Trends in alcohol-related liver disease mortality in Australia: An age-period-cohort perspective

BACKGROUND AND AIMS

There have been few systematic attempts to examine how alcohol-related mortality has changed in Australia, and no studies that have explored cohort effects in alcohol-related mortality. This study uses more than 50 years of data to measure age, period and cohort trends in alcohol-related liver disease (ALD) mortality.

DESIGN, SETTING AND CASES

This was a retrospective age-period-cohort analysis of total Australian ALD mortality data from 1968 to 2020 in Australia. There was a total of 35 822 deaths-27 208 men (76%) and 8614 women (24%).

MEASUREMENTS

Deaths from ALD were grouped into 5-year age groups and periods (e.g. deaths for 20-24-year-olds between 1968 and 1972 were combined).

FINDINGS

ALD mortality peaked in the late 1970s and early 1980s for both men and women. In age-period-cohort models, mortality was highest for cohorts born 1915-30. For example, men born between 1923 and 1927 had a relative risk of 1.58 [95% confidence interval (CI) = 1.52, 1.64] compared with men born between 1948 and 1952. For women, there was an increase in risk for cohorts born in the 1960s [e.g. the 1963-67 cohort had a relative risk (RR) of 1.16 (95% CI = 1.07, 1.25) compared with women born in 1948-52]. For men, there was a broad decline in mortality over time [e.g. in 2020, the RR was 0.87 (95% CI = 0.82, 0.92) compared with the reference year of 2000]. For women, mortality declined until 2000 and has been stable since.

CONCLUSIONS

Alcohol-related liver disease mortality has declined across the Australian population since the 1970s and 1980s partly due to cohort-specific shifts as the highest-risk birth cohorts age. For women, this decline had stalled by the year 2000, and cohorts of women born during the 1960s were at higher risk than earlier cohorts, suggesting the need for thoughtful interventions as this population enters its highest-risk years for ALD mortality.

Mortality rates for Parkinson's disease are increasing in Spain. An Age-Period-Cohort and Joinpoint Analysis in Mortality Rates from 1981 to 2020

BACKGROUND

Mortality in Parkinson's disease is increasing worldwide, but Spanish data need further study.

OBJECTIVE

To analyse the mortality trends of Parkinson's disease in Spain between 1981 and 2020.

METHODS

This observational retrospective study assessed the Parkinson's disease mortality data from 1981 to 2020 were collected from the National Statistics Institute of Spain. Age-standardized mortality rates were analysed by age and sex groups, detecting significant mortality trends through a joinpoint analysis. Age-period-cohort effect and potential years of life lost analyses were conducted. The European standard population of 2013 was considered for the analyses.

RESULTS

A total of 88,034 deaths were assessed. The overall age-standardized mortality rate rose throughout the period from 3.67 to 8.57 per 100,000 inhabitants. Mortality rates in men were higher than in women, 11.63 versus 6.57 deaths per 100,000 inhabitants. The sex ratio showed an increase in premature mortality in men during 2020. The overall joinpoint analysis recorded a rise in mortality, primarily since the twentieth century, mainly in male and older groups, that matched with a period effect. The age effect was detected, confirming higher mortality at an older age. The analysis of potential years of life lost detected a growth in this rate, changing from 0.66 in 1981 to 1.06 in 2020.

CONCLUSIONS

Mortality data for Parkinson's disease in Spain rose significantly in forty years. Mortality rate was higher in the male and age group above 75 years of age. The sex ratio showed premature mortality in men in 2020, which will need further study.

Age, period and cohort effects on time trends in monthly cannabis use in adult population: 1996-2019

INTRODUCTION

With changes in norms related to cannabis use and in the regulation of cannabis, understanding trends in cannabis use is important, especially differentiating between trends that affect cohorts of all ages similarly, versus trends that disproportionately affect a younger generation. The present study examined the age-period-cohort (APC) effects on monthly cannabis use among adults in Ontario, Canada over a 24-year period.

METHODS

Data were utilised from the Centre for Addiction and Mental Health Monitor Survey, an annual repeated cross-sectional survey of adults 18 years of age and older. The present analyses focused on the 1996 to 2019 surveys, which employed a regionally stratified sampling design using computer-assisted telephone interviews (N = 60,171). Monthly use of cannabis stratified by sex were examined.

