China has the highest incidence of liver cancer in the world, accounting for about more than half of all liver cancer cases worldwide. Liver cancer is a serious health hazard for our people, and it is necessary to understand the epidemiological characteristics of liver cancer in China.
Here are three aspects to analyze the overview and epidemiological characteristics of liver cancer in China.
Geographical differences
There is a clear geographical variation in the incidence of liver cancer in China, with Shanghai, Fujian, Guangdong, Jiangsu, Guangxi, and Zhejiang provinces being the most affected areas, while Yunnan, Guizhou, Gansu, and Xinjiang provinces have the lowest incidence of liver cancer.
Fusui and Longan in Guangxi, Xiamen and Tongan in Fujian, Qidong and Haimen in Jiangsu, and Chongming and Nanhui in Shanghai are nationally known as areas with high incidence of liver cancer, all located along the southeast coast. What exactly is causing the high incidence of liver cancer in these areas?
A large number of studies have found that the high incidence of liver cancer in these areas may be related to the following factors:
Hepatitis virus
China is a large hepatitis country in the world, and the infection rate of hepatitis B virus in the southeast coastal region is higher than the national average. The hot and humid climate, high population density, lifestyle habits, and consumption of contaminated seafood all contribute to the high incidence of hepatitis in this zone.
aflatoxin
The hot and humid climate of the southeastern coastal region with its subtropical climate creates favorable conditions for aflatoxin contamination. The severity of aflatoxin contamination in the main rations of the local population is much higher than in other regions.
Drinking water contamination
Microcystins decomposed by microcystins in drinking water have carcinogenic and pro-carcinogenic effects, and they can cause liver and gallbladder lesions. The most serious of these are ditch water, river water and reservoir water.
Researchers in China have detected large amounts of microcystins in many ditches and ponds in areas with high incidence of primary liver cancer, such as Haimen, Jiangsu, where long-term consumption can cause nonalcoholic fatty liver by interfering with lipid metabolism, and hepatocellular carcinoma by acting synergistically with hepatitis viruses and aflatoxins.
Gender differences
Studies have shown that the male to female ratio of primary liver cancer patients is 2 to 5 : 1, with men at significantly higher risk than women.
Why are men more likely to develop liver cancer? It may be related to the following factors: men’s social roles make them more likely to have adverse behavioral and psychological factors such as smoking, drinking alcohol, and higher psychological stress.
Age differences
Hepatocellular carcinoma can occur at all ages, from as young as 2 months old to as old as 80 years old, with a high incidence concentrated in the 40s and 60s.
In areas with a high prevalence of liver cancer, the age of onset can be as early as 35 years; in areas with a low prevalence of liver cancer, it is more delayed. Surveys show that the more severe the prevalence of liver cancer, the younger the average age of patients.
In recent years, the age of high incidence of liver cancer in China has advanced by 10 years, and liver cancer has surpassed gastric cancer to top the mortality rate of gastrointestinal malignancies in China. This may be related to people’s stressful work, mental pressure, irregular life, and long-term excessive alcohol consumption in modern society.