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Oral Presentations

Session Title: Parallel Session: ASH/NASH CLINICAL
Presentation Date: 31 MAR, 2011

THE CHANGING FACE OF CHRONIC LIVER DISEASE (CLD) IN THE UNITED STATES: THE RISING EPIDEMIC OF NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD)

Z. Younossi^1,2*, M. Stepanova^1,2, M. Afendy², Y. Fang², Y. Younossi², H. Mir¹, M. Srishord^1,2
1Center for Liver Diseases, Inova Fairfax Hospital, ²Betty and Guy Beatty Center for Integrated Research, Inova Health System, Falls Church, VA, USA. *zobair.younossi@inova.org

Chronic liver diseases are among major causes of morbidity and mortality worldwide. In recent decades, epidemic of obesity may be responsible for a shift in the prevalence of different types of CLD in the United States.
Methods: Three cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 1988 and 2008 were used. Diagnoses of CLDs were established using standard serologic and clinical data. Statistical analyses were performed using SUDAAN 10.0.
Results: A total of 39,500 adults from three NHANES cycles (1988-1994, 1999-2004 and 2005-2008) with complete clinico-demographic data were included. The prevalence rates for CLD were 11.78±0.48% (1988-1994), 15.66±0.41% (1999-2004) and 14.78±0.58% (2005-2008) (p< 0.0001). During the same time period, prevalence of hepatitis B (0.36±0.08%, 0.33±0.06% and 0.34±0.08%, p=0.80), hepatitis C (1.95±0.22%, 1.97±0.20% and 1.68±0.15%, p=0.30), iron overload (3.59±0.23%, 2.84±0.20% and 1.70±0.39%, p=0.0004) and alcoholic liver disease (1.38±0.16%, 2.21±0.18% and 2.05±0.21%, p =0.0143), remained stable or decreased. However, NAFLD prevalence increased: 5.51±0.31% (1988-1994), 9.84±0.33% (1999-2004) and 11.01±0.51% (2005-2008) (p< 0.0001). During 1988-1994, NAFLD comprised 46.8±1.9% of all CLD while during 1994-2004 and 2005-2008, NAFLD´s share increased to 62.84±1.52% and 75.1±1.6%; respectively (p< 0.0001). During the same period, the only component of metabolic syndrome which didn´t increase was hyperlipidemia, while obesity (BMI>30) [21.74±0.65% in 1988-1994 to 30.02±0.67% in 1999-2004 to 33.22±1.08% in 2005-2008], visceral obesity (ATP-III definition) [35.18±0.73% to 48.16±0.84% to 51.43±1.25%], type 2 diabetes (DM) [5.55±0.29% to 7.88±0.33% to 9.11±0.47%], insulin resistance (defined as HOMA>3.0) [23.29± 0.80% to 32.50±0.94% to 35.00±1.41%] and hypertension [22.68±0.80% to 33.11±0.73% to 34.08±1.05%] were increasing steadily (p< 0.0001). In multivariate analysis, obesity and DM remained independent predictors of NAFLD in all three NHANES cycles. If the current rates of increase in these two NAFLD risks (Obesity and DM) continue for another two decades, the prevalence of NAFLD in the U.S. is expected to increase by 50% by 2030.
Conclusions: While the prevalence of other major causes of CLD remained stable or decreased in U.S. population, the prevalence of NAFLD is steadily rising. Over the next decades, this rate is expected to increase, substantially contributing to the burden of CLD in the U.S.