Obesity and Its Related Diseases in China: The Impact of the Nut ...

Bicycling and walking remain the dominant forms of transportation. The Chinese spent more time on commuting physical activity (about 30 min) than on leisure-time exercise (only about 10 min). Only around 10% of Tianjin residents pursued leisure-time exercise, and 60% of residents did not exercise at all (12). However, with economic development, there was a tendency to acquire motorized vehicles for more and more families. From 1989 to 1997, 13% of households acquired a motorized vehicle. Bell et al. (13) reported household ownership of motorized transportation was associated with obesity in both men and women in China. This may indirectly document that the energy expenditure of commuting is tending to decrease.

Technology has created opportunities for increasing sedentary leisure time. For example, television viewing has been found to be associated with an increase in the prevalence of obesity. Television set ownership in China increased considerably and by 1997, close to 90% of Chinese households owned TV sets (1).

2.1.1.4 Prevalence of Obesity and its Related Chronic Diseases

Obesity is a metabolic disorder characterized by an excess of body fat. Because body fat cannot be easily measured, BMI is used to identify obesity in population studies. According to WHO’s recommendation, obesity is classified as BMI ≥ 30.0 kg/m² and overweight as BMI ≥ 25 kg/m². Using these criteria, the prevalence of overweight and obesity was low in 1982 in China. It was only 3.5% and 0.2%, respectively, in adults aged 20 to 45 years. These rates increased four-fold to 14.1% and 1.3% in 1997, respectively. The prevalence of overweight and obesity was much higher in urban than in rural regions (18.7% vs. 13.7%).

Accompanying the marked increment in the rates of overweight and obesity, the prevalence of chronic disease increased considerably in China.