Breast cancer incidence trends in Golestan, Iran: An age-period-cohort analysis by ethnic region, 2004-2018

BACKGROUND

We aimed to examine the effects of age, diagnosis year (calendar period) and birth year (cohort) on the incidence trends of breast cancer among Golestan women, Northeast Iran, 2004-2018.

METHODS

Incidence data were obtained by residential status (urban/rural) and ethnic region (Turkmens/non-Turkmens). We calculated age-standardized incidence rates (ASRs) per 100,000 person-years. The estimated annual percentage change (EAPC) were calculated, and age-period-cohort (APC) models fitted to assess non-linear effects of period and cohort as incidence rate ratios (IRRs).

RESULTS

The total number of female breast cancer cases in Golestan, 2004-2018, were 3853, with an overall ASR of 31.3. We found higher rates in urban population (40.5) and non-Turkmens region (38.5) compared to rural area (20.8) and Turkmens region (20.2), respectively. There were increasing trends in incidence rates overall (EAPC= 4.4; 95%CI: 2.2, 6.7), with greater changes in rural areas (EAPC=5.1), particularly among non-Turkmens (EAPC=5.8). The results of the APC analysis indicate the presence of significant non-linear cohort effects with increasing IRRs across successive birth cohorts (IRR=0.1 and IRR= 2.6 for the oldest and the youngest birth cohorts vs. the reference birth cohort, respectively).

CONCLUSION

We found increasing trends in breast cancer incidence among Golestan women over the study period, with disparities in patterns and trends by residence area and ethnic region. The observed cohort effects suggest an increasing prevalence of key risk factors for breast cancer in this Iranian population. Further investigations are warranted to clarify the relationships between determinants such as reproductive factors and ethnicity in the region.

The growing cancer burden: Age-period-cohort projections in Aotearoa New Zealand 2020-2044

BACKGROUND

Cancer is a major cause of premature death and inequity, and global case numbers are rapidly expanding. This study projects future cancer numbers and incidence rates in Aotearoa New Zealand.

METHODS

Age-period-cohort modelling was applied to 25-years of national data to project cancer cases and incidence trends from 2020 to 2044. Nationally mandated cancer registry data and official historical and projected population estimates were used, with sub-groups by age, sex, and ethnicity.

RESULTS

Cancer diagnoses were projected to increase from 25,700 per year in 2015-2019 to 45,100 a year by 2040-44, a 76% increase (2.3% per annum). Across the same period, age-standardised cancer incidence increased by 9% (0.3% per annum) from 348 to 378 cancers per 100,000 person years, with greater increases for males (11%) than females (6%). Projected incidence trends varied substantially by cancer type, with several projected to change faster or in the opposite direction compared to projections from other countries.

CONCLUSIONS

Increasing cancer numbers reinforces the critical need for both cancer prevention and treatment service planning activities. Investment in developing new ways of working and increasing the workforce are required for the health system to be able to afford and manage the future burden of cancer.

Trends and projections of cause-specific premature mortality in Australia to 2044: a statistical modelling study

Background

Long-term projections of premature mortality (defined as deaths age <75 years) help to inform decisions about public health priorities. This study aimed to project premature mortality rates in Australia to 2044, and to estimate numbers of deaths and potential years of life lost (PYLL) due to premature mortality overall and for 59 causes.

Methods

We examined the past trends in premature mortality rates using Australian mortality data by sex, 5-year age group and 5-year calendar period up to 2019. Cigarette smoking exposure data (1945-2019) were included to project lung cancer mortality. Age-period-cohort or generalised linear models were developed and validated for each cause to project premature mortality rates to 2044.

Findings

Over the 25-year period from 1990-1994 to 2015-2019, there was a 44.4% decrease in the overall age-standardised premature mortality rate. This decline is expected to continue, from 162.4 deaths/100,000 population in 2015-2019 to 141.7/100,000 in 2040-2044 (12.7% decrease). Despite declining rates, total numbers of premature deaths are projected to increase by 22.8%, rising from 272,815 deaths in 2015-2019 to 334,894 deaths in 2040-2044. This is expected to result in 1.58 million premature deaths over the 25-year period 2020-2044, accounting for 24.5 million PYLL. Of the high-level cause categories, cancer is projected to remain the most common cause of premature death in Australia by 2044, followed by cardiovascular disease, external causes (including injury, poisoning, and suicide), and respiratory diseases.

Interpretation

Despite continuously declining overall premature mortality rates, the total number of premature deaths in Australia is projected to remain substantial, and cancer will continue to be the leading cause. These projections can inform the targeting of public health efforts and can serve as benchmarks against which to measure the impact of future interventions. They emphasise the ongoing importance of accelerating the prevention, early detection, and treatment of key health conditions.

Funding

No funding was provided for this study.

Age-period-cohort analysis of incidence, mortality and disability-adjusted life years of esophageal cancer in global, regional and national regions from 1990 to 2019

OBJECTIVE

In view of the high incidence and mortality of esophageal cancer, the latest statistical data on the disease burden of esophageal cancer can provide strategies for cancer screening, early detection and treatment, and help to rationally allocate health resources. This study provides an analysis of the global disease burden and risk factors of esophageal cancer from 1990 to 2019.

METHODS

Using the 2019 Global Burden of Disease, Injury and Risk Factor (GBD) data, we present the incidence, mortality and disability-adjusted life years (DALY) of esophageal cancer in 21 regions and 204 countries and different sociodemographic index (SDI) regions from 1990 to 2019. The age-period-cohort model was used to estimate the age, period, and cohort trend of esophageal cancer in different SDI regions. The estimated proportion of DALY attributable to each risk factor from 1990 to 2019.

RESULTS

From 1990 to 2019, the number of new cases of esophageal cancer, the number of deaths and DALY increased by 67.07%, 55.97% and 42.13%, respectively, but age standardized incidence rate (ASIR), age standardized mortality rate (ASMR) and age standardized DALY rate (ASDR) decreased by 19.28%, 25.32% and 88.22%, respectively. Overall, the results of the age-period-cohort model showed that the incidence, mortality, and DALY rates in countries and regions with higher SDI levels showed a downward trend over time and with the passage of time. Conversely, there were no significant changes in incidence and mortality in countries and regions with low SDI levels. In the past 30 years, the incidence and death of esophageal cancer in the world has gradually changed to people over 80 years old, but the population aged 60-79 still accounts for the largest proportion. The global DALY in esophageal cancer is mainly attributable to smoking, followed by alcohol consumption and occupational exposure.

CONCLUSIONS

Although ASIR, ASMR and ASDR have decreased significantly, esophageal cancer is still the main factor causing the disease burden worldwide. Public health administrators in low SDI and low-middle SDI countries are high-risk areas for esophageal cancer, and preventive control measures should be implemented to raise awareness, screening, and treatment of esophageal cancer in these areas. Tobacco and alcohol control and reduction of occupational hazards are key steps in reducing the burden of esophageal cancer.

Changing Patterns of Mortality in Diabetes Mellitus Among Older Adults - China, 1987-2021

What is already known about this topic?

Diabetes mellitus poses a significant public health concern for older adults in China, resulting in increased mortality rates.

What is added by this report?

This study investigates the evolving pattern of mortality associated with diabetes mellitus and analyzes the contributions of age, period, and cohort effects from 1987 to 2021. The results demonstrate a consistent rise in diabetes mellitus mortality over the last 30 years, notably in rural regions.

What are the implications for public health practice?

This research offers valuable insights to aid policymakers in developing targeted intervention strategies that address the specific needs of higher-risk populations, such as women, older adults, and individuals in rural areas.

Time trends in the burden of autoimmune diseases across the BRICS: an age-period-cohort analysis for the GBD 2019

BACKGROUND

This study aims to evaluate the long-term trend of prevalence and DALY (disability-adjusted life-year) rate on the age, period and cohort (APC) of the BRICS (Brazil, Russia, India, China and South Africa) country for autoimmune diseases (rheumatoid arthritis (RA), inflammatory bowel disease (IBD), multiple sclerosis (MS) and psoriasis).

METHODS

The data are sourced from the Global Burden of Disease Study 2019, and it uses the Joinpoint regression model to estimate the time trends of autoimmune diseases from 1990 to 2019. Additionally, it employs the Age-Period-Cohort (APC) model to estimate the age, period, and cohort effects from 1990 to 2019.

