ABSTRACT
The variation in human body physique has been a subject of interest to physical anthropologists and human biologists since time immemorial. It is important to understand and analyze the factors associated with body physique, in order to have a better understanding of the morphological structure of the human body. Despite several decades of research, the relevance of body fat distribution to the risk of cardiovascular disease remains unclear. This study aimed to investigate the relationship between the somatotypes and cardiovascular disease risk factors in Nigerian undergraduate students. This is a cross sectional study conducted among the undergraduate students of Kaduna State University, Kaduna, Nigeria. Relationships between somatotype, physiological and biochemical parameters were considered in five hundred and sixty (560) apparently healthy students consisting of females (n = 181) and males (n = 379), aged 17 - 33 years. Somatotype was assessed using the Heath Carter anthropometric somatotype method. Risk factors included systolic and diastolic blood pressures (SBP, DBP), triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol fraction (HDL-C), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C) and atherogenic index (TC/HDL-C ratio, AI). Anthropometric assessment included measurement of weight, height, waist and hip circumferences, biepicondylar breadth of humerus and femur and skinfold thickness at different sites. Serum levels of TC, HDL-C and TG were measured. LDL-C was calculated by the Friedewald formula. Statistical analysis was done to examine the associations between anthropometric variables and lipid. One-way analysis of variance (ANOVA) was used to evaluate the statistical significance of differences between sex and age related groups. The comparison of somatotype components within the BMI classification was also analyzed using ANOVA. A significant level at 0.05 was used for all analyses employing IBM SPSS version 20. Pearson's correlation coefficients between each somatotype component and each blood pressure were calculated. Correlations between risk factors and each somatotype component were calculated. Significant correlations ranging from - 0.23 to + 0.23 in males and - 0.20 to + 0.30 in females. The statistical analysis showed that females were significantly more endomorphic and less ectomorphic than males. SBP and DBP showed an upward tendency with age in both sexes. The results suggest that in females, correlations between somatotype and blood pressure tended to be stronger, while in males this pattern was less consistent. The results showed that, the somatotype component ratings of females and males were found to be 2.50 - 3.07 - 2.54 and 2.30 - 3.25 - 2.66 respectively. There was also significant association between somatotype components and BMI, depicting that the increase in endomorphy and mesomorphy components were a risk factor having predisposition towards certain diseases. In general, for males and females, correlation between blood pressure and endomorphy were positive, while between blood pressure and ectomorphy were negative. This suggests that ponderosity and muscularity have the opposite effect; however linearity of physique could offer an adaptive advantage. For each cardiovascular risk, those with a poorer profile tended to be more endomorphic and mesomorphic and less ectomorphic than those with a better profile who were more ectomorphic and less endomorphic and mesomorphic. The association was more apparent in males than in females and more so in those at 26 - 33 years of age than in the younger age group. Although the correlations suggest that body type is weakly associated with common cardiovascular risk factors in healthy females and males, somatotype associations are more apparent at the extremes of the distributions of specific risk factors.BMI, WC and WHR were similarly and importantly associated with blood pressure and lipids. The findings from this study highlights the importance of these intermediate risk factors on the pathway between excess body fat and cardiovascular disease.