Abstract
Background
To analyze trends in liver cancer mortality rates among Chinese residents from 2002 to 2021, which are currently unknown.
Methods
In accordance with the standardisation of liver cancer mortality rates obtained from the “Causes of Illness, Injury, and Death Among Residents” section of the China Health Statistics Yearbook (2002–2021), these rates were analysed for temporal trends using the Joinpoint regression model. A subsequent cohort analysis was conducted using an age-period-cohort (APC) model to investigate the impact of age, period, and birth cohort on these changes.
Results
Over the 20-year evaluation period, the standardized mortality rate of liver cancer among Chinese residents exhibited a fluctuating downward trend, with rural residents experiencing a faster decline than urban residents (AAPC of -2.9 and − 2.7, respectively; P < 0.05). However, the standardized mortality rate of liver cancer was higher among rural residents than among those from urban areas and was higher among males than among females. Liver cancer standardised mortality rate exhibited an increasing trend with respect to age. Regarding the cohort effect, liver cancer mortality gradually decreased in more recent birth cohorts.
Conclusion
In recent years, the mortality rate of liver cancer among Chinese residents has generally declined; however, it remains relatively high, especially in rural individuals and middle-aged men. Vaccination of hepatitis virus, clean drinking water and healthy foods, regular physical examinations, good lifestyle habits, and improved medical standards are the keys to reducing the risk of liver cancer-related death in China.
Keywords: Liver cancer, Mortality, Trend, Joinpoint regression
Background
Cancer is a major chronic disease that poses a serious threat to human life and health worldwide, with liver cancer being the sixth most common type of cancer globally. Due to the fact that most cases of liver cancer are not detected until the middle and late stages of the disease, the prognosis is often poor, and cure rates remain low due to limited available treatment options [1, 2]. In 2022, global liver cancer deaths reached 759,000 cases, accounting for 7.8% of all cancer deaths worldwide and ranking as the third leading cause of cancer mortality globally. In China, liver cancer accounted for 316,500 deaths, constituting 10.1% of all cancer deaths nationwide and ranking as the second leading cause of cancer mortality nationally [3]. In recent years, China’s economy has continued to develop, and the rate of urbanization has accelerated annually, effectively improving societal conditions and living standards among the general population. However, urbanization has also led to new environmental pollution problems; coupled with lifestyle changes and the aging of the population, among other factors, these changes mean that the importance of the prevention and control of liver cancer cannot be ignored, and treatment strategies must be improved. Thus, the aim of this study was to analyze liver-cancer related deaths, trends, and differences between subgroups of Chinese residents from 2002 to 2021. The findings of this study could provide a theoretical basis for the country to formulate national cancer prevention policies, facilitate active and effective prevention and treatment measures, protect high-risk groups, and curb the prevalence of liver cancer, and the conclusions could be generalizable to other low- and middle-income countries.
Methods
Sources of data
The data on liver cancer mortality is derived from the liver cancer section, which is part of the “Causes of Illness and Injury Deaths Among Residents” category, in the China Health Statistics Yearbook from 2002 to 2021. The China Health Statistics Yearbook, a reference publication issued by the National Health Commission of China, reflects the development of China’s health sector and the health status of its residents. Annual liver cancer mortality rates were extracted and organised by age group for urban and rural residents (including males and females) from the China Health Statistics Yearbook (2002–2021).
The cases of liver cancer in the dataset were defined in accordance with the International Classification of Diseases, 10th Revision (ICD-10) code C22 (malignant neoplasm of the liver and intrahepatic bile ducts). This coding standard is recognised on an international level and applied uniformly in the China Health Statistics Yearbook for the classification of deaths related to liver cancer, thus ensuring consistency in case identification across years and regions. Due to the retrospective nature of the study and the use of anonymized data, ethics and approval and consent to participate were not required.
Analytical methodology
Data standardization
The liver cancer mortality rates of all urban residents, urban male residents, and urban female residents, as well as those of all rural residents, rural male residents, and rural female residents of China were collated for each age group over the period from 2002 to 2021. To eliminate any potential influence of ages, data from the 6th population census of China, which was conducted in 2010, were used to calculate the age-standardized mortality rate of liver cancer.