RESULTS

There was about a five-fold increase in monthly cannabis use from 1996 (3.1%) to 2019 (16.6%). The youngest adults use cannabis monthly more, but the patterns of monthly cannabis use appeared to be increasing among older adults. Adults born in the 1950s had higher prevalence of cannabis use (1.25 times more likely to use) compared to those born in 1964, with strongest period effect in 2019. The subgroup analysis of monthly cannabis use by sex showed little variation in APC effects.

DISCUSSION AND CONCLUSIONS

There is a change in patterns of cannabis use among older adults and inclusion of birth cohort dimension improves the explanation of cannabis use trends. Adults in the 1950s birth cohort and increases in the normalisation of cannabis use could also be the key to explaining increasing monthly cannabis use.

Trends in cannabis use intention around the period of cannabis legalisation in Australia: An age-period-cohort model

INTRODUCTION

This study examines age, time period and birth cohort trends in cannabis use intention and weekly use in Australia over a period in which medicinal cannabis was legalised.

METHODS

Hierarchical age-period-cohort models were used to analyse the National Drug Strategy Household Survey between 2001 and 2019, including 158,395 participants aged 18-79 years.

RESULTS

The hierarchical age-period-cohort model demonstrated a decrease in likelihood of intending to try cannabis as age increases. Similar age effects were found in intending to use cannabis as often or less often. There was broad-based shift in attitudes for people wanting to try cannabis (2007: b = -0.51 [-0.82, -0.21]; 2019: b = 0.68 [0.38, 0.98]) or use cannabis more often (2007: b = -0.15 [-0.50, 0.20]; 2019: b = 0.83 [0.49, 1.18]). The population trend of weekly cannabis use decreased in the earlier periods but increased since 2013 (b = -0.13 [-0.25, -0.02] vs 2019: b = 0.06 [-0.09, 0.20]). This suggests that legalisation would increase uptake of cannabis and consumption among current consumers. There were distinctive inter-generation variations: people born between 1950s and 1960s had more liberal views towards cannabis use than people born before or after (p < 0.05). There were indications that young people born in the 1990 s are catching up with the baby boomers in using cannabis more often if it was legal.

DISCUSSION AND CONCLUSIONS

There has been a population-based shift in Australia in favourable attitudes towards cannabis use, more so among those born in the 1950s to 1960s than other generations. Liberal attitudes and more frequent cannabis use may put certain cohorts at higher risks of cannabis dependence and related harms.

Epidemiological and sociodemographic transitions of severe periodontitis incidence, prevalence, and disability-adjusted life years for 21 world regions and globally from 1990 to 2019: An age-period-cohort analysis

BACKGROUND

Severe periodontitis is one of the most prevalent diseases and a global public health problem due to its high incidence and prevalence. However, there are few studies on the burden of periodontitis in different regions of the world.

METHODS

We extracted data on the incidence, prevalence, and disability-adjusted life years (DALYs) from the Global Burden of Disease study as severe periodontitis burden measures. We also explored the global burden of severe periodontitis according to 21 world regions and Socio-Demographic Index (SDI) quintiles. The joinpoint model was used to analyze temporal trends of major regions from 1990 to 2019, and the age-period-cohort model was used to estimate age, period, and cohort trends in severe periodontitis.

RESULTS

Globally, the age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), and disability-adjusted life years (DALYs) rate increased from 1990 to 2019 (percentage change: 5.77%, 7.78%, and 8.01%, respectively), with average annual percent changes of 0.2%, 0.3%, and 0.3%, respectively. The region with the highest DALY rate was western sub-Saharan Africa with a value of 142.5 (95% uncertainty interval: 56.3, 303.7) per 100,000 in 2019. For the ASIR, ASPR, and DALY, the age effect of severe periodontitis showed an increase followed by a decrease, the period effect showed an upward trend, the cohort effect showed an overall decreasing trend, and the cohort relative risk for incidence for some SDI quintiles showed a slight increase in recent years.

CONCLUSIONS

Oral health varies significantly across regions, and it is essential to address inequalities in oral health between countries. Effective measures to prevent severe periodontitis risk factors should also be taken in regions with low SDI.

Mental health over the life course: Evidence for a U-shape?

