Alcohol drinking patterns and the risk of fatty liver in Japanese men

The intersection between alcohol-related liver disease and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) are the leading causes of chronic liver disease worldwide. NAFLD and ALD share pathophysiological, histological and genetic features and both alcohol and metabolic dysfunction coexist as aetiological factors in many patients with hepatic steatosis. A diagnosis of NAFLD requires the exclusion of significant alcohol consumption and other causes of liver disease. However, data suggest that significant alcohol consumption is often under-reported in patients classified as having NAFLD and that alcohol and metabolic factors interact to exacerbate the progression of liver disease. In this Review, we analyse existing data on the interaction between alcohol consumption and metabolic syndrome as well as the overlapping features and differences in the pathogenesis of ALD and NAFLD. We also discuss the clinical implications of the coexistence of alcohol consumption, of any degree, in patients with evidence of metabolic derangement as well as the use of alcohol biomarkers to detect alcohol intake. Finally, we summarize the evolving nomenclature of fatty liver disease and describe a recent proposal to classify patients at the intersection of NAFLD and ALD. We propose that, regardless of the presumed aetiology, patients with fatty liver disease should be evaluated for both metabolic syndrome and alcohol consumption to enable better prognostication and a personalized medicine approach.

Fatty Liver Disease, Metabolism and Alcohol Interplay: A Comprehensive Review

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, and its incidence has been increasing in recent years because of the high prevalence of obesity and metabolic syndrome in the Western population. Alcohol-related liver disease (ArLD) is the most common cause of cirrhosis and constitutes the leading cause of cirrhosis-related deaths worldwide. Both NAFLD and ArLD constitute well-known causes of liver damage, with some similarities in their pathophysiology. For this reason, they can lead to the progression of liver disease, being responsible for a high proportion of liver-related events and liver-related deaths. Whether ArLD impacts the prognosis and progression of liver damage in patients with NAFLD is still a matter of debate. Nowadays, the synergistic deleterious effect of obesity and diabetes is clearly established in patients with ArLD and heavy alcohol consumption. However, it is still unknown whether low to moderate amounts of alcohol are good or bad for liver health. The measurement and identification of the possible synergistic deleterious effect of alcohol consumption in the assessment of patients with NAFLD is crucial for clinicians, since early intervention, advising abstinence and controlling cardiovascular risk factors would improve the prognosis of patients with both comorbidities. This article seeks to perform a comprehensive review of the pathophysiology of both disorders and measure the impact of alcohol consumption in patients with NAFLD.

Complete alcohol abstinence increases the risk of NAFLD but not severity. A population analysis with transient elastography

BACKGROUND & AIMS

As the global prevalence of non-alcoholic fatty liver disease (NAFLD) continues to rise, ubiquity of alcohol use has also prompted discussion regarding the potential interactions between the two. This study aims to examine the effects of modest alcohol consumption on the prevalence and complications of NAFLD in a multi-ethnic population.

METHODS

This study analyses the 2017-2018 cycles of NHANES that examined liver fibrosis and steatosis with vibration controlled transient elastography. A coarsened exact matching was conducted to reduce confounding. Logistic regression was done with a multivariate model to assess the relationship between alcohol consumption (modest drinkers and non-drinkers) and risk of NAFLD and its complications.

RESULTS

2,067 individuals were found to have NAFLD and 284 NAFLD patients had a total history of alcohol abstinence. After coarsened exact matching, the prevalence of NAFLD was 49% (CI: 0.41 - 0.58) in non-drinkers and 33% (CI: 0.26 - 0.41) in modest drinkers. Non-drinkers had twice the odds of NAFLD compared to modest drinkers (OR: 1.99, CI: 1.22 - 3.22, p<.01) after adjustment for confounders. There were no significant differences in the odds of significant fibrosis, advance fibrosis, cirrhosis, cardiovascular disease and stroke between non-drinkers and modest drinkers. The odds of malignancy in non-drinkers were almost significantly less than modest drinkers (OR: 0.28, CI:0.08 - 1.02, p=.053).

CONCLUSION

Interestingly, modest alcohol consumption is associated with decreased odds of NAFLD. Further investigations are required to examine the relationship between alcohol consumption and NAFLD and subsequently the potential impact on NAFLD management.

Alcohol and Metabolic-associated Fatty Liver Disease

The diagnosis of metabolic-associated fatty liver disease is based on the detection of liver steatosis together with the presence of metabolic dysfunction. According to this new definition, the diagnosis of metabolic-associated fatty liver disease is independent of the amount of alcohol consumed. Actually, alcohol and its metabolites have various effects on metabolic-associated abnormalities during the process of alcohol metabolism. Studies have shown improved metabolic function in light to moderate alcohol drinkers. There are several studies focusing on the role of light to moderate alcohol intake on metabolic dysfunction. However, the results from studies are diverse, and the conclusions are often controversial. This review systematically discusses the effects of alcohol consumption, focusing on light to moderate alcohol consumption, obesity, lipid and glucose metabolism, and blood pressure.

Alcohol consumption in patients with nonalcoholic fatty liver disease: yes, or no?

Excessive alcohol intake is an established risk factor for chronic liver disease. At the same time, moderate alcohol intake appears to reduce cardiovascular morbidity. Accordingly, recommendations for alcohol intake in patients with nonalcoholic fatty liver disease (NAFLD), who are at increased risk for liver-related and cardiovascular events, are a point of debate. Some studies have shown beneficial effects of alcohol on cardiovascular and overall mortality in this specific subset of patients. Nonetheless, even light alcohol intake appears to aggravate liver disease and increase the risk of hepatocellular cancer. Therefore, patients with nonalcoholic steatohepatitis or advanced fibrosis should be advised against consuming alcohol. On the other hand, only light alcohol consumption (<10 g/day) might be permitted in patients without significant hepatic fibrosis, provided that they are carefully followed-up. As the research field focusing on NAFLD keeps widening, more prospective studies regarding this specific subject are expected, and may provide a basis for less ambiguous recommendations.

Changes in body composition and low blood urea nitrogen level related to an increase in the prevalence of fatty liver over 20 years: A cross-sectional study

AIM

Qualitative body composition (BC) change, characterized by the combination of visceral fat gain and muscle loss, is drawing attention as a risk factor for fatty liver (FL). The present study aimed to describe trends in BC change and its association with FL in the Japanese population.