Trend analyses
Joinpoint Regression software (4.8.0.1), developed by the National Cancer Institute, was used to analyze trends in liver cancer mortality. The annual percent change (APC) and average annual percent change (AAPC) of the age-standardized mortality rates of liver cancer were calculated [4], and a log-linear model of the liver cancer mortality rate was fitted, with the number, location, and P-value of the turning points determined using the Monte Carlo permutation test, according to the modified Bayesian information criterion (BIC) to select the optimal model, as previously described [5]. An APC < 0 was indicative of an annual decrease in mortality rate; conversely, an APC > 0 was indicative of an annual increase in mortality rate. An APC equal to the AAPC indicated that there was no inflection point and that the mortality rate within a given group exhibited a monotonically increasing or decreasing trend, in general. The criterion for statistical significance was set at α = 0.05.
Because of the covariance of age, period, and birth cohort in the age-period-cohort model, the endogenous variable method (IE) [6] was used in the present study to overcome the limitations of the traditional model analysis methodology. More specifically, the Stata 17.0 IE software package was used to analyze the effect coefficients of age, period, and cohort on liver cancer-related deaths, as well as the relative risk (RR) values, with positive effect coefficients indicating an increased risk and negative effect coefficients indicating a decreased risk (RR = exp [effect coefficients]), and the larger the RR value, the higher the risk of morbidity. The function used in the basic expression of the APC model was as follows:
ln(Yabc)=µ + αa + βb + γc + εabc, where ln(Yabc) represents the natural logarithm of the mortality rate of liver cancer; µ is the intercept, which represents the reference level of disease risk for the age, period, and cohort parameter; αa is the age effect of the ath age group, for a = 1,2,…; βb represents the period effect of the bth, for b = 1,2,…; γc represents the cohort effect for the cth cohort, γc = b-a + n, with n denoting the number of age groups and εabc denoting the error or residual term.
Results
Liver cancer-related deaths in China
Over the period 2002–2021, the standardized mortality rate of liver cancer among Chinese residents was the highest in rural males, followed by urban males, rural females, and, finally, urban females. The standardized liver cancer mortality rate of all rural residents was higher than that of all urban residents, with higher rates in men than in women (Table 1; Fig. 1).
Table 1.
Standardized mortality rates of liver cancer among urban and rural Chinese residents during 2002–2021
| Year | Urban residents | Rural residents | ||||
|---|---|---|---|---|---|---|
| Total | Male | Female | Total | Male | Female | |
| 2002 | 26.97 | 40.36 | 13.98 | 32.99 | 50.62 | 12.64 |
| 2003 | 29.00 | 42.19 | 15.59 | 38.46 | 55.95 | 20.19 |
| 2004 | 22.00 | 33.05 | 11.05 | 29.91 | 43.82 | 15.68 |
| 2005 | 30.14 | 45.12 | 15.28 | 27.39 | 38.90 | 14.08 |
| 2006 | 22.82 | 34.75 | 11.42 | 29.25 | 44.47 | 14.22 |
| 2007 | 22.69 | 34.65 | 11.20 | 32.19 | 49.17 | 15.63 |
| 2008 | 18.52 | 27.81 | 9.57 | 33.55 | 51.16 | 16.57 |
| 2009 | 19.28 | 29.16 | 9.73 | 32.91 | 49.91 | 16.33 |
| 2010 | 22.26 | 33.35 | 11.59 | 27.17 | 42.34 | 12.79 |
| 2011 | 20.13 | 30.51 | 10.16 | 27.45 | 41.92 | 13.19 |
| 2012 | 18.99 | 28.57 | 9.66 | 25.75 | 38.91 | 12.62 |
| 2013 | 19.26 | 29.05 | 9.69 | 23.24 | 34.91 | 11.64 |
| 2014 | 20.53 | 30.97 | 10.22 | 24.26 | 36.58 | 11.99 |
| 2015 | 20.71 | 31.28 | 11.99 | 24.00 | 36.07 | 11.99 |
| 2016 | 19.36 | 29.26 | 9.61 | 22.79 | 34.48 | 11.19 |
| 2017 | 19.19 | 28.96 | 9.57 | 22.35 | 33.93 | 10.89 |
| 2018 | 17.89 | 26.84 | 9.02 | 21.57 | 32.67 | 10.57 |
| 2019 | 16.20 | 24.57 | 8.10 | 20.54 | 31.38 | 10.04 |
| 2020 | 15.89 | 23.86 | 8.21 | 20.48 | 31.22 | 10.14 |
| 2021 | 14.56 | 22.19 | 7.33 | 19.76 | 30.12 | 9.66 |
Fig. 1.
