Association of melanocortin 4 receptor (MC4R) gene mutation, physical activity, and food intake between normal and overweight Malay children
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Date
2013-06
Authors
Tan, Yee Lin
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Overweight and obesity has become an alarming issue worldwide and the
problem is on the rise. Obesity arises when there is energy imbalance where
energy intake exceeding energy expenditure. It can be resulted from the
interaction between genetic, behavioral and environmental factors.
Melanocortin 4 receptor (MC4R) mutation is the most common known
monogenic cause of human obesity that impairs energy homeostasis by
increasing food intake and decreasing energy expenditure. MC4R mutation
N62S which was found in children of Pakistani origin was found to partially
impair the receptor function which might cause obesity. On the other hand,
behavioral factors leading to obesity include increased energy intake and
reduced physical activity. Thus, the present study aimed to determine the
presence and frequency of MC4R mutation N62S among Malay children, and
to determine the influence of mutation N62S, physical activity level and total
caloric intake on overweight. One hundred and twenty children of the age of
9-11 years were recruited and analyzed for the presence of mutation N62S
through high resolution melt (HRM) analysis; activity counts by using
accelerometer GT3X+ (Actigraph, UK); physical activity level based on
activity count according to Yildirim et al. (2011); and total caloric intake and
percentage of fat intake goal achieved per day through the subjects' food
diary analysis by DAPlus software (Esha Research, USA). N62S mutant was
not found in all Malay children from both of the normal and overweight
groups. No significant difference was found between the two groups in terms
of activity count (P = 0.282) and total caloric intake (P = 0.179). No
association was found between BMI status and physical activity level (P =
0.660). Normal weight children achieved significantly higher percentage of fat
intake goal than overweight children with the mean(standard deviation) of
91.17(40.91) and 63.60(27.98) %, respectively (P < 0.001). The absence of
N62S mutant in the Malay children in the present study might be due to its
low prevalence. The belief that overweight children take in more energy and
fat, and have lesser energy output than non-overweight children was not
proven in the present study. These findings suggested that overweight and
obesity might be resulted from other environmental factors, or even an
underreport of fat intake, which worth future study taking all these factors into
consideration. Besides, future study with larger sample size is suggested to
determine if the N62S mutant is really absent in Malay children, and inactivity
and high energy intake among children would be the important factors for
childhood obesity development in Malaysia.
Description
Keywords
Obesity