Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype

Nutrition, Metabolism & Cardiovascular Diseases (2018) xx, 1e7

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Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype P. Di Bonito a, E. Miraglia del Giudice b, C. Chiesa c, M.R. Licenziati d, M. Manco e, F. Franco f, G. Tornese g, M.G. Baroni h, A. Morandi i, C. Maffeis i, L. Pacifico j, G. Valerio k,*, for the CARITALY Study on the behalf of the Childhood Obesity Study Group of the Italian Society of Pediatric Endocrinology and Diabetology a

Department of Internal Medicine, “S. Maria delle Grazie”, Pozzuoli Hospital, Naples, Italy Department of Woman, Child and General and Specialized Surgery, University of Campania “Luigi Vanvitelli”, Naples, Italy Institute of Translational Pharmacology, National Research Council, Rome, Italy d Obesity and Endocrine disease Unit, Department of Neuroscience, Santobono-Pausilipon Children’s Hospital, Naples, Italy e IRCCS Bambino Gesù Children’s Hospital, Rome, Italy f Pediatric Unit, Azienda Ospedaliero Universitaria Santa Maria della Misericordia, Udine, Italy g Institute for maternal and child health IRCCS “Burlo Garofolo”, Trieste, Italy h Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy i Pediatric Diabetes and Metabolic Disorders Unit, University of Verona, Verona, Italy j Policlinico Umberto I Hospital, Sapienza University of Rome, Rome, Italy k Department of Movement Sciences and Wellbeing, University of Naples Parthenope, Naples, Italy b c

Received 28 June 2018; received in revised form 26 August 2018; accepted 27 August 2018 Handling Editor: A. Siani Available online - - -

KEYWORDS Cardiometabolic risk factors; Hepatic steatosis; Left ventricular hypertrophy; Metabolically healthy obese phenotype

Abstract Background and aims: We aimed to evaluate whether the metabolically healthy obese (MHO) phenotype was associated with hepatic steatosis (HS) or left ventricular hypertrophy (LVH) in young people with overweight (OW), obesity (OB) and morbid obesity (MOB) and whether the prevalence of these comorbidities was affected by OB severity. Methods and results: An abdominal ultrasound was performed in 1769 children and adolescents, mean age 10.6 years (range 5e18) with MHO phenotype, defined as the absence of traditional cardiometabolic risk factors, in order to identify HS. In a subsample of 177 youth the presence of LVH, defined by 95th percentile of LV mass/h2.7 for age and gender, was also analyzed. The prevalence of HS increased from 23.0% in OW to 27.8% in OB and 45.1% in MOB (P < 0.0001). The proportion of LVH increased from 36.8% in OW to 57.9% in OB and 54.5% in MOB (P < 0.05). As compared with OW, the odds ratio (95% CI) for HS was 2.18 (1.56e3.05), P < 0.0001) in OB and 6.20 (4.26e9.03), P < 0.0001) in MOB, independently of confounding factors. The odds ratio for LVH was 2.46 (1.20e5.06), P < 0.025) in OB and 2.79 (1.18e6.61), P < 0.025) in MOB, as compared with OW.

Abbreviations: ALT, alanine aminotransferase; BMI, body mass index; BP, blood pressure; CI, confidence interval; CV, cardiovascular; DBP, diastolic blood pressure; FPG, fasting plasma glucose; HDL-C, high density lipoprotein cholesterol; HOMA-IR, homeostasis model assessment insulin-resistance; HS, hepatic steatosis; IVST, interventricular septum thickness; LVDD, left ventricular diastolic diameter; LVH, left ventricular hypertrophy; LVMi, left ventricular mass index; MHO, metabolically healthy obese; PWT, posterior wall thickness; RWT, relative wall thickness; OW, overweight; OB, obese; MOB, morbid obese; SBP, systolic blood pressure; Tg, triglycerides. * Corresponding author. Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, via Medina 40, 80133, Naples, Italy. Fax: þ39 081 5474678. E-mail address: [email protected] (G. Valerio). https://doi.org/10.1016/j.numecd.2018.08.007 0939-4753/ª 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007

