ABSTRACT

Previous studies have suggested an association of somatotype with body composition and

the organ dimensions among individuals and populations. However, the relationship of

somatotypes of medical students of Ahmadu Bello University (ABU), Zaria with body

composition, organ dimensions and some anthropometric variables has not been

evaluated. This cross-sectional study consisted of 350 apparently healthy medical

students of ABU, Zaria (175 males and 175 females) aged 18-35 years. Stature, four

skinfold sites, body mass, two bone breadths and two girths were measured according to

the International Society for the Advancement of Kinanthropometry (ISAK). The body

composition variables were computed using the Durnin and Wormersely method and

hepatobiliary dimensions were measured with an ultrasound machine. Chi-square test,

independent sample t-test, one-way Analysis of variance (ANOVA), somatotype analysis

of variance (SANOVA), Pearson’s correlation, partial correlation and multiple linear

regression were used. P < 0.05 was set at the level of significance. The mean somatoype

was 1.61-4.28-3.04 (ectomorphic-mesomorph) for the males and 1.75-4.21-1.96

(balanced mesomorph) for the females and were significantly different (F=30.06,

p<0.001). Seven major somatotype categories were found irrespective of the sexes:

endomorphic-mesomorph, balanced-mesomorph, ectomorphic-mesomorph, mesomorph-

ectomorph, mesomorphic- ectomorph, balanced-ectomorph and central. There was a

significant association for male and female subjects based on the somatotype categories

(χ2 = 44.87, p < 0.05). The height, body mass index (BMI), body surface area (BSA),

skin folds, bone breadth and body composition variables showed significant sexual

dimorphism based on the dominant somatotypes (p< 0.05). The BMI, BSA, gall bladder

width, common bile duct diameter (CBDD) and body composition variables indicated

significant differences according to the age groups in the dominant mesomorphs and

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ectomorphs (p< 0.05). Dominant endomorphy was positively correlated with some skin

folds and body composition variables in both sexes. Mesomorphy correlated positively

with upper arm girth, calf girth, BBH and BBF in both sexes. Ectomorphy showed more

sparing correlation with other variables, i.e., it showed a significant positive correlation

with BBH and BBF in male subjects only. No significant correlations were observed in

blood pressure and hepatobiliary dimensions with the dominant somatotypes. Tricep skin

fold, subscapular skin fold, and medial calf skin fold were the joint best predictors of

percent body fat in both sexes (R2= 0.999). In conclusion, the relationship between

dominant somatotypes with body composition, hepatobiliary dimensions and some

anthropometric variables have been established.

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CHAPTER ONE

1.0       INTRODUCTION

1.1       Background

The interest in the classification and analysis of human physique or body types of

individuals and populations has a long history going back to the ancient Greeks,

Hippocrates (460-377 BC). Over the centuries, various systems for classifying physique

have been proposed, leading to the system called somatotyping as proposed by Sheldon et

al. (1940), and subsequently modified by others, notably Parnell (1958), Heath and Carter

(1967) and Carter and Heath (1990). Sheldon believed that somatotype was immutable

i.e., it relies solely on genetic basis, but the present view is that the somatotype is

phenotypical and thus amenable to change under the influence of both internal and

external factors such as growth (Carter and Heath, 1990), aging (Gakhar and Malik,

2002; Bhasin and Jain, 2007), sex (Kalichman and Kobliansky, 2006), nutrition

(Chakrabarty et al., 2008), physical activity (Chandel and Malik, 2012), occupation

(Singh and Singh, 2006), socioeconomic differences (Rahmawati et al., 2004; Singh,

2011) and pathological conditions (Williams et al., 2000; Eiben et al., 2004; Kalichman

et al., 2004).

The technique of somatotyping is used to appraise body shape and composition (Bailey et

al., 2009). The resulting somatotype gives a gestalt or quantitative summary of the

physique as a unified whole (Carter, 1996; Rajajeyakumar, 2015). Somatotyping is

defined as the quantification of the present shape and composition of the human bo