Motorized transportation, social status, and adiposity: the China Health and Nutrition Survey

Background: Increased dependence on motorized transportation may contribute to obesity. Countries in rapid socioeconomic transitions, such as China, provide an opportunity to investigate such an association.

Purpose: The aim of the study was to examine the hypotheses that increased dependence on motorized transportation is related to adiposity and that this effect will be more pronounced in adults with high SES or those who live in urban regions.

Methods: Data from the longitudinal China Health and Nutrition Survey conducted from 1997 to 2006 (n=3853, aged 18-55 years at baseline, 52% women, ~7.8 years' follow-up) were used to examine the association between motorized transportation (none, 1-5 years, >5 years) and changes in body weight and waist circumference (WC) by using multivariate regression. SES factors were obtained from questionnaires. Data were analyzed in 2010.

Results: Use of motorized transportation for >5 years was related to ~1.2 kg greater weight gain (p=0.006) and ~1.0 cm larger WC gain (p=0.017) in men, when compared with the nonmotorized transportation group and adjusted for baseline age, anthropometry, dietary intake, and follow-up time. These changes were slightly more pronounced in men with higher income or from rural areas, but the difference was not significant. In women, the tendency to have motorized transportation with weight gain was less pronounced (+1.1 kg, p=0.008). Low education and high income were the most predominant factors. In 2006, motorized transportation was associated with a 1.3-fold higher OR for obesity (p(trend)=0.054) and abdominal obesity (p(trend)=0.047) in men, and a 2-fold higher OR of obesity in women (p(trend) <0.001).

Conclusions: Motorized transportation was related to an increase in adiposity in the Chinese population, particularly in men.