Age variations of head-face morphological traits of Hakka in Guangdong province / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the age variations of head-face morphological traits of Hakka in Guangdong Province.</p><p><b>METHODS</b>Thirty-eight physical indices of head and face of 671 Hakka adults (151 urban males, 181 urban females, 162 rural males and 177 rural females) from Meizhou city of Guangdong were investigated. Twelve physical indices of head and face were calculated and counted its indices distributions. The age changes of morphological traits of head and face were analyzed.</p><p><b>RESULTS</b>With the age growing, the rate of eyefold of the upper eyelid was increased, and the Mongoloid fold decreased, the direction of eyeslits tended to level, nasal root height dropped, the zygomatic projection was more projected, the eye color turned to lighter, the upper red lips became thinner; medium-sized facial height, nasal height, upper lip skin height, physiognomic ear length, physiognomic ear breadth and breadth of alae nasi were decreased. The index of mouth breadth, morphological facial skin fold were positively correlated with the age. The index of minimum frontal breadth, face breadth, bigonial diameter, interocular breadth, external biocular breadth, lip height, thickness of lips and horizontal head circumference were negatively correlated with the age. With the age growing, morphological facial index and vertical cephalo-facial index was ascending. Moreover, length-height index of head, transverse frontoparietal index, zygomatico-frontal index and lip index were declining.</p><p><b>CONCLUSION</b>With the age growing, the head and face measurements, physical indices and the proportion of observed indices have changed in Hakka in Guangdong province.</p>

Genetic study on somatotype of child and adolescent twins in Han nationality / 中华预防医学杂志

<p><b>OBJECTIVE</b>To assess the genetic and environmental influences on the somatotype of children and adolescents, and the effects of sex and age.</p><p><b>METHODS</b>The components of somatotype were calculated by using Heather-Cater method in a total of 376 twin pairs of Han nationality, including 245 monozygotic (MZ) and 131 like-sex dizygotic (DZ) twin pairs aged 6 to 18 years. Model-fitting method by Mx package was performed to evaluate the proportion of variance components and to analyze the effects of sex and age on each component of somatotype using the adjusted data for other two somatotype components. The heritability of each component in different development periods divided by growth spurt was also evaluated.</p><p><b>RESULTS</b>The estimated heritabilities of endomorphic, mesomorphic and ectomorphic components were 0.45, 0.80, 0.44 in boys, 0.82, 0.79 and 0.81 in girls respectively after adjusting age. In boys, the heritability of endomorphic component during late puberty was significantly higher than that during pre-puberty (t = 4.99, P < 0.01) and puberty (t = 6.16, P < 0.01), while the heritability of ectomorphic component during late puberty was significantly lower than that during pre-puberty (t = 3.35, P < 0.01) and puberty (t = 4.12, P < 0.01). In girls, the heritability of endomorphic (t = 2.77, P < 0.01) or mesomorphic (t = 2.08, P < 0.05) component during pre-puberty was significantly higher than that in early puberty.</p><p><b>CONCLUSION</b>The genetic influence on somatotype of girls should be much more than that of boys, especially on the endomorphic and ectomorphic components. For boys, the mesomorphic component is mainly determined by genetic factors, but the other components are mainly affected by environmental ones. The effects of the development periods on the heritability of somatotype should be paid much attention to.</p>

Genetic effects on physical growth items of child twins in Han nationality / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyse the heritabilities of physical growth items of body and its related factors.</p><p><b>METHODS</b>An 116 twin pairs of Han nationality, 67 monozygotic (MZ) and 49 like-sex dizygotic (DZ) aged 6 to 12 years, were investigated from June to October in 2004. The measurements included height, weight, sitting height, chest circumference, biacromial breadth and biiliac breadth, and BMI index calculated by the former two measurements. The heritabilities were estimated by using intraclass correlation coefficient method from the adjusted data for age.</p><p><b>RESULTS</b>The intraclass correlation coefficient was greater in the MZ twins than in the DZ twins. The estimated heritabilities of height, weight, BMI, sitting height, chest circumference, biacromial breadth and biiliac breadth were 0.89, 0.88, 0.73, 0.87, 0.78, 0.78, 0.73 in boys and 0.87, 0.74, 0.72, 0.86, 0.62, 0.56, 0.59 in girls adjusted for age. Therefore, there were no sex difference for the heritabilities of height, sitting height and BMI, but the male heritabilities of weight, chest circumference, biacromial breadth and biiliac breadth were higher than the female's respectively.</p><p><b>CONCLUSION</b>Physical growth items should be mainly determined by the genetic factors. There are sex differences for the heritabilities of weight, chest circumference, biacromial breadth and biiliac breadth, i.e., the girls might be affected more easily by environmental factors than the boys in these items.</p>