Comparison between Body Mass Index and Measures of Central Obesity in Predicting Prehypertension Risk among Selected Workers in Kano State, Nigeria

The study aimed at testing the null hypothesis that body mass index (BMI) is not associated with higher risk of prehypertension. This was a cross-sectional study of a group of workers enrolled in a part-time degree program at Bayero University Kano, Kano State Nigeria. Body weight was measured using a digital weighing scale, body height was measured using a portable stadiometer, and waist and hip circumferences were measured using an inelastic measuring tape. All anthropometric measurements were done based on standardized protocols. Blood pressure was measured using a mercury sphygmomanometer. Data analysis was done using R software. Null hypothesis was rejected only if its probability was less than 0.05. Four hundred subjects had their data analyzed. There were 200 prehypertensive cases consisting of 125 males (mean age = 38 years, ±7.8) and 75 females (mean age = 35 years, ±8.6). The 200 normotensive subjects consisted of 118 males (mean age = 39 years, ± 7.0) and 82 females (mean age = 32 years, ±8.6). Among the female subjects, the probabilities of null hypotheses comparing BMI with the three measures of central obesity i.e. waist circumference, waist to-height ratio and weight-to-hip ratio were 0.83, 0.57 and 0.4 respectively. The corresponding probabilities among the male subjects were 0.53, 0.62 and 0.2 respectively. In conclusion, the null hypothesis was accepted and thus generalized obesity was not associated with greater risk of prehypertension than central obesity among the study subjects.

Key Words: body mass index, central obesity, prehypertension, Nigeria