Original Article

POPULATION HEALTH MANAGEMENT Volume 0, Number 0, 2015 ª Mary Ann Liebert, Inc. DOI: 10.1089/pop.2015.0088

Effects of Eating Fast and Eating Before Bedtime on the Development of Nonalcoholic Fatty Liver Disease Takumi Nishi, MPH,1,2 Akira Babazono, MD, MS, PhD,1 Toshiki Maeda, MD, MPH,1 Takuya Imatoh, PhD,3 and Hiroshi Une, MD, PhD 4

Abstract

Few studies have evaluated the effects of lifestyle habits, such as eating behaviors, on the development of nonalcoholic fatty liver disease (NAFLD). It is known that NAFLD increases the risk of type 2 diabetes, prediabetes, cardiovascular disease, and chronic kidney disease. Therefore, a retrospective cohort study was conducted to evaluate the effect of eating behaviors and interactions between these behaviors on the development of NAFLD among health insurance beneficiaries without NAFLD. Study subjects were 2254 male and female insurance beneficiaries without NAFLD who had attended specific health checkups during fiscal years 2009 and 2012 among health insurance societies located in Fukuoka and Shizuoka Prefectures ( Japan). The incidence of NAFLD was defined as Fatty Liver Index scores ‡60 or visiting medical organizations for fatty liver disease treatment according to claims data. Eating behaviors, including eating speed and eating before bedtime, were evaluated by a self-administered questionnaire. During the study period, 52 (2.3%) subjects progressed to NAFLD. Subjects who ate before bedtime but did not eat fast had a higher risk of NAFLD (adjusted odds ratio [AOR] = 2.15; 95% confidence interval [CI]: 1.03–4.46). Those with both negative eating habits had a significantly higher risk of NAFLD (AOR = 2.48; 95% CI: 1.09–5.63). Subjects who habitually ate before bedtime, and those who ate fast and before bedtime, tended to have an increased risk of NAFLD. Earlier intervention to modify these poor eating behaviors could be useful to prevent NAFLD. (Population Health Management 2015;xx:xxx–xxx)

of body mass index (BMI), waist circumference (WC), triglycerides (TGs), and gamma-glutamyltransferase (GGT).8 Although it was developed and its validity has been evaluated in European populations,8,9 the FLI also has been validated in Korean populations.10 Specific health checkups and guidance were implemented to reduce the prevalence of lifestylerelated diseases since fiscal year (FY) 2008 in Japan.11 The components of FLI were measured during this program. Recent studies have reported that self-reported eating speed is not only positively associated with alanine aminotransferase activity,12,13 but also is associated with insulin resistance and overweight,14,15 which might lead to NAFLD. Additionally, eating before bedtime might contribute to weight gain as reported in a previous study, in which latenight eating could result in greater total daily food intake.16 Furthermore, a recent prospective cohort study revealed that consuming more of the daily energy intake at dinner was

Introduction

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n developed countries, nonalcoholic fatty liver disease (NAFLD) is the most common liver disease.1,2 A recent study showed that the prevalence of NAFLD in Japan was 24.6%: 68.5% in obese subjects and 15.2% in nonobese subjects.3 Moreover, the presence of NAFLD is associated with increased risk of type 2 diabetes, prediabetes, cardiovascular disease, and chronic kidney disease.4–7 Because of the increasing prevalence of NAFLD and its secondary adverse hepatic and extrahepatic effects, widespread screening for the prevention of NAFLD has become a relevant issue. Although abdominal ultrasonography is not the gold standard for diagnosing NAFLD, it is widely used in combination with other bioindicators to detect NAFLD because the diagnosis of NAFLD by liver biopsy is regarded as clinically problematic. Bedogni et al developed the Fatty Liver Index (FLI), consisting 1

Department of Health Care Administration and Management, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. 2 Fukuoka Institute of Health and Environment Sciences, Fukuoka, Japan. 3 Division of Medicinal Safety Science, National Institute of Health Sciences, Tokyo, Japan. 4 Medical Research Center, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.

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NISHI ET AL.

associated with increased risk of NAFLD among middleaged adults.17 Lifestyle modifications have been reported to have favorable effects on parameters of liver function among patients with NAFLD.18,19 However, few studies have evaluated the effect of lifestyle habits, such as eating behaviors, on the development of NAFLD among the general population. It is necessary to explore relationships between eating behaviors and NAFLD. Therefore, the authors conducted a retrospective cohort study to evaluate the effect of eating behaviors and the interaction between these behaviors on the development of NAFLD among health insurance beneficiaries who initially did not have this disorder. Methods Data sources

As shown in Figure 1, the authors identified 11,442 insurance beneficiaries aged 40 years or older as of March 31, 2010, who were insured through a health insurance society located in Fukuoka and Shizuoka Prefectures ( Japan), and who attended a specific health checkup in FY 2009. In this study, 2777 insurance beneficiaries who had not attended a follow-up checkup in FY 2012 were excluded. From the identified eligible subjects, another 4787 insurance beneficiaries were identified who had rarely drunk or could not drink alcohol, or whose alcohol consumption was less than 19 g/day based on a self-administered questionnaire in FY 2012. For these subjects, the FLI score was calculated as a surrogate measure for fatty liver using the following equation8: FLI ¼ exp [0:953  log (TGs) þ 0:139  BMI þ 0:718  log (GGT) þ 0:053  WC  15:745]= [1 þ exp (0:953  log (TGs) þ 0:139  BMI þ 0:718  log (GGT) þ 0:053  WC  15:745)]  100 According to Bedogni et al8 FLI