Is the 1975 Reference Man still a suitable reference?

Background/Objective: In 1975, a Reference Man for the estimation of radiation doses without adverse health effects was created. However, during the past few decades, considerable changes in body weight and body composition were observed, as a result of which, new in vivo technologies of body composition analysis are now available. Thus, the Reference Man might be outdated as adequate standard to assess medication and radiation doses. The objective of this study was to compare body composition of an adult population with 1975 Reference Man data, thereby questioning its value as a suitable reference. Methods: Body composition was assessed in 208 healthy, Caucasian subjects (105 males, 103 females) aged 18-78 years with a body mass index range of 16.8-35.0 kg/m(2). Fat mass (FM) and muscle mass (MM) were assessed by dual-energy X-ray absorptiometry, organ masses (OMs) were measured by magnetic resonance imaging. Results: There was a considerable variance in body weight and body composition. When compared with Reference Man, great differences in body composition were found. Men and women of the study population were heavier, taller and had more FM, MM and higher masses of brain, heart and spleen. These differences did not depend on age. Relationships between body weight and body composition were investigated by general linear regression models, whereby deviations in FM, MM and heart mass disappeared, whereas differences in brain and spleen mass persisted. Conclusions: Our data indicate the need of a modern Reference Man and thus a recalculation of medical radiation doses and medication. European Journal of Clinical Nutrition (2010) 64, 1035-1042; doi:10.1038/ejcn.2010.125; published online 28 July 2010