Liver cancer standardized mortality rates among all Chinese residents over the period 2002–2021. The graph shows data for all residents in either setting, as well as sex-stratified data
Trend analysis of liver cancer-related deaths among Chinese residents
The standardized mortality rate of liver cancer for all urban residents, as well as for urban males and urban females, exhibited a decreasing trend from 2002 to 2021 (APC=AAPC=-2.7, -2.7, and − 2.9, respectively), and the best-fit models for all three subgroups were smooth curves, with no inflection points (joinpoints = 0), as shown in Fig. 2.
Fig. 2.
Trends in liver cancer standardized mortality rates among urban Chinese during 2002–2021. The graph plots the annual percent change (APC) for certain time periods as well as the number of joinpoints
The standardized mortality rate of liver cancer among all rural residents, as well as among rural males and rural females, also exhibited a decreasing trend from 2002 to 2021 (APC=AAPC=-2.9, -3.0, and − 2.8, respectively). Although the best-fit models for all rural residents and rural females over this period were also smooth curves with no inflection points (joinpoints = 0), the best-fit model for the rural male subgroup exhibited three inflection points (joinpoints = 3): one in 2005, one in 2008, and one in 2013. Among the rural male residents, the decreasing trend was statistically significant in 2002–2005 and in 2008–2013, with an average annual decrease of 9.40% and 6.99% over those respective periods, as shown in Fig. 3.
Fig. 3.
Trends in liver cancer standardized mortality rates among Chinese rural residents during 2002–2021. The graph plots the annual percent change (APC) for certain time periods as well as the number of joinpoints
The declining trend in the standardized mortality rate of liver cancer was faster for rural residents than for urban residents (APC=AAPC=-2.9 and − 2.7, respectively), whereas it was slower among rural women than among urban women (APC=AAPC=-2.8 and − 2.9, respectively), as shown in Table 2.
Table 2.
APC and AAPC of the standardized mortality rate of liver cancer during 2002–2021
| Group | Period | APC | APC 95% CI | AAPC | AAPC 95% CI |
|---|---|---|---|---|---|
| All urban residents | 2002–2021 | -2.73a | (-3.52~-1.94) | -2.73a | (-3.50~-1.96) |
| Urban males | 2002–2021 | -2.67a | (-3.43~-1.90) | -2.67a | (-2.67~-3.43) |
| Urban females | 2002–2021 | -2.86a | (-3.68~-2.03) | -2.86a | (-2.86~-3.68) |
| All rural residents | 2002–2021 | -2.94a | (-3.59~-2.30) | -2.94a | (-3.59~-2.30) |
| Rural males | 2002–2005 | -9.40a | (-17.22~-0.84) | -3.01 | (-5.96 ~ 0.04) |
| 2005–2008 | 8.56 | (-9.38 ~ 30.04) | |||
| 2008–2013 | -6.99a | (-12.15~-1.53) | |||
| 2013–2021 | -2.08 | (-4.18 ~ 0.06) | |||
| Rural females | 2002–2021 | -2.78a | (-3.65~-1.90) | -2.78a | (-3.65~-1.90) |
AAPC Average annual percent change, APC Annual percent change, 95% CI 95% Confidence interval
aIndicates a statistically significant difference
Age-period-cohort effect analysis of liver cancer-related deaths among Chinese residents
Age effects
The risk of death from liver cancer generally exhibited an increasing trend followed by a decreasing trend with respect to age in both men and women. Among urban and rural men, the risk of liver-cancer related death gradually increased in the 20–59 years age group, and the slope of the rate was the largest and increased the most rapidly in the 30–44 years age group; in men, 40–69 years represented the high-risk age group. Among rural and urban women, the risk of liver cancer-related death gradually increased with age in the 20–59 years and 20–79 years age groups, with 50–79 years and 60–84 years representing the high-risk age groups during those respective periods. These data are summarized in Table 3; Fig. 4.