RESULTS

For 1990 to 2019, the ASPR (age-standardised prevalence rate) of IBD increased significantly for China and South Africa, and decreased significantly for Brazil, India, Russian. The Russian ASPR of MS demonstrated a significantly decreasing trend (average annual percent change=-0.5%, 95% CI -0.6 to -0.5), with the most increased occurring in Brazil at 2009-2014. The cohort effect on DALY rates for Psoriasis displayed an ongoing decreasing trend from the 1929-1933 birth cohort to the 1999-2003 birth cohort. Specifically, the five countries relative risk values (RRs) of DALYs due to RA increased significantly by 7.98, 16.07, 5.98, 3.19, 9.13 times, from 20 to 24 age group to 65 to 69 age group.

CONCLUSIONS

The population of the BRICS countries accounts for more than 40% of the global population. And we found that the age effect of various autoimmune diseases is heavily influenced by population ageing.

The mortality of oral cancer attributable to tobacco in China, the US, and India

PURPOSE

Assessing the mortality rates associated with tobacco-related oral cancer (OC) is crucial for effective allocation of resources within healthcare and economic systems.

METHODS

In this study, data from the Global Burden of Disease Study (GBD) 2019 were utilized to analyze the burden of tobacco-attributable OC in China, the United States (US), and India from 1990 to 2019. Descriptive statistics and an age-period-cohort model were employed to examine and compare the effects on OC mortality.

RESULTS

1. Attributable to tobacco, the deaths remained stable in the US, but increased in China and India. The trend of age-standardized mortality rate of OC increased in China, and decreased in the US and India, whereas the rate in India was the highest. 2. According to the APC model, the risk of death increased with age in all three countries. The period and later birth cohort effects were identified as risk factors in China and India, while in the US, the previous cohorts were identified as a risk factor. Except for India, males faced higher death risk than females in China and the US.

CONCLUSIONS

The burden of OC attributable to tobacco remains substantial in China and India. Public health officials in these countries should implement prevention and treatment strategies for OC, and interventions aimed at regulating the tobacco industry. The elderly is at an elevated risk for OC, and medical resources and policies should be directed toward this population. The successes experience in tobacco control and OC prevention in the US may serve as a model for other countries.

Trends and disparities in China's cardiovascular disease burden from 1990 to 2019

BACKGROUND AND AIMS

In order to find the exact strategies in the prevention of cardiovascular diseases (CVD), it is necessary to assess their risk factors systematically. Here, we used the Global Burden of Disease (GBD) to review the long-term trends and epidemiological characteristics among Chinese.

METHODS AND RESULTS

We comprehensively analyzed the burden of CVD for the Chinese population using GBD 2019, including prevalence, incidence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life years (DALYs). Then, we analyzed trends over time, and predicted mortality and morbidity, using joinpoint regression, age-period-cohort (APC) model, and Bayesian APC approach. Finally, we analyzed the attributable burden of CVD. In 2019, the prevalence of CVD in China was 120 million, representing a 140.02% increase since 1990. The number of DALYs attributed to CVD increased by 52.56% compared to 1990. Joinpoint showed a fluctuating incidence downward, while mortality significantly declined. The APC fitting results indicated that recent generations have a higher prevalence than the past, and the prevalence has increased among individuals of the same age group. The BAPC predicted that CVD's prevalence and mortality in the Chinese would stabilize and decline between 2020 and 2030, with a significant decline among males. The main CVD-attributable burdens in 2019 were metabolic risks, especially high blood pressure.

CONCLUSION

Given China's large and rapidly aging population, the burden of CVD is a major concern. Practical strategies to prevent and manage CVD are urgently needed to address this public health challenge.

Disease burden of chronic kidney disease attributable to lead exposure: A global analysis of 30 years since 1990

BACKGROUND

Exposure to lead (Pb) is associated with an increased risk of chronic kidney disease (CKD). However, limited studies explored the global burden of CKD attributable to Pb exposure, especially in countries with different development levels. This study aimed to comprehensively evaluate the temporal and spatial trend in the disease burden of CKD attributable to Pb exposure in 204 countries and territories from 1990 to 2019.

METHODS

We used the data from Global Burden of Disease Study (GBD) 2019 to estimate annual deaths, disability-adjusted life years (DALYs), age-standardized mortality rates (ASMR), and age-standardized DALYs rate (ASDR) of CKD attributable to Pb exposure. The annual average percentage change (AAPCs) was calculated using the Joinpoint model to evaluate the changing trend of CKD ASMR and ASDR attributable to Pb exposure from 1990 to 2019. Meanwhile, age-period-cohort (APC) model was used to assess changes in the mortality of CKD attributable to Pb exposure from 1990 to 2019.

RESULTS

Global ASMR for CKD attributable to Pb exposure trended upward from 1990 to 2019. ASMR and ASDR were the highest in low and low-middle SDI regions. With the APC model, we found that global mortality rates for CKD attributable to Pb exposure increased with age. The global period rate ratio showed the highest value in 2000-2004 and the lowest in 2015-2019, while the global cohort rate ratio showed the highest value in 1941-1949 and the lowest during 1986-1994.

CONCLUSIONS

From 1990 to 2019, the global burden of CKD attributable to Pb exposure increased globally, especially in low and low-middle SDI regions, as well as the elderly. Pb exposure is still a great threat to the global burden of CKD, and the implementation of effective prevention measures to reduce Pb exposure in the environment should be continually strengthened.

Long-term trends of nasopharyngeal carcinoma mortality in China from 2006 to 2020 by region and sex: an age-period-cohort analysis

BACKGROUND

China has a high mortality from nasopharyngeal carcinoma (NPC). The NPC mortality trends in China from 2006 to 2020 were described and analyzed to understand its epidemiological characteristics by region and sex and to explore age, period, and cohort effects.

METHODS

This study utilized NPC mortality data from the China Health Statistical Yearbook. A joinpoint regression model was used to fit the standardized NPC mortality and age-specific mortality. The age-period-cohort model was applied to investigate age, period, and cohort effects on NPC mortality risk.

RESULTS

The results showed that the NPC mortality rate in China has been declining steadily. From 2006 to 2020, the standardized NPC mortality rate in most age groups showed a significant downward trend. The annual percentage change was smaller in rural areas than in urban areas. The mortality risks of rural males and rural females from 2016 to 2020 were 1.139 times and 1.080 times those from 2011 to 2015, respectively. Both urban males born in 1984-1988 and rural males born in 1979-1983 exhibited an increasing trend in NPC mortality risk.

CONCLUSIONS

Our study confirmed the effectiveness of NPC prevention and treatment strategies in China from 2006 to 2020. However, it underscored the urgent need for targeted interventions in rural areas to further reduce NPC mortality rates.

Comparative age-period-cohort analysis

BACKGROUND

Cancer surveillance researchers analyze incidence or mortality rates jointly indexed by age group and calendar period using age-period-cohort models. Many studies consider age- and period-specific rates in two or more strata defined by sex, race/ethnicity, etc. A comprehensive characterization of trends and patterns within each stratum can be obtained using age-period-cohort (APC) estimable functions (EF). However, currently available approaches for joint analysis and synthesis of EF are limited.

METHODS

We develop a new method called Comparative Age-Period-Cohort Analysis to quantify similarities and differences of EF across strata. Comparative Analysis identifies whether the stratum-specific hazard rates are proportional by age, period, or cohort.

RESULTS

Proportionality imposes natural constraints on the EF that can be exploited to gain efficiency and simplify the interpretation of the data. Comparative Analysis can also identify differences or diversity in proportional relationships between subsets of strata ("pattern heterogeneity"). We present three examples using cancer incidence from the United States Surveillance, Epidemiology, and End Results Program: non-malignant meningioma by sex; multiple myeloma among men stratified by race/ethnicity; and in situ melanoma by anatomic site among white women.

CONCLUSIONS

For studies of cancer rates with from two through to around 10 strata, which covers many outstanding questions in cancer surveillance research, our new method provides a comprehensive, coherent, and reproducible approach for joint analysis and synthesis of age-period-cohort estimable functions.

Global burden and trends of respiratory syncytial virus infection across different age groups from 1990 to 2019: A systematic analysis of the Global Burden of Disease 2019 Study

OBJECTIVE

Understanding the global patterns of respiratory syncytial virus (RSV) is crucial for developing effective prevention and control strategies.

METHODS

Data on RSV-related burden were extracted from the Global Burden of Disease 2019. Joinpoint regression models were used to assess the global temporal trends of RSV and further stratified analyses were conducted according to the Socio-demographic Index (SDI), which is a composite measure of income, education, and total fertility. Age-period-cohort model was used to evaluate age, period, and cohort effects.