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Conclusion: In spite of the absence of traditional cardiometabolic risk factors, the prevalence of HS and LVH progressively increased across BMI categories. MHO phenotype does not represent a “benign” condition in youth. ª 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Introduction

Methods

It is becoming increasingly recognized that young people with obesity (OB) are at greater risk of developing premature morbidity and mortality for cardiovascular (CV) events in adulthood [1]. Therefore, there is a need for an early identification and treatment of youth who are at greater risk of developing these obesity-related complications. Besides the severity of obesity [2], other features, such as visceral fat, inflammation, insulin resistance, and any component of the metabolic syndrome may mediate the increased CV disease risk in individuals with overweight (OW) or OB. A unique obesity subset known as “healthy obesity” has been proposed in adults for those individuals who do not display the typical obesity-associated metabolic disorders. These individuals are assumed to have lower risk of cardiometabolic complications compared with their counterparts with a metabolically unhealthy phenotype [3]. However, the clinical implications of this metabolically healthy obese (MHO) phenotype remain controversial. While prospective studies have reported that MHO adults were not at an increased risk of CV events compared to normal weight individuals during 3e13 years of follow-up [4], more recent data have shown an increased risk of CV events over more extended follow-up periods [5]. Compared to adults, research on the MHO phenotype in the pediatric population is relatively more recent. The majority of studies compared OW or OB youth with healthy and unhealthy phenotypes using different definitions of this condition, since no uniform criterium to identify MHO phenotype in children and adolescents exists [6e9]. In addition, no study has evaluated whether a healthy phenotype in obese youth is associated with unfavorable CV risk profile. In particular, whether the MHO phenotype is associated to target organ involvement, such as hepatic steatosis (HS) or abnormal cardiac structure, remains to be determined in childhood. This is an important issue in the light of the role played by fatty liver disease as predictor of type 2 diabetes [10] and LVH as predictor of CV events [11] Therefore, the aims of the present study were to assess whether MHO phenotype in youth was associated with HS or abnormal cardiac structure, such as left ventricular hypertrophy (LVH), and whether the prevalence of these comorbidities was affected by OB severity.

Study population The CARdiometabolic risk factors (CMRFs) in OW and OB children in ITALY (CARITALY) Study is a multi-center, retrospective, cross-sectional study endorsed by the Childhood Obesity Group of the Italian Society of Pediatric Endocrinology and Diabetology. This study investigated the prevalence of the major cardiometabolic risk factors in Italian children and adolescents with OW/OB in outpatient clinics [12]. CARITALY included secondary or tertiary centers with proved experience in the care of pediatric obesity, distributed throughout the national territory. Between 2003 and 2016 each center reviewed medical records of young people with OW/OB aged 5e18 years consecutively referred by general practitioners to the center for assessment of health status and implementation of weight loss programs. Exclusion criteria were: recent history of acute infectious or non-infectious inflammatory disorders, secondary obesity, past history of diabetes mellitus, hypertension, liver disease, or lowdensity lipoprotein-cholesterol 190 mg/dL. Anthropometric measures, biochemical variables and abdominal ultrasound examination, were available in 4449 records. This retrospective study was approved by the Ethics Committee of the University of Campania “Luigi Vanvitelli” (reference number 834/2016) and conformed to the guidelines of the European Convention of Human Rights and Biomedicine for Research in Children. Informed consent was obtained from the parents of all participants. To ensure data protection and confidentiality, data extracted from the medical records were de-identified before being transmitted to the coordinating center for analyses. Measurements Body weight and height were measured following standard procedures in ach center. Body mass index (BMI) was calculated as weight (Kg)/height (m2) and transformed into standard deviation score (SDS), based upon the established Italian BMI normative curves [13]. Pubertal status was evaluated by Tanner staging (IeV) [14]. Blood pressure (BP) was measured using aneroid sphygmomanometers with cuffs of appropriate size, according to

Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007

Preclinical signs of liver and cardiac damage in youth

standard procedures as recommended by European Society of Hypertension [15]. After 12 h of fasting, blood samples were drawn for analysis of fasting plasma glucose (FPG), alanine aminotransferase (ALT), triglycerides (Tg), high-density lipoprotein-cholesterol (HDL-C), and insulin. All biochemical analyses were performed in the centralized laboratory of each center, as described elsewhere [12]. Although analyses were performed in different laboratories, all laboratories are part of the Italian National Health System, are certified according to International Standards ISO 9000 (www.iso9000.it/) and undergo semiannual quality controls and inter-lab comparisons. Definitions OW, OB or Morbid Obesity (MOB) were defined when the BMI cut point was equal to or greater than the value plotted on the sex related curve crossing respectively the BMI of 25, 30 and 35 kg/m2 at age 18 years, as recommended by the World Obesity Federation [16]. Prepubertal stage was defined by Tanner Stage I [14]. MHO phenotype was defined as the absence of any of the following risk factors [17]: BP  95th percentile for age, sex and height in children and BP  130/80 mmHg in adolescents, as proposed by the American Academy of Pediatrics in 2017 [18], FPG 100 mg/dL, Tg  100 mg/dL in children and 130 mg/dL in adolescents, HDL-C <40 mg/dL [19]. Waist circumference was not included since the majority of the OW/OB children met the criteria [17]. On the contrary, the metabolically unhealthy phenotype was defined as the presence of at least one of the above listed risk factors. Insulin resistance was defined as the homeostasis model assessment of insulin resistance (HOMA-IR) 97th percentile for age and sex in normal weight children [20]. Liver ultrasound scan and definition of HS Abdominal ultrasound scan was available in all participants. Abdominal ultrasound was performed in a clinical setting, and a single expert operator in each center was blinded to clinical and biological data. Assessment of HS was based on the presence of increased echogenicity (brightness) of the liver as compared with the renal cortex. HS was assessed as present or absent [12]. Echocardiographic examination and definition of LVH Echocardiographic examination was available in a subsample of 177 healthy obese participants randomly recruited in Pozzuoli and Rome by a single expert operator in each center as elsewhere described [21]. LV mass was calculated according to the joint American Society of Echocardiography/European Association of Echocardiography recommendations [22]. LV mass was normalized for height in meters2.7 (LVMi). RWT was calculated from posterior wall thickness (PWT), interventricular septum thickness (IVST) and left ventricular diastolic diameter (LVDD) using the formula: (PWT þ IVST)/LVDD [14,21].

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LVH was defined by normal distribution, by Khoury et al. [23] and Society of Hypertension

the 95th percentile of the LVMi age and gender, as proposed by recommended by the European [15].

Statistical analysis Data are expressed as Mean  Standard Deviation, or proportions (%) and 95% confidence interval (CI). Given the skewed distribution of Tg, ALT and HOMA-IR, the statistical analysis of these variables was applied after log-transformation with back transformation to natural units for presentation in the text and tables. Means were compared by analysis of covariance after correction for centers, age, sex, and prepubertal stage. To evaluate the association between HS or LVH across the categories of BMI, we performed a logistic regression analysis, with enter selection procedure, using the preclinical signs of liver or cardiac damage as the dependent variables and the categories of BMI (where OW was the reference category), centers, age, prepubertal status and insulinresistance as covariates. A two-sided P value < 0.05 was considered statistically significant. The statistical analysis was performed with IBM SPSS Statistics, version 20.0. Results Out of 4449 records available with complete anthropometric, biochemical and liver ultrasound scan data, 2680 were excluded for the presence of an unhealthy phenotype (60%) defined as the presence of at least one of the risk factors listed in Methods. Therefore, 1769 records of MHO children were analyzed. Table 1 summarizes the clinical and metabolic features of the study population according to BMI categories (OW, OB, MOB). The three categories differed in age, prepubertal stage, HOMA-IR, HDL-C, Tg, and ALT (P < 0.002, P < 0.0001). The echocardiographic examination was performed in 177 children and adolescents who were similar to the whole sample for age, gender distribution and SBP, but showed slightly lower BMI SDS (1.8  0.5 vs 2.0  0.6 kg/m2, P < 0.0001) and DBP (62.6  7.5 vs 64.6  7.8 mmHg, P Z 0.001). Table 2 shows the clinical and metabolic features of the subsample who underwent the echocardiographic examination, according to BMI categories. Again, the three categories differed in age, prepubertal stage, HOMA-IR, Tg, and ALT (P Z 0.013, P < 0.0001). A significant difference in LVMi was observed among groups (P Z 0.036), while no difference was observed in RWT. The prevalence of HS significantly increased from 23% in OW to 27.8% in OB and 45.1% in MOB (Fig. 1, Panel A). Compared to OW, OB youth showed an Odds ratio (95% CI) for HS of 2.18 (1.56e3.05, P < 0.0001), adjusted for centers, age, and prepubertal stage, which did not substantially change when insulin-resistance was added to the model. Compared to OW, MOB youth had an Odds ratio for HS of 6.20 (4.26e9.03, P < 0.0001), which was also significantly higher than that observed in young people with OB

Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007

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Table 1 Demographic and clinical characteristics of children and adolescents with metabolically healthy phenotype according to Body Mass Index categories. n Z 1769

Age, years Girls, n (%) Prepubertal stage I, n (%) Body Mass Index, kg/m2 Body Mass Index, SDS FPG, mg/dl HOMA-IR Total cholesterol, mg/dl HDL-Cholesterol, mg/dl Triglycerides, mg/dl ALT, IU/L SBP, mmHg DBP, mmHg

Overweight

Obese

Morbid obese

383

694

692

11.4  2.3 208 (54) 56 (15) 23.6  2.4 1.25  0.3 83.3  7.3 2.5  1.5 160.0  29.1 54.7  11.7 65.5  22.9 22.5  21.2 105.7  9.6 65.3  7.3

11.3  2.6 338 (49) 200 (29) 26.9  3.2 1.90  0.3 83.1  8.2 3.0  2.2 157.0  28.7 53.3  10.2 64.7  22.8 24.0  21.4 105.5  10.5 65.1  7.7

9.7  2.6 326 (47) 392 (56) 30.4  5.0 2.5  0.4 83.0  8.5 3.2  2.1 157.7  28.0 52.6  10.1 67.7  22.0 27.8  24.2 102.9  11.3 63.3  8.0

P value

<0.0001 0.077 <0.0001 <0.0001 <0.0001 0.323* <0.0001* 0.510* <0.0001* 0.002* <0.0001* 0.067* 0.937*

Data are expressed as Mean  Standard Deviation or n (%). *P value adjusted for centers, age, and prepubertal stage. Abbreviations: ALT: alanine aminotransferase; DBP: diastolic blood pressure; FPG: fasting plasma glucose; HOMA-IR: homeostasis model assessment insulin-resistance; SBP: systolic blood pressure; Tg: triglycerides.

Table 2 Demographic, clinical and echocardiographic characteristics of the subsample who underwent echocardiograms according to Body Mass Index categories. n Z 177

Age, years Girls, n (%) Prepubertal stage I, n (%) Body Mass Index, kg/m2 Body Mass Index, SDS FPG, mg/dl HOMA-IR Total cholesterol, mg/dl HDL-Cholesterol, mg/dl Triglycerides, mg/dl ALT, IU/L SBP, mmHg DBP, mmHg LVMi, g/h2.7 RWT

Overweight

Obese

Morbid obese

57

76

44

10.7  2.4 29 (51) 10 (17) 22.9  2.3 1.21  0.3 81.4  5.8 1.9  1.1 155.0  27.7 54.2  9.3 60.6  20.8 23.1  35.5 104.4  10.0 63.1  6.6 38.2  13.2 0.353  0.06

10.1  2.3 34 (45) 17 (22) 25.6  2.8 1.8  0.2 83.0  6.3 2.6  1.8 154.6  28.0 53.8  10.6 62.7  24.2 21.8  12.8 106.3  9.2 62.2  8.1 42.5  10.3 0.357  0.06

9.8  3.3 14 (32) 18 (41) 30.0  5.9 2.4  0.4 83.4  5.9 3.0  2.2 168.0  29.3 52.0  9.8 72.1  23.9 35.5  49.0 105.1  9.4 62.7  7.8 43.2  13.0 0.353  0.06

