China's transition: the effect of rapid urbanization on adult occupational physical activity.

China has recently undergone rapid social and economic change. Increases in urbanization have led to equally rapid shifts toward more sedentary occupations through the acquisition of new technology and transitions away from a mostly agricultural economy. Our purpose was to utilize a detailed measure of urbanicity comprising 10 dimensions of urban services and infrastructure to examine its effects on the occupational physical activity patterns of Chinese adults. Longitudinal data were from individuals aged 18-55 from the years 1991-1997 of the China Health and Nutrition Survey (N=4376 men and 4384 women). Logistic multilevel regression analyses indicated that men had 68% greater odds, and women had 51% greater odds, of light versus heavy occupational activity given the mean change in urbanization over the 6-year period. Further, simulations showed that light occupational activity increased linearly with increasing urbanization. After controlling for individual-level predictors, community-level urbanization explained 54% and 40% of the variance in occupational activity for men and women, respectively. This study provides empirical evidence of the reduction in intensity of occupational activity with modernization. It is likely that urbanization will continue unabated in China and this is liable to lead to further transitions in the labor market resulting in additional reductions in work-related activity. Because occupational activity remains the major source of energy expenditure for adults, unless alternative forms are widely adopted, the Chinese population is at risk of dramatic increases in the numbers of overweight and obese individuals.