RESULTS

In 2019, the global age-standardized rate of mortality (ASMR) and disability-adjusted life years (ASR-DALYs) of RSV were 4.79/100,000 (95% uncertainty interval [95% UI]: 1.82/100,000-9.32/100,000) and 218.34/100,000 (95% UI: 92.06/100,000-376.80/100,000), respectively. The burden of RSV was higher in men than women. The highest ASMR (10.26/100,000, 3.80/100,000-20.16/100,000) and ASR-DALYs (478.71/100,000, 202.40/100,000-840.85/100,000) were reported in low-SDI region. Although mortality and DALYs rates in all age groups declined globally, the pace of decline was not uniform across age groups. Mortality rate in the elderly over 70 years surpassed that in children under 5 years in 2019.

CONCLUSION

This study highlights the need for targeted interventions to reduce the burden of RSV, particularly in low-SDI region, and among the elderly over 70 years.

Time trend of pancreatic cancer mortality in the Western Pacific Region: age-period-cohort analysis from 1990 to 2019 and forecasting for 2044

BACKGROUND

Pancreatic cancer poses a serious medical problem worldwide. Countries in the Western Pacific Region are facing public health challenges from cancer. This study assesses the time trends of pancreatic cancer mortality in the Western Pacific Region from 1990 to 2019 and predicts its trend to 2044.

METHODS

Mortality data were obtained from the Global Health Data Exchange. We used an age-period-cohort model to estimate age, period and birth cohort effects on pancreatic cancer mortality from 1990 to 2019 by calculating net drift, local drift, age-specific rate, period rate ratio, and cohort rate ratio. We also predict pancreatic cancer mortality to 2044 in Western Pacific countries.

RESULTS

Overall, there were 178,276 (95% uncertain interval: 157,771 to 198,636) pancreatic cancer deaths in the Western Pacific Region in 2019, accounting for 33.6% of all deaths due to pancreatic cancer worldwide. There were significant increases in pancreatic cancer disability-adjusted life years between 1990 and 2019 in the Western Pacific Region, mainly due to population growth and aging. Pancreatic cancer mortality increased with age. The period effect showed an increasing trend of mortality for both sexes over the study period. Compared to the reference period (2000 to 2004), the rate ratio was elevated in both males and females in the period of 2015 to 2019. There was an overall increasing rate ratio from early birth cohorts to recent cohorts. Deaths may continue to increase in the next 25 years in the ten countries, while most countries have seen their age-standardized rate forecasts fall.

CONCLUSION

The mortality of pancreatic cancer is still high in the Western Pacific Region. Countries/territories should focus on pancreatic cancer prevention and early cancer screening in high-risk populations. Specific public health methods and policies aimed at reducing risk factors for pancreatic cancer are also needed.

Trends in disease burden of hepatitis B infection in Jiangsu Province, China, 1990-2021

Background

The incidence of hepatitis B virus (HBV) has decreased year by year in China after the expansion of vaccination, but there is still a high disease burden in Jiangsu Province of China.

Methods

The year-by-year incidence data of HBV in Jiangsu Province from 1990 to 2021 were collected. The incidence rates of males and females age groups were clustered by systematic clustering, and the incidence rates of each age group were analyzed and studied by using Joinpoint regression model and age-period-cohort effect model (APC).

Results

Joinpoint regression model and APC model showed a general decrease in HBV prevalence in both males and females. In addition, the results of the APC model showed that the age, period, and cohort effects of patients all affected the incidence of HBV, and the incidence was higher in males than in females. The incidence is highest in the population between the ages of 15 and 30 years (mean: 21.76/100,000), especially in males (mean: 31.53/100,000) than in females (mean:11.67/100,000). Another high-risk group is those over 60 years of age (mean: 21.40/100,000), especially males (mean: 31.17/100,000) than females (mean: 11.63/100,000). The period effect of the APC model suggests that HBV vaccination is effective in reducing the incidence of HBV in the population.

Conclusions

The incidence of HBV in Jiangsu Province showed a gradual downward trend, but the disease burden in males was higher than that in females. The incidence is higher and increasing rapidly in the population between the ages of 15 and 30 years and people over 60 years of age. More targeted prevention and control measures should be implemented for males and the elderly.

Epidemiological characteristics of leukemia in China, 2005-2017: a log-linear regression and age-period-cohort analysis

BACKGROUND

Leukemia is a threat to human health, and there are relatively few studies on the incidence, mortality and disease burden analysis of leukemia in China. This study aimed to analyze the incidence and mortality rates of leukemia in China from 2005 to 2017 and estimate their age-period-cohort effects, it is an important prerequisite for effective prevention and control of leukemia.

METHODS

Leukemia incidence and mortality data from 2005 to 2017 were collected from the Chinese Cancer Registry Annual Report. Joinpoint regression model was used to estimate the average annual percentage change (AAPC) and annual percentage change (APC) response time trend. Age-period-cohort model was constructed to analyze the effects of age, period and cohort.

RESULTS

The age-standardized incidence rate of leukemia was 4.54/100,000 from 2005 to 2017, showed an increasing trend with AAPC of 1.9% (95% CI: 1.3%, 2.5%). The age-standardized mortality rate was 2.91/100,000, showed an increasing trend from 2005 to 2012 with APC of 2.1% (95%CI: 0.4%, 3.9%) and then a decreasing trend from 2012 to 2017 with APC of -2.5% (95%CI: -5.3%, 0.3%). The age-standardized incidence (mortality) rates of leukemia were not only higher in males than that in females, but also increased more rapidly. The incidence of leukemia in rural areas was lower than in urban areas, but the AAPC was 2.2 times higher than urban areas. Children aged 0-4 years were at higher risk of leukemia. The risk of leukemia incidence and mortality increased with age. The period effect of leukemia mortality risk showed a decreasing trend, while the cohort effect showed an increasing and then decreasing trend with the turning point of 1955-1959.

CONCLUSIONS

The age-standardized incidence rate of leukemia in China showed an increasing trend from 2005 to 2017, while the age-standardized mortality rate increased first and then decreased in 2012 as a turning point. Differences existed by gender and region. The risk of leukemia incidence and mortality increased accordingly with age. The risk of mortality due to leukemia gradually decreased from 2005 to 2017. Leukemia remains a public health problem that requires continuous attention.

The mortality trends analysis of ischemic heart disease attributed to (PM) 2.5 exposure in China from 1990 to 2019 in APC model

OBJECTIVE

To analyze the mortality trend of ischemic heart disease (IHD) attributed to particulate matter (PM) 2.5 exposure among Chinese populations from 1990 to 2019. To evaluate the influences of cohort, period, and age on long-term of IHD mortality trends.

METHODS

Global burden of disease (GBD) data in 2019 regarding IHD death rate attributed to exposure to (PM) 2.5 in China from 1990 to 2019 were adopted. The age-period-cohort (APC) model based on the R language produced by the National Cancer Institute of the United States was used for statistical analysis to investigate the influences of different ages, periods, and cohorts on IHD death rate attributed to exposure to (PM) 2.5.

RESULTS

The age-standardized death rate of IHD attributed to exposure to ambient (PM) 2.5 in China revealed an uptrend from 1990 to 2019. This increased from 8.63/100,000 in 1990 to 21.31/100,000 in 2019. This was an increase of 1.47%. The age-standardized IHD death rate attributed to exposure to household (PM) 2.5 showed a decreasing trend. This decreased from 19.61/100,000 in 1990 to 8.72/100,000 in 2019. This was a decrease of 0.74%. The results of the APC model indicated that the annual net drift of IHD mortality attributed to exposure to (PM) 2.5 was -0.10%. The annual net drifts of exposure to household and ambient (PM) 2.5 were -4.54% and 3.44%, respectively. The IHD death rate attributed to ambient and household (PM) 2.5 exposure in the same birth cohort enhanced with age. With time, the rate ration (RR) of period effects of IHD mortality attributed to ambient (PM) 2.5 exposure for both male and female showed an upward trend. The RR of period effects of IHD death rate attributed to household (PM) 2.5 exposure suggested a downtrend. In the consecutive birth cohorts, the population in China with a later birth cohort presented a higher risk of IHD death attributed to exposure to ambient (PM) 2.5 and a lower risk of IHD death attributed to household (PM) 2.5 exposure.

CONCLUSIONS

In China for the burden of IHD attributed to exposure to (PM) 2.5, the primary environmental risk was ambient (PM) 2.5 exposure compared to exposure to household PM2.5. IHD exposure to environmental air pollution posed a greater risk to young people.

Time trend of global uterine cancer burden: an age-period-cohort analysis from 1990 to 2019 and predictions in a 25-year period

BACKGROUND

Uterine cancer remains a serious medical problem worldwide. This study aimed to explore the global time trends of uterine cancer burden using the age-period-cohort model and forecast incidence to 2044.

METHODS

Data were downloaded from the Global Burden of Disease 2019. The age-period-cohort model was used to estimate age, period and birth cohort effects. We also predict uterine cancer incidence to 2044.

