A first analysis of time trends in cancer mortality in China at the national level is presented. Using a joinpoint regression model, based on data from a national mortality routine reporting system in China (CHIS), time trends in mortality for 9 major cancers are analyzed. Between 1987 and 1999, the age-standardized mortality rates for all cancers combined declined slightly in rural areas but have increased since 1996 in urban areas. The mortality rates for cancers in oesophagus, stomach, cervix uteri, leukaemia (except for urban males after 1996) and nasopharynx declined, while lung cancer and female breast cancer showed significant increasing trends in both urban and rural areas and for both sexes. Cancers of the colon-rectum and liver had different trends in mortality in urban and rural populations. The trends in agespecific mortality rates suggest some different trends in the younger population, which may presage future overall trends, for example, increasing mortality from cancer of the cervix. The observed trends primarily reflect the dramatic changes in socioeconomic circumstances and lifestyles in China in the last 2 decades. Tobacco smoking remains a major problem, with increases in mortality from lung cancer. The improvements in socioeconomic status, diet and nutrition may be responsible for the declining risk of some cancers (oesophagus, stomach and nasopharynx), while increasing the risk for others (breast and colon-rectum). Screening programs (especially for cervix cancer), and more available and better facilities for cancer therapy, may have helped to reduce mortality for several cancers. The large increases in the absolute number of deaths that resulted from the increasing and aging population are much more important in determining the future cancer burden than any changes due to change in risk, emphasizing the increasing importance of cancer as a health problem in the 21st century in China.
The relationship between air pollution and daily mortality in 1989 was examined in two residential areas in Beijing, China. Very high concentrations of sulfur dioxide (SO2) (mean = 102 micrograms/m3, maximum = 630 micrograms/m3) and total suspended particulates (TSPs) (mean = 375 micrograms/m3, maximum = 1,003 micrograms/m3) were observed in these areas. Daily counts of deaths were regressed, using Poisson regression on the logarithm of (SO2) and/or TSPs controlling for effects of temperature, humidity, and day of week. A highly significant association was found between In(SO2) and daily mortality. The risk of total mortality was estimated to increase by 11% (95% confidence interval [95% CI] = 5%-16%) with each doubling in SO2 concentration. Separately, the association of In(TSP) with total daily mortality was positive but not significant (4% increase in mortality with each doubling in TSP; 95% CI = -2%-11%). When mortality was analyzed separately by cause, the association with a doubling in SO2 was significant for chronic obstructive pulmonary disease (29%), pulmonary heart disease (19%), and cardiovascular disease (11%), and marginally significant for the other nonmalignant causes (8%), but not statistically significant for cancer (2%). A similar association was noted for a doubling in TSP (4%, 38%, and 8% for total, chronic obstructive pulmonary disease, and pulmonary heart disease mortality, respectively), but the result was only statistically significant for chronic obstructive pulmonary disease. In the season-specific analysis, both SO2 and TSP were found to be significant predictors of total daily mortality in summer. In winter, SO2 was again significantly associated with increased mortality, but no positive association was found between TSP and mortality.(ABSTRACT TRUNCATED AT 250 WORDS)
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