THUMBPRINT, FACIAL ANTHROPOMETRY AND BODY MASS INDEX IN HAUSA ETHNIC GROUP OF KANO STATE, NIGERIA

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Department of Medicine

ABSTRACT
Exploration of human variation using dermatoglyphics and facial features has long been considered as an important marker within the domain of biological anthropology. The aim of the study was to discriminate sexes using thumbprint and facial profiles, and also to determine asymmetry and the relationship between facial profiles with thumbprint profile and body mass index in Hausas of Kano State, Nigeria. A total of 534 participants, comprising 398 male and 136 females participated. Direct sensing fingerprint capturing method was used to obtain the fingerprints. Ridge density, thickness, and pores, counts were determined within a 25 mm2 area. Using photometric methods, 19 unpaired, four paired dimensions, and six facial angles were measured. Three indices of fluctuating asymmetry were calculated. Chi-square test, independent sample t-test, Pearson’s correlation, multiple and binary logistic regression and receiver operating characteristic curve were used. The results showed that there was no statistically significant association between sex and pattern of thumbprints. The ulna ridge density of male (10.01 ± 1.31) was significantly (P < 0.05) lower than that of females (10.91 ± 1.69) in the right thumb. The ridge thickness had inverse relation with ridge density. Pores count in the proximal the right thumb were significantly different (P < 0.05) between males (55 ± 7.96) and females (63 ± 6.91). It was shown that right ulna ridge count was the single best variable to discriminate sex (with 63.4% accuracy). For the left thumbprints, the proximal ridge thickness discriminates sex better (62.8% accuracy). Sexual dimorphism was observed in mean minutiae count. In the two minutiae, ridge return (0.09 ± 0.32 against 0.001 ± 0.001) and ridge convergence (1.98 ± 2.00 against 1.17 ± 1.34) females have higher mean in left thumbprints. Ridge break (with 66.4% accuracy) and ridge end (65.4% accuracy) were the xxii single best sex discriminator in right and left thumb, respectively. Upper facial height (76.2% accuracy) was the best discriminator of sex. Only nasomental (70.3% accuracy)angle indicate a good probability of prediction. Significant differences (p <0.05) in signed asymmetry occurred in bifurcation, cross-bar, break, bridge, point/dot into ridges and point/dot between the ridges. In most of the minutiae types, males tend to have significantly higher (P < 0.05) mean values. In facial dimension, a significant difference (P < 0.05) was observed. Facial proportion analyses show no occurrence of classical canon in both sexes. There was also no significant (P < 0.05) association between sexes invariant of the canon. Body mass index correlated with most the linear facial dimensions. Similarly, lower facial width was the single best predictor (males; R2=8.8, females; R2=0.26, P < 0.05) of body mass index. Radial ridge thickness and enclosure (small) were the best predictiors of body mass index in males and females respectively. In conclusion, a linear relationship between thumbprint and the facial profile was established. Facial profiles were the predictors of the body mass index, compared to the thumbprint profiles among Hausas of Kano State, Nigeria.