Table 3.
Age-period-cohort modeling results of liver cancer-related deaths among Chinese residents during 2002–2021
| Projection | Urban males | Urban females | Rural males | Rural females | ||||
|---|---|---|---|---|---|---|---|---|
| RR | 95%CI | RR | 95%CI | RR | 95%CI | RR | 95%CI | |
| Age (years) | ||||||||
| 20–<25 | 0.12 | (0.00 ~ 4.15) | 0.17 | (-3.86 ~ 4.20) | 0.12 | (-3.91 ~ 4.15) | 0.16 | (-3.87 ~ 4.19) |
| 25–<30 | 0.21 | (-3.82 ~ 4.24) | 0.23 | (-3.80 ~ 4.26) | 0.24 | (-3.79 ~ 4.27) | 0.20 | (-3.83 ~ 4.23) |
| 30–<35 | 0.49 | (-3.54 ~ 4.52) | 0.44 | (-3.59 ~ 4.47) | 0.57 | (-3.46 ~ 4.60) | 0.41 | (-3.62 ~ 4.44) |
| 35–<40 | 1.01 | (-3.02 ~ 5.04) | 0.73 | (-3.30 ~ 4.76) | 1.37 | (-2.66 ~ 5.40) | 0.77 | (-3.26 ~ 4.80) |
| 40–<45 | 1.58 | (-2.45 ~ 5.61) | 1.13 | (-2.90 ~ 5.16) | 2.03 | (-2.00 ~ 6.06) | 1.35 | (-2.68 ~ 5.38) |
| 45–<50 | 1.86 | (-2.17 ~ 5.89) | 1.38 | (-2.65 ~ 5.41) | 2.02 | (-2.01 ~ 6.05) | 1.44 | (-2.59 ~ 5.47) |
| 50–<55 | 1.89 | (-2.14 ~ 5.92) | 1.35 | (-2.68 ~ 5.38) | 1.89 | (-2.14 ~ 5.92) | 1.71 | (-2.32 ~ 5.74) |
| 55–<60 | 2.12 | (-1.91 ~ 6.15) | 1.68 | (-2.35 ~ 5.71) | 2.04 | (-1.99 ~ 6.07) | 2.38 | (-1.65 ~ 6.41) |
| 60–<65 | 2.04 | (-1.99 ~ 6.07) | 1.95 | (-2.08 ~ 5.98) | 1.70 | (-2.33 ~ 5.73) | 2.12 | (-1.91 ~ 6.15) |
| 65–<70 | 1.81 | (-2.22 ~ 5.84) | 2.00 | (-2.03 ~ 6.03) | 1.47 | (-2.56 ~ 5.50) | 1.89 | (-2.14 ~ 5.92) |
| 70–<75 | 1.66 | (-2.37 ~ 5.69) | 2.01 | (-2.02 ~ 6.04) | 1.41 | (-2.62 ~ 5.44) | 2.10 | (-1.93 ~ 6.13) |
| 75–<80 | 1.35 | (-2.68 ~ 5.38) | 1.97 | (-2.06 ~ 6.00) | 1.16 | (-2.87 ~ 5.19) | 1.63 | (-2.40 ~ 5.66) |
| 80–<85 | 0.84 | (-3.19 ~ 4.87) | 1.52 | (-2.51 ~ 5.55) | 0.68 | (-3.35 ~ 4.71) | 0.88 | (-3.15 ~ 4.91) |
| Period (years) | ||||||||
| 2002―2006 | 1.13 | (-2.90 ~ 5.16) | 1.22 | (-2.81 ~ 5.25) | 1.07 | (-2.96 ~ 5.10) | 0.84 | (-3.19 ~ 4.87) |
| 2006―2011 | 1.01 | (-3.02 ~ 5.04) | 0.98 | (-3.05 ~ 5.01) | 1.10 | (-2.93 ~ 5.13) | 1.16 | (-2.87 ~ 5.19) |
| 2011―2016 | 0.89 | (-3.14 ~ 4.92) | 0.89 | (-3.14 ~ 4.92) | 0.94 | (-3.09 ~ 4.97) | 1.02 | (-3.01 ~ 5.05) |
| 2016―2021 | 0.97 | (-3.06 ~ 5.00) | 0.94 | (-3.09 ~ 4.97) | 0.91 | (-3.12 ~ 4.94) | 1.00 | (-3.03 ~ 5.03) |
| Cohort (years) | ||||||||
| 1922―1926 | 1.78 | (-2.25 ~ 5.81) | 1.31 | (-2.72 ~ 5.34) | 1.32 | (-2.71 ~ 5.35) | 2.64 | (-1.39 ~ 6.67) |
| 1927―1931 | 1.82 | (-2.21 ~ 5.85) | 1.87 | (-2.16 ~ 5.90) | 1.61 | (-2.42 ~ 5.64) | 1.98 | (-2.05 ~ 6.01) |
| 1932―1936 | 1.76 | (-2.27 ~ 5.79) | 1.99 | (-2.04 ~ 6.02) | 1.61 | (-2.42 ~ 5.64) | 2.02 | (-2.01 ~ 6.05) |
| 1937―1941 | 1.58 | (-2.45 ~ 5.61) | 1.97 | (-2.06 ~ 6.00) | 1.54 | (-2.49 ~ 5.57) | 1.60 | (-2.43 ~ 5.63) |
