A Study to Correlate the Predictability of Waist Circumference and Body Mass Index on Respiratory Function in Obese Children

To correlate the predictability of waist circumference and body mass index on respiratory function in obese children.

Childhood obesity has been linked with increased risk of obesity in adulthood. During childhood growth, body fat is deposited both subcutaneously and intra- abdominally. But Body Mass Index (BMI) gives neither any indication about the distribution of fat mass in the body, nor the difference in proportion of fat and lean mass. So, a person classified as obese according to BMI may have a higher ventilatory muscle mass which could influence the spirometric values by exerting a stronger expiratory and inspiratory effort. Waist Circumference (WC) gives an indication of intra- abdominal fat mass distribution. Intra -abdominal fat will affect the normal biomechanics of breathing leading to reduced lung volumes^..

To correlate BMI and WC to respiratory function in obese children and to compare the correlation of body mass index and waist circumference to respiratory function in these obese children.

Correlation study.

ICSE and CBSE Schools in Bangalore.

60 obese subjects (BMIH”30 in adults) in the age group of 7–15 years were randomly selected. WC was measured using non-elastic measuring tape. FVC, FEV₁, PEF was measured using portable spirometer. By doing 3 measurements, best value was taken.

Correlation and regression analysis were done.

Comparing the correlations, WC has shown more correlation to all the respiratory function parameters than BMI with p<0.001** Comparing the regression coefficients, WC has shown negative correlations to all the respiratory function parameters with p<0.001** Proportion of variation in respiratory function parameters were more for variation in WC than for variation in BMI. This study shows that there is a significant negative correlation of WC and BMI on respiratory function. And the WC has shown more correlation than BMI to respiratory function. The results were found to be significant at p<0.001**

It is concluded from this study that WC is more predictable than BMI in assessing respiratory functions of obese children. From this study we can also conclude that WC can be used as the most simple anthropometric tool than BMI in screening the obese children and then categorize those children who are at a greater risk of developing pulmonary dysfunction in their adulthood through spirometric test.