Mental health problems impose substantial individual and societal costs over the life-cycle. The age-profile of mental health problems is, however, not well understood. Hence, we study the age-profile of mental health while introducing minimal bias to reach identification. Using mental health data from the United States Panel Study of Income Dynamics we apply first difference estimation to derive an unbiased estimate of the second derivative of the age effect as well as an estimate up to a linear period trend of the first derivative. Next, we use a battery of estimators with varying restrictions to approximate the first derivative. Our results suggest that the age profile of mental health in the US is not U-shaped and we find tentative evidence that the age-profile could follow an inverse U-shape where individuals experience a mental health high during their life course. Further analyses, using German and Dutch data, confirm that these results do not only apply to the US, but also to Germany and the Netherlands.

Trends in gestational diabetes mellitus among nulliparous pregnant individuals with singleton live births in the United States between 2011 to 2019: an age-period-cohort analysis

BACKGROUND

The rate of gestational diabetes mellitus has increased over the past decade. An age, period, and cohort epidemiologic analysis can be used to understand how and why disease trends have changed over time.

OBJECTIVE

This study aimed to estimate the associations of age (at delivery), period (delivery year), and cohort (birth year) of the pregnant individual with trends in the incidence of gestational diabetes mellitus in the United States.

STUDY DESIGN

We conducted an age, period, and cohort analysis of nulliparous pregnant adults aged 18 to 44 years with singleton live births from the National Vital Statistics System from 2011 to 2019. Generalized linear mixed models were used to calculate the adjusted rate ratios for the incidence of gestational diabetes mellitus for each 3-year maternal age span, period, and cohort group compared with the reference group for each. We repeated the analyses with stratification according to self-reported racial and ethnic group (non-Hispanic Asian-Pacific Islander, non-Hispanic Black, Hispanic, and non-Hispanic White) because of differences in the incidence of and risk factors for gestational diabetes mellitus by race and ethnicity.

RESULTS

Among 11,897,766 pregnant individuals, 5.2% had gestational diabetes mellitus. The incidence of gestational diabetes mellitus was higher with increasing 3-year maternal age span, among those in the more recent delivery period, and among the younger birth cohort. For example, individuals aged 42 to 44 years at delivery had a 5-fold higher risk for gestational diabetes mellitus than those aged 18 to 20 years (adjusted rate ratio, 5.57; 95% confidence interval, 5.43-5.72) after adjusting for cohort and period. Individuals who delivered between 2017 and 2019 were at higher risk for gestational diabetes mellitus than those who delivered between 2011 and 2013 (adjusted rate ratio, 1.24; 95% confidence interval, 1.23-1.25) after adjusting for age and cohort. Individuals born between 1999 and 2001 had a 3-fold higher risk for gestational diabetes mellitus than those born between 1969 and 1971 (adjusted rate ratio, 3.12; 95% confidence interval, 2.87-3.39) after adjusting for age and period. Similar age, period, and cohort effects were observed for the assessed racial and ethnic groups, with the greatest period effects observed among Asian and Pacific Islander individuals.

CONCLUSION

Period and birth cohort effects have contributed to the rising incidence of gestational diabetes mellitus in the United States from 2011 to 2019.

Hepatitis B and C mortality from 1990 to 2019 in China: a Bayesian age-period-cohort analysis

Background

Significant decreases in hepatitis B virus (HBV) and hepatitis C virus (HCV) infections have been observed in China, but both remain leading public health challenges. Estimating the components and trends in HBV and HCV mortality is vital for disease control planning. The current analysis investigated time trends in hepatitis B and C mortality and the relationships with age, period, and birth cohort from 1990 to 2019. We also made projections for 2030-2034 in China.

Methods

Mortality data related to hepatitis B and C were obtained from the Global Burden of Disease (GBD) study, which was stratified by complications, age, sex, and specific geographical locations. An age-period-cohort (APC) analytical framework was adopted to measure age, period, and cohort effects, which fits a log-linear Poisson model over a Lexis diagram of observed rates and quantifies the additive effects of age, period, and birth cohorts. We estimated longitudinal age curves (expected longitudinal age-specific rates), net drift (overall annual percentage change), local drift (annual percentage change in each age group), period, and cohort relative risks. A Bayesian APC analysis was used to project future age-specific hepatitis B and C deaths.