| 1942―1946 | 1.41 | (-2.62 ~ 5.44) | 1.80 | (-2.23 ~ 5.83) | 1.44 | (-2.59 ~ 5.47) | 1.35 | (-2.68 ~ 5.38) |
| 1947―1951 | 1.43 | (-2.60 ~ 5.46) | 1.75 | (-2.28 ~ 5.78) | 1.47 | (-2.56 ~ 5.50) | 1.38 | (-2.65 ~ 5.41) |
| 1952―1956 | 1.53 | (-2.50 ~ 5.56) | 1.78 | (-2.25 ~ 5.81) | 1.75 | (-2.28 ~ 5.78) | 1.45 | (-2.58 ~ 5.48) |
| 1957―1961 | 1.53 | (-2.50 ~ 5.56) | 1.70 | (-2.33 ~ 5.73) | 1.67 | (-2.36 ~ 5.70) | 1.31 | (-2.72 ~ 5.34) |
| 1962―1966 | 1.18 | (-2.85 ~ 5.21) | 1.19 | (-2.84 ~ 5.22) | 1.10 | (-2.93 ~ 5.13) | 0.82 | (-3.21 ~ 4.85) |
| 1967―1971 | 1.36 | (-2.67 ~ 5.39) | 1.30 | (-2.73 ~ 5.33) | 1.32 | (-2.71 ~ 5.35) | 1.21 | (-2.82 ~ 5.24) |
| 1972―1976 | 0.99 | (-3.04 ~ 5.02) | 0.84 | (-3.19 ~ 4.87) | 0.92 | (-3.11 ~ 4.95) | 0.87 | (-3.16 ~ 4.90) |
| 1977―1981 | 0.77 | (-3.26 ~ 4.80) | 0.72 | (-3.31 ~ 4.75) | 0.64 | (-3.39 ~ 4.67) | 0.52 | (-3.51 ~ 4.55) |
| 1982―1986 | 0.54 | (-3.49 ~ 4.57) | 0.50 | (-3.53 ~ 4.53) | 0.47 | (-3.56 ~ 4.50) | 0.43 | (-3.60 ~ 4.46) |
| 1987―1991 | 0.50 | (-3.53 ~ 4.53) | 0.36 | (-3.67 ~ 4.39) | 0.62 | (-3.41 ~ 4.65) | 0.54 | (-3.49 ~ 4.57) |
| 1992―1996 | 0.38 | (-3.65 ~ 4.41) | 0.47 | (-3.56 ~ 4.50) | 0.57 | (-3.46 ~ 4.60) | 0.75 | (-3.28 ~ 4.78) |
| 1997―2001 | 0.19 | (-3.84 ~ 4.22) | 0.14 | (-3.89 ~ 4.17) | 0.22 | (-3.81 ~ 4.25) | 0.21 | (-3.82 ~ 4.24) |
| Deviance | 0.35 | 0.14 | 0.81 | 0.54 | ||||
| AIC | 3.63 | 2.71 | 3.89 | 2.85 | ||||
| BIC | -86.57 | -86.79 | -86.12 | -86.39 | ||||
AIC Akaike information criterion, BIC Bayesian information criterion, RR, Relative risk 95% CI 95% Confidence interval
Fig. 4.
Longitudinal age profile of the relative risk of liver cancer-related deaths in China (2002–2021). The graph shows data stratified by sex and geographical classification (rural or urban)
Period effects
To assess the effect of time periods on the outcomes, the data were analyzed after being stratified into shorter time intervals. The analysis revealed an overall fluctuating downward trend in the risk of liver cancer-related death among Chinese residents over time. Among rural men, rural women, and urban women, the risk of death exhibited a continuous downward trend after the year 2006; among urban men, this risk showed a downward trend from 2002 to 2016, followed by a slight increase from 2016 to 2021, as shown in Table 3; Fig. 5.
Fig. 5.
Relative risk of liver cancer-related deaths in China during 2002–2021 for each observation period. The graph shows data stratified by sex and geographical classification (rural or urban)
Cohort effects