RESULTS

Globally, there were 435,041 incident cases (95% UI: 245,710 to 272,470) and 91,640 deaths of uterine cancer (95% UI: 39,910 to 44,140) in 2019. During the past 30 years, the age-standardized incidence and death rates increased by 15.3% and decreased by 21.6%, respectively. Between 1990 and 2019, the high-sociodemographic index region had the highest overall annual percentage changes. The age effect showed the uterine cancer incidence rate first increased and then decreased with age. The period and cohort relative rate ratio showed upward trends during the study period. Incident cases of uterine cancer may increase to more than six hundred thousand in 2044.

CONCLUSION

Uterine cancer causes a high disease burden in high-income regions and the global incidence may continue to increase in the future. Improving awareness of risk factors and reducing the proportion of the obese population are necessary to reduce future burden.

Non-progressive breast carcinomas detected at mammography screening: a population study

BACKGROUND

Some breast carcinomas detected at screening, especially ductal carcinoma in situ, may have limited potential for progression to symptomatic disease. To determine non-progression is a challenge, but if all screening-detected breast tumors eventually reach a clinical stage, the cumulative incidence at a reasonably high age would be similar for women with or without screening, conditional on the women being alive.

METHODS

Using high-quality population data with 24 years of follow-up from the gradually introduced BreastScreen Norway program, we studied whether all breast carcinomas detected at mammography screening 50-69 years of age would progress to clinical symptoms within 85 years of age. First, we estimated the incidence rates of breast carcinomas by age in scenarios with or without screening, based on an extended age-period-cohort incidence model. Next, we estimated the frequency of non-progressive tumors among screening-detected cases, by calculating the difference in the cumulative rate of breast carcinomas between the screening and non-screening scenarios at 85 years of age.

RESULTS

Among women who attended BreastScreen Norway from the age of 50 to 69 years, we estimated that 1.1% of the participants were diagnosed with a breast carcinoma without the potential to progress to symptomatic disease by 85 years of age. This proportion of potentially non-progressive tumors corresponded to 15.7% [95% CI 3.3, 27.1] of breast carcinomas detected at screening.

CONCLUSIONS

Our findings suggest that nearly one in six breast carcinomas detected at screening may be non-progressive.

Global, regional, and national time trends in incidence, prevalence, years lived with disability for uterine fibroids, 1990-2019: an age-period-cohort analysis for the global burden of disease 2019 study

BACKGROUND

Uterine fibroids are the most common benign neoplasm of the uterus and a major source of morbidity for women. We report an overview of trends in uterine fibroids of incidence rate, prevalence rate, years lived with disability (YLDs) rate in 204 countries and territories over the past 30 years and associations with age, period, and birth cohort.

METHODS

The incident case, incidence rate, age-standardized rate (ASR) for incidence, prevalent case, prevalence rate, ASR for prevalence, number of YLDs, YLD rate, and ASR for YLDs were derived from the Global Burden of Disease 2019 (GBD 2019) study. We utilized an age-period-cohort (APC) model to estimate overall annual percentage changes in the rate of incidence, prevalence, and YLDs (net drifts), annual percentage changes from 10 to 14 years to 65-69 years (local drifts), period and cohort relative risks (period/cohort effects) between 1990 and 2019.

RESULTS

Globally, the incident cases, prevalent cases, and the number of YLDs of uterine fibroids increased from 1990 to 2019 with the growth of 67.07%, 78.82% and 77.34%, respectively. High Socio-demographic Index (SDI) and high-middle SDI quintiles with decreasing trends (net drift < 0.0%), and increasing trends (net drift > 0.0%) were observed in middle SDI, low-middle SDI, and low SDI quintiles in annual percentage change of incidence rate, prevalence rate and YLDs rate over the past 30 years. There were 186 countries and territories that showed an increasing trend in incidence rate, 183 showed an increasing trend in prevalence rate and 174 showed an increasing trend in YLDs rate. Moreover, the effects of age on uterine fibroids increased with age and peaked at 35-44 years and then declined with advancing age. Both the period and cohort effects on uterine fibroids showed increasing trend in middle SDI, low-middle SDI and low SDI quintiles in recent 15 years and birth cohort later than 1965.

CONCLUSIONS

The global burden of uterine fibroids is becoming more serious in middle SDI, low-middle SDI and low SDI quintiles. Raising awareness of uterine fibroids, increasing medical investment and improving levels of medical care are necessary to reduce future burden.

The role of environmental factors on sporadic Creutzfeldt-Jakob disease mortality: evidence from an age-period-cohort analysis

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common form of prion diseases. The causes of sCJD are still unknown and exogenous factors may play a role. Worldwide, the number of patients with sCJD has progressively increased over time. This increase can be partly explained by increasing life expectancy and better case ascertainment, but a true increase in the number of sCJD cases cannot be excluded. We estimated mortality rates from sCJD in France (1992-2016) and studied variation in mortality rates by age, period, and time.We included all cases aged 45-89 years old who died with a probable/definite sCJD diagnosis based on the French national surveillance network. We used age-period-cohort (APC) Poisson regression models to study variation in mortality rates by sex, age, period, and time.A total of 2475 sCJD cases aged 45-89 years were included. Mortality rates increased with age, reached a peak between 75 and 79 years, and decreased thereafter. Mortality rates were higher in women than men at younger ages and lower at older ages. The full APC model with a sex×age interaction provided the best fit to the data, thus in favour of sex, age, period, and cohort effects on mortality rates. In particular, mortality rates increased progressively with successive birth cohorts.Based on 25 years of active surveillance in France, we show evidence for sex, age, period, and cohort effects on sCJD mortality. The identification of cohort effects suggests that environmental exposures may play a role in sCJD etiology.

Burden of chronic obstructive pulmonary disease attributable to non-optimal temperature from 1990 to 2019: a systematic analysis from the Global Burden of Disease Study 2019

Chronic obstructive pulmonary disease (COPD) has been the third leading cause of death worldwide. As the traditional risk factors (like smoking and ambient air pollution) on the burden of COPD being well characterized, the burden of COPD due to non-optimal temperature has been widely concerned. In this study, we extracted the relevant burden data of COPD attributable to non-optimal temperature from GBD 2019 and adopted estimated annual percent changes, Gaussian process regression (GPR), and age-period-cohort model to evaluate the spatiotemporal patterns, relationships with socio-demographic level, and the independent effects of age, period and cohort from 1990 to 2019. In brief, the global COPD burden attributable to non-optimal temperatures showed declining trends but was still more severe in the elderly, males, Asia, and regions with low socio-demographic index (SDI). And cold had a greater burden than heat. The inverted U-shape is expected for the relationship between SDI and the burden of COPD caused by non-optimal temperatures according to the GPR model, with the inflection point around SDI 0.45. Besides, the improvements were observed in period and cohort effects but were relatively limited in low and low-middle SDI regions. Public health managers should execute more targeted programs to lessen this burden predominantly among lower SDI countries.

Describing and explaining age, period, and cohort trends in Americans' vocabulary knowledge

For a quarter of a century researchers have been documenting and trying to explain trends in Americans' vocabulary knowledge using data from the General Social Survey (GSS) and its WORDSUM test. Trends in Americans' vocabulary knowledge have important practical implications-for example, for educational policy and practice-and speak to the American workforce's competitiveness in the global knowledge economy. We contribute to this debate by analyzing 1978-2018 GSS data using an improved analytical approach that is consistent with theoretical notions of cohort effects and that permits simultaneously estimating inter-cohort average differences and intra-cohort life-course changes. We find that WORDSUM scores peak around age 35 and gradually decline in older ages; the scores were significantly lower in the 1980s and higher in the late 2000s and 2010s; and the 1940-1954 birth cohorts and the 1965 and later birth cohorts had notably higher and lower scores, respectively, than the expectation based on age and period main effects. We provide new evidence that such cohort differences tend to persist over the life course. Interestingly, the effects of increasing educational attainment and decreasing reading behaviors seemed to cancel out, leading to a relatively flat overall period trend. Trends in television viewing and word obsolescence did not appear to affect age, period, or cohort trends in WORDSUM scores.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11113-023-09771-5.