Results

In China, the age-standardized mortality rate (ASMR) of hepatitis B and C decreased by 67% and 58% from 1990 to 2019, respectively. The overall annual percentage changes in hepatitis B and C were -4.97% and -6.49% for males and -3.85% and -6.09% for females, respectively. After adjusting for period and cohort effects, we observed an exponential increase in hepatitis C mortality with age, with the Bell-like curves peaking at approximately 50 years old for hepatitis B. The Bayesian APC analysis projected that hepatitis B and C deaths would decrease dramatically by 42% and 22% for the periods 2016-2019 and 2030-2034, respectively. The declines in ASMRs related to hepatitis B and C were associated with the improvements in the Chinese Socio-Demographic Index.

Conclusions

Although the burden of hepatitis B and C mortality is likely to continue declining in China, the hepatitis B and C mortality was still high. Therefore, the national efforts should still be strengthened to achieve the global hepatitis elimination targets.

Secular Trends in Incidence of Esophageal Cancer in Taiwan from 1985 to 2019: An Age-Period-Cohort Analysis

In Taiwan, the age-standardized incidence of EC, especially esophageal squamous cell carcinoma (ESCC), has increased substantially during the past thirty years. We described the incidence trends of EC from 1985−2019 by an average annual percentage change (AAPC) and age-period-cohort model by using Taiwan Cancer Registry data. Age-period-cohort modeling was used to estimate the period and cohort effects of ESCC and esophageal adenocarcinoma (EAC). The Spearman’s correlation coefficient was used to analyze the correlation between age-adjusted incidence rates of EC and the prevalence of risk factors from national surveys. The results showed the incidence rate of ESCC in men (AAPC = 4.2, 95% CI = 3.1−5.4, p < 0.001) increased prominently from 1985−1989 to 2015−2019 while that of EAC in men (AAPC = 1.2, 95% CI = 0.9−1.5, p < 0.001) and ESCC in women (AAPC = 1.7, 95% CI = 1.4−2.1, p < 0.001) increased to a lesser degree. Increased period effects were observed in ESCC in men, ESCC in women, and EAC in men. High correlations were found between the risk factors and the increased birth-cohort effects of ESCC (p < 0.05). To conclude, the incidence of ESCC in both sex and EAC in men increased with statistical significance in recent decades. The increased prevalence of risk factors from approximately 1970−1995 could explain the increased cohort effects of ESCC.

Age-period-cohort analysis of trends in tobacco smoking, cannabis use, and their co-use in the Australian population

BACKGROUND AND AIM

The prevalence of tobacco smoking has declined in most high-income countries, while cannabis use has been rising. Moreover, cannabis use has been found to have increased among cigarette smokers in recent years in jurisdictions where it has been either decriminalized or legalized. This study measured trends in cannabis, tobacco and the co-use of cannabis and tobacco in Australia.

DESIGN

Age-period-cohort analysis.

SETTING AND PARTICIPANTS

Participants were n = 143 344 individuals aged 18-80 years who participated in Australia's National Drug Strategy Household Surveys (NDSHS) between 2001 and 2019.

MEASUREMENTS

Regular (weekly/more frequently): (1) tobacco smoking only, (2) cannabis use only and (3) the co-use of cannabis and tobacco.

FINDINGS

Prevalence of only smoking tobacco decreased in all age groups (P < 0.001) and birth cohorts between 2001 and 2019, but the co-use of cannabis and tobacco did not. Younger cohorts were much less likely to co-use tobacco and cannabis (P = 0.02). Period trends showed that both cannabis use only and the co-use of cannabis and tobacco have increased since 2013.

CONCLUSION

There has been a consistent decrease in exclusive tobacco smoking across age, period and birth cohorts between 2001 and 2019 in Australia, although there is a recent increasing period trend in cannabis use with or without tobacco. The non-decreasing trend of co-use may reflect the strong tobacco control policies introduced over the period and changing attitudes towards cannabis use in Australia.

Aging, generational shifts, and energy consumption in urban China

China is recognized as the largest energy consumer and is also the country with the largest and fastest-aging population. Ongoing demographic changes may reshape China's household-based energy consumption patterns because of the large gap in consumption behavior between the elderly and the young as well as varying attitudes toward the environment among generations. However, when the impact of China's aging population on energy consumption is projected, the heterogeneous cognitive norms of generations in the process of demographic transition are not well understood. In this study, we assessed the future impact of China's demographic transition on energy consumption using a proposed theoretical framework to distinguish between age and generational effects. Specifically, we used age-period-cohort (APC) detrended analysis to estimate age and generational effects based on China's urban household survey data from 1992 to 2015. The results indicated large differences in energy use propensity across ages and generations. The elderly and younger generations tended to be energy-intensive consumers, resulting in higher energy consumption in this aging society. Our results consequently show that future changes in China's elderly population will result in a substantial increase in energy consumption. By 2050, the changing consumption share of the elderly population will account for ∼17 to 26% of total energy consumption in the residential sector, which is close to 115 million tons of standard coal (Mtce). These findings highlight the need to interlace environmental education policies and demographic transitions to promote energy conservation behavior in children and youth for low-carbon, sustainable development.

