Table of Contents
Epidemiology Research International
Volume 2015, Article ID 295958, 10 pages
http://dx.doi.org/10.1155/2015/295958
Research Article

Radiation May Indirectly Impair Growth Resulting in Reduced Standing Height via Subclinical Inflammation in Atomic-Bomb Survivors Exposed at Young Ages

1Department of Statistics, Radiation Effects Research Foundation, Hijiyama Park 5-2, Minami-ku, Hiroshima 732-0815, Japan
2Department of Clinical Studies, Radiation Effects Research Foundation, Hijiyama Park 5-2, Minami-ku, Hiroshima 732-0815, Japan

Received 23 October 2014; Revised 16 January 2015; Accepted 16 January 2015

Academic Editor: Leo J. Schouten

Copyright © 2015 Eiji Nakashima et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

For young atomic-bomb (A-bomb) survivors, A-bomb radiation’s (total) effect on standing height is thought to comprise the sum of direct effect and indirect effect via inflammation. With the data of five inflammatory markers—white blood cell count, sialic acid, corrected erythrocyte sedimentation rate (ESR), 1 globulin, and 2 globulin—obtained in adulthood during the period 1988 to 1992, a summary inflammatory index was constructed as a surrogate for the five subclinical inflammatory markers. For 3,327 A-bomb survivors exposed at ages of less than 25 years, a structural equation model was analyzed to measure direct radiation effects on adult height as well as mediating effect of radiation via inflammation on the height after adjustment for other risk factors, smoking, cancer, inflammatory disease, obesity, and diabetes mellitus. The mediation proportion of the radiation effect on height via inflammation was approximately 5% for both sexes for all ages, and indirect dose effects via inflammation were statistically significant for both sexes combined and for females exposed at ages 0 to 5 years. Indirect dose effects for all ages via sialic acid, corrected ESR, and 2 globulin were marginally significant for both sexes combined and for females. These proportions are likely underestimated.