ORIGINAL ARTICLE Genetic and environmental correlations between bone phenotypes and anthropometric indices in Chinese Yan-Jun Yang Æ Volodymyr Dvornyk Æ Wei-Xia Jian Su-Mei Xiao Æ Hong-Wen Deng Received: 3 August 2004 / Accepted: 29 November 2004 / Published online: 12 February 2005 Ó International Osteoporosis Foundation and National Osteoporosis Foundation 2005 Abstract Height, weight, bone mineral density (BMD), and bone size are all influenced by genetic and environ- mental factors as well as interactions between them. Height and weight are often used in population studies to adjust the bone phenotypes. However, it is still unknown what proportion of genetic and environmental variabil- ity is shared between these anthropometric characteris- tics and the bone phenotypes. The genetic and environmental correlations between the bone phenotypes and anthropometric indices in Chinese subjects were studied by bivariate quantitative genetic analysis on a sample of 931 healthy subjects from 292 Chinese nuclear families aged from 19 to 79 years. BMD and bone size at the lumbar spine (L1–L4) and the hip of all subjects were measured by dual-energy X-ray absorptiometry. We found significant genetic correlations between weight and spine BMD, hip BMD, spine bone size and hip bone size, which were 0.50 (P<0.01), 0.45 (P<0.01), 0.36 (P=0.02), and 0.38 (P<0.01), respectively. Likewise, significant genetic correlations between height and spine BMD, spine bone size, and hip bone size were 0.30 (P=0.02), 0.54 (P<0.01), and 0.58 (P<0.01), respec- tively. The environmental correlations were found to be significant only between height and spine bone size (P<0.001) and weight and hip BMD (P=0.02). These results suggest the probability that the same genetic and environmental factors contribute to these different phe- notypes. Moreover, when a candidate gene or genomic region is responsible for the variation of both bone phenotypes and anthropometric indices, its true genetic effect on the bone phenotypes may be lost after one has adjusted the phenotypic values with weight and height as random environmental factors. It may have implications for population studies of candidate genes that underlie the complex bone phenotypes and for the development of strategies for therapeutic application. Keywords Anthropometric indices Æ Bone mineral density Æ Bone size Æ Environmental correlation Æ Genetic correlation Introduction Osteoporosis is a serious health problem in the world, affecting both Caucasian and Asian people. Bone min- eral density (BMD) and bone size, which are among major risk factors for osteoporotic fractures (OFs) [1, 2], have been demonstrated to be under significant genetic determination, with the heritability estimates ranging from 0.5 to 0.9 [3, 4]. Anthropometric indices, e.g., weight and height, have been recognized as important parts of human physical development. It is widely ac- cepted that weight and height have high heritability. The heritability of height is approximately 75%–90% [5]. Genetic factors also significantly influence the variation of weight [6]. Although both bone phenotypes and anthropometric indices are under significant genetic determination in Chinese people [7, 8], the shared ge- netic component between pairs of these traits in this ethnicity is poorly known. On the other hand, as com- plex traits, bone phenotypes and anthropometric indices are partially affected by environmental factors. Associ- ations between height, weight, and environment have been extensively studied [9, 10]. Likewise, environmental factors were reported to contribute to BMD and bone size variation [4, 11]. However, data about environ- mental correlations between bone phenotypes and anthropometric indices in the Chinese are still lacking. Weight and height are two important factors that influence BMD and bone size variation [4, 12]. Since an Osteoporos Int (2005) 16: 1134–1140 DOI 10.1007/s00198-004-1825-9 Y.-J. Yang Æ W.-X. Jian Æ S.-M. Xiao Æ H.-W. Deng Laboratory of Molecular and Statistical Genetics, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China V. Dvornyk Æ H.-W. Deng (&) Osteoporosis Research Center and Department of Biomedical Sciences, Creighton University, 601 N. 30th St., Suite 6787, Omaha, NE 68131, USA E-mail: deng@creighton.edu Tel.: +1-402-2805911 Fax: +1-402-2805034