Urban-Rural Disparity in Birth Cohort Effects on Breast Cancer Incidence

Breast cancer is the most commonly diagnosed cancer among women worldwide. Studies have reported minimal birth cohort effects on the incidence rates of breast cancer in Western countries but have reported notable birth cohort effects in some Asian countries. The risks of breast cancer may also vary within a country. In the present study, we abstracted female invasive breast cancer data from the Taiwan Cancer Registry for the period 1997-2016. We used the age-period-cohort model to compare birth cohort effects on breast cancer incidence rates between urban and rural regions in Taiwan. We identified a notable urban-rural disparity in birth cohort effects on breast cancer incidence rates in women in Taiwan. The incidence rates in the urban regions were higher than those in the rural regions across all cohorts. However, the incidence rates rose faster in the rural regions than in the urban regions across the cohorts. The risks of breast cancer observed for women born in 1992 were approximately 22 and 11 times than those observed for women born in 1917 in rural and urban regions, respectively. The observed gap in breast cancer incidence rates between the urban and rural regions gradually disappeared across the cohorts. Accordingly, we speculate that urbanization and westernization in Taiwan may be the drivers of female breast cancer incidence rates across birth cohorts.

Gender disparities in incidence and projections of lung cancer in China and the United States from 1978 to 2032: an age-period-cohort analysis

PURPOSE

Lung cancer incidences tend to be higher among males than females in both China and the United States, yet secular incidence patterns are different due to distinct population and environmental exposures. We examined long-term and future trends of lung cancer incidence, as well as the associations of age, period, and cohort effects with gender disparities.

METHODS

Using data from the Cancer Incidence in Five Continents from 1978 to 2012, we calculated age-standardized, age-specific incidence, and male-to-female incidence rate ratios (IRR), and conducted an age-period-cohort analysis. The average annual percentage change (AAPC) of the trends was obtained by Joinpoint Regression. Bayesian age-period-cohort analysis was also conducted to project incidences to 2032.

RESULTS

In China, age-standardized incidence revealed a decreasing trend among males, but showed increasing trends among the younger age groups (30-54 years) in females. Age-standardized incidence rates of males decreased but remained stable among females from 1972 to 2012 in the United States. Male-to-female incidence rate ratios narrowed in both countries and reversed among younger birth cohorts in the United States. Gender disparities are expected to continue to diminish in both countries, and incidence among females appears to exceed that of males in the United States by around 2023-2027.

CONCLUSION

Gender disparities in lung cancer incidence persist and will continue into the future in both countries, but our findings suggested that smoking may play different roles in gender disparities in lung cancer incidence between the two countries. Further population-based epidemiological studies among females in China are imperative.

Trends in the disease burden of congenital heart disease in China over the past three decades

OBJECTIVE

To investigate the disease burden of congenital heart disease (CHD) in China from 1990 to 2019.

METHODS

Using the data from Global Burden of Disease (GBD) study 2019, the incidence, age-standardized incidence rates, the mortality, age-standardized mortality rates, disability-adjusted life year (DALY) and age-standardized DALY rates of CHD were calculated. Time trend analysis of disease burden-related indicators was analyzed by Joinpoint regression model. Age-period-cohort model was used to describe age, period, and birth cohort effects in CHD mortality population. The relationship between age-standardized incidence, mortality, DALY rates of congenital heart disease and human development index (HDI) were analyzed by Pearson correlation.

RESULTS

From 1990 to 2019, the mean annual percentage change (AAPC) in age-standardized incidence rate, mortality rate and DALY rate of CHD in China were -0.1%(95% CI: -0.7%-0.4%)、-3.5%(95% CI: -3.7%--3.2%) and -3.5%(95% CI: -3.7%--3.2%), respectively. CHD usually occurred in the first year of life. The mean incidence rate at birth was 2497.9/100 000, and the mean incidence rate under 1 year of age was 2626.6/100 000. During the period of 1995-2000, the incidence rate in newborn and <1 year children showed an exponential upward trend, then it remained a steady downward trend. However, there was an exponential increase in <1 year children during 2010-2013 and 2014-2015, followed by an exponential decrease to the lowest value in the last three decades. The mortality of CHD tended to decrease with age, with mortality of 101.67/100 000 for children under 5 years of age and a decrease after 5 years of age. However, there was a transient increase in mortality in age group 55-<60. From 1995 to 2019, the relative risk of death of patients with CHD showed a downward trend. Compared with 1995-1999, the rate ratio of death decreased by 24% in 2015-2019. Such downward trend was also observed in the birth cohort after 1945. Compared with the 1945-1949 birth cohort, the rate ratio of death for patients with CHD decreased by 75% in the 2015-2019 birth cohort. When HDI<0.58 (before 1999), the age-standardized incidence of CHD was positively correlated with HDI ( r=0.74, P<0.05). When HDI≥0.58 (after 1999), the age-standardized incidence of CHD was negatively correlated with HDI ( r=-0.76, P<0.01). The age-standardized mortality and DALY rates were negatively correlated with HDI ( r=-0.95 and -0.93, both P<0.01).

CONCLUSIONS

During 1990 to 1999, the incidence of CHD increases and is positively correlated with the social development. During 1999 to 2019, the incidence of CHD decreases and is negatively correlated with the social development. The disease burden of CHD decreases and is negatively correlated with the social development. Some progress has been made in the field of prevention and control of CHD, but the disease burden remains high among younger population in China.

Understanding long-term trends in smoking in England, 1972-2019: an age-period-cohort approach

BACKGROUND AND AIMS

Smoking prevalence has been falling in England for more than 50 years, but remains a prevalent and major public health problem. This study used an age-period-cohort (APC) approach to measure lifecycle, historical and generational patterns of individual smoking behaviour.

DESIGN

APC analysis of repeated cross-sectional smoking prevalence data obtained from three nationally representative surveys.

SETTING

England (1972-2019).

PARTICIPANTS

Individuals aged 18-90 years.

MEASUREMENTS

We studied relative odds of current smoking in relation to age in single years from 18 to 90, 24 groups of 2-year survey periods (1972-73 to 2018-19) and 20 groups of 5-year birth cohorts (1907-11 to 1997-2001). Age and period rates were studied for two groups of birth cohorts: those aged 18-25 years and those aged over 25 years.

FINDINGS

Relative to age 18, the odds of current smoking increased with age until approximately age 25 [odds ratio (OR) = 1.48, 95% confidence interval (CI) = 1.41-1.56] and then decreased progressively to age 90 (OR = 0.06, 95% CI = 0.04-0.08). They also decreased almost linearly with period relative to 1972-73 (for 2018-19: OR = 0.30, 95% CI = 0.26-0.34) and with birth cohort relative to 1902-06, with the largest decreased observed for birth cohort 1992-96 (OR = 0.44, 95% CI = 0.35-0.46) and 1997-2001 (OR = 0.35, 95% CI = 0.74-0.88). Smoking declined in the 18-25 age group by an average of 7% over successive 2-year periods and by an average of 5% in those aged over 25.

CONCLUSIONS

Smoking in England appears to have declined over recent decades mainly as a result of reduced smoking uptake before age 25, and to a lesser extent to smoking cessation after age 25.

Gender disparity in disability among Chinese oldest-old: Age and cohort trends

This study aimed at exploring gender disparity in disability and identifying related disablement process factors among Chinese oldest-old. Data came from eight waves of the Chinese Longitudinal Healthy Longevity Study (CLHLS). A hierarchical logistic Age-Period-Cohort (A-P-C) model was used to estimate the trend of gender disparity, and related disablement process factors were further decomposed by the Oaxaca-Blinder decomposition. Our results found that women had higher disabilities than men. The age-based trend of gender disparity in Instrumental Activities of Daily Living (IADL) continued to decline; that in Functional Limitation (FL) increased at first and then declined. The cohort-based trend of gender disparity in IADL showed a decreasing trend with each subsequent cohort; that in FL showed an increasing trend. Among the disablement process factors, health behaviors and social supports were the most important contributors to gender disparity in disability. The disability was higher for women than men, and the gender differences were attenuated at very old ages. To reduce gender disparities in disability, more attention should be paid to relevant factors of gender disparity in disability.

Secular trends in chronic respiratory diseases mortality in Brazil, Russia, China, and South Africa: a comparative study across main BRICS countries from 1990 to 2019

Background

As the emerging economies, the BRICS (Brazil, Russia, India, China, and South Africa) shared 61.58% of the global chronic respiratory diseases (CRD) deaths in 2017. This study aimed to assess the secular trends in CRD mortality and explore the effects of age, period, and cohort across main BRICS countries.

Methods

Data were obtained from the Global Burden of Disease Study (GBD) 2019 and analyzed using the age-period-cohort (APC) model to estimate period and cohort effects between 1990 and 2019. The net drifts, local drifts, longitudinal age curves, period/cohort rate ratios (RRs) were obtained through the APC model.