Ways of HIV transmission in China: The effect of age, period, and cohort

Background

Acquired immunodeficiency syndrome (AIDS) is a global pandemic caused by human immunodeficiency virus (HIV), which is transmitted through human behaviors, such as sexual intercourse, intravenous drug injection, and blood transfusion. Rare studies have focused on the evaluation of the effects of culture, society, and HIV-related policies in adjusting people's HIV-related behaviors, i.e., ways of HIV transmission.

Methods

By taking the new HIV infections in Hubei Province each year from 1995 to 2020 as the sample, our study used the Hierarchical Age-Period-Cohort (HAPC) model to analyze the effects of age, period, and cohort on the trends of ways of HIV transmission.

Results

From 1995 to 2020, the number of new HIV infections in Hubei presented a general upward trend. A total of 34,636 HIV infections were reported during this period. According to the statistics of the new HIV infections in Hubei Province between 1995 and 2020, there is a negative correlation between age (-0.099, p < 0.001), squared age (-0.002, p < 0.001), and the rate of blood transmission. While there is a positive correlation between age (0.143, p < 0.001), squared age (0.002, p < 0.001), and the rate of HIV infection through sexual transmission. The significant period and cohort effects on ways of HIV transmission were also observed in the Chinese population.

Conclusion

Sexual and blood transmission are the two main ways of HIV infection in China and Hubei. The trend of blood transmission is in accordance with the wave of blood trade in the early 1990s in China. The trend of sexual transmission indicates an increasing need to promote safer sexual behavior among the older population and later generations and design more tailored, innovative, and diverse HIV prevention strategies, especially for the high-risk groups.

Racial/ethnic disparities in hepatocellular carcinoma incidence and mortality rates in the United States, 1992-2018

BACKGROUND AND AIMS

HCC is characterized by racial/ethnic disparities in rates. Recent USA reports suggest that incidence has begun to decline, but it is not clear whether the declines have occurred among all groups, nor whether mortality has declined. Thus, the current study examined USA incidence and mortality between 1992 and 2018.

APPROACH & RESULTS

HCC incidence and incidence-based mortality data from the Surveillance, Epidemiology, and End Results program were used to calculate age-standardized rates by race/ethnicity, sex, and age. Trends were analyzed using joinpoint regression to estimate annual percent change (APC). Age-period-cohort models assessed the effects on trends of age, calendar period, and birth cohort. Overall, HCC incidence significantly declined between 2015 and 2018 (APC, -5.6%). Whereas most groups experienced incidence declines, the trends were most evident among Asians/Pacific Islanders, women, and persons <50 years old. Exceptions were the rates among non-Hispanic Black persons, which did not significantly decline (APC, -0.7), and among American Indians/Alaska Natives, which significantly increased (APC, +4.3%). Age-period-cohort modeling found that birth cohort had a greater effect on rates than calendar period. Among the baby boom cohorts, the 1950-1954 cohort had the highest rates. Similar to the overall incidence decline, HCC mortality rates declined between 2013 and 2018 (APC, -2.2%).

CONCLUSIONS

HCC incidence and mortality rates began to decline for most groups in 2015, but persistent differences in rates continued to exist. Rates among non-Hispanic Black persons did not decline significantly, and rates among American Indians/Alaska Natives significantly increased, suggesting that greater effort is needed to reduce the HCC burden among these vulnerable groups.

Effects of age, period, and cohort on the prevalence of frailty in Chinese older adults from 2002 to 2014

Background

Currently, longitudinal studies on frailty are in an early stage, particularly in low- and middle-income countries. Only one study was conducted in Hong Kong to examine age-period-cohort effects on the prevalence of frailty among Chinese older adults.

Objectives

This study aims to shed light on the prevalence trajectory of frailty among older adults in mainland China through the APC model and to analyze the effects of age, period, and cohort on the prevalence trajectory.