P value

<0.0001 0.153 0.020 <0.0001 <0.0001 0.323* <0.0001* 0.073* 0.137* 0.013* 0.001* 0.052* 0.566* 0.034* 0.927*

Data are expressed as Mean  Standard Deviation or n (%). *P value adjusted for centers, age, and prepubertal stage. Abbreviations: ALT, alanine aminotransferase; DBP, diastolic blood pressure; FPG, fasting plasma glucose; HOMA-IR, homeostasis model assessment insulin-resistance; LVMi, left ventricular mass index; RWT, relative wall thickness; SBP, systolic blood pressure; Tg, triglycerides.

(Table 3). The Odds ratios did not change when insulinresistance was added into the models. The proportion of LVH significantly increased from 36.8% in OW to 57.9% in OB and 54.5% in MOB (Fig. 1, Panel B). OB youth showed an Odds ratio for LVH of 2.46 (1.20e5.06, P < 0.025) adjusted for confounding factors as compared with OW; similarly MOB youth exhibited an Odds ratio of 2.79 (1.18e6.61, P < 0.025) compared with OW (Table 3). The Odds ratios did not change when insulin-resistance was added into the models. Discussion This study provides evidences that in young people, despite the presence of a metabolically healthy phenotype

the transition from OW to MOB is associated with progressive increase of the prevalence of HS and LVH. These data, being remarkable for the young age of the population studied, suggest that despite the absence of classical cardiometabolic risk factors, uncomplicated obesity is not a “benign” phenotype. In children/adolescents, the definition of metabolically healthy phenotype has been based on the exclusion of abnormal levels of BP, glucose and lipids; some Authors indeed excluded also insulin-resistance [6,7]. In addition, the definition was not uniform since the phenotype was defined on the basis of the absence of at least 2 or all factors, leading to evident heterogeneity of its frequency. In our sample, 40% youth with OW or OB had a MHO phenotype, fulfilling rigorous criteria based on the absence

Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007

Preclinical signs of liver and cardiac damage in youth %

Panel A

5

Hepatic steatosis

Overweight

Morbid obese

Obese

P <0.0001

n=

88/383

Panel B

312/692

Left ventricular hypertrophy

Overweight

n=

193/694

21/57

Obese

Morbid obese P < 0.05

44/76

24/44

Figure 1 Proportions of youth with hepatic steatosis or left ventricular hypertrophy according to Body Mass Index categories: overweight (white bars), obese (grey bars), morbid obese (black bars).

of any cardiometabolic risk factor including BP, glucose and lipids, in agreement with another European cohort [24]. As far as we know, pediatric studies on the metabolically healthy phenotype have generally addressed the prevalence and features of this phenotype, while studies on the assessment of preclinical organ involvement are lacking. The relationship between OB and HS is well established both in childhood and in adulthood. In addition HS is considered a relevant risk factor for the development of diabetes [10] and CV disease [25]. However, the association between metabolically healthy phenotype and HS in childhood is poorly explored. The only two studies that evaluated fatty liver in MHO youth considered the absence of HS as an additional criterion to define the phenotype [8,9]. Therefore no information is available with regard to