Results

In 2019, the CRD deaths across the BRICS were 2.39 (95%UI 1.95 to 2.84) million, accounting for 60.07% of global CRD deaths. Chronic obstructive pulmonary disease (COPD) and asthma remained the leading causes of CRD deaths. The age-standardized mortality rates (ASMR) have declined across the BRICS since 1990, with the most apparent decline in China. Meanwhile, the downward trends in CRD death counts were observed in China and Russia. The overall net drifts per year were obvious in China (-5.89%; -6.06% to -5.71%), and the local drift values were all below zero in all age groups for both sexes. The age effect of CRD presented increase with age, and the period and cohort RRs were following downward trends over time across countries. Similar trends were observed in COPD and asthma. The improvement of CRD mortality was the most obvious in China, especially in period and cohort effects. While South Africa showed the most rapid increase with age across all CRD categories, and the period and cohort effects were flat.

Conclusions

BRICS accounted for a large proportion of CRD deaths, with China and India alone contributing more than half of the global CRD deaths. However, the declines in ASMR and improvements of period and cohort effects have been observed in both sexes and all age groups across main BRICS countries. China stands out for its remarkable reduction in CRD mortality and its experience may help reduce the burden of CRD in developing countries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12484-z.

Trends in breast and cervical cancer in India under National Cancer Registry Programme: An Age-Period-Cohort analysis

BACKGROUND

Trend analysis in cancer quantifies the incidence rate and explains the trend and pattern. Breast and cervical cancers are the two most common cancers among Indian women which contributed 39.4 % to the total cancer in India for the year 2020. This study aimed to report the time trends in cancer incidence of breast and cervical cancer using Age-Period-Cohort (APC) model from five Population Based Cancer Registries (PBCRs) in India for the period of 1985-2014.

METHOD

Age-Period-Cohort model was fitted to five PBCRs of Bangalore, Chennai, Delhi, Bhopal and Barshi rural for breast and cervical cancer for 25-74 age-groups. The Estimated Annual Percent Change (EAPC) was calculated. Rate Ratio (RR) of cohort effects were estimated with a constraint of period slope to be zero (p = 0) since cohort has a stronger association with incidence than period.

RESULT

A significant increase was noted in breast cancer in all PBCRs (EAPC, Range: Delhi, 1.2 % to Bangalore, 2.7 %) while significant decrease in cervical cancer (EAPC, Range: Bangalore -2.5 % to Chennai, -4.6 %) from all the PBCRs including Barshi rural during the period. RR estimates for breast cancer showed increasing trend whereas cervical cancer showed decreasing trend in successive birth cohorts across all five PBCRs.

CONCLUSION

In both breast and cervical cancers, a significant age, cohort and period effect was noted in Bangalore, Chennai and Delhi. Despite period effect, the cohort effect was predominant and it may be attributed to the generational changes in risk factors among cancer breast and cervix.

Trends in cervical cancer mortality in China from 1989 to 2018: an age-period-cohort study and Joinpoint analysis

Background

Worldwide, cervical cancer is the second-most-common malignancy of the female reproductive system. Due to its large population, China accounted for 11.9% of cervical cancer deaths, and 12.3% of global cervical cancer DALYs in 2017. In 2009, China launched a nationwide screening program, yet mortality from cervical cancer has shown an upward trend in recent years. The aim of this study was to explore factors affecting cervical cancer mortality rates in China, and contribute to their future reduction.

Methods

In this descriptive study, a Joinpoint regression analysis and age-period-cohort (APC) model based on the intrinsic estimator (IE) algorithm were utilized. Data from the period 1989–2018 were extracted from the International Agency for Research on Cancer (IARC) Database of WHO (1989–2000) and China Health Statistical Yearbook database (2002–2018).

Results

Our study found mortality from cervical cancer to have initially declined, but increase thereafter over the entire observation period in both rural and urban China. The influence of age, period and cohort effect on the mortality rate had statistical significance. The effect of age increased with years, becoming a contributing factor in women aged over 45 years countrywide. Conversely, the cohort effect became a protective factor for women born after 1938 in urban areas, and for women born after 1958 in rural areas. The period effect was relatively less impactful.

Conclusions

The study indicates that organized cervical screening projects facilitated the identification of potential patients, or patients with comorbidities. Correspondingly, mortality was found to increase with incidence, particularly among elderly women, indicating that newly diagnosed patients were at an advanced stage of cervical cancer, or were not receiving appropriate treatment. Therefore, the coverage of cervical cancer screening should be improved, and women’s health awareness promoted. Early diagnosis and treatment is critical to reduce the disease burden and improve outcomes.

Tracheal, bronchus, and lung cancer burden and related risk factors in the United States and China

Tracheal, bronchus, and lung (TBL) cancer is the most common malignant tumor worldwide. This study aims to grasp the characteristics of the TBL cancer burden in China and the United States (USA). Data included incidence, deaths, and disability-adjusted life years (DALYs) as well as their age-standardized rates (ASRs) among different gender, age and risk factors. Joinpoint Regression Model and Age-period-cohort (APC) analysis were used to evaluate the variation tendency and effect of the risk factors. China and USA bore almost half of the TBL cancer burden, especially for males. ASRs of TBL cancer increased in China, but decreased in USA. In China, three factors related to TBL cancer deaths and DALYs related were tobacco, air pollution, and diet low in fruits; in USA, these are tobacco, occupational carcinogens, and high fasting plasma glucose. The younger the population, the less impact of birth cohort on morbidity and mortality. According to APC analysis, age effect played a key role in morbidity and mortality of TBL cancer, and the risk increased with age. Period effect kept increasing over time, while cohort effect decreased with the time of birth. Tobacco was always the top risk factor of death and DALYs in both countries. The policy should be tilted towards air pollution and a diet low in fruits in China, as well as occupational carcinogens and high fasting plasma glucose in USA. Healthcare reform in both countries should focus on planning how its health system could effectively prevent and manage TBL cancer at low cost.

[Time trends and age-period-cohort effects on the incidence of the most frequent cancers in Oran, Algeria, 1999-2018]

BACKGROUND

Cancer is currently one of the major public health problems in Algeria. The aim of this study was to examine time trends and the effects of age, period and cohort on incidence at the major cancer locations from 1999 to 2018 in Oran, Algeria.

METHODS

Data on the five most frequent primary cancer locations among patients aged 20-79 years were collected from the Oran cancer registry. Annual percentile changes in incidence rates were evaluated using the Joinpoint regression program. Age-period-cohort models were designed to examine the effects of age, period and birth cohort on cancer incidence.

RESULTS

From 1999 to 2018, there were 12,278 incident cases at the five major cancer locations. Unfavorable trends in incidence were observed regarding lung and colorectal cancers in both sexes, as well as breast cancer in women. Age-period-cohort analysis showed that age, period and birth cohort yielded different effects at different cancer locations.

CONCLUSION

The observed trends primarily reflect lifestyle changes in Algeria over the course of recent years.

Gender-specific temporal trends in overweight prevalence among Chinese adults: a hierarchical age-period-cohort analysis from 2008 to 2015

Background

As a key health risk, the prevalence of overweight has been strikingly increasing worldwide. This study aimed to disentangle the net age, period, and cohort effects on overweight among Chinese adults by gender.

Methods

Data came from the Chinese General Social Survey from 2008 to 2015, which was a repeated cross-sectional survey (n = 55,726, aged 18 and older). χ² or t tests were used to estimate the gender disparities in overweight and socioeconomic status (SES). A series of hierarchical age-period-cohort cross-classified random-effects models were performed using SAS version 9.4 to estimate the overall and gender-specific temporal trends of overweight, as well as the association between SES and overweight. Further, a series of line charts were used to present the age and cohort variations in overweight.

Results

After controlling for covariates, significant age and cohort effects were observed among adults in China (b = 0.0205, p < 0.001; b = 0.0122, p < 0.05; respectively). Specifically, inverted U-shaped age effects were identified for both genders, with a high probability of overweight occurring in middle age (b = -0.0012, p < 0.001). Overweight was more prevalent among men than women before 60 years old, and this trend reversed thereafter (b = -0.0253, p < 0.001). Moreover, men born during the war (before 1950) and reform cohorts (after the 1975s) demonstrated a substantial decline in overweight, while men born in 1950-1975 showed an increasing trend in overweight prevalence (b = 0.0378, p < 0.05). However, the cohort effect on women was not statistically significant. Additionally, a higher SES was related to an elevated probability of overweight.

Conclusion

Gender-specific age and cohort effects on the prevalence of overweight were observed among Chinese adults. Both China and other developing countries need to pay attention to the coming obesity challenge and related health inequality. Full life-cycle overweight prevention interventions should focus on middle-aged adults, men born in the war and reform eras, and adults with a higher SES.

Oral cancer incidence rates from 1997 to 2016 among men in Taiwan: Association between birth cohort trends and betel nut consumption

OBJECTIVES

Oral cancer is the fourth most common cancer among men in Taiwan. Betel nut consumption is a major risk factor for oral cancer, but the association between betel nut chewing and the long-term secular trend of oral cancer incidence is unclear.

