Age-period-cohort Model Research Articles

Decomposing Employment Trends of Disabled Workers

Many OECD countries are facing decreases in the employment rates of disabled workers. To uncover the driving forces of these trends, this paper estimates Age-Period- Cohort (APC) models on administrative data of Disability Insurance (DI) application cohorts for the Netherlands between 1999 and 2013. Our main finding is that the substantial decrease in employment rates of applicant cohorts in this time period is almost fully explained by cohort effects – equalling about 30 percentage points – and that the impact of period effects is only small. In turn, cohort effects stem from changes in the observed composition of applicants, with increasing shares of workers without (permanent) contracts in the year before the application. These changes are largely confined to years following two major DI reforms that increased self-screening among potential applicants. We also expand the APC model by allowing for distinct effects for awarded and rejected DI applicants. Assuming common compositional cohort effects for these two groups, difference-in-difference estimates of cohort effects indicate that the effect of changes in benefit conditions ('incentive effects') is limited. Disability reforms thus predominantly affected the stringency of the DI system and induced substantial self-screening in the sickness period before the DI decision, rather than changing individual employment rates.

Biased estimation of trends in cohort effects: the problems with age-period-cohort models in ecology.

Environmental variation can generate life-long similarities among individuals born in the same breeding event, so-called cohort effects. Studies of cohort effects have to account for the potentially confounding effects of current conditions (observation year) and age of individuals. However, estimation of such models is hampered by inherent collinearity, as age is the difference between observation year (period) and cohort year. The difficulties of separating linear trends in any of the three variables in Age-Period-Cohort (APC) models are the subject of ongoing debate in social sciences and medicine but have remained unnoticed in ecology. After reviewing the use of APC models, we investigate the consequences of model specification on the estimation of cohort effects, using both simulated data and empirical data from a long-term individual-based study of reindeer in Svalbard. We demonstrate that APC models are highly sensitive to the model's treatment of age, period and cohort, which may generate spurious temporal trends in cohort effects. Avoiding grouping ages and using environmental covariates believed to be drivers of temporal variation reduces the APC identification problem. Nonetheless, ecologists should use caution, given that the specification issues in APC models may have substantial impacts on estimated effect sizes and therefore conclusions.

Different trends in colorectal cancer mortality between age groups in China: an age-period-cohort and joinpoint analysis.

China is undergoing a rapid aging transition. The trends in age-specific mortality rates from colorectal cancer remain unknown, and a number of studies have not distinguished the age, period, and cohort effects simultaneously. A descriptive study was implemented with a joinpoint regression analysis and age-period-cohort (APC) model based on the intrinsic estimator (IE). Age-specific mortality rates of colorectal cancer (1987-2016) were collected by gender (men/women) and region (urban/rural). The average annual percentage change (AAPC) and relative risks in the trend were identified using joinpoint Poisson regression and APC model (IE), respectively. Joinpoint regression analysis revealed that the rates decreased in the younger (men aged <45 years and women aged <75 years) but increased in the older (men aged >75 years and women aged >80 years) age groups. The APC model (IE) showed that the rates increased with age and time period but decreased with birth cohorts. But from 2000 to 2005, the period effects showed a substantial decline among urban residents. From the 1910-1914 to the 1915-1919 birth cohort, mortality increased among men, and from the 1925-1929 to the 1930-1934 birth cohort, mortality increased among rural residents. The trends in colorectal cancer mortality are different between age groups. The younger age groups show a decreasing trend, whereas the older age groups an increasing trend. Cost-effective prevention and control should be implemented more in the elderly and for older cohorts at high risk.

Use of age-period-cohort analysis in cancer epidemiology research.

Age-period-cohort (APC) models simultaneously estimate the effects of age - biological process of aging; time period - secular trends that occur in all ages simultaneously; and birth cohort - variation among those born around the same year or from one generation to the next. APC models inform understanding of cancer etiology, natural history, and disparities. We reviewed findings from recent studies (published 2008-2018) examining age, period, and cohort effects and summarized trends in age-standardized rates and age-specific rates by birth cohort. We also described prevalence of cancer risk factors by time period and birth cohort, including obesity, current smoking, human papilloma virus (HPV), and hepatitis C virus (HCV). Studies (n=29) used a variety of descriptive analyses and statistical models to document age, period, and cohort trends in cancer-related outcomes. Cohort effects predominated, particularly in breast, bladder, and colorectal cancers, whereas period effects were more variable. No effect of time period was observed in studies of breast, bladder, and oral cavity cancers. Age-specific prevalence of obesity, current smoking, HPV, and HCV also varied by birth cohort, which generally paralleled cancer incidence and mortality rates. We observed strong cohort effects across multiple cancer types and less consistent evidence supporting the effect of time period. Birth cohort effects point to exposures early in life - or accumulated across the life course - that increase risk of cancer. Birth cohort effects also illustrate the importance of reconsidering the timing and duration of well-established risk factors to identify periods of exposure conferring the greatest risk.