Regarding the effect on birth cohorts, the RR of liver cancer-related deaths progressively decreased over time, with more recent birth cohorts exhibiting lower risks than older ones, and the RR values were all < 1 for the 1997–2021 birth cohort. For details, see Table 3; Fig. 6.
Fig. 6.
Relative risk of liver cancer-related deaths in China during 2002–2021 for each age cohort. The graph shows data stratified by sex and geographical classification (rural or urban)
Discussion
The overall fluctuating downward trend in the standardized mortality rate of liver cancer among urban and rural residents of China over the period 2002–2021 can be attributed to several factors, including the widespread vaccination against hepatitis B, increasing health awareness in the population, progressive improvement in the health care system, and the obvious enhancement of the standard of medical care being administered. The following analysis will employ age-period-cohort (APC) methods to explore the factors influencing mortality trends in greater depth, elucidating how these factors correspond to effects attributable to age, period, or cohort respectively.
Age factor
The application of an age-period-cohort model to analyse trends in liver cancer mortality revealed that standardised mortality rates among Chinese residents exhibited an initial rise followed by a decline with increasing age. The age group demonstrating the highest risk of mortality from liver cancer among males in both urban and rural areas was found to be 40–69 years. For female subjects, the high-risk age groups in urban and rural areas were identified as 60–84 years and 50–79 years, respectively. This finding suggests that age exerts a substantial influence on liver cancer mortality rates, with distinct high-risk age groups observed between genders. Specifically, male subjects typically enter the high-risk period approximately 10 years earlier than their female counterparts. This phenomenon may be attributed to the elevated exposure of Chinese males to risk factors associated with liver cancer, including smoking, alcohol abuse, and hepatitis B virus infection, when compared to their female counterparts. Furthermore, males exhibit a higher standardised mortality rate for liver cancer, with the high-risk age group falling within the range of middle age [7–9]. These findings suggest that tailored intervention programmes should be developed for males in liver cancer prevention and health education, with a particular focus on middle-aged males, alongside enhanced health promotion and risk factor control.