METHODS

Data from medical checkups carried out on 56 639 Japanese participants every 5 years from 1997 to 2017 were analyzed. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated using body mass index and body fat percentage. Subjects were divided into two groups according to deviations from the correlation line of FMI and FFMI as the reference: FMI-predominant BC and FFM-dominant BC. Fatty liver was determined using abdominal ultrasonography.

RESULTS

The prevalence of FL significantly increased from 27.3% to 42.7% in men and from 18.0% to 25.5% in women. The prevalence of FMI predominance significantly increased from 33.6% to 43.9% in men and from 29.1% to 47.0% in women. Fat mass index predominance was independently associated with FL in men and women (odds ratio: 1.96 and 1.94, respectively). Serum blood urea nitrogen level was inversely associated with FL in men and women (0.958 and 0.961, respectively) and significantly decreased from 15.8 to 14.9 mg/dl in men and from 15.1 to 14.0 mg/dl in women.

CONCLUSIONS

Increasing FMI-predominant BC and decreasing serum blood urea nitrogen level could account for the increase in the prevalence of FL over 20 years. We believe that these factors stem from current lifestyle habits in Japan.

A Cohort Study Examining the Interaction of Alcohol Consumption and Obesity in Hepatic Steatosis and Mortality

OBJECTIVE

To study the interaction of alcohol consumption with body mass index (BMI) in the development of hepatic steatosis and mortality.

PARTICIPANTS AND METHODS

We conducted a retrospective cohort study of 18,506 participants without fatty liver disease or cirrhosis at enrollment in the Mayo Clinic Biobank from April 9, 2009, through March 31, 2016. Participants were classified by self-reported alcohol consumption status (nondrinkers, moderate drinkers [0 to 2 drinks per day], and heavy drinkers [>2 drinks per day]). The primary outcome of interest was the incidence of hepatic steatosis, identified by International Classification of Diseases, Ninth Revision code and confirmed with imaging. The secondary outcome of interest was all-cause mortality. Multivariate Cox regression analysis determined the impact of alcohol consumption stratified by BMI on outcomes compared with nondrinkers.

RESULTS

The cohort (mean ± SD age, 55.8±16.9 years; 63.8% female; mean ± SD BMI, 28.8±6.1 kg/m²) of 18,506 participants included 3657 (19.8%) nondrinkers, 14,236 (76.9%) moderate drinkers, and 613 (3.3%) heavy drinkers at enrollment. After a median follow-up of 5.8 years (interquartile range, 3.8 to 7.2 years), 684 participants had development of hepatic steatosis and 968 died. In moderate drinkers, the risk of hepatic steatosis development was high in the obese group (adjusted hazard ratio [AHR], 1.31; 95% CI, 1.03 to 1.67), insignificant in the overweight group (AHR, 0.86; 95% CI, 0.58 to 1.26), and decreased in the normal-BMI group (AHR, 0.48; 95% CI, 0.26 to 0.90). Heavy drinkers had an increased risk of hepatic steatosis irrespective of BMI. Moderate alcohol use was associated with decreased mortality in the normal-weight (AHR, 0.44; 95% CI, 0.34 to 0.58) and overweight (AHR, 0.70; 95% CI, 0.56 to 0.88) groups but not in the obese group (AHR, 0.80; 95% CI, 0.64 to 1.00).

CONCLUSION

In obese individuals, even moderate alcohol use is associated with the development of hepatic steatosis. Moderate alcohol consumption is associated with lower mortality in normal-BMI and overweight individuals but not in those who are obese.

The effect of moderate alcohol drinking in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is defined by fat accumulation in liver that is not caused by excessive alcohol consumption. Safe limits of alcohol consumption in NAFLD are usually defined as alcohol consumption of less than 210 g per week for men and 140 g per week for women (30 g/day in men, 20 g/day in women) and alcohol consumption below safe limits is generally regarded as moderate alcohol consumption. Many studies have investigated the effects of moderate alcohol consumption on NAFLD patients. Some studies showed that moderate alcohol consumption prevented the progression of fibrosis in the liver, whereas other reports showed worsening of fibrosis in the liver based on serologic, radiologic and liver biopsy findings compared with effects on total abstainers. NAFLD is also thought to be a hepatic manifestation of metabolic syndrome, and when combined with excessive alcohol consumption results in the development of components of metabolic syndrome and systemic harmful effects. The effects of moderate alcohol consumption on NAFLD have yet to be established.

Non-alcoholic Fatty Liver Disease and Alcohol-Related Liver Disease: Two Intertwined Entities

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, with a prevalence of 25-30%. Since its first description in 1980, NAFLD has been conceived as a different entity from alcohol-related fatty liver disease (ALD), despite that, both diseases have an overlap in the pathophysiology, share genetic-epigenetic factors, and frequently coexist. Both entities are characterized by a broad spectrum of histological features ranging from isolated steatosis to steatohepatitis and cirrhosis. Distinction between NAFLD and ALD is based on the amount of consumed alcohol, which has been arbitrarily established. In this context, a proposal of positive criteria for NAFLD diagnosis not considering exclusion of alcohol consumption as a prerequisite criterion for diagnosis had emerged, recognizing the possibility of a dual etiology of fatty liver in some individuals. The impact of moderate alcohol use on the severity of NAFLD is ill-defined. Some studies suggest protective effects in moderate doses, but current evidence shows that there is no safe threshold for alcohol consumption for NAFLD. In fact, given the synergistic effect between alcohol consumption, obesity, and metabolic dysfunction, it is likely that alcohol use serves as a significant risk factor for the progression of liver disease in NAFLD and metabolic syndrome. This also affects the incidence of hepatocellular carcinoma. In this review, we summarize the overlapping pathophysiology of NAFLD and ALD, the current data on alcohol consumption in patients with NAFLD, and the effects of metabolic dysfunction and overweight in ALD.