Methods

The sample for this study was older adults aged 65-109 years old from the 2002 to 2014 Chinese Longitudinal Healthy Longevity Survey (CLHLS). Frailty status was measured by Rockwood FI. An age-period-cohort model was used to describe the effects of age, period, and cohort on the prevalence trajectory of frailty.

Results

The prevalence of frailty among Chinese older adults changed significantly with age, period, and cohort. Furthermore, the effect of age was much stronger than the effect of period and cohort. The prevalence of frailty in the 101-103 and 104-106 age groups was 8.998 (95% CI 13.667-5.924) and 8.699 (95% CI 13.037-5.805) times higher than the in the 65-67 age group, respectively. The sensitivity analysis based on Fried's frailty phenotype showed similar results, confirming the robustness of our findings.

Conclusion

All of the age effect reflecting the individual aging process, period effect reflecting change in the social environment, and birth cohort effect reflecting different generations could influence the prevalence of frailty at the population level. In contrast, the age effect was the main effect.

Age, Period, and Cohort Effects in Alcohol Use in the United States in the 20th and 21st Centuries: Implications for the Coming Decades

This article is part of a Festschrift commemorating the 50th anniversary of the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Established in 1970, first as part of the National Institute of Mental Health and later as an independent institute of the National Institutes of Health, NIAAA today is the world's largest funding agency for alcohol research. In addition to its own intramural research program, NIAAA supports the entire spectrum of innovative basic, translational, and clinical research to advance the diagnosis, prevention, and treatment of alcohol use disorder and alcohol-related problems. To celebrate the anniversary, NIAAA hosted a 2-day symposium, "Alcohol Across the Lifespan: 50 Years of Evidence-Based Diagnosis, Prevention, and Treatment Research," devoted to key topics within the field of alcohol research. This article is based on Dr. Keyes' presentation at the event. NIAAA Director George F. Koob, Ph.D., serves as editor of the Festschrift.

Global, regional, and national time trends in mortality for congenital heart disease, 1990-2019: An age-period-cohort analysis for the Global Burden of Disease 2019 study

BACKGROUND

Congenital heart disease (CHD) is the leading cause of morbidity and mortality from birth defects worldwide. We report an overview of trends in CHD mortality in 204 countries and territories over the past 30 years and associations with age, period, and birth cohort.

METHODS

Cause-specific CHD mortality estimates were derived from the Global Burden of Disease 2019 study. We utilised an age-period-cohort model to estimate overall annual percentage changes in mortality (net drifts), annual percentage changes from 0 to 4 to 65-69 years (local drifts), period and cohort relative risks (period/cohort effects) between 1990 and 2019. This approach allows for the examination and differentiation of age, period, and cohort effects in the mortality trends, with the potential to identify disparities and treatment gaps in cardiac care.

FINDINGS

CHD is the leading cause of deaths from non-communicable diseases (NCDs) in those under 20 years. Global CHD deaths in 2019 were 217,000 (95% uncertainty interval 177,000-262,000). There were 129 countries with at least 50 deaths. India, China, Pakistan, and Nigeria had the highest mortality, accounting for 39.7% of deaths globally. Between 1990 and 2019, the net drift of CHD mortality ranged from -2.41% per year (95% confidence interval [CI] -2.55, -2.67) in high Socio-demographic Index (SDI) countries to -0.62% per year (95% CI: -0.82, -0.42) in low-SDI countries. Globally, there was an emerging transition in the age distribution of deaths from paediatric to adult populations, except for an increasing trend of mortality in those aged 10-34 years in Mexico and Pakistan. During the past 30 years, favourable mortality reductions were generally found in most high-SDI countries like South Korea (net drift = -4.0% [95% CI -4.8 to -3.1] per year) and the United States (-2.3% [-2.5 to -2.0]), and also in many middle-SDI countries like Brazil (-2.7% [-3.1 to 2.4]) and South Africa (-2.5% [-3.2 to -1.8]). However, 52 of 129 countries had either increasing trends (net drifts ≥0.0%) or stagnated reductions (≥-0.5%) in mortality. The relative risk of mortality generally showed improving trends over time and in successively younger birth cohorts amongst high- and high-middle-SDI countries, with the exceptions of Saudi Arabia and Kazakhstan. 14 middle-SDI countries such as Ecuador and Mexico, and 16 low-middle-SDI countries including India and 20 low-SDI countries including Pakistan, had unfavourable or worsening risks for recent periods and birth cohorts.