Mortality forecasting in Colombia from abridged life tables by sex

BackgroundAn adequate forecasting model of mortality that allows an analysis of different population changes is a topic of interest for countries in demographic transition. Phenomena such as the reduction of mortality, ageing, and the increase in life expectancy are extremely useful in the planning of public policies that seek to promote the economic and social development of countries. To our knowledge, this paper is one of the first to evaluate the performance of mortality forecasting models applied to abridged life tables.ObjectiveSelect a mortality model that best describes and forecasts the characteristics of mortality in Colombia when only abridged life tables are available.Data and methodWe used Colombian abridged life tables for the period 1973–2005 with data from the Latin American Human Mortality Database. Different mortality models to deal with modeling and forecasting probability of death are presented in this study. For the comparison of mortality models, two criteria were analyzed: graphical residuals analysis and the hold-out method to evaluate the predictive performance of the models, applying different goodness of fit measures.ResultsOnly three models did not have convergence problems: Lee-Carter (LC), Lee-Carter with two terms (LC2), and Age-Period-Cohort (APC) models. All models fit better for women, the improvement of LC2 on LC is mostly for central ages for men, and the APC model’s fit is worse than the other two. The analysis of the standardized deviance residuals allows us to deduce that the models that reasonably fit the Colombian mortality data are LC and LC2. The major residuals correspond to children’s ages and later ages for both sexes.ConclusionThe LC and LC2 models present better goodness of fit, identifying the principal characteristics of mortality for Colombia.Mortality forecasting from abridged life tables by sex has clear added value for studying differences between developing countries and convergence/divergence of demographic changes.

Trends in smoking initiation in Europe over 40 years: A retrospective cohort study.

BackgroundTobacco consumption is the largest avoidable health risk. Understanding changes of smoking over time and across populations is crucial to implementing health policies. We evaluated trends in smoking initiation between 1970 and 2009 in random samples of European populations.MethodsWe pooled data from six multicentre studies involved in the Ageing Lungs in European Cohorts consortium, including overall 119,104 subjects from 17 countries (range of median ages across studies: 33–52 years). We estimated retrospectively trends in the rates of smoking initiation (uptake of regular smoking) by age group, and tested birth cohort effects using Age-Period-Cohort (APC) modelling. We stratified all analyses by sex and region (North, East, South, West Europe).ResultsSmoking initiation during late adolescence (16–20 years) declined for both sexes and in all regions (except for South Europe, where decline levelled off after 1990). By the late 2000s, rates of initiation during late adolescence were still high (40–80 per 1000/year) in East, South, and West Europe compared to North Europe (20 per 1000/year). Smoking initiation rates during early adolescence (11–15 years) showed a marked increase after 1990 in all regions (except for North European males) but especially in West Europe, where they reached 40 per 1000/year around 2005. APC models supported birth cohort effects in the youngest cohorts.ConclusionSmoking initiation is still unacceptably high among European adolescents, and increasing rates among those aged 15 or less deserve attention. Reducing initiation in adolescents is fundamental, since youngsters are particularly vulnerable to nicotine addiction and tobacco adverse effects.

Time trends and future prediction of coal worker\u2019s pneumoconiosis in opencast coal mine in China based on the APC model

BackgroundThe 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.MethodsAll 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.Results8191 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.ConclusionsThe 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.

