Comparison of the status of overweight/obesity among the youth of local Shanghai, young rural-to-urban migrants and immigrant origin areas.

Background: Obesity in adolescents and children has become a global public health problem and lots of factors influence the status of obesity and overweight. The present study aims to compare the health-related factors which could influence the obesity in Chinese children and adolescents in three different groups which including the local developed city group, rural-to-urban migrants group and immigrants origin areas group.
Methods: We conducted a cross-sectional study consisted of 2457 children and adolescents aged 7-10 years old including 914 rural-to-urban migrants subjects, 795 local Shanghai subjects and 748 from immigrant origin areas. Physique measurements and self-reported information on health-related factors, such as physical activities, dietary habits, socio-economic factors such as family income, sleep habits, etc. were collected by questionnaire. SPSS16.0 was used in the analysis.
Results: Mean level of body height, body weight and sitting height were different among the three groups, local youth group was higher in all the indexes than the other two groups. Grip for both hands were higher in local group also, while the heart rate was lowest in rural-to-ruban migrants group. The mean BMI in three groups showed significant difference, highest for local group. Higher SBP level was found in city and rural-to-urban migrants group also. However, no difference of DBP between groups was detected. The distribution of pre-hypertension and hypertension in three groups were significantly different and the distribution of overweight and obesity between genders in all three groups were different. The prevalence of overweight was 19.04% in rural-to-urban migrants group (19.92% for male and 17.64% for female), 28.21% for city group (35.64% for male and 20.72% for female); while no overweight or obesity subjects were found in immigrant origin areas group in this study. When compared the overweight and obesity prevalence between city group and rural-to-urban migrants, we found the overweight was more common in the local youth group. Univariable Logistic regression analysis and multivariable analysis results suggested that the more rice intake, higher family income and SBP higher than 140 mmHg were risk factors to obesity for rural-to-ruban migrants, while good dietary habits (no TV watching during meals) was preventive factor to obesity and SBP higher than 120 mmHg and unsocial factor were associated with obesity for rural-to-urban migrants.
Conclusions: Our study revealed the prevalence of overweight and obesity in developed city children and adolescents and rural-to-urban migrants were relatively high, especially more common in local population and male gender. Lifestyle, dietary and psychological factors offered important contribution in increasing or decreasing the risk of obesity.