the presence of HS in youth presenting without any component of the metabolic syndrome. In order to fill the gap in the pediatric literature, we aimed to evaluate whether MHO phenotype, defined by the absence of all the classical cardiometabolic risk factors, was free from preclinical signs of hepatic and cardiac involvement. In particular, we adopted the new normative BP tables based on normal-weight children as proposed by the American Academy of Pediatrics for the definition of hypertension [18]. We observed that OB and MOB youth with MHO phenotype had a 2.0e5.4 fold increased risk of HS, compared with OW youth, independently of insulinresistance. Noteworthy, young people with severe obesity not only have a significantly higher likelihood of HS than those with OW, but even than those with moderate obesity. A recent systematic review with meta-analysis demonstrated that the risk of HS was higher in OB youth than OW, but no further distinction was done with respect to the degree of obesity [26]. Therefore, to the best of our knowledge, this is the first study demonstrating that morbid obesity represents a more severe condition than moderate obesity with regard to the prevalence of HS. Importantly, the strong association between the degree of weight excess and the prevalence of HS, despite the adjustment for metabolic confounders, suggests a key role of obesity in the development of this kind of organ damage. The high rate of HS (45.3%) found in MOB children is worrisome, considering that the trajectory of adiposity into adulthood is extremely strong in these individuals [27]. Interestingly, a longitudinal study conducted in a large cohort of young adults in South Korea demonstrated that healthy individuals with OW or OB were strongly and progressively exposed to an increased incidence of nonalcoholic fatty liver disease [28]. Besides HS, we aimed at exploring whether MHO phenotype was associated to LVH. In adults LVH has been established as a strong predictor of heart failure and CV events [13], but no studies have been performed in MHO youth. We demonstrated that in the absence of cardiometabolic risk factors, OB in youth is associated with LVH as compared with OW. Since the three categories of BMI were similar for the BP levels, we found no difference in RWT, suggesting that the increase of LV mass was mainly due to eccentric LVH. This feature can be viewed as a consequence of an adaptation to volume overload. In fact, this phenotype may be mediated by several

Table 3 Odds ratio (95%CI) of hepatic steatosis and left ventricular hypertrophy according to Body Mass Index categories. Hepatic steatosis

Overweight

Obese

Morbid obese

Model 1 Model 2 Left ventricular hypertrophy Model 1 Model 2

1.00 1.00

2.18 (1.56e3.05)* 2.09 (1.49e2.94)*

6.20 (4.26e9.03)* 5.65 (3.87e8.25)*

1.00 1.00

2.46 (1.20e5.06) 2.44 (1.18e5.05)

2.79 (1.18e6.61) 2.73 (1.11e6.70)

Model 1: adjusted for centers, age, prepubertal stage. Model 2: adjusted for centers, age, prepubertal stage and insulin-resistance. *P < 0.0001,  P < 0.025.

Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007

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mechanisms involving renin-angiotensin and others hormones (insulin, adiponectin or leptin) that in turn should increase the circulating volume with consequent adaptive increase of the left ventricular chamber without any RWT increase [29]. Similarly to HS, the increasing risk of LVH across the BMI categories, even after adjustment for metabolic confounders such as HOMA-IR, suggests that obesity per se contributes to the development of this organ damage. Some limitations need to be considered when interpreting our results. First, our cross-sectional analysis cannot imply a causal relation between MHO phenotype and pre-clinical organ damage. Second, our findings are based on data derived from youth referred to secondary or tertiary clinical centers, therefore they are not representative of the general population of OW or OB youth. In addition, we used BMI as measure of adiposity; though BMI is satisfactory predictor of the percentage of body fat, it should be considered as a proxy measure of global adiposity. Since liver ultrasound scan and echocardiographic examination are operator-dependent techniques, we cannot exclude some technical biases produced by the lack of a core-lab. However, the size of the sample is sufficiently large to offset technical imprecisions, if any, as demonstrated by the consistent pathophysiological relations. Finally, we cannot exclude the possibility of residual confounding factors due to unmeasured parameters such as inflammation [30], dietary variables, physical activity and cardiorespiratory fitness [31], which may contribute to the different prevalence of HS and LVH across categories of BMI. Despite these limitations, our study has also some strengths. The study cohort included a reasonably large sample size. Unlike previous studies in childhood, we assessed the prevalence of HS and LVH. Also, comparisons between metabolically healthy young people with OW, OB and MOB allow to specifically dissect the contribution of weight status and obesity per se. Finally, additional strengths include the use of a very rigorous definition of a metabolically healthy status, even after controlling for insulin-resistance. In conclusion, our study showed for the first time that children and adolescents with MHO phenotype have target organ involvement, characterized by HS or LVH. The presence of these abnormalities at an early stage of life should alert pediatricians that MHO phenotype is not a safe condition. Given that childhood is a critical period of lifestyle changes, intensive programs addressed to weight control through healthy diet and physical activity should be undertaken in young people with OB and MOB, independent of the presence of metabolic comorbidities. Further longitudinal studies will contribute to clarify whether such early hepatic and cardiac alterations in MHO youth progress to more serious organ damage, and to identify proper follow-up strategies in these subjects. Conflicts of interest The authors declare no conflict of interest.

