by Bianca Garilli, ND
Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in Western industrialized countries, can be categorized into two major groups – non-alcoholic fatty liver (NAFL), which is not associated with significant inflammation, and non-alcoholic steatohepatitis (NASH), which is associated with hepatic inflammation.1 Both of these conditions involve hepatic steatosis.
The US prevalence of NAFLD is 10-46%.1,2 Worldwide, the prevalence is estimated to be between 6-35%, with some researchers noting up to 50% incidence in the European population.1,2 Major risk factors associated with NAFLD include: central obesity, type 2 diabetes (T2D), dyslipidemia, and metabolic syndrome.1 NAFLD is strongly associated with high BMI, therefore, management recommendations frequently include weight loss, dietary changes, and exercise.2,3 However, approximately, 10-20% of patients with NAFLD are not obese, and benefits of weight loss are unclear for this population.4
To that end, a study published in the Journal of Hepatology investigated the efficacy of a 12-month lifestyle intervention program in non-obese vs. overweight/obese NAFLD patients to learn more about the impact of weight loss in these individuals on NAFLD remission;4 patients with NAFLD (N=154) were randomized into one of two groups:4
- Intervention (n=77; 39 with baseline [BL] BMI <25 and 38 with BL BMI >25): participated in 12 months of a targeted lifestyle program and regular exercise
- Control (n=77; 39 with BL BMI <25 and 38 with BL BMI >25) received usual care
After 12 months, more individuals from the intervention group (vs. control group) attained remission of NAFLD (as measured by proton-magnetic resonance spectroscopy); this was true for both the non-obese (67%) and obese (61%) intervention participants.4 In comparison, only 18% of the non-obese and 21% of the obese in the control group achieved NAFLD remission in the same time frame.4
Interestingly, remission of NAFLD in half of the non-obese individuals only required a modest 3-5% weight reduction, while in the obese patients, a 7-10% weight reduction was required for the same outcome.4 Also noteworthy: An extended follow-up period revealed that by year 6, the non-obese patients from the intervention group were more likely to have maintained their weight loss and normalization of liver function (e.g. ALT) than individuals from the control group.4
The authors of the study concluded that a lifestyle intervention program is an effective approach for treating NAFLD in both non-obese and obese patients, with only a modest weight reduction of 3-10% needed to achieve remission.4
Why is this Clinically Relevant?
- Both obese and non-obese patients with NAFLD benefit from a weight loss of 3-10%4
- For remission, individuals with NAFLD should implement a long-term lifestyle modification strategy that includes weight loss and exercise4
- Non-obese individuals with NAFLD are more likely to maintain weight loss and liver function normalization than their obese counterparts over the long term4
- UpToDate. Epidemiology, clinical features, and diagnosis of nonalcoholic fatty liver disease in adults. https://www.uptodate.com/contents/epidemiology-clinical-features-and-diagnosis-of-nonalcoholic-fatty-liver-disease-in-adults. Accessed August 31, 2018.
- Tomic D, Kemp WW, Roberts SK. Nonalcoholic fatty liver disease: current concepts, epidemiology and management strategies. Eur J Gastroenterol Hepatol. 2018;30(10):1103-1115.
- Lee SW, Yang SS, Lee TY, Yeh HZ, Tung CF, Chang CS. The association of non-alcoholic fatty liver disease with body mass index and waist circumference in a Chinese population. J Adv Nutr Hum Metab. 2016;2:e1483
- Wong VWS, Wong GLH, Chan RSM, et al. Beneficial effects of lifestyle intervention in non-obese patients with non-alcoholic fatty liver disease. J Hepatol. 2018;pii:S0168-8278(18)32293-1.