Trends in women's informal eldercare in China, 1991–2011: an age–period–cohort analysis

AbstractAlthough many studies have described society-wide changes in adult women's care-giving for ageing family members, few have examined how this informal eldercare has changed across care-givers’ lifecourse and the temporal changes across different time periods and birth cohorts. Using a hierarchical age–period–cohort model to disentangle the confounding effects of age, period and cohort, this study examines the lifecourse and temporal changes in women's informal eldercare in China that can be attributed to the processes of ageing and social transformation. It advances understanding of the extent to which urbanisation and education have affected women's care-giving over time. The results reveal positive age, period and cohort effects which, together, indicate that the tradition ofxiao(filial piety) is in a stable state or even resurgent. Higher education and urban residency are both positively related to women's care-giving behaviour. As women age, the gap between residency differences in eldercare decreases. This study supports the argument thatxiaoculture is resilient and resistant to change, and that education can function as an enabler to promote it.

Cohort contributions to trends in the incidence and mortality of intrahepatic cholangiocarcinoma.

The incidence and mortality of intrahepatic cholangiocarcinoma (ICC) are increasing worldwide. We used age-period-cohort (APC) modeling to evaluate the contribution of cohort effects to trends in ICC incidence and mortality in the US. Incidence data were acquired from the Surveillance, Epidemiology and End-Results (SEER) program. Mortality data were obtained from the Centers for Disease Control and Prevention WONDER Database. APC models using restricted cubic splines were fitted to estimate change in incidence and mortality risk over age, and modification of incidence and mortality risks according to birth cohort and period of diagnosis or death. Likelihood ratio tests were used to summarize improvement in model fit with APC modeling. There were 4,053 cases of ICC at SEER registry sites between 1973-2012. ICC incidence increased with older age and across all birth cohorts examined. Inclusion of cohort effects tended to improve model fit relative to an age-period model (likelihood ratio test P=0.082). The national crude ICC-related mortality rate increased from 2.9 to 5.0 per 100,000 among males and 2.7 to 4.6 per 100,000 among females. Among males, ICC mortality risk varied across birth cohorts, and inclusion of cohort effects in a model predicting ICC mortality risk improved model fit (likelihood ratio test P=0.001), but cohort effects did not alter model fit among females (P=0.223). ICC incidence and mortality have increased over time in the United States. Birth cohort effects influenced increased ICC incidence and ICC mortality among males, but were not evident in the trend of ICC mortality among females.

Relation between mortality trends of cardiovascular diseases and selected cancers in the European Union, in 1970–2017. Focus on cohort and period effects

AimTo characterise mortality trends from major non-communicable diseases in the European Union (EU) analysing data from the World Health Organization (WHO) Mortality Database. MethodsWe obtained EU population and death certification data for major non-communicable diseases, i.e. seven cancer sites (stomach, intestine, pancreas, lung, breast, prostate and haematopoietic), total cancers, coronary heart diseases (CHDs) and cerebrovascular diseases (CVDs) from the WHO Mortality Database over the 1970 and 2012 period. We computed age-standardised rates (world standard population) and applied joinpoint regression models to identify temporal trends and age period cohort (APC) models to disentangle the effects of age, period of death and cohort of birth on mortality. ResultsIn 2012, 2.4 million deaths were recorded in the EU (1.3 million from cancers and 1.1 million from CHD and CVD combined). Over the last decade, mortality from cancer fell by 14% in men and 8% in women, resulting in age-standardised rates of 144 and 88/100,000 persons, respectively, in 2012. The only exceptions to the general downward trends were pancreatic cancer and female lung cancer. Both cardiovascular diseases mortality fell over 35% in both sexes with rates of 60 and 28/100,000 for CHD, and of 30 and 23/100,000 for CVD, in men and women, respectively, in 2012. ConclusionsOverall trends in mortality rates from non-communicable diseases in the EU were favourable, and the joinpoint and APC models indicated these trends are likely to continue in the near future. Lack of progress in tobacco-related mortality in women underlines the importance of female-specific anti-tobacco policies.

Incidence trends and age-period cohort effect on ovarian cancer in high-income countries