Chronic Alcohol Consumption is Inversely Associated with Insulin Resistance and Fatty Liver in Japanese Males

We aimed to elucidate the effect of chronic alcohol consumption on fatty liver. We assessed the consumption of alcohol in 2429 Japanese males (mean age: 54.2 ± 9 years); they were classified according to average consumption into non-drinkers (ND), light drinkers (LD), moderate drinkers (MD), and heavy drinkers (HD). The prevalence of fatty liver was the lowest in the MD and highest in the ND group (p < 0.001), while obesity was not significantly different among the groups (p = 0.133). Elevated levels of alanine aminotransferase (ALT) were the lowest in the MD group (p = 0.011) along with resistance to insulin (homeostasis model assessment-insulin resistance (HOMA-IR)), which was highest in the ND group (p = 0.001). Chronic consumption of alcohol was independently and inversely associated with fatty liver and insulin resistance after adjusting for obesity, hypertension, fasting hyperglycemia, habit of drinking sweet beverages, physical activity, and age (odds ratios are as follows: ND, 1; LD, 0.682; MD, 0.771; HD, 0.840 and ND, 1; LD, 0.724; MD, 0.701; HD, 0.800, respectively). We found that regardless of the type of alcoholic beverage, chronic consumption of alcohol is inversely associated with insulin resistance and fatty liver in Japanese males. This study had limitations, most notably the lack of investigation into diet and nutrition.

Epidemiology of non-alcoholic and alcoholic fatty liver diseases

Liver diseases are fast emerging as global health priorities. Fatty liver is described in the setting of non-alcoholic fatty liver disease (NAFLD) as well as alcoholic liver disease (ALD), the pathogenesis of excess fat being different in the two conditions while both are important components of the changing face of burden of liver diseases worldwide. They are intimately associated with a globalized economy and an increasingly homogenous socio- cultural order with a westernized lifestyle. The accompanying adoption of a progressively sedentary life, consumption of diet dense in calories facilitate development of NAFLD while a spiraling upward trend in alcohol use along with earlier age of drinking as well as increased amount of per capita alcohol consumption increases the prevalence of ALD globally. Adverse health outcomes in NAFLD as well as ALD are caused not only by progressive liver fibrosis that is the most significant factor for liver related and all-cause mortality in both but also by non-liver (cardiovascular, cancer, accidents, neurological) clinical outcomes that calls for a multidisciplinary and social approach to these conditions. We present here an outline of facets of epidemiology of both NAFLD as well as ALD along with its' public health implications. A broad-based integrated approach that incorporates social, behavioral as well as biological targets need to be undertaken at a health system level in a planned manner for these evolving liver health priorities that disproportionately challenges the low- and middle-income countries of Asia, South America and Africa.

Moderate Alcohol Intake in Non-Alcoholic Fatty Liver Disease: To Drink or Not to Drink?

Nonalcoholic fatty liver disease (NAFLD) is defined by hepatic steatosis in the presence of alcohol intake within safe limits, defined by guidelines of scientific associations (usually 20 g or 2 units/day in women, 30 g or 3 units in men). The diagnosis is usually followed by medical counseling of total abstinence, in order to prevent disease progression. This policy has been challenged by epidemiological studies, suggesting that the risk of liver disease and disease progression is lower in modest drinkers than in total abstainers. We revised the literature on the effects of modest alcohol intake on disease burden. Epidemiological data may suffer from several potential biases (recall bias for retrospective analyses, difficulties in the calculation of g/day), limiting their validity. Prospective data suggest that NAFLD patients with regular alcohol intake, although within the safe thresholds, are at higher risk of liver disease progression, including hepatocellular carcinoma; a detrimental effect of modest alcohol drinking is similarly observed in liver disease of viral etiology. Alcohol intake is also a risk factor for extrahepatic cancers, particularly breast, oral, and pharyngeal cancers, with gender difference and no floor effect, which outweigh the possible beneficial effects on cardiovascular system, also derived from retrospective studies. Finally, the negative effects of the calorie content of alcohol on dietary restriction and weight loss, the pivotal intervention to reduce NAFLD burden, should be considered. In summary, the policy of counseling NAFLD patients for alcohol abstinence should be maintained.

Association of alcohol consumption with prevalence of fatty liver after adjustment for dietary patterns: Cross-sectional analysis of Japanese middle-aged adults

Background & aims

Moderate alcohol intake is associated with reduced prevalence or incidence of fatty liver. However, whether or not the association is independent of dietary patterns remains unclear. We aimed to evaluate the cross-sectional association of alcohol intake with fatty liver after accounting for dietary patterns and obesity.

Methods

We assessed 4579 adults aged 30–79 years who participated in routine clinical examinations in St. Luke's International Hospital, Japan (January to March, 2015). We assessed their habitual diet using diet-history questionnaire, estimated alcohol intake, and derived dietary pattern variables using factor analysis. Fatty liver was ascertained using ultrasonography. Linear and U-shaped associations of alcohol intake with fatty liver were evaluated using Poisson regression, and a post hoc analysis was conducted after detecting potential outliers for alcohol intake and excluding them using sex-specific statistics (median plus 2 × interquartile range).

Results

Fatty liver was ascertained in 1120 participants (24.5%). Whereas no significant association of alcohol intake with fatty liver was observed when potential outliers of alcohol intake were included (p = 0.25), a significant U-shaped association was observed after excluding the outliers with and without adjustment for dietary patterns (p = 0.003 and 0.02, respectively). The lowest prevalence was estimated when alcohol consumption was approximately 7% of energy, with a prevalence ratio of 0.72 (95% confidence interval = 0.59–0.86) compared to non-drinkers. The association became imprecise and attenuated toward the null after further adjustment for body mass index (p = 0.06).

Conclusions

Alcohol intake showed a U-shaped association with fatty liver prevalence. This association was independent of underlying dietary patterns, while it was sensitive to excessive alcohol intake and obesity status, providing clinical implications for the prevention of fatty liver.

The bidirectional impacts of alcohol consumption and the metabolic syndrome: Cofactors for progressive fatty liver disease

Current medical practice artificially dichotomises a diagnosis of fatty liver disease into one of two common forms: alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Together, these account for the majority of chronic liver diseases worldwide. In recent years, there has been a dramatic increase in the prevalence of obesity and metabolic syndrome within the general population. These factors now coexist with alcohol consumption in a substantial proportion of the population. Each exposure sensitises the liver to the injurious effects of the other; an interaction that drives and potentially accelerates the genesis of liver disease. We review the epidemiological evidence and scientific literature that considers how alcohol consumption interacts with components of the metabolic syndrome to exert synergistic or supra-additive effects on the development and progression of liver disease, before discussing how these interactions may be addressed in clinical practice.

Mendelian randomisation suggests no beneficial effect of moderate alcohol consumption on the severity of nonalcoholic fatty liver disease

BACKGROUND

Previous epidemiological studies suggest that patients diagnosed with nonalcoholic fatty liver disease (NAFLD) who drink light to moderate amounts of alcohol (up to ~30 g per day) have less severe histological lesions compared with nondrinkers. However, while the cross-sectional nature of current evidence precludes assessment of causality, cumulative lifetime-exposure of moderate alcohol consumption on histological outcomes has never been evaluated.

