Obesity has overtaken smoking as the top cause of major cancer in the UK, and it is already of great concern with more and more people being overweight.
Childhood obesity is a good breakthrough in reducing the obesity rate of a nation. Overweight people are more likely to become obese than be of weight health. Therefore, childhood obesity has become an important hot topic in the research field of obesity.
Scientists from the University of Bristol and the University of Birmingham in the UK investigated the association of body mass index (BMI) with the change in children’s physical activity and sedentary time between ages 6 and 11. The research was granted by the British Heart Foundation.
The study recruited a total of 2,132 eligible children from 57 schools in Southwest England. They were required to wear an accelerometer to calculate the mean minutes of moderate-to-vigorous-intensity physical activity.
The measurements show that children became less active from ages 6 to 11. Their weekday physical activities decreased between ages 6 and 11 by 2.2min/day/year, while their physical activities on weekends decreased steeply by 3.1min/day/year.
To find the association between physical activity level and obesity, the study also recorded children’s BIM scores. The percentage of children who were overweight increased from 11% to 14%. Similarly, the percentage of children who were obese increased from 8% to 15%.
Are overweight children more likely to be physically inactive? Children are divided into three categories based on the Body Mass Index: healthy, overweight, obese. At age 6, there were no differences in the average physical activity levels of children who were of healthy weight, overweight and obese. However, as they grew, BMI was found to be associated with weekday physical activity. Children who were overweight and obese had a lower level of weekday physical activity at age 11.
The increasing association between physical activity level and BIM suggested that overweight and obese children shall be encouraged to do more physical activity in the primary school.
The study also investigated whether gender and household education are associated with the change in physical activity level.
At the baseline age 6, boys were more physically active than girls. as age grew, girls did fewer physical activities. Though boys also shew a decline in physical activity level, the gap becomes larger at age 11. Girls of healthy weight engaged in less physical activity and boys with obesity at all time points.
Sedentary time also shows the same patterns. Girls were more sedentary at age 6 than boys, and their sedentary time increased over time.
In terms of household education, researchers found that the education level of the family members was associated with sedentary time on weekdays at age 6 and weakly associated with the change in weekday sedentary time between ages 6 and 11, but no on weekend days. This trend is also true when it comes to sedentary time. These results indicate that household education will play a less important role for children aged over 6.
The findings of the study suggested that children shall be encouraged to become more physically active to have a healthy weight. Also, girls shall be given more attention during the career of improving public health.