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Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-forprofit sectors. Acknowledgements Members of CARITALY Study Group: Di Sessa A., Department of Woman, Child and General and Specialized Surgery, University of Campania “Luigi Vanvitelli”, Naples, Italy. Driul D., Azienda Sanitaria Universitaria Integrata di Udine, SOC Pediatric Unit, Udine, Italy. Forziato C., Pediatric Unit, “S. Maria delle Grazie”, Pozzuoli Hospital, Naples, Italy; Invitti C., IRCCS Istituto Auxologico Italiano, Department of Medical Sciences & Rehabilitation, Milan, Italy; Loche S., Pediatric Endocrine Unit, pediatric hospital for microcitemia, AO Brotzu, Cagliari, Italy; Moio N., Department of Cardiology, “S. Maria delle Grazie”, Pozzuoli Hospital, Naples, Italy; Pellegrin M.C., Institute for maternal and child health IRCCS “Burlo Garofolo”, Trieste, Italy. References [1] Twig G, Yaniv G, Levine H, Leiba A, Goldberger N, Derazne E, et al. Body-mass index in 2.3 million adolescents and cardiovascular death in adulthood. N Engl J Med 2016;375:1300e1. [2] Zabarsky G, Beek C, Hagman E, Pierpont B, Caprio S, Weiss R. Impact of severe obesity on cardiovascular risk factors in youth. J Pediatr 2018 Jan;192:105e14. [3] Phillips CM. Metabolically healthy obesity across the life course: epidemiology, determinants, and implications. Ann N Y Acad Sci 2017;1391:85e100. [4] Hamer M, Stamatakis E. Metabolically healthy obesity and risk of all-cause and cardiovascular disease mortality. J Clin Endocrinol Metab 2012;97:2482e8. [5] Hinnouho GM, Czernichow S, Dugravot A, Nabi H, Brunner EJ, Kivimaki M, et al. Metabolically healthy obesity and the risk of cardiovascular disease and type 2 diabetes: the Whitehall II cohort study. Eur Heart J 2015;36:551e9. [6] Prince RL, Kuk JL, Ambler KA, Dhaliwal J, Ball GD. Predictors of metabolically healthy obesity in children. Diabetes Care 2014;37: 1462e8. [7] Blüher S, Schwarz P. Metabolically healthy obesity from childhood to adulthood - does weight status alone matter? Metabolism 2014;63:1084e92. [8] Sénéchal M, Wicklow B, Wittmeier K, Hay J, MacIntosh AC, Eskicioglu P, et al. Cardiorespiratory fitness and adiposity in metabolically healthy overweight and obese youth. Pediatrics 2013;132:e85e92. [9] Elmaogullari S, Demirel F, Hatipoglu N. Risk factors that affect metabolic health status in obese children. J Pediatr Endocrinol Metab 2017;30:49e55. [10] Jung CH, Kang YM, Jang JE, Hwang JY, Kim EH, Park JY, et al. Fatty liver index is a risk determinant of incident type 2 diabetes in a metabolically healthy population with obesity. Obesity (Silver Spring) 2016;24:1373e9. [11] Bluemke DA, Kronmal RA, Lima JA, Liu K, Olson J, Burke GL, et al. The relationship of left ventricular mass and geometry to incident cardiovascular events: the MESA (Multi-Ethnic Study of Atherosclerosis) study. J Am Coll Cardiol 2008;52:2148e55. [12] Di Bonito P, Valerio G, Grugni G, Licenziati MR, Maffeis C, Manco M, et al. Comparison of non-HDL-cholesterol versus triglycerides-toHDL-cholesterol ratio in relation to cardiometabolic risk factors

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Preclinical signs of liver and cardiac damage in youth

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Please cite this article in press as: Di Bonito P, et al., Preclinical signs of liver and cardiac damage in youth with metabolically healthy obese phenotype, Nutrition, Metabolism & Cardiovascular Diseases (2018), https://doi.org/10.1016/j.numecd.2018.08.007