INTERPRETATION

CHD mortality is a useful and accessible indicator of trends in the provision of congenital cardiac care both in early childhood and across later life. Improvements in the treatment of CHD should reduce the risk for successively younger cohorts and shift the risk for all age groups over time. Although there were gains in CHD mortality globally over the past three decades, unfavourable period and cohort effects were found in many countries, raising questions about adequacy of their health care for CHD patients across all age groups. These failings carry significant implications for the likelihood of achieving the Sustainable Development Goal targets for under-5 years and NCD mortality.

FUNDING

Supported by the National Natural Science Foundation of China (81525002, 31971048, 82073573 to ZZ and HZ), Shanghai Outstanding Medical Academic Leader program (2019LJ22 to HZ), and Collaborative Innovation Program of Shanghai Municipal Health Commission (2020CXJQ01 to HZ), the Bill & Melinda Gates Foundation for the Global Burden of Disease Project (to NJK) and NHMRC fellowship administered through the University of Melbourne (to GCP).

Trends in Cognitive Function Among Chinese Elderly From 1998 to 2018: An Age-Period-Cohort Analysis

Objectives: To investigate the effects of age, period, and cohort (APC) on trends in cognitive function among the Chinese elderly, and to explore how gender gaps in cognitive function change with age, period, and cohort. Methods: This study used data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 1998 to 2018, and included 90,432 participants aged above 65 years old. The measurement of cognitive function was the score of the Mini-Mental State Examination (MMSE). Cross-classified random-effect models were used to investigate age, period, and cohort trends in cognitive function. Results: Mini-Mental State Examination scores decreased with age at an increasing rate. While the cohort effect was nearly stable, the period effect demonstrated a downward trend from 1998 to 2002 followed by a nearly flat line. Females were associated with lower MMSE scores than males. When age increased, the gender gaps in MMSE scores further increased. The period-based gender gaps in MMSE scores diverged throughout the 20 years, while the cohort-based gender disparities in MMSE scores converged with successive cohorts. Conclusions: Age, period, and cohort had different and independent effects on cognitive function among the Chinese elderly. The effect of age was stronger than that of period and cohort. Gender disparities in cognitive function increased with age and period, and decreased with successive cohorts.

Forecasting of Lung Cancer Incident Cases at the Small-Area Level in Victoria, Australia

Predicting lung cancer cases at the small-area level is helpful to quantify the lung cancer burden for health planning purposes at the local geographic level. Using Victorian Cancer Registry (2001-2018) data, this study aims to forecast lung cancer counts at the local government area (LGA) level over the next ten years (2019-2028) in Victoria, Australia. We used the Age-Period-Cohort approach to estimate the annual age-specific incidence and utilised Bayesian spatio-temporal models that account for non-linear temporal trends and area-level risk factors. Compared to 2001, lung cancer incidence increased by 28.82% from 1353 to 1743 cases for men and 78.79% from 759 to 1357 cases for women in 2018. Lung cancer counts are expected to reach 2515 cases for men and 1909 cases for women in 2028, with a corresponding 44% and 41% increase. The majority of LGAs are projected to have an increasing trend for both men and women by 2028. Unexplained area-level spatial variation substantially reduced after adjusting for the elderly population in the model. Male and female lung cancer cases are projected to rise at the state level and in each LGA in the next ten years. Population growth and an ageing population largely contributed to this rise.

Disease burden of liver cancer attributable to specific etiologies in China from 1990 to 2019: An age-period-cohort analysis