Background Ovarian cancer is the seventh most common cancer worldwide. Historically, the incidence of ovarian cancer in Europe and North America had been higher compared to other regions of the world. Among European countries, the incidence of ovarian cancer has steadily declined over the years, nevertheless, countries in Europe continues to have the highest incidence of ovarian cancer. The aim of the study is to provide an overview of ovarian cancer incidence trends for high-income countries that are currently part of the Cancer Survival in High-Income Countries (SURVMARK-2) project. These countries include Norway, Denmark, Ireland, the United Kingdom, Canada, Australia and New Zealand. In addition, an age-period-cohort (APC) analysis was also conducted utilizing data from population-based cancer registries from these seven countries. Methods Ovarian cancer incidence rates were calculated using data from three sources, namely, SURVMARK-2, the Cancer Incidence in Five Continents database (CI5plus), and the European cancer registries (EUREG) database. The study contains all available years included in the databases until 2014, with Norway and Denmark having the longest study periods (1953–2014). The overall age-standardized incidence rates for ovarian cancer in women aged 20 and above were computed per year. SURVMARK-2 was utilized to calculate the incidence rates from 1995 to 2014. Incidence rates prior to 1995 were then derived from the CI5plus and the EUREG databases. Additionally, the estimated annual percent change (EAPC) between 1999 and 2013 was calculated for all women age 20 and above, women age 25–49 years and 50–74 years. Lastly, the data was grouped into 5-year age groups starting with 20–24 through 70–74 years, and APC analysis was performed to examine the effects of birth cohort and period. In addition, the goodness-of-fit of the models were assessed and the likelihood ratio test was used for APC model comparison. Results In general, Norway, Denmark, Ireland and the United Kingdom, consistently had higher incidence of ovarian cancer compared to non-European countries. Nevertheless, the incidence trends revealed decreasing incidence trends of ovarian cancer in all countries evaluated. Additionally, in the last 15-year period of the study, the overall incidence rate of ovarian cancer has generally been stable. Between 1999 and 2013 the highest decline of ovarian incidence rate was observed in Norway (EAPC: −1.9, 95% CI: −4.0, 0.4). Incidences of ovarian cancer in 25–49 years and 50–74 years age groups have also declined for most countries. Notably, among the age group 25–49 years, a statistically significant decline of ovarian cancer incidence rate was observed in Norway (EAPC: −4.2, 95% CI: −7.7, −0.6). In contrast, a modest increase of incidence rate in Canada (EAPC: 1.8, 95% CI: −2.2, 5.9) was observed in this age group. Moreover, the United Kingdom (EAPC: −1.8, 95% CI: −3.3, −0.3) had statistically significant decline of incidence rates among women 50–74 years. In addition, the APC analysis yielded the full APC model as the best fitting model for all countries. After adjusting for the period effect, a statistically significant cohort effect (P Conclusion In summary, a gradual decline of ovarian cancer was observed for all countries in the study. The birth cohort effect observed in the study may be linked to the changes in the prevalence of ovarian cancer risk factors, such as the use of oral contraceptive pill. In the other hand, the period effect observed may be explained partly by changes in disease classifications and cancer registry practices.

Global trends and projections in colorectal cancer mortality

Introduction Colorectal cancer (CRC) is one of most common cause of cancer death worldwide. Mortality rate from CRC has been decreasing in many high-income countries yet in many low and middle-income countries its rate continues to rise. The lack of resources and basic health infrastructure may face many developing countries with important challenges to decrease the CRC mortality rates. Past trends and future predictions of CRC mortality can inform health planners and raise awareness of the need for cancer control action. Methods Numbers of deaths from malignant neoplasms of the colon (ICD-10 C18) and the rectum (C19–21) were obtained from the World Health Organization (WHO) mortality database for the period 1988–2012, by year, sex and age for 49 countries, where high quality data were available for the period of interest. To predict numbers of deaths and mortality rates of colon and rectal cancer up to 2035, we fitted a log-linear age–period–cohort model. We reported both numbers of expected deaths and age-standardized mortality rates per 100,000 person-years for the total population studied as well as country and subsite. Results Mortality rates for colon and rectal cancer are predicted to continue decreasing in most populations studied (32 out of 49 countries), except for most countries in Latin America and the Caribbean. Where rates have decreased in the past, colon cancer mortality rates for these countries combined was 7.2 in 2012 and is expected to be 6.6 per 100,000 person-years in 2035. In countries where rates have increased, the rate was 6.7 in 2012 and will be 7.4 by 2035. In most countries where colon cancer rates have decreased, we also predicted a decline in future rectal cancer mortality (ASR: 3.5 in 2012 and 3.2 in 2035), except, in Ireland, United Kingdom, Australia, Canada and United States, where age-standardized rates are predicted to increase by 2035 (ASR 4.1 vs. 2.9 in 2012). Despite contrasting trends in rates, number of deaths is expected to rise for both colon and rectal cancer in all countries (colon cancer: from 203,690, to 304,440 between 2012 and 2035 (+49.4%), respectively, and rectal cancer: 85,547, and 136,948 in 2012, and 2035, (+60.0%) respectively). Conclusions We highlight further decline in colon and rectal cancer mortality rates in most of countries studied, which however will not compensate the expected rise in number of deaths from this cancer, mainly due to population ageing and growth. Projected reductions of colon and rectal cancer mortality rates in Europe, North America and Oceania are partly related to earlier detection and improved cancer management. The predicted increases in rectal cancer mortality rates in some developed countries are worrisome and warrant further investigations.

