The two-year longitudinal relationships between changes in body composition and changes in selected metabolic risk factors (abdominal obesity and blood pressure) among adolescents from Potchefstroom in the North West Province of South Africa

Abstract

Objectives: To determine the longitudinal relationship between changes in body composition and selected metabolic risk factors (abdominal obesity and BP) among adolescents from the Tlokwe Municipality in the North West Province of South Africa

Methods: 289 adolescent boys and girls aged 14.9 ± 0.76 years participated in the study. Body composition was measured following the International Society of the Advancement of Kinanthropometry (ISAK) standard procedures. Abdominal obesity was determined using the waist circumference measurements (WC) measurements and resting BP was determined by Omron MIT Elite Plus.

Results: Significant mean changes were found for stature, body mass index (BMI), body mass, WC, systolic (SBP) and diastolic blood pressure (DBP) over the measurements period (p < 0.05). Pre-hypertension increased by 5% for the total group (from 5% in 2011 to 10% in 2013) with boys having higher percentage scores of 14% in 2012 (compared to 5% for girls) and 18% (compared to 4% in girls) in 2013. Overweight increased (5%) from 13% to 18% for the total group, with girls being more overweight (9%) compared to the boys (1.9%). BMI for the group was significantly related to WC (p = 0.01) and SBP (p < 0.05). BMI among the boys, was significantly related to abdominal obesity (p < 0.01) and positively but non-significantly related to BP. In girls, BMI was significantly related to WC. (p < 0.01) and systolic blood pressure (SBP) in 2012 (p = 0.05).

Conclusion: Overweight (among the girls), BP and abdominal obesity (among the boys) are on the rise among the adolescents. BMI is significantly related to selected metabolic risk factors (BP and abdominal obesity). BMI is predictor of abdominal obesity in boys while in girls, BMI is a predictor of both WC and are SBP