Temporal trends of total liver cancer have been well reported in China, especially the trends caused by hepatitis B (HBV); however, the trends of liver cancer attributable to specific etiologies have rarely been reported in China. Thus, this study aims to describe the temporal trends in the incidence, mortality and DALYs of total and etiology-specific liver cancer in China from 1990 to 2019. We extracted the incidence, mortality and disability-adjusted life years (DALYs) of total and etiology-specific liver cancer in China from 1990 to 2019 from global disease burden (GBD) 2019. We plotted the trends in the age-standardized rates for incidence, mortality, and DALYs using locally weighted regression (LOESS)-smoothed data from 1990 to 2019. The age-standardized rate for the incidence of liver cancer was analyzed with an age-period-cohort method. The age-standardized rates for incidence, death, and DALYs decreased by -58.8%, -63.8%, and -65.6%, respectively, between 1990 and 2019. The age-standardized rates of incidence, mortality, and DALYs of total liver cancer showed similar temporal patterns, presenting an overall decline, with the average annual percentage change (AAPC) ranging from -3.3% to -3.8%. People in the period before 2007 had a higher risk, and people after 2007 had a lower risk. The cohort risk ratios (RRs) showed decreasing patterns, with the most rapid decline observed in the 1910 to 1960 cohorts. Our study generally revealed favorable decreasing trends for total and etiology-specific liver cancer in China from 1990 to 2019. Despite the overall decline in liver cancer due to heavy alcohol use and obesity from 1990 to 2019, there have been apparent upward trends since 2006. Planned population-wide interventions targeting heavy alcohol use and obesity may mitigate the increasing trends in liver cancer attributable to alcohol use and NASH.

Age, Period and Cohort Analysis of Rates of Emergency Department Visits Due to Pneumonia in Taiwan, 1998-2012

Background

Emergency room (ER) physicians need to face clinically suspected pneumonia patients in the front line of medical care and must do to give major medical interventions if patients show severity in pneumonia.

Methods

The data of pneumonia-related ER visit rates were categorized based on the International Classification of Disease (ICD) Codes (480–486) between 1998 and 2012. We use an age-period-cohort (APC) model to separate the pneumonia-related ER visit rates to identify the effects of age, time period, and cohort for a total of 1,813,588 patients.

Results

The age effect showed high risk for pediatric and elder populations. There is a significant increasing period effect, which increased from 1998 to 2012. The cohort effect tended to show an oscillation from 1913 to 1988 and the reverse in a recent cohort. Furthermore, the visit rate of pneumonia showed an increase from 1998 to 2012 for both genders.

Conclusion

Age is a risk factor for pneumonia-related ER visits, especially for children and adolescents and older patients. Period and cohort effects were also found to increase the pneumonia visit rates. An APC model used to provide an advance clue for trend of pneumonia-related ER visit rates diversified.

Identifying subgroups of age and cohort effects in obesity prevalence

The obesity epidemic represents an important public health issue in the United States. Studying obesity trends across age groups over time helps to identify crucial relationships between the disease and medical treatment allowing for the development of effective prevention policies. We aim to define subgroups of age and cohort effects in obesity prevalence over time by considering an optimization approach applied to the age-period-cohort (APC) model. We consider a heterogeneous regression problem where the regression coefficients are age dependent and belong to subgroups with unknown grouping information. Using the APC model, we apply the alternating direction method of multipliers (ADMM) algorithm to develop a two-step algorithm for (1) subgrouping of cohort effects based on similar characteristics and (2) subgrouping age effects over time. The proposed clustering approach is illustrated for the United States population, aged 18-79, during the period 1990-2017.

Testicular cancer incidence predictions in Europe 2010-2035: A rising burden despite population ageing

Testicular cancer is the most common cancer among young men of European ancestry, with about one-third of all cases occurring in Europe. With the historically increasing trends in some high-incidence populations reported to have stabilised in recent years, we aimed to assess recent trends and predict the future testicular cancer incidence burden across Europe. We extracted testicular cancer (ICD-10 C62) incidence data from Cancer Incidence in Five Continents Volumes VII-XI and complemented this with data published by registries from 28 European countries. We predicted cancer incidence rates and the number of incident cases in Europe in the year 2035 using the NORDPRED age-period-cohort model. Testicular cancer incidence rates will increase in 21 out of 28 countries over the period 2010-2035, with trends attenuating in the high-incidence populations of Denmark, Norway, Switzerland and Austria. Although population ageing would be expected to reduce the number of cases, this demographic effect is outweighed by increasing risk, leading to an overall increase in the number of cases by 2035 in Europe, and by region (21, 13 and 32% in Northern, Western and Eastern Europe, respectively). Declines are however predicted in Italy and Spain, amounting to 12% less cases in 2035 in Southern Europe overall. In conclusion, the burden of testicular cancer incidence in Europe will continue to increase, particularly in historically lower-risk countries. The largest increase in the number of testicular cancer patients is predicted in Eastern Europe, where survival is lower, reinforcing the need to ensure the provision of effective treatment