MATERIALS AND METHODS

We conducted an age-period-cohort analysis to examine the incidence rates of oral cancer among men in Taiwan from 1997 to 2016.

RESULTS

The oral cancer incidence rate among men doubled between 1997 and 2009, but the trend leveled off thereafter. Oral cancer incidence rates in the oldest age group (80-84y) were approximately 85 times those of the youngest group (25-29y). The period effect was weak, and the cohort effect exhibited a drastically increasing trend from 1917 (midyear for 1913-1921) to 1972 (1968-1976) birth cohorts and then a decreasing trend afterward. The Spearman rank correlation coefficient between the cohort effects on oral cancer incidence among men and the average consumption of betel nut with a lag time of 30 years had a significant and extremely high value of 0.993.

CONCLUSIONS

Our findings suggest that betel nut chewing is the main driver of the cohort effect for oral cancer incidence rates among men in Taiwan. In addition to reduced betel nut consumption, a decrease in smoking prevalence may also have contributed to the reduction in oral cancer incidence after the 1972 birth cohort; moreover, the increasing prevalence of alcohol consumption in Taiwan is unlikely to be the reason for the cohort effect for oral cancer.

Social transition and health inequality in China: an age-period-cohort analysis

OBJECTIVES

To examine self-rated health (SRH) trajectories by age, period and cohort in the dynamic environment of China and to focus on sex, educational, family economic status (FES) and regional disparities in these temporal trajectories.

STUDY DESIGN

Repeated cross-sectional data from the World Value Survey from 1990 to 2012 (n = 7731) were used.

METHODS

An age-period-cohort (APC) model with an intrinsic estimator method was applied, using SRH as a continuous variable to analyse SRH trajectories by age, period and cohort in different groups in China. Robust analyses were conducted using SRH as a binary variable and a hierarchical APC cross-classified random effects model.

RESULTS

SRH was adversely associated with age, and a global trend of declining SRH was observed between 1990 and 2012; however, SRH generally increased across successive cohorts in China. SRH was better in males, individuals from the eastern region, and in those with higher levels of education and higher FES. Regional and FES disparities in SRH increased with age and across successive cohorts; however, educational disparities in SRH first decreased and then increased with age and across successive cohorts, and sex disparities in SRH decreased across successive cohorts, in general.

CONCLUSIONS

A well-performing social environment is related to better population health. The cumulative disadvantage in health among individuals from underprivileged regions/families with less education should be the focus of social transition in China.

[Mortality trend and age-period-cohort analysis of colorectal cancer among residents in Yangpu District of Shanghai from 1975 to 2014]

Objective: To describe the 40-years trend for the mortality of colorectal cancer (CRC) in Shanghai and to estimate the effect of age, period, and birth cohort with Age-Period-Cohort (APC) model. Methods: Data on tumor-releated death from 1975 Janurary 1 to 2014 December 31 was derived from the Yangpu District of Shanghai Center for Diseases Prevention and Control tumor registration system. Colonrectal cancer cases (C18.2-C18.9 and C20 in ICD10) were selected for analyses. Crude mortality, age-adjusted mortality, and Average Annual Percent Changes (AAPCs) were calculated for colon cancer and rectal cancer. The difference of AAPCs between male/female and different age groups were tested. An APC model (reference cohort and period were 1900 and 1975, respectively) was constructed to estimate the age-effect, period-effect, and cohort-effect on the colorectal cancer death. Results: During 1975-2014, 6 725 cases died of colorectal cancer (the cased of colon and rectal cancer were 3 684 and 3 041, respectively). The crude mortality and age-adjusted mortality of colon cancer was 8.83/100 000 and 6.76/100 000, respectively. The crude mortality and age-adjusted mortality of rectal cancer were 7.32/100 000 and 5.67/100 000, respectively. For population in Yangpu District, the crude mortality and age-adjusted mortality of colon cancer increased with time, and the crude mortality of rectal cancer increased with time (P<0.001). AAPC of the crude mortality rate (5.6%) and age-adjusted mortality rate (2.3%) of colon cancer were higher than those in rectal cancer (3.0% and -0.3%), respectively (both P values <0.001). AAPC of the crude mortality rate (males vs. females was 6.2% vs. 5.0%, P<0.05) and age-adjusted mortality rate (males vs. females was 2.7% vs. 1.7%, P<0.05) of colon cancer were higher in males than in females. APC model indicted that CRC-related death increased with age. During 1901 to 1941, the RR values of cohort effects for colon and rectal cancer death were 1.09-5.57 and from 1.04-2.28, respectively; During 1946 to 1991, the RR values of cohort effects for colon cancer and rectal cancer were 5.51-4.32 and 2.16-0.89. Conclusion: From 1975 to 2014, the mortality of CRC in Yangpu District increased gradually, and colon cancer mortality in males increased faster than that in females. The risk of death from colorectal cancer in the 1946-1991 birth cohort declined.

Smoking Trends among Thailand's Youths from 1996-2015: An Age-Period-Cohort Analysis of National Health Surveys

BACKGROUND

This study aimed to investigate secular trends of smoking among Thailand's youths.

METHODS

We combined 8 datasets from national representative surveys between 1996 and 2015. Multi-stage cluster sampling was applied in all studies. Overall, 231459 participants aged 11-26 yr were included and analyzed. Participants were classified as current smokers if they responded "yes" to the question "Do you currently smoke?", and former smoker if they reported no current smoking but had smoked previously. Age-period-cohort (APC) models were used to estimate age, period, and cohort effects on smoking for investigating secular trend of smoking.

RESULTS

The prevalence of smoking tended to decrease over time. Among those aged 11-14, the prevalence of current and former smoking was low but not negligible. Rates of underage smoking remained quite steady, around 3.8% in 1996 and 3.6% in 2015. The results of the APC model show that the prevalence of smoking among young male cohorts was lower than in older cohorts.

CONCLUSION

Thailand's tobacco control program has been effective in deterring youths from smoking. The prevalence of smoking in this population needs to be reduced further though, something achieved by reorienting tobacco consumption prevention campaigns towards this age group.

Trends and future burden of tobacco-related cancers incidence in Delhi urban areas: 1988-2012

INTRODUCTION

Tobacco products are the major contributors for various cancers and other diseases. In India, tobacco-related cancers (TRCs) contribute nearly half of the total cancers in males and one-fifth in females.

OBJECTIVE

The objective of the study is to investigate 25-year trends and projection of TRCs for 2018-2022.

METHODS

Joinpoint analysis was performed to assess the trends of TRCs on world age-adjusted rates. Age-period-cohort model with power link function was performed to project the future incidence burden of TRCs in urban Delhi.

RESULTS

During the 25 years, a total of 67,129 TRCs (53,125 males and 14,004 females) were registered which was 25.4% of total cancer cases registered. Males contributed 39.1% and females 10.8% of total cases. In males, TRCs declined significantly from 1988 to 2003 with estimated annual percentage change (EAPC) = -0.91% and thereafter increasing trend was observed with EAPC = 3.42%, while in females, the EAPC values were 2.2% and 3.54% respectively for the same period. The total burden of TRCs will be doubled in 2018-2022 with around 46% change due to cancer risk and around 54% due to population age and size in both the genders. The average annual count in males will be 7310 in 2018-2022 as compared to 3571 in 2008-2012 while in females this count will be increased to 2066 from 955 based on recent slope.

CONCLUSION

The incidence of TRCs is increasing due to increase in population age, size, and factors other than population. TRCs are the preventable cancers, and load of these cancers can be controlled with strictly adhering the policy and acts.

Time trends and future prediction of coal worker's pneumoconiosis in opencast coal mine in China based on the APC model

BACKGROUND

The opencast coal mine is a specific mine differing from the underground mine. There are differences in the way into the ore body, the organization of production, transport technology and other aspects. This study aimed to describe the prevalence of CWP among ex-dust miners in opencast coal mines and estimate the incidence trend of CWP by APC model in the future.

METHODS

All opencast miners who had been exposed to dust for at least 1 year in opencast mines were enrolled in this study. The database included demographic details, occupational history records with the date of dust exposure, physical examination records and pneumoconiosis diagnosis records. An age-period-cohort (APC) model has been carried out in order to explore the effects of the age, period and cohort on the prevalence of CWP among ex-dust opencast miners.

RESULTS

8191 opencast miners were enrolled in the study, including 259 miners with CWP and 7932 miners without CWP. The incidence density of CWP would have an increasing trend in opencast mines from 2005 to 2024. The number of possible CWP patients predicted in this period was approximately 492. Of them, 275 miners could have suffered from CWP in 2005-2014 and 217 miners would suffer from CWP in 2015-2024 among the ex-dust opencast miners.