AIM

To overcome these limitations, a Mendelian randomisation study was performed using a validated genetic variant (rs1229984 A;G) in the alcohol dehydrogenase (ADH1B) gene as a proxy of long-term alcohol exposure.

METHODS

We first assessed whether the instrumental variant (rs1229984) was associated with the amount of alcohol consumption in our cohort. We further explored the association between the variant and histological outcomes; a sample of 466 individuals, including 266 patients with NAFLD confirmed by liver biopsy, was studied.

RESULTS

We found that carriers of the A-allele consumed significantly lower amounts of alcohol compared with noncarriers (2.3 ± 5.3 vs. 8.18 ± 21 g per day, mean ± s.d., P = 0.03). The analysis of association with the disease severity showed that carriers of the A-allele had lower degree of histological steatosis (1.76 ± 0.83 vs. 2.19 ± 0.78, P = 0.03) and lower scores of lobular inflammation (0.54 ± 0.65 vs. 0.95 ± 0.92, P = 0.02) and NAFLD-Activity Score (2.9 ± 1.4 vs. 3.7 ± 1.4, P = 0.015) compared with noncarriers.

CONCLUSION

Mendelian randomisation analysis suggests no beneficial effect of moderate alcohol consumption on NAFLD disease severity.

The Association between Alcohol Consumption and β-Cell Function and Insulin Sensitivity in Korean Population

This cross-sectional study was performed to examine the association between alcohol consumption and insulin secretion and sensitivity using the Korean Genome and Epidemiology Study. Alcohol consumption levels were categorized into four groups: (i) abstainers, (ii) low (<5 g/day), (iii) intermediate (<30 g/day), and (iv) high (≥30 g/day) alcohol consumption. β-cell function and insulin sensitivity were estimated using the insulinogenic index (IGI60), and Matsuda insulin sensitivity index (ISI), respectively. IGI60 and ISI were dichotomized into high and low groups using median cut-off values and four groups were defined (G-I: high IGI60/high ISI; G-II: high IGI60/low ISI; G-III: low IGI60/high ISI; and G-IV: low IGI60/low ISI). Men consumed 26.5 g alcohol per day on average, whereas women only consumed 5.7 g/day, so women were excluded from subsequent analyses due to their low drinking levels. Alcohol consumption was positively associated with high-density lipoprotein (HDL) cholesterol, aspartate aminotransferase (AST), and triglycerides (TG) in men, but was negatively associated with IGI60 (p < 0.05). TG levels were only increased in individuals with decreased insulin sensitivity (G-II) or decreased β-cell function (G-III) with high alcohol consumption. In addition, alcohol consumption increased HDL cholesterol in the four groups (p < 0.001). In subjects with decreased insulin sensitivity (G-II), intermediate and high alcohol consumption increased the risk of high cholesterol and TG. In individuals with decreased β-cell function (G-III), alcohol consumption increased the risk of high TG and high AST levels. High alcohol consumption was significantly associated with reduced insulin secretion. In addition, alcohol consumption was related to some metabolic risk factors depending on insulin secretion or sensitivity.

Alcohol consumption and risk of fatty liver disease: a meta-analysis

BACKGROUND

Observational studies have shown inconsistent results regarding alcohol consumption and risk of fatty liver. We performed a meta-analysis of published literature to investigate the association between alcohol consumption and fatty liver disease (FLD).

METHODS

We searched Medline, Embase, Web of Science, and several Chinese databases, identifying studies that reported an association between alcohol consumption and the risk of FLD.

RESULTS

A total of 16 studies with 76,608 participants including 13 cross-sectional studies, two cross-sectional following longitudinal studies, and one cohort study met the inclusion criteria. For light to moderate alcohol consumption (LMAC), there was a 22.6% reduction in risk of FLD (odds ratio [OR] = 0.774, 95% confidence interval CI [0.695-0.862], P <0.001), and subgroup analysis showed that a greater reduction in risk of FLD was found in the female drinkers (30.2%) and the drinkers with BMI ≥25 kg/m2(31.3%) compared with the male drinkers (22.6%) and the drinkers with BMI <25 kg/m2(21.3%), respectively. For heavy alcohol consumption, there was no significant influence on risk of FLD (OR = 0.869, 95% CI [0.553-1.364], P = 0.541) in Japanese women, but there was a 33.7% reduction in risk of FLD (OR = 0.663, 95% CI [0.574-0.765], P < 0.001) in Japanese men and a significant increased risk of FLD (OR = 1.785, 95% CI [1.064-2.996], P = 0.028) in Germans.

CONCLUSION

LMAC is associated with a significant protective effect on FLD in the studied population, especially in the women and obese population. However, the effect of heavy alcohol consumption on FLD remains unclear due to limited studies and small sample sizes.

The Effects of Alcohol on Other Chronic Liver Diseases

Alcohol consumption is often a comorbid condition in other chronic liver diseases. It has been shown to act in synergy to increase liver injury in viral hepatitis, hereditary hemochromatosis, and nonalcoholic fatty liver disease (NAFLD), leading to an increased risk of cirrhosis, hepatocellular carcinoma, and liver-related mortality. Data suggest that modest alcohol consumption may be inversely related to the risk of developing NAFLD and lower rates of progression of NAFLD to nonalcoholic steatohepatitis (NASH). This article reviews data on the relationship between alcohol consumption and other chronic liver diseases.

Ethnicity matters: A Systematic Review and Meta-Analysis of the Non-Linear Relationship Between Alcohol Consumption and Prevalence and Incidence of Hepatic Steatosis

BACKGROUND

Fatty liver (hepatic steatosis) is one of the most common diseases globally, with increasing prevalence. The role of alcohol consumption in the development of hepatic steatosis has not been systematically examined.

METHODS

We searched Medline, Embase, and ProQuest Dissertations & Theses Global for original data on the relationship between alcohol consumption and hepatic steatosis measured by non-invasive imagery, excluding studies conducted in participants <18years, or subgroups related to viral and drug-induced liver disease. We identified 18 articles reporting adjusted data (Japan=11, other high-income countries=7). Random-effect categorical meta-analyses (<20g/day pure alcohol consumption vs non-drinkers) and dose-response meta-analyses for the whole range of alcohol consumption were conducted.