It Is Not a Cohort Thing: Interrogating the Relationship Between Age, Cohort, and Support for the Environment

Cohort replacement is one widely implicated, but seldom studied, mechanism of long-term change in public opinion toward environmental protection. A key difficulty in extant research has been empirically distinguishing cohort effects from those of age. Applying recent methodological advances in age–period–cohort models, we examine the disaggregated effects of age, time period, and birth cohort on changes in Americans’ support of federal spending for environmental protection between 1973 and 2016. Results suggest that cohort replacement provides little explanatory power. Instead, we find large age effects, with the young more likely to be pro-environmental in their views, and substantial changes across time periods (but not steady rising support). These results suggest that there is no inexorable march toward greater environmentalism as younger cohorts with greater environmental awareness replace older ones, and highlight the relative lack of explicit theorizing about the relationship between age and the environment.

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

BackgroundThe 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.MethodsWe 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.ResultsThe 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.ConclusionsThe 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.

Socialization and generational political trajectories: an age, period and cohort analysis of political participation in Britain

ABSTRACTThe role of political socialization in explaining disengagement from specific modes of activism beyond voting remains largely unexplored, limited to date by available data and methods. While most previous studies have tended to propose explanations for disengagement linked to specific repertoires of political action, we propose a unified theory based on the different socialization experiences of subsequent generations. We test this theory using a new dataset of collated waves of the British Social Attitudes Survey and by applying age–period–cohort models for repeated cross-sectional data and generalized additive models to identify generational effects. We show that generational effects underlie the participatory decline across repertoires. Consistent with our expectations, the results reveal that the generation of “Thatcher’s Children” are much less likely to engage in a range of repertoires of political action than “Wilson/Callaghan’s Children”, who came of age in the more politicized 1960s and 1970s. Significantly, and in line with our theoretical expectations, the “Blair’s Babies” generation is the least politically engaged of all. We reflect on these findings and highlight the concerning implications of falling levels of activism for advanced democracies.

Time trends in first hospitalization for heart failure in a community-based population

BackgroundThis study aims to assess time trends in first hospitalization for heart failure (HF) in a community-based population over the period from 1977 to 2014. MethodsPopulation-based cohort study using resources from the “Martignacco project” started in 1977 and promoted by the WHO. Three thousand and sixty-six subjects were involved in the project with follow-up through December 2014. Estimates were made for age-specific incidence rates for the first hospitalization for HF by birth cohort, calendar period, and gender. To disentangle the effects of age, calendar period, and birth cohort on the overall temporal trend in HF, we performed an age-period-cohort (APC) analysis. ResultsAn incident hospitalization for HF was reported for 427 subjects. In the APC model, a cohort effect with a turning point in 1930 was observed. After 1930, a sharp decrease in the rate ratios (RRs) occurred in among both genders. The estimated RR in the 1940 birth cohort decreased to 0.43, (95% CI 0.19–0.92), in men and to 0.45, (95% CI 0.16–1.26), in women. A residual effect of calendar period on RR was observed with a plateau in 1995 for women and in 2000 for men, followed by a decline. ConclusionsThe current findings showed that HF hospitalization incidence has declined over the period considered in subjects over 65 years living in a geographically defined community in Northeast Italy. Moreover, the age of birth, calendar period of diagnosis, and birth cohort play an important role in the incidence of the first hospitalization for HF.