CONCLUSIONS

The APC model had a goodness of fit in predicting the incidence trend of CWP in opencast coal mines. By this model, we predicted that 492 opencast miners could be diagnosed as CWP from 2005 to 2024. Therefore ex-dust opencast miners cannot be ignored and they should have regular physical examinations and detection for CWP.

The distance and chance of lifetime geographical movement of physicians in Japan: an analysis using the age-period-cohort model

BACKGROUND

The uneven geographical distribution of physicians in Japan is a result of those physicians electing to work in certain locations. In order to understand this phenomenon, it is necessary to analyze the geographic movement of physicians across the Japanese landscape.

METHODS

We obtained individual data on physicians from 1978 to 2012 detailing their attributes, work institutions, and locations. The data are from Japanese governmental sources (the Survey of Physicians, Dentists, and Pharmacists). The total sample size was 122 150 physicians, with 77.5% being male and 22.5% female. After obtaining the data, we calculated the geographical distance of each physician's movement by using geographic information systems software (GIS; ArcGIS, ESRI, Inc., CA, USA). Geographical distance was then converted into time distance. We compared the resulting median values through nonparametric testing and then conducted a multivariate analysis. Our next step involved the use of an age-period-cohort (APC) model to measure the degree of impact three points of data, experience (experience years), the historical and environmental context of the data (survey year), and physician cohort (registration year) had on the movement of each physician.

RESULTS

The ratio of female physicians who selected an urban area as their first working location was higher than that of male physicians. However, the selection of an urban area was becoming more popular as a first working location for both males and females as the year of data increased. The overall distance of geographical movement for female physicians was less than it was for male physicians. Physicians moved the greatest distance between their second and fourth years following license acquisition, at which point the time distance became shorter. The median time distance was 46 min in 2000 and 22 min in 2008. The physicians in our study did not move far from their first working location, and the overall distance of movement lessened in the more recent years of study. The median distance of movement after 20 years was 25.9 km for male physicians, and 19.1 km for female physicians. The results of the APC model indicated that the effects of experience years (age) gradually declined, that the survey year (period) effects increased, and that the registration year (cohort) effects increased initially before leveling off.

CONCLUSIONS

The trends following the introduction of the new mandatory training system in 2004 may imply that the concentration of physicians in Japan's urban areas is expected to increase. After 2000, the effect of that period on physicians explains their geographical movements more so than the factor of their age.

Sex ratio in multiple sclerosis mortality over 65 years; an age-period-cohort analysis in Norway

Increasing female: male ratio in multiple sclerosis (MS) has been assigned to cohort effects, with females in more recent birth cohorts possibly being more exposed or vulnerable to environmental risk factors than males. We collected MS mortality data in Norway from 1951 to 2015 from The Norwegian Cause of Death registry. Age-Period-Cohort analysis was conducted using log-linear Poisson models, including sex interaction terms. MS was registered as the underlying, contributing or direct cause in 6060 deaths. MS associated mortality remained stable with a slight preponderance among males until after 1980, and have since increased preferentially among females. Throughout the study period the mean annual increase was 1.25% for females and 0.3% for males (p < 0.0001). Age-period-cohort analysis revealed limited evidence of cohort effects for the gender differences; the best fitting model only included gender-age and gender-period interaction terms. The period effect evened out for males in the last three decades but increased for females, especially among the oldest age-groups. In conclusion, the increased female: male mortality ratio in MS associated mortality is driven mainly by increased mortality among females in the three last decades, particularly in the older age groups. It is best explained by disproportional period effects, providing evidence of time-varying external factors including improved access to diagnosis among females.

Age-Period-Cohort Modeling of Multiple Sclerosis Incidence Rates in Kuwait: 1980-2014

BACKGROUND

Multiple sclerosis (MS) is a complex immune-mediated disorder of the central nervous system with undefined etiology. Genetic predisposition and environmental factors play an imperative role in MS causation and its sustained increasing burden worldwide. This study examined the age, period, and cohort effects on MS incidence rates in Kuwait.

METHODS

In this retrospective cohort study, data on MS cases diagnosed between January 1, 1980 and December 31, 2014 and registered in National MS Registry and reference population were obtained. Age-period-cohort (APC) analysis was conducted using a loglinear Poisson regression model to supplement the descriptive and graphical presentation. Descriptive statistics were complemented with APC parameters' estimates including net drift, local drift, age at onset curve, and longitudinal age trend. Age effect was presented as incidence rates (per 105 person-years), whereas period and cohort effects were presented as adjusted relative rates.

RESULTS

A total of 1,131 cases were diagnosed in 1,385,923 person-years. Overall age-standardized MS incidence rate was 64.5 (95% CI 52.4-79.8). An estimated annual percentage change revealed 7.4% annual increase in MS incidence rate during the study period (Net drift = 7.4%; 95% CI 4.1-10.8%). APC "fitted" age-at-onset curve showed a bimodal pattern with peaked incidence rates at 20-24 years and 45-49 years of age. Compared with the referent period (1980-1984) and cohort (1970-1974), MS incidence rates progressively and significantly (p < 0.001) increased during subsequent time periods and in successive cohorts. Results of APC analysis are descriptive in nature and specific etiological hypotheses were not evaluated. However, the findings of this study substantiated the notion of multiplicity of genetic and/or environmental risk factors' contributions.

CONCLUSION

A substantial increase in MS incidence rates was recorded, which significantly varied in all 3 temporal dimensions during the study period. Future studies may contemplate biological basis for recorded temporal increase in MS risk.

Time trend analysis of primary liver cancer incidence in Sihui county of Guangdong Province, China (1987-2011)

BACKGROUND

Southern China is an endemic area for primary liver cancer (PLC), but it is unclear if rates have changed in recent decades. We evaluated PLC incidence and estimated the effects of age, period of diagnosis, and birth cohort in Sihui City, Guangdong Province, China.

METHODS

Age-standardized rates (ASRs) of PLC were examined for both males and females from 1987 to 2011. Joinpoint regression analysis was conducted to estimate the annual percent changes in PLC incidence. The age-period-cohort (APC) model was used to investigate the effects of age, diagnosis period, and birth cohort on the relative risk (RR) of PLC.

RESULTS

A total of 2988 PLC cases were identified in this period, with average ASRs of 51.1/100,000 for males and 11.7/100,000 for females. Joinpoint regression analysis revealed increasing PLC incidence throughout the entire period in both males (average annual change of 1.65 %) and females (0.20 %). RRs increased gradually in both sexes from the youngest age group (30-34 years) to the oldest (80-84 years). In males, the RR decreased during diagnosis period from 1987-1991 to 1997-2001 and remained stable thereafter. In females, RRs fluctuated with diagnosis period throughout the entire period. Incidence tended to increase with birth cohort from 1905-1909 to 1975-1979 in both males and females; however, female incidence plateaued in the youngest cohorts born between 1955 and 1974, while incidence in males increased sharply in the cohorts born between 1965 and 1974. According to APC analysis, the full age-period-cohort (APC) model fit the data best, and the period-cohort (PC) model would be enough to explain variability of rates in females.

CONCLUSION

The PLC incidence rate in males of Sihui City has increased more significantly than female over the last 25 years. Despite the age effect in male, this trend mainly reflects the effects of risk factors that are present in early life (birth cohort) and period change in both genders.

Black-white disparity in disability among U.S. older adults: age, period, and cohort trends

OBJECTIVES

This study delineates activities of daily living (ADL) and instrumental activities of daily living (IADL) black-white disparity trends by age, period, and cohort (APC) and explores sociodemographic contributors of cohort-based disparity trends.

METHOD

We utilized multiple cross-sectional waves of National Health Interview Survey data (1982-2009) to describe APC trends of ADL and IADL disparities using a cross-classified random effect model. Further, we decomposed the cohort-based disparity trends using Fairlie's decomposition method for nonlinear outcomes.

RESULTS

The crossover ADL and IADL disparities (whites > blacks) occurring at age 75 increased with age and reached a plateau at age of 80, whereas period-based ADL and IADL disparities remained constant for the past 3 decades. The cohort disparity trends for both disabilities showed a decline with each successive cohort except for ADL disparity among women.

DISCUSSION

We examined the role of aging on racial disparity in disability and found support for the racial crossover effect. Further, the racial disparity in disability will disappear should the observed pattern of declining cohort-based ADL and IADL disparities persist. Although education, income, and marital status are important sociodemographic contributors to cohort disparity trends, future studies should investigate individual behavioral health determinants and cohort-specific characteristics that explain the cohort-based racial difference in ADL and IADL disabilities.