The Changing Prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) in Turkey in the Last Decade.

BACKGROUND/AIMS: The true prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) is unknown in Turkey due to a lack of population-based studies. The aim of this study was (i) to determine the overall and region-specific prevalence of NAFLD in Turkey; (ii) to analyze the factors associated with the prevalence; and (iii) to determine the nationwide change in the prevalence of NAFLD in the last decade. MATERIALS AND METHODS: The 10-year data (2007 to 2016) of 113,239 apparently healthy subjects visiting the check-up clinics of Acibadem Hospitals Group were retrospectively analyzed. A subgroup of patients (n=8120) statistically representing the bigger cohort were selected. The prevalence was analyzed according to ultrasound findings, age, sex, body mass index (BMI), geographical region, and time periods trisected as 2007-2010, 2011-2013 and 2014-2016. RESULTS: The overall prevalence of NAFLD in Turkey was found to be 48.3%. It was highest among people >50 years of age (65.6%), male sex (64.0%), with a BMI>25 kg/m2 (63.5%) and in Central and Eastern Anatolia regions (57.1% and 55.7%, respectively). The prevalence of NAFLD was 43.5% between 2007-2010, 47.6% between 2011-2013 and 53.1% between 2014-2016 and the rate of increase was 22%. Multivariate analysis showed that male sex, serum alanine aminotransferase (ALT) level, older age, BMI, type-II diabetes mellitus, hypertension and dyslipidemia were independent factors associated with NAFLD. CONCLUSION: NAFLD is a highly prevalent disease affecting almost half of the Turkish population (48.3%). We are faced with a dramatic increase in NAFLD prevalence in the past 10 years.

Determination of the upper limits of normal serum alanine aminotransferase (ALT) level in healthy Turkish population.

Background and Aim: Recent studies have reported that the widely accepted range of upper limits of normal (ULN) alanine aminotransferase (ALT) levels (ULN<40U/L) is high for the healthy population. We aimed to find the correct ULN level for men and women in a presumed healthy liver population group. Materials and Methods: The data of 7410 healthy subjects visiting the check-up clinics were retrospectively analysed in this study. Patients were divided in to "healthy liver group" (n=2694) and "high-risk liver group" (n=4716) based on fatty liver on ultrasound, existing of chronic liver disease, ongoing significant alcohol consumption, diabetes mellitus and dyslipidaemia. Receiver operating characteristic (ROC) curves were generated and the area under the curve (AUC) was calculated at the 95th percentiles for both men and women. Results: The AUC score of ALT for men was 0.92, and the ULN for the serum ALT in men was found as 32.10 U/L (sensitivity of 0.89, specificity 0.85). The AUC score of ALT for women was 0.90, and the ULN for serum ALT was found as 23.15 U/L (sensitivity of 0.90, the specificity of 0.88). Conclusion: ULN for serum ALT level should be lowered and different cut-off values should be used for men (32.10 U/L) and women (23.15 U/L).