RESULTS

In total, 99,370 participants and 25,662 cases of hepatic steatosis were included. In Japan, low alcohol consumption was consistently associated with substantially reduced incidence and prevalence of hepatic steatosis compared to non-drinkers (RR for <20g pure alcohol/day=0.75, 95% CI: 0.71-0.79, I(2)=0%). No overall association was found in other countries (RR=1.05, 95% CI: 0.86-1.30, I(2)=84%). Dose-response analyses in Japan (up to 80g/day) showed an inverse relationship in men and a J-shape in women.

CONCLUSIONS

Alcohol consumption showed a complex association with hepatic steatosis with substantial differences by ethnicity and sex. Low alcohol consumption was beneficial in Japan with good epidemiological evidence, whereas there was no association in other countries. However, heterogeneity was large in countries other than Japan. More and higher quality research in diverse ethnic populations is needed to further clarify this relationship.

Caring for children with NAFLD and navigating their care into adulthood

NAFLD is the most common chronic liver disease in children and adults, with its prevalence closely associated with obesity and other features of the metabolic syndrome. As young adults with NAFLD transition from the paediatric care environment to adult services, establishing a coordinated model of transition to ensure ongoing and appropriate care is critical. Enabling a smooth transfer begins with an understanding of the key differences between paediatric and adult NAFLD as well as the psychosocial factors that affect older adolescents. This Review summarizes the literature on paediatric NAFLD from the past two decades with a focus on the differences in epidemiology, pathology, pathophysiology and treatment that are relevant to clinicians who transition paediatric patients to adult care. An integrated model, which employs a team of adult and paediatric providers who can address the psychosocial, cognitive and logistical challenges of transition, provides the best opportunity for a seamless and coordinated transfer to adult care.

Biphasic effect of alcohol intake on the development of fatty liver disease

BACKGROUND

Fatty liver is an important clinical feature not only in alcoholic and non-alcoholic fatty liver diseases, but in other chronic liver diseases as well. Our aim was to elucidate the effect and relationship between habitual alcohol intake and obesity in the development of fatty liver disease.

METHODS

We enrolled 8,029 subjects undergoing abdominal ultrasonography with general medical examinations, and analyzed the factors associated with fatty liver based on daily alcohol intake, body mass index (BMI), and waist circumference.

RESULTS

For fatty liver, BMI, waist circumference, total cholesterol, triglycerides, and fasting plasma glucose were significant and independent risk factors. Heavy alcohol intake (50 g/day) was a significant risk factor for fatty liver in women (odds ratio [OR], 3.35). Analysis based on the presence or absence of obesity revealed that moderate alcohol intake was a significant negative risk factor for fatty liver in both male and female obese (BMI ≥25 kg/m(2)) subjects (OR, 0.74 for non-obese and 0.39 for obese patients, respectively). Heavy alcohol intake was also a significant negative risk factor in obese males (0.62). In contrast, heavy alcohol intake was a risk factor in non-obese males (OR, 1.29) and in all females (OR, 2.22 for non-obese and 6.6 for obese patients, respectively).

CONCLUSIONS

The influence of alcohol intake on fatty liver differed depending on the level of alcohol consumption, gender, and the presence of obesity, and showed biphasic effects.

Light alcohol consumption plays a protective role against non-alcoholic fatty liver disease in Japanese men with metabolic syndrome

BACKGROUND & AIMS

Although excess alcohol consumption has been believed to cause liver injury, light alcohol consumption (LAC) has been reported to play a protective role against fatty liver in recent studies. However, the association between non-alcoholic fatty liver disease (NAFLD) and LAC in men with metabolic syndrome (MS) is unclear. The aim of this study was to examine the association between NAFLD and LAC in men with MS.

METHODS

Subjects were 1055 men with MS who underwent a regular health check-up and drank less 20 g/day of alcohol. A distinction was made between non-drinkers and light drinkers and the association between NAFLD and LAC in men with MS was elucidated. NAFLD was referred as fatty liver with alanine aminotransferase (ALT) levels ≧31 IU/L in this study.

RESULTS

Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and the prevalence of NAFLD were significantly lower in light drinkers than in non-drinkers. Logistic regression analysis showed body mass index (BMI), waist circumference (WC), uric acid (UA), haemoglobin A1c (HbA1c), visceral fat type MS and LAC (odds ratios: 0.654; 95% confidence intervals: 0.473-0.906; <0.05) were significant predictors of the prevalence of NAFLD.

CONCLUSION

The prevalence of NAFLD in light drinkers was significantly lower than in non-drinkers, and supporting previous reports studying the general population, LAC is one of the significant predictors of a decreased prevalence of NAFLD in men with MS.

Roles of alcohol consumption in fatty liver: a longitudinal study

BACKGROUND & AIMS

Roles of alcohol consumption in non-alcoholic fatty liver disease are still controversial, although several cross-sectional studies have suggested the beneficial effect of light to moderate drinking on fatty liver. We analyzed the longitudinal relationship between drinking pattern and fatty liver.

METHODS

We included 5297 Japanese individuals (3773 men and 1524 women) who underwent a baseline study in 2003 and follow-up at least once from 2004 to 2006. Generalized estimating equation was used to estimate any association between drinking pattern and fatty liver assessed by ultrasonography.

RESULTS

At baseline, 1179 men (31.2%) and 235 women (15.4%) had fatty liver; 2802 men (74.2%) and 436 women (28.6%) reported alcohol consumption. At the latest follow-up, 348 of 2594 men (13.4%) and 101 of 1289 women (7.8%) had newly developed fatty liver; 285 of 1179 men (24.2%) and 70 of 235 women (29.8%) demonstrated a remission of fatty liver. In men, drinking 0.1-69.9 g/week (odds ratio, 0.79 [95% confidence interval, 0.68-0.90]), drinking 70.0-139.9 g/week (0.73 [0.63-0.84]), drinking 140.0-279.9 g/week (0.69 [0.60-0.79]), and drinking ⩾280.0 g/week (0.68 [0.58-0.79]) were inversely associated with fatty liver after adjusting for obesity, exercise, and smoking. In women, drinking 0.1-69.9 g/week (0.71 [0.52-0.96]) and drinking 70.0-139.9 g/week (0.67 [0.45-0.98]) were inversely associated with fatty liver after the adjustment.

CONCLUSIONS

Light to moderate alcohol consumption, or even somewhat excessive amounts especially in men, was likely to protect most individuals against fatty liver over time.

