Cancer has become the most common cause of death in China. Owing to rapid economic development, improved livelihood, and shifts in risk factors, cancer epidemiology has experienced substantial changes during the past several decades. In this review, we aim to describe the current cancer epidemiology of the main types of cancer in China, report major risk factors associated with cancer development, and summarize the contributions of the Chinese government to controlling the cancer burden. A total of 4,064,000 new cases were diagnosed in China in 2016. The most frequent types are lung cancer (828,100; 20.4%), colorectal cancer (408,000; 10.0%), and gastric cancer (396,500; 9.8%). Lung (657,000; 27.2%), liver (336,400, 13.9%), and stomach (288,500; 12.0%) cancers are the 3 most deadly cancers in the general population. The 5-year survival rate for cancer has dramatically increased in recent decades. However, liver and particularly pancreatic cancers still have the poorest prognosis. The main modifiable risk factors associated with cancer development include infectious agents, smoking, alcohol consumption, obesity, unhealthful dietary habits, and inadequate physical activity. The Chinese government has made unremitting efforts to decrease the cancer burden, including cancer education and investment in cancer screening programs.

ObjectiveChina and the United States (the U.S.) have the heaviest colorectal cancer (CRC) burden with considerable variations in temporal trends. This study aims to analyze the temporal patterns of CRC burden and its risk factors in China and the U.S. across the past three decades. MethodsData were extracted from the Global Burden of Disease (GBD) Study in 2019, including cases, deaths, disability-adjusted life-years (DALYs), age-standardized rate (ASR), and summary exposure value (SEV) of CRC in China and the U.S. between 1990 and 2019. Annual average percentage changes (AAPCs) of CRC burden were calculated using the Joinpoint regression model. The mortality in CRC attributable to potential risk factors was characterized by countries, gender, and age groups. ResultsIn 2019, there were 607,900 and 227,241 CRC cases, and 261,777 and 84,026 CRC deaths in China and the U.S., respectively. The age-standardized incidence rate (ASIR) was 30.55 per 100,000 in China and 41.86 per 100,000 in the U.S., and the age-standardized mortality rate (ASMR) was 13.86 per 100,000 in China and 14.77 per 100,000 in the U.S. CRC incidence, mortality, and DALY rate in the U.S. showed downward trends in the past three decades (AAPC=−0.47, −1.06, and −0.88, respectively), while upward trends were observed in China (AAPC=3.11, 1.05, and 0.91, respectively). Among the cause of CRC, the leading risk factor contributing to CRC death was low milk in China and smoking in the U.S., respectively. ConclusionsFrom 1990 to 2019, the burden of CRC in China increased dramatically, particularly for males and middle-aged and elderly people. The management of the major risk factors associated with the high burden of CRC should be enhanced.

China is faced with heavy burdens caused by lung cancer, which has climbed to the top of both cancer incidence and mortality spectrums. The age-standardized rates of incidence and mortality have shown a trend of gradual up-trends in the last decades, while the crude rates rise much quickly due to the aging of population. Although the improvement in health care has contributed to better survival of lung cancer, its prognosis is still challenging. Apart from the common risk factors such as tobacco use, air pollution, and occupational hazards, some specific factors like Chinese-style cooking also have posed great threats to human health. In light of such national conditions, specific interventions should be conducted to curb the burden of lung cancer including smoking cessation, improvement of air quality, early detection and effective treatment of lung cancer.

Objective: To investigate the association between ambient air pollution and stroke morbidity in different subgroups and seasons. Methods: We performed a time-series analysis based on generalised linear models to study the short-term exposure–response relationships between air pollution and stroke hospitalisations, and conducted subgroup analyses to identify possible sensitive populations. Results: For every 10 µg/m ³ increase in the concentration of air pollutants, across lag 0–3 days, the relative risk of stroke hospitalisation was 1.029 (95% CI 1.013 to 1.045) for PM _2.5 , 1.054 (95% CI 1.031 to 1.077) for NO ₂ and 1.012 (95% CI 1.002 to 1.022) for O ₃ . Subgroup analyses showed that statistically significant associations were found in both men and women, middle-aged and older populations, and both cerebral infarction and intracerebral haemorrhage. The seasonal analyses showed that statistically significant associations were found only in the winter. Conclusions: Our study indicates that short-term exposure to PM _2.5 , NO ₂ and O ₃ may induce stroke morbidity, and the government should take actions to mitigate air pollution and protect sensitive populations.

Background: The incidence rates of thyroid tumors and nodular goiter show an upward trend worldwide. There are limited reports on the risk of perchlorate and iodine on thyroid tumors, but evidence from population studies is scarce, and their impact on thyroid function is still uncertain. Therefore, the objective of this study was to investigate the association of perchlorate and iodine with the risk of nodular goiter (NG), papillary thyroid microcarcinoma (PTMC), and papillary thyroid carcinoma (PTC) and to assess the correlation between perchlorate and iodine with thyroid function indicators. Methods: A case–control population consisting of 184 pairs of thyroid tumors and nodular goiter matched by gender and age (±2 years) was recruited in this study. Serum and urine samples were collected from each participant. Thyroid function indicators in serum were tested by automatic chemical immunofluorescence, and perchlorate and iodine levels in urine were determined by ultra-high performance liquid chromatography tandem-mass spectrometry and inductively coupled plasma-mass spectrometry, respectively. Conditional logistic regressions and multiple linear regressions were used to analyze the associations. Results: Urinary perchlorate concentration was significantly higher in total cases, NG and PTC than in the corresponding controls (P < 0.05). Perchlorate was positively associated with PTC (OR = 1.058, 95% CI: 1.009, 1.110) in a non-linear dose–response relationship, but there was no association between perchlorate and NG or PTMC. Iodine was not associated with the risk of thyroid tumors and NG and did not correlate with the thyroid function indicators. Furthermore, perchlorate showed a positive correlation with thyroid stimulating hormone (TSH) at iodine adequate levels (P < 0.05), and a negative correlation with free triiodothyronine (FT3) and a positive correlation with thyroglobulin antibody (TgAb) at iodine more than adequate or excess levels (P < 0.05). Conclusions: Perchlorate can increase the risk of PTC in a non-linear dose–response relationship and disturb the thyroid hormone homeostasis and thyroid autoantibody levels.