Shifting causes of death in Shanghai, China, over many decades
A large study conducted over 42 years in Shanghai—China's largest city—indicates that socioeconomic development most likely contributed to lower death rates for most diseases (except for cancer and diabetes, for which death rates increased), likely because of lifestyle factors. The study is published in CMAJ (Canadian Medical Association Journal).
The study looked at data on deaths among inhabitants of Yangpu, an area of Shanghai with a relatively stable population and low levels of people moving in or leaving. The study period included several key events in recent Chinese history, including the rise of polluting industries (1949 to the 1980s), the Great Chinese Famine (1959 to 1961), the Cultural Revolution (1966 to 1976) and economic reforms (1979 to present).
Out of almost 42 million person-years, there were 290 332 deaths categorized into cause groups: infectious diseases, maternal, perinatal and nutritional issues (group 1), chronic diseases (group 2) and injuries (group 3).
Researchers found that deaths from causes in groups 1 and 3 decreased between 1974 and 2015. After 1988, age-standardized deaths in group 1 decreased because of public health and health care improvements and the removal of polluting industries in that decade. People who experienced severe starvation in utero or in infancy during the Great Chinese Famine were more likely to die from heart disease, stroke, cancer and diabetes. Deaths from chronic diseases reduced over time, except for people born after 1949, among whom deaths from cancer and diabetes increased.
Prior to 1994, Shanghai was a low-income region according to World Bank income categories, but by 2006 it had become an upper-middle income area.
"Socioeconomic development has contributed to a decrease in deaths from most diseases in China," says Dr. Guangwen Cao, Department of Epidemiology, Second Military Medical University, Shanghai, China. "However, for cancer and diabetes, the benefits from socioeconomic development appear to be overridden by new risk factors, such as changing diets and alcohol consumption, smoking, lack of physical activity, overweight and obesity."
Few studies have looked at the effect of socioeconomic events on deaths from specific causes. The authors hope their study will help with health-system planning and disease-control strategies.
The authors note that, as this is a descriptive study, it is difficult to determine if socioeconomic events and cause-specific mortality are causal or represent an association.
"Influence of socioeconomic events on cause-specific mortality in urban Shanghai, China, from 1974 to 2015: a population-based longitudinal study" is published October 1, 2018.