Trends in thyroid cancer: Retrospective analysis of incidence and survival in Denmark 1980–2014

BackgroundThyroid cancer incidence has been reported to be increasing since the 1970 s. The aim of this study was to investigate the change in incidence and survival from 1980 to 2014 in Denmark. MethodsWe identified patients registered with thyroid cancer in the period 1980–2014. We evaluated the age-adjusted incidence rate (AAIR) and the average annual percentage change (AAPC), constructed age–period–cohort models (APCs), and evaluated relative survival (RS). ResultsWe included 5139 patients. The AAIR was 1.6 cases per 100,000 in 1980 and 4.5 cases in 2014 with an AAPC of 3.4%. The AAIR for papillary carcinomas (n = 2864) quintupled in the study period, and accounts for most of the observed increase in incidence with an AAPC of 4.9%. Follicular carcinomas (n = 920) nearly tripled in AAIR and had the second greatest increase in AAPC. Papillary carcinomas had the best prognosis with 1-year and 5-year RSs of 95% and 91%, followed by the follicular carcinomas with 1-year and 5-year RSs of 90% and 80%, respectively. Anaplastic carcinomas (n = 320) had the worst prognosis with 1-year and 5-year RSs of 18% and 12%. We found a significant age effect in the APC model for the incidence of thyroid cancer but no significant cohort or period effects. ConclusionThe incidence of thyroid cancer is rising. This is primarily attributable to an increase in papillary carcinomas. The relative survival has improved significantly in Denmark since 1980. The cause of the increasing incidence remains to be established, but enhanced diagnostic scrutiny and increased iodine intake may be influential.

Covering the Cover

Covering the Cover

Seroprevalence of hepatitis B virus in Taiwan 30 years after the commencement of the national vaccination program.

BackgroundIn this study, the long-term efficacy of hepatitis B virus (HBV) vaccination was assessed using seroprevalence and an age–period–cohort (APC) model of HBV seromarkers among university entrants 30 years after the introduction of the national neonatal HBV vaccination program in Taiwan.MethodsIn total, data of 17,611 university entrants who underwent university entrance health examinations between 2005 and 2016 were included. The seroprevalence of the HBV surface antigen (HBsAg) and the levels of the antibody against the HBV surface antigen (anti-HBs) in each year group and sex were calculated. The levels of the antibody against the HBV core antigen were examined only for 2012 and 2016. The APC model was used to analyze the HBV carrier rates.ResultsThe chronic HBV infection (HBsAg positivity) rate decreased from 9.7% in university students born before June 1974 to <1.0% in students born after 1992. The prevalence of anti-HBs positivity declined, particularly between the 1984–1988 cohort (78.2%–53.2%) and the 1990–1994 cohort (60.6%–44.4%). Our APC model revealed that the chronic HBV carrier rate among the student population was affected significantly by age, period, and cohort (P < 0.001).ConclusionsHBV vaccination is one of the most effective strategies for preventing HBV infection. However, for complete eradication of HBV infection, the development of strategies that detect vaccination failure more effectively than current strategies do and early implementation of appropriate treatments are both necessary.

Current and Future Burden of Prostate Cancer in Songkhla, Thailand: Analysis of Incidence and Mortality Trends From 1990 to 2030.

PurposeProstate cancer is the second most common malignancy among men worldwide, and it poses a significant public health burden that has traditionally been limited mostly to developed countries. However, the burden of the disease is expected to increase, affecting developing countries, including Thailand. We undertook an analysis to investigate current and future trends of prostate cancer in the province of Songkhla, Thailand, using data from the Songkhla Cancer Registry from 1990 to 2013.MethodsJoinpoint regression analysis was used to examine trends in age-adjusted incidence and mortality rates of prostate cancer and provide estimated annual percent change (EAPC) with 95% CIs. Age-period-cohort (APC) models were used to assess the effect of age, calendar year, and birth cohort on incidence and mortality rates. Three different methods (Joinpoint, Nordpred, and APC) were used to project trends from 2013 to 2030.ResultsEight hundred fifty-five cases of prostate cancer were diagnosed from 1990 to 2013 in Songkhla, Thailand. The incidence rates of prostate cancer significantly increased since 1990 at an EAPC of 4.8% (95% CI, 3.6% to 5.9%). Similarly, mortality rates increased at an EAPC of 5.3% (95% CI, 3.4% to 7.2%). The APC models suggest that birth cohort is the most important factor driving the increased incidence and mortality rates of prostate cancer. Future incidence and mortality of prostate cancer are projected to continue to increase, doubling the rates observed in 2013 by 2030.ConclusionIt is critical to allocate resources to provide care for the men who will be affected by this increase in prostate cancer incidence in Songkhla, Thailand, and to design context-appropriate interventions to prevent its increasing burden.