EFFECTS OF BODY ADIPOSITY INDICES, DIGIT RATIO AND LEVEL OF PHYSICAL ACTIVITY ON METABOLIC SYNDROME AND SERUM BIOMARKERS AMONG THE HAUSAS OF KANO STATE, NIGERIA

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Department of Medicine

ABSTRACT
Various anthropometric markers of adiposity such as body mass index (BMI), waist circumference (WC), neck circumference (NC), hip circumference (HC), waist-hip ratio (WHR), waist-height ratio (WHtR) and body adiposity index (BAI) have shown varying degree of correlation with the components of metabolic syndrome (MetS) among different sexes, races and ethnic groups. There are conflicting data from previous reports on the relationship between digit ratio(2D:4D) and adiposity markers. Data on relationship between 2D:4D and MetS are scarce. The aim of the study was to investigate the effects of body adiposity indices, 2D:4D and level of physical activity (PA) on metabolic syndrome components and biomarkers among Hausas of Kano, Nigeria. The study comprised of a total of 465 participants pooled from rural and urban communities comprising of 266 males and 199 females selected by systematic random sampling out of which blood samples of 161 subjects were used for serum analysis (male n = 120, female n = 41). Body mass index (BMI), waist circumference (WC), neck circumference (NC), hip circumference (HC), waist-hip ratio (WHR), waist-height ratio (WHtR), body adiposity index (BAI), digit length and 2D:4D were measured and calculated using standard protocols. Visceral adiposity was measured using sex specific visceral adiposity index (VAI). After at least 8 hours of fasting, venous blood samples were drawn for estimation of glucose, high density lipo-protein cholesterol (HDL–C), low density lipo-protein cholesterol (LDL–C), total cholesterol (TC), triglyceride (TG), uric acid (UA) and adiponectin using standard laboratory protocols. Physical activity levels were assesed using self reported PA questionnaire. Chi-square test, independent sample t-test, Pearson?s correlation, multiple and binary logistic regression, receiver operating characteristic curve were used as statistical tools. P < 0.05 was set as the level of significance. The results show that 2D:4D and all the indices of adiposity with exception of BAI, WC and BMI are sexually dimorphic. 2D:4D, HC, WHtR and VAI were higher in females than in males whereas, WHR, NC were higher in males. TC, HDL-Cand fasting blood glucose (FBG) were significantly higher in females (P< 0.05). TG, LDL, SUA, adiponectin and blood pressure (BP) showed no significant sex difference. 2D:4D, all the indices of body adiposity and BP were significantly higher in urban participants (P < 0.05). While adiponectin and HDL were significantly higher (P < 0.05) in rural subjects, all other serum parameters were higher in urban participants (P < 0.05). Effect of urbanization was higher on central indices (P < 0.05) and in females (P < 0.05). 2D:4D, VAI and other adiposity indices correlated positively with serum uric acid (SUA) and serum components of MetS but negatively with HDL and adiponectin. VAI was superior to all the anthropometric indices. WHR was the best anthropometric predictor of MetS [example for LDL-C = 361.12 (WHR) + ( -215.15) in males and LDL-C = 472.19 (WHR) + ( -308.21) in females]. BAI, NC and HC were weak predictors. Compared to L2D:4D, R2D:4D was a stronger MetS correlate (with adiponectin, L2D:4D and R2D:4D correlation coefficients were -0.572 and - 0.634 respectively, P < 0.001). Adiposity measures and MetS components decreased significantly (P < 0.05) with increased PA level. The effects of moderate and optimal PA levels on most adiposity and metabolic indices showed no significant difference (P > 0.05). 2D:4D correlated inversely with PA levels. MetS components were predicted from anthropometric measures of adiposity, digit length and digit ratio with WHR having the highest percentage contribution (for LDL, 67% in males and 82% in females). Cut off values of adiposity measures for MetS components were mostly higher in males than in females and slightly different from those reported for other races. It is conluded that 2D:4D is a positive correlate of body adiposity and MetS, a possible marker of physical activity behaviour and that WHR is the best anthropometric predictor of MetS while VAI is superior to simple anthrpometric measure for MetS prediction in Hausas of Kano. Also, urbanization adversely affects body adiposity and MetS, while PA lowers adiposity and MetS measures.