Causes and consequences of obesity: the contribution of recent twin studies

• Published in: International Journal of Obesity Vol. 36; no. 8; pp. 1017 - 1024
• Main Authors: Naukkarinen, J, Rissanen, A, Kaprio, J, Pietiläinen, K H
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2012; Nature Publishing Group
• Subjects: 631/250/256; 692/699/2743/393; Abdomen; Adipocytes; Adipose tissue; Adolescent; Adult; Biological and medical sciences; Body fat; Body mass index; Child; Child, Preschool; Distillation; Epidemiology; Exercise; Female; Finland - epidemiology; Genes; Genetic aspects; Genetic Predisposition to Disease; Health aspects; Health problems; Health Promotion and Disease Prevention; Humans; Infant; Inflammation - epidemiology; Inflammation - etiology; Inflammation - genetics; Insulin resistance; Internal Medicine; Life Style; Longitudinal studies; Male; Medical research; Medical sciences; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolism; Miscellaneous; Mitochondrial DNA; Mutation; Obesity; Obesity - complications; Obesity - epidemiology; Obesity - etiology; Obesity - genetics; Other metabolic disorders; Pedigree; Physiological aspects; Physiology; Prediabetic State - epidemiology; Prediabetic State - etiology; Prediabetic State - genetics; Public Health; review; Risk Assessment; Risk Factors; Twin studies; Twins; Twins, Dizygotic - genetics; Twins, Dizygotic - statistics & numerical data; Twins, Monozygotic - genetics; Twins, Monozygotic - statistics & numerical data; Young Adult; Finland; metabolic syndrome; adipose tissue; inflammation; insulin resistance; liver fat; BMI; Endocrinopathy; Obesity; Pancreatic hormone; Adipose tissue; Nutrition; Digestive system; Liver; Nutrition disorder; Cardiovascular disease; Metabolic diseases; Inflammation; Metabolic syndrome; Insulin; Twin; Body mass index; Target tissue resistance; Cause; Fat; Insulin resistance; Nutritional status
• ISSN: 0307-0565; 1476-5497
• DOI: 10.1038/ijo.2011.192

Obesity is a genetically complex disorder that produces a myriad of health problems. Most of the recognized complications of obesity are not only strongly influenced by lifestyle factors, but also present with independent genetic predispositions that are notoriously difficult to disentangle in humans. Most studies on the causes and consequences of acquired obesity are encumbered by the incomplete ability to control for genetic influences. However, utilizing a unique experiment of nature, namely monozygotic twins (MZ) discordant for obesity as ‘clonal controls’ of obese and non-obese individuals has enabled the fine characterization of the effects and possible antecedents of acquired obesity while controlling for the genetic background, as well as pointed to novel obesity predisposing candidate genes. This review is a distillation of the findings from more than 10 years of research done in an exceptionally well-characterized collection of MZ and dizygotic (DZ) twins, based on the Finnish Twin Cohorts. Topics covered include the nature of development of obesity from the childhood onwards, the role of exercise in modifying the genetic susceptibility, the resulting inflammatory, prediabetic and preatherosclerotic changes in whole body and adipose tissue physiology, as well as the newest insights provided by the omics revolution.