Association of BMI with motor performance in undernourished Santal children of Purulia district, West Bengal, India

Children’s motor development is closely associated with their adiposity status. Association between adiposity in terms of BMI and motor performance has been established in children and adults by few researchers. These results were observed in children from nontribal population, BMI related differences in motor skills have not been studied in tribal children and specifically in Santal children. The present study was undertaken to assess the adiposity status by measuring body mass index (BMI) and to investigate the influence of BMI on motor performance in 5-12 years aged Santal children. This study was conducted on 816 Santal children. The adiposity status of each child was assessed by BMI-for-age z-score based on WHO reference data. Motor development was measured using the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2). Mean BMI values of Santal children remained around the 50^th percentile values of WHO reference data. The normal weight (NW) children scored higher in some individual motor subtests (bilateral coordination, balance, running speed and agility, upper limb coordination, and strength) and in total BOT-2 score (p<0.05) compared to that of underweight (UW) and overweight (OW) children. A significant association was observed between distribution of children in BOT-2 z-scores categories and BMI-for-age z-score categories (X²=71.36, df=3, p<0.01). Stepwise regression analyses showed that BMI have significant impact on motor performance of Santal children. Motor performance showed a curvilinear relationship with BMI as the motor scores found lower in both UW and OW children compared to NW children. The results also indicated that gross motor skills are more affected with the change of BMI in comparison to fine motor skills.