Periodic factors
Hepatitis B prevention and control measures
There was a time when hepatitis B was highly prevalent in China, and a national seroepidemiologic survey of hepatitis B virus (HBV) conducted in 1992 demonstrated that the hepatitis B surface antigen (HBsAg) carrier rate in the overall population was 9.75% [10]. There is an etiologic link between HBV infection and the development of liver cancer, and according to the World Health Organization (WHO) Conference on the Prevention of liver cancer, the correlation coefficient between the two variables is as high as 0.80 [11]. Vaccination against hepatitis B can effectively prevent the transmission of HBV and control its spread. As a preventative strategy, in 2002, the Chinese government began including hepatitis B vaccination in the immunization program and providing free vaccines to all newborns, with the exception of a small administrative fee; such fees were eliminated altogether in 2005 for all newborns [12]. These policy changes in hepatitis B vaccination coverage among children have led to a steady increase in vaccination rates from approximately 30% in 1992 to 90% in 2005 [13]. In combination with the implementation of an increasingly sophisticated blood product management system and improved sewage purification, these changes have effectively reduced the incidence of both hepatitis B and C, thereby effectively lowering the number of liver cancer-related deaths caused by the two diseases [14–17].
Economic development and medical advancement
Since 2002, the rapid rise in China’s gross domestic product, the increasing disposable income of its residents, and the progressive improvements in its medical insurance system have led to an increasing awareness of the health of Chinese residents and resulted in health care checkups becoming more widely accepted among the general population, as well as greater workplace benefits for employees. The increasing popularization of health checkups has laid a solid foundation for the prevention and control of liver cancer, facilitating early diagnosis and treatment, and effectively reducing the mortality of liver cancer [18]. Advances in the development of technology and medical sciences as well as the continuous improvement of medical professionalism have increased the number and quality of available treatment options for patients with liver cancer, including targeted pharmaco- and immunotherapies, which have also reduced the mortality rate to a certain extent [19].
Water supply improvement project
Drinking polluted water is an independent risk factor for liver cancer, and the greater the proportion of people drinking contaminated water, the higher the mortality rate of liver cancer [20]. Thoughtful urban planning have ensured that potable tap water has been available to residents of Chinese cities for a long time, whereas rural residents are more likely not to have access to clean water and are forced to drink water collected from ditches and ponds, resulting in a higher risk of liver cancer development and related deaths in rural communities. With increasing economic development, however, the Chinese government has been increasingly focused on strategies to improve access to potable water and has conducted extensive infrastructure reform. To date, up to 88% of rural areas have been granted access to piped water services [21], which has effectively lowered the risk of liver cancer development and death, narrowing the gap between urban and rural residents in terms of standardized mortality rates.
The implementation of cancer screening programmes
Since 2005, the Chinese government has provided additional support to some rural areas with a high cancer incidence through major public health programs to explore and carry out cancer screening, including that for liver cancer [22]. This policy yielded noteworthy short-term outcomes: the detection rate of liver cancer among rural residents exhibited a significant increase, while concurrently, the number of confirmed liver cancer deaths demonstrated a gradual upward trend. Specifically, a close examination of the data presented in this model reveals a marginal increase in liver cancer mortality rates between 2005 and 2008 [23]. It is imperative to acknowledge that during the nascent stage of policy implementation, advancements in diagnostic technology and augmented screening coverage resulted in the concentrated diagnosis of numerous previously undetected advanced-stage cases. This is indicative of a provisional adjustment in disease surveillance data, as opposed to an actual increase in the incidence or mortality risk of liver cancer. In the long term, the continued development of cancer screening programmes is likely to have substantial consequences for the prevention and management of liver cancer. As screening initiatives progress, the proportion of early-stage cases is expected to rise gradually. Subsequent standardised treatment regimens has been shown to be an effective means of reducing liver cancer mortality rates, thereby playing a positive and significant role in lowering overall mortality from this disease [24].