The combined effects of alcohol consumption and body mass index on hepatic steatosis in a general population sample of European men and women

BACKGROUND

Research on the association between alcohol consumption and hepatic steatosis revealed conflictive results.

AIM

To investigate the associations between average daily alcohol consumption and binge drinking with hepatic steatosis, and to analyse combined effects of average daily alcohol consumption and binge drinking with body mass index (BMI) on hepatic steatosis.

METHODS

Data from the population-based Study of Health in Pomerania (SHIP) conducted in north-east Germany comprising 4009 adults were used. Alcohol consumption was assessed by self-report. Serum carbohydrate-deficient transferrin (CDT) was analysed as biomarker for alcohol consumption. Hepatic steatosis was diagnosed by ultrasonography.

RESULTS

Analyses revealed a dose-response relationship between average daily alcohol consumption and hepatic steatosis in men starting with a consumption of 20 g of alcohol per day [adjusted odds ratio (OR) compared to abstainers 1.53; 95% confidence interval (CI) 1.15-2.05]. Using CDT as alternative exposure variable confirmed these results. Binge drinking was associated with hepatic steatosis in men (adjusted OR of binge drinkers compared to nonbinge drinkers 1.36, 95% CI 1.06-1.74). The likelihood of having hepatic steatosis increased in men and women with increasing levels of average daily alcohol consumption in combination with overweight or obesity. Similarly, binge drinking in combination with overweight or obesity enhanced the likelihood of having hepatic steatosis.

CONCLUSIONS

Overweight or obesity substantially enhanced the effect of high levels of average daily alcohol consumption and binge drinking on hepatic steatosis in the present study population. This finding underlines the necessity to screen for multiple risk factors in the prevention of hepatic steatosis.

Clinical features of hepatocellular carcinoma associated with nonalcoholic fatty liver disease: a review of human studies

Most cases of hepatocellular carcinoma (HCC) in Japan develop in the background of chronic liver disease caused by hepatitis C virus (HCV). Recently, however, HCV-associated HCC has been shown to be decreasing, while non-B and non-C HCC (NBNC-HCC), which is negative for HCV and hepatitis B virus infection, has increased. The main cause of NBNC-HCC is alcoholic liver disease, but the recent increase of NBNC-HCC is thought to be due to an increase in patients with nonalcoholic fatty liver disease (NAFLD). Approximately 10% of NAFLD cases involve nonalcoholic steatohepatitis (NASH), and NASH can progress to liver cirrhosis and its associated complications such as HCC. There are no accurate data on the percentage of NASH-related HCC among all-cause HCC in Japan, because no large-scale investigation has been performed. However, the rate is thought to be about 3% of overall HCC, which is lower than that in the United States. The incidence of HCC in patients with NASH-related cirrhosis is thought to be 2% per year, which is lower than that in HCV-related cirrhosis. Risks for NASH-related HCC include advanced hepatic fibrosis, older age, and being male. NAFLD that includes NASH is associated with metabolic syndrome, which includes obesity and diabetes, and metabolic syndrome is a risk factor for HCC. Genetic factors and dietary patterns may also be related to NASH-related HCC. Thus, regular HCC surveillance, as performed for patients with viral chronic liver disease, is required for patients with NAFLD, and diagnostic markers are required for simple, rapid and specific detection of NASH-related HCC.

Increasing prevalence of diabetes mellitus in association with fatty liver in a Japanese population

BACKGROUND

The prevalence of diabetes mellitus (DM) has been increasing. The present study was carried out to examine the relationship between this increase and fatty liver.

METHODS

Japanese participants who underwent regular health examinations in 1991, 1996, 2001, 2006, and 2011 were enrolled. Fatty liver was diagnosed using ultrasonography. DM was defined as requiring the use of medication for DM, having a fasting blood glucose level ≥ 126 mg/dl, or hemoglobin A1c level ≥ 6.5 %.

RESULTS

Logistic regression analysis on data from 11,235 participants (6,882 men and 4,271 women) in 2011 revealed that the association between fatty liver and DM was independent of age, body composition, and other confounders [odds ratio (OR) 1.97, 95 % confidence interval (95 % CI) 1.66-2.32 in men, and OR, 3.12; 95 % CI, 2.29-4.26 in women]. In 2006, 5,318 participants did not have DM and were able to be followed up in 2011. Fatty liver in 2006 was an independent predictor of DM in 2011 [OR 1.73 (95 % CI 1.20-2.50) in men, 4.13 (2.16-8.10) in women]. The prevalence of DM increased significantly during the 20-year period examined among both men (6.0, 8.9, 10.0, 10.8, 12.0 %, P < 0.001) and women (3.3, 4.5, 4.2, 4.1, 5.1 %, P = 0.004), accompanied with an increased prevalence of fatty liver among both men (10.8, 26.3, 33.8, 36.7, and 38.0 %, P < 0.001) and women (6.5, 16.7, 22.2, 21.3, and 20.8 %, P < 0.001).

CONCLUSION

Fatty liver independently predicts both present and future DM. Fatty liver may play an important role in the recent increases in the prevalence of DM.

Effect of lifetime alcohol consumption on the histological severity of non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is defined based on recent alcohol consumption; however, remote or lifetime alcohol consumption is not taken into account. It is not known whether lifetime alcohol consumption contributes to the severity of disease in patients with NAFLD. To determine the effect of lifetime alcohol consumption on the histological severity in patients with NAFLD.

PATIENTS & METHODS

Adults >18 years of age with presumed NAFLD and alcohol consumption <40 g/week were enrolled. Lifetime alcohol consumption was determined using a questionnaire. Patients with a history of long-term alcohol abuse or dependence were excluded. A liver biopsy was reviewed by a single pathologist in a blinded fashion. Demographic, clinical and histological findings were compared in those who had regular alcohol consumption and those who did not.

RESULTS

A total of 77 patients had fatty liver on biopsy. Fifty-two patients had a history of regular alcohol consumption. The median lifetime cumulative alcohol intake was 24 gram-years. On multivariable analysis, increasing age (OR 1.07, 95% CI 1.01-1.14) was associated with severe liver disease, whereas alcohol consumption of ≥24 gram-years was associated with less severe disease (OR 0.26, 95% CI 0.07-0.97, P = 0.04). Patients who continued to consume alcohol or had been abstinent for ≤1 year had less severe disease.

CONCLUSION

Some degree of regular alcohol consumption over the course of a lifetime compared to minimal intake appears to have a protective effect on the histological severity of liver disease among patients with strictly defined NAFLD.

