A selection of abstracts presented at the BDA's Research Symposia for Dietitians New to Research on 30th November 2010 at the Institute of Child Health, London, UK and on 15th March 2011 at the University of Ulster, Northern Ireland
Screening and selection of human volunteers at increased cardio-metabolic risk for a dietary intervention study, with particular reference to levels of liver fat
Article first published online: 6 MAY 2011
© 2011 The Authors. Journal of Human Nutrition and Dietetics © 2011 The British Dietetic Association Ltd
Journal of Human Nutrition and Dietetics
Volume 24, Issue 3, pages 306–307, June 2011
How to Cite
Thornton-Wood, C., Isherwood, C., Umpleby, M. and Griffin, B. (2011), Screening and selection of human volunteers at increased cardio-metabolic risk for a dietary intervention study, with particular reference to levels of liver fat. Journal of Human Nutrition and Dietetics, 24: 306–307. doi: 10.1111/j.1365-277X.2011.01175_38.x
- Issue published online: 6 MAY 2011
- Article first published online: 6 MAY 2011
Vol. 24, Issue 4, 415, Article first published online: 4 JUL 2011
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Background: Individuals at increased cardio-metabolic (CM) risk have a greater chance of developing diabetes mellitus and suffering premature cardiovascular events. The metabolic syndrome (MetS) is a constellation of risk factors which confer increased CM risk. MetS was originally proposed by Reaven (1998) and the currently accepted definition was agreed by AHA/NHLBI,WH,IASIASO (Alberti et al., 2009). More recently, increased liver fat has been proposed as a marker of CM risk. The aims of this study were to evaluate the inter-relationships between percentage liver fat and established CM risk factors and identify those with MetS.
Methods: This paper presents a secondary analysis of baseline data from a sample (n = 37) (56 ± 5.32 years), of overweight men who were at increased CM risk but otherwise healthy,, and recruited into a randomised dietary intervention crossover study to investigate how dietary carbohydrate influences the metabolism of plasma lipoproteins in overweight volunteers with moderately high (>10% <20%) and low (<2%) levels of liver fat. Anthropometric and biochemistry measurements were obtained, and from a sub-sample, the percentage of liver fat by magnetic resonance imaging. The participants were also assigned a metabolic score based on the number of indicators of the MetS according to the AHA/NHLBI, WH, IASIASO definition (Alberti, 2009). Non-parametric statistical analyses was used, as not all variables were normally distributed, there were a number of outliers and a small sample size. Pearson Correlation Co-efficients were used to investigate relationships between continuous and categorical variables. The variables were not adjusted for age or BMI because of a small sample size. Statistical significance was set at P ≤ 0.05 and all analyses were carried out using SPSS 16.0.
Results: Fifty nine per cent of the participants had MetS (n = 21). There was evidence of significant, positive associations between the metabolic score for MetS and total cholesterol:HDL-C ratio (P = 0.030), and between percentage liver fat and plasma glucose and insulin (P = 0.010 and P = 0.003 respectively). The percentage of liver fat was also notably higher than that reported in other studies (Yamada et al., 2010; Kotronen et al., 2007) and there was positive correlation between the liver enzyme alanine transaminase (ALT) and plasma insulin (P = 0.012).
Conclusion: The strong associations between established risk factors and liver fat suggest that the latter may be clinically useful as a marker for CM risk in MetS.
References: Alberti, K., Eckel, R., Grundy, S. et al. (2009) Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation120, 1640–1645.
Kotronen, A., Westerbacka, A., Bergholm, R., Pietilainen, K.H. & Yki-Jarvinen, H. (2007) Liver fat in the metabolic syndrome. J. Clin. Endocrinol. Metab. 92, 3490–3497.
Reaven, G. (1998) Insulin resistance and human disease: a short history. J. Basic Clin. Physiol. Pharmacol.9, 387–406.
Yamada, T., Fukatsu, M., Suzuki, S. et al. (2010) Fatty liver predicts impaired fasting glucose and type 2 diabetes mellitus in Japanese undergoing a health checkup. J. Gastroenterol. Hepatol.25, 352–356.