forms of NAFLD but also chronic vascular complications of diabetes (mainly cardiovascular disease and chronic kidney disease). However, the links between NAFLD and diabetes are more complex than previously thought. Accumulating evidence now suggests that there is a bi-directional association between NAFLD and T2DM, and that NAFLD may also promote the development of incident T2DM. Recent evidence also suggests that NAFLD is frequently present in patients with other common endocrine diseases, such as polycystic ovary syndrome (PCOS) and primary hypothyroidism. Worryingly, these patients seem to be also more likely to develop the more severe histologic forms of NAFLD (i.e., NASH with varying degrees of fibrosis). Therefore, the major aim of this chapter is to not only to examine the rapidly expanding body of clinical evidence that supports a strong association of NAFLD with type 1 or type 2 diabetes, PCOS and primary hypothyroidism but also raise awareness of the importance of these associations within the endocrine community.