Roles of alcohol drinking pattern in fatty liver in Japanese women

PURPOSE

Several studies have reported an inverse association between moderate alcohol consumption and prevalence of fatty liver (FL) in men. We aimed to clarify this association in women.

METHODS

We collected health checkup data from 4,921 Japanese women without concurrent liver disease (mean age 46.4 years) and performed a cross-sectional study to evaluate the influence of alcohol drinking patterns (frequency and amount) on the prevalence of FL as assessed by ultrasonography.

RESULTS

Alcohol consumption was reported in 30.8 % of participants, and FL was observed in 13.8 % (15.5 % nondrinkers, 10.1 % drinkers). Alcohol consumption was inversely associated with FL prevalence [adjusted odds ratio (AOR) 0.79, 95 % confidence interval (CI) 0.63-0.98]. In analyses stratified by drinking frequency and/or amount of alcohol consumed, the risk of FL decreased for the following categories: 0.1-19.9 g/drinking day (AOR 0.61, 95 % CI 0.44-0.83) and 0.1-69.9 g/week (AOR 0.74, 95 % CI 0.55-0.98). The amount of alcohol consumed directly correlated with the prevalence of FL in daily drinkers (p < 0.05), whereas there was no correlation between the frequency of alcohol consumption and FL prevalence. Alanine aminotransferase levels were significantly lower for the following categories: 0.1-19.9 g/drinking day for 1-3 days a week (p = 0.016) and 0.1-69.9 g within 1-3 drinking days a week (p = 0.004).

CONCLUSIONS

Minimal alcohol consumption appears to have protective effects against nonalcoholic FL disease in women, although an increase in the amount of alcohol consumed appears to nullify the protective effect.

Independent and supra-additive effects of alcohol consumption, cigarette smoking, and metabolic syndrome on the elevation of serum liver enzyme levels

We investigated the independent and combined effects of alcohol consumption, cigarette smoking and metabolic syndrome on abnormal liver function, i.e., the elevation of serum liver enzyme levels. Participants of a Korean population-based prospective cohort aged ≥30 years without liver disease, diabetes, or cardiovascular diseases were included. Information on alcohol consumption, smoking status, and metabolic syndrome, defined as per the criteria of the Adult Treatment Panel III, were applied to evaluate their impact on serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyl transferase (GGT). Alcohol consumption, cigarette smoking and metabolic syndrome were the significant individual factors that elevated serum liver enzyme levels. Supra-additive effects of metabolic syndrome and either alcohol consumption or cigarette smoking were also identified. The combination of heavy drinking (≥24 g/day) and metabolic syndrome conferred an effect that was higher than the sum of the two individual effects (Synergic Index (SI): AST, 2.37 [1.20-4.67]; GGT, 1.91 [1.17-3.13]). Only GGT level (odds ratio 6.04 [3.68-9.94], SI 2.33 [1.24-4.41]) was significantly elevated when the effect of moderate drinking (<24 g/day) and metabolic syndrome was combined. The combined effect of any level of alcohol consumption and cigarette smoking was also supra-additive on the elevation of GGT level with SIs of 5.57 for drinking <24 g/day and smoking ≤20 pack years, 5.12 for <24 g/day and >20 pack years, 1.80 for ≥24 g/day and ≤20 pack years, 2.03 for ≥24 g/day and >20 pack years, while only the combined effect of drinking ≥24 g/day and smoking >20 pack years elevated the AST level (SI 4.55 [3.12-6.61]). The combined effect of cigarette smoking and metabolic syndrome was not supra-additive. To prevent fatty liver disease and other related diseases, a multifactorial prevention strategy that includes limited alcohol consumption, smoking cessation and rectification of adverse metabolic profiles is required.

Adiponectin negatively correlates with alcoholic and non-alcoholic liver dysfunction: Health check-up study of Japanese men

AIM

  Central obesity, insulin resistance and alcohol consumption are thought to be major risk factors for fatty liver formation. Adiponectin (APN) prevents fatty liver formation, and its serum levels are lower in subjects with central obesity and/or insulin resistance. The aim of this study was to explore the association among serum APN levels, central obesity, insulin resistance and liver dysfunction with or without fatty liver classified by alcohol consumption in healthy subjects.

METHODS

  A total of 5588 Japanese male subjects who underwent a health check-up were classified into three groups according to alcohol consumption: non- or light drinkers (15 g/day ≥ ethanol); mild drinkers (15 g/day < ethanol ≤ 30 g/day); and moderate- or heavy drinkers (30 g/day < ethanol). Central obesity and insulin resistance were assessed by waist circumference (WC) and Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR), respectively.

RESULTS

  WC was significantly increased, while HOMA-IR was significantly decreased according to the extent of alcohol consumption. Serum alanine aminotransferase levels were significantly lower and serum APN levels were significantly higher in mild drinkers than in the other two groups. Multiple linear regression analysis showed that serum APN level served as the significant and independent determinant for liver dysfunction in the subjects with fatty liver, irrespective of alcohol consumption. However, WC became a non-significant determinant of liver dysfunction as alcohol consumption increased.

CONCLUSION

  Hypoadiponectinemia is a significant determinant for steatotic dysfunction for all levels of alcohol consumption, but central obesity was not a significant determinant for alcoholic fatty liver-induced liver dysfunction.

Alcohol's effect on other chronic liver diseases

In addition to directly causing liver disease, alcohol consumption is a common comorbid condition with other chronic liver diseases and may exacerbate liver injury, particularly in nonalcoholic fatty liver disease, chronic viral hepatitis, hereditary hemochromatosis, and autoimmune liver diseases. This synergism can result in increased hepatic inflammation and accelerated rates of fibrosis, with more rapid and earlier development of cirrhosis, and also increase the risk for liver cancer and death from liver disease.

Fatty liver in men is associated with high serum levels of small, dense low-density lipoprotein cholesterol

AIMS

Our study addressed potential associations between fatty liver and small, dense low-density lipoprotein cholesterol (sd-LDL-C) levels using a cross-sectional analysis.

METHODS

We enrolled 476 male subjects. Serum sd-LDL-C concentrations were determined using precipitation assays.

RESULTS

Subjects were divided into four groups based on triglyceride (TG) and LDL-C levels: A, TG < 150 mg/dl and LDL-C < 140 mg/dl; B, TG < 150 mg/dl and LDL-C ≥ 140 mg/dl; C, TG ≥ 150 mg/dl and LDL-C < 140 mg/dl; and D, TG ≥ 150 mg/dl and LDL-C ≥ 140 mg/dl. sd-LDL-C levels and the prevalence of fatty liver were significantly higher in groups B, C, and D than in group A. Subjects were also categorized into four groups based on serum sd-LDL-C levels; the prevalence of fatty liver significantly increased with increasing sd-LDL-C levels. Additionally, logistic regression analysis revealed an independent association between sd-LDL-C concentrations and fatty liver using such potential confounders as obesity and hyperglycemia as variables independent of elevated TG or LDL-C levels.

CONCLUSIONS

Fatty liver is a significant determinant of serum sd-LDL-C levels independent of the presence of obesity or hyperglycemia. Fatty liver may alter hepatic metabolism of TG and LDL-C, resulting in increased sd-LDL-C levels.

Calorie and alcohol consumption in nonalcoholic fatty liver disease

OBJECTIVES AND METHODS

Most definitions of nonalcoholic fatty liver disease (NAFLD) allow some intake of alcohol but little attention has been paid to the possible contribution of alcohol-derived calories in the overall daily intake. The aim of the present study was to determine whether, in a group of 144 patients referred to liver outpatients with NAFLD, a more structured questioning of dietary habits and alcohol consumption would provide better information on alcohol-derived and dietary-derived calorie intake and the relationship with the BMI.

RESULTS

Both food intake and calories resulting from alcohol ingestion were frequently underestimated as was the percentage of patients who were drinking excessively (>30 U a week), which was surprisingly high at 40%. The substantial calorie intake resulting from alcohol consumption in this group was associated with a reduction in dietary calorie intake, so that the total daily calorie intake remained similar to those with low-to-moderate or no alcohol consumption. The findings also showed that the BMI, although still elevated, was significantly reduced in those drinking heavily compared with low and nondrinkers.

CONCLUSION

Patients with NAFLD can have substantially higher levels of alcohol consumption than usually recognized. The additional calorie intake resulting from this is to some extent balanced by a reduction in dietary calorie intake with less elevation in BMI, and a clear distinction from an alcohol-induced steatosis may be difficult.

Potential health benefits of moderate alcohol consumption: current perspectives in research

The benefits of moderate amounts of alcohol for a better health and longer life expectancy compared with abstinence have been suggested by the findings of numerous studies. However, controversies have emerged regarding the influence of confounding factors and the systematic errors that might have been inadvertently disregarded in the early studies. This review includes a description of the findings of those research studies published in the last 5 years on the effects of moderate alcohol consumption on all-cause mortality, CVD and inflammation, the immune system, insulin sensitivity, non-alcoholic fatty liver disease (NAFLD) and cancer. Promising evidences exist from both animal studies and human clinical trials regarding intermediate end-points of CHD and insulin sensitivity, such as HDL, adiponectin or fibrinogen. However, controversies and inconsistent findings exist regarding many of these diseases and related functions and biomarkers. Further research and human randomised-controlled trials with adequate standardisation of the study conditions are necessary in order to draw a comparison between studies, establish the causal effect of moderate alcohol intake on disease protection and reach consensus on the circumstances that allow the recommendation of moderate alcohol habitual intakes as a strategy for health maintenance.

Association of alcohol consumption with lipid profile in hypertensive men

AIMS

Alcohol consumption is known to be closely related with alterations in blood lipid levels as well as in blood pressure. The objective of this study was to evaluate the association between alcohol consumption and blood lipid levels in hypertensive men.

METHODS

A cross-sectional study involving participants (n = 2014) aged 20-69 years from the Korea National Health and Nutrition Examination Survey, 1998-2009. Demographic characteristics, dietary intake and medical history were obtained from the participants by questionnaire, and lipid levels were determined by analysis of blood samples.

RESULTS

After adjusting for demographic and dietary factors, alcohol consumption was negatively associated with risk of low high-density lipoprotein cholesterol [HDL-C; odds ratio (OR): 0.29, 95% confidence interval (CI): 0.22-0.40 in heavy (≥30 g/day) drinkers; P for trend <0.001], whereas the risk of high triglycerides increased with increasing alcohol consumption (OR: 2.04, 95% CI: 1.53-2.72 in heavy drinkers; P for trend <0.001). However, the OR of high non-HDL-C and the ratio of high triglycerides to HDL-C did not change significantly with an increase in alcohol consumption.

CONCLUSION

These data suggest that alcohol consumption differentially affected lipid measures according to the amount of alcohol intake in hypertensive men.

Impact of cigarette smoking on onset of nonalcoholic fatty liver disease over a 10-year period

BACKGROUND

Metabolic syndrome, which includes obesity, hyperglycemia, dyslipidemia, and hypertension, is a major risk factor for the development of nonalcoholic fatty liver disease (NAFLD). Cigarette smoking is a well-known risk factor for metabolic syndrome, but the epidemiological impact of cigarette smoking on development of NAFLD is unclear.

METHODS

In this retrospective study, 2,029 subjects underwent a complete medical health checkup in 1998 and again in 2008. Those who were positive for hepatitis B surface antigen or hepatitis C virus antibody, or had an alcohol intake of > 20 g/day as assessed by questionnaire, were excluded. Fatty liver was diagnosed by abdominal ultrasonography. Independent risk factors associated with the development of NAFLD were determined by multiple logistic regression analysis. Smoking status was expressed using the Brinkman index (BI), which was calculated as the number of cigarettes smoked per day multiplied by the number of years of smoking.

RESULTS

Of 1,560 subjects without NAFLD in 1998, 266 (17.1%) were newly diagnosed with NAFLD in 2008. Multiple logistic analysis identified age [adjusted odds ratio (AOR) 0.95, 95% confidence interval (95% CI) 0.94-0.97], male sex (AOR 1.46, 95% CI 1.01-2.10), body mass index ≥ 25 (AOR 3.08, 95% CI 2.20-4.32), dyslipidemia (AOR 1.79, 95% CI 1.25-2.58) and cigarette smoking (AOR 1.91, 95% CI 1.34-2.72) as risk factors associated with the development of NAFLD. Smoking status at baseline was also associated with the development of NAFLD (BI 1-399: AOR 1.77, 95% CI 1.02-3.07, BI ≥ 400: AOR 2.04, 95% CI 1.37-3.03).

CONCLUSION

Cigarette smoking is an independent risk factor for onset of NAFLD.