Background: The puerpose of this study was to assess the association between anthropometric measures and skinfold thickness as well as parental obesity and physical activity with body fat percentage (BFP) percentiles using a quantile regression (QR) model within a representative sample of Iranian adolescents.
Methods: In this cross-sectional study, 2873 school children (1472 girls) aged 14-20 years old were selected by multi-stage random sampling approach from different areas of two cities of Fars Province in southern Iran. Demographic characteristics, parental history of obesity, physical activity were collected by using a self-reported questionnaire. Height, weight, waist (WC), hip (HC), arm (AC) circumferences, triceps (TST), abdominal (AST), clavicle muscle (CMST) skinfold thicknesses, and BFP were measured. A QR analysis was used to evaluate the association between the obesity measures with BFP at different quantiles.
Results: The results of QR models showed that circumference measures and skinfold thicknesses were statistically significant positive associations with BFP across all quantiles (P< 0.05). Among boys, having a history of obesity in mothers associated with higher BFP at the 15th to 95th percentiles (the parameter estimates ranged from 1.9 to 4.9, P<0.05). However, there were statistically significant positive associations between parental obesity with BFP in girls at the 25th to 95th and all percentiles for maternal and paternal obesity, respectively (the prameter estimates ranged 1.6-2.6 and 2.7- 5.6 with P<0.05). Moreover, physical activity negatively associated with the lower BFP at 50th to 95th only in grils (prameter estimates ranged -2.5 to -1.7 with P<0.05).
Conclusions: This study revealed that anthropometric measures and SF measures associated with higher BFP at all quantiles in Iranian adolescents. The findings of the study also showed that having a history of parental obesity as well as a high physical activity associated with higher and lower BFP, respectively.