A convenience sampling method was conducted to recruit the participants in this survey. Penang Island was chosen according to the availability of the major three races in Malaysia (Malay, Chinese and Indian). The list of the primary schools and the total numbers of schoolchildren from grades five and six according to their ethnic background have been obtained from the Education Department of Penang Island. The total number of schoolchildren in grades five in Penang Island was 9274, whereas the total number of schoolchildren in the grades six was 10,089. The sample size was calculated for each grade separately through the Raosoft sample size calculator, with 95% confidence level and 5% margin of error, that is, 369 from grade five and 371 from grade six. The sample size was proportionate based on the total percentage of each race. Four primary schools were selected purposively based on the race of children to generate the required sample. For convenient and possibility of drop out, all schoolchildren in grades five and six were recruited in the survey. The final number of participants was 1000 children.