Cohort factors
The differences between town and country
Over the past 20 years, the standardized mortality rate of liver cancer among rural residents in China has always been higher than that of urban residents, although this gap has gradually narrowed. The characteristics of rural residents’ living and working environments mean they face greater potential health risks in daily life. For instance, with regard to living conditions, certain rural areas may have relatively poor sanitation and face water pollution issues [25]; in terms of working conditions, many rural residents are employed in agricultural production, which frequently involves contact with pesticides [26]. These harmful chemicals may damage the human liver. Moreover, in the dietary patterns of rural residents, the proportion of foods contaminated with aflatoxins and the consumption of preserved foods are relatively high. Aflatoxin is a potent carcinogen, and prolonged exposure to it significantly increases the risk of developing liver cancer [27]. Pickled foods often contain high levels of harmful substances, such as nitrites, which are closely associated with liver cancer [28]. The combined effect of the aforementioned factors may result in a relatively higher risk of liver cancer mortality among rural residents [29].
Gender differences
In both urban and rural areas, the standardized mortality rate of liver cancer in China has been shown to be higher in men than in women, consistent with the present findings [30]. Certain factors can predispose men to elevated liver cancer risks; for example, Chinese men eat out much more frequently than women do, men exhibit higher HBsAg carrier rates than women [31], and men smoke and drink and abuse alcohol more frequently than women do, all of which are risk factors for liver cancer [32].
Limitations
This study has several limitations. Firstly, the study relied on secondary aggregated data, which may introduce information bias. Secondly, the development of liver cancer is a complex process influenced by the interaction of multiple factors. The existence of potential unidentified or difficult-to-quantify factors is a possibility. These factors may potentially interfere with the research findings to some extent. Thirdly, the present study is chiefly concerned with the general situation of the Chinese population, with no consideration given to considerable regional variations across provinces and municipalities in socioeconomic conditions, cultural customs, and the distribution of healthcare resources. Despite the above limitations, the substantial sample size, extensive official and authoritative data, and the analytical method combining multiple models serve to enhance the robustness of the research findings.
Conclusion
In summary, this study demonstrated an overall fluctuating downward trend in the standardized mortality rate of liver cancer among Chinese residents over the period 2002–2021 and confirmed that the rates are affected by sex, age, and geographic variables. More specifically, the results showed that the high-risk age for liver cancer-related death was ten years lower in men than in women, and the mortality rate was higher in men. Finally, the standardized mortality rate of liver cancer was higher among rural residents than among urbanites, although the gap between the two groups has been narrowing continuously over time. Vaccination, access to clean drinking water and healthy foods, regular health checkups, maintaining good lifestyle habits, and ensuring access to a sound medical security system and improved medical care are the keys to continuing to reduce the risk of liver cancer and death among all residents [33, 34]. These changes must be achieved at the government level, and health education should be enhanced in a targeted manner to minimize liver cancer-related risks and mortality.
Acknowledgements
We would like to thank Wannan Medical College for data support.
Abbreviations
- HBV
Hepatitis B virus
- HBsAg
Hepatitis B surface antigen
- RR
Relative risk
- APC
Annual percent change
- AAPC
Average annual percent change
Authors’ contributions
YXW conceived and designed the study; acquired and analyzed data; and wrote the draft of the manuscript. ML, XS, and CYC collected and prepared the related papers. WZ provided guidance throughout the preparation of this manuscript. GPW reviewed and made signifcant revisions to the manuscript. All authors read and approved the final manuscript.
Funding
This study was supported by the Major Project of Humanities and Social Sciences of the Anhui Provincial Education Department (Grant No. SK2019ZD19).
Data availability
Data available on request from authors.
Declarations
Ethics approval and consent to participate
Due to the retrospective nature of the study and the use of anonymized data, ethics and approval and consent to participate were not required.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Contributor Information
Wei Zhang, Email: 1024031413@qq.com.
Guoping Wang, Email: 304111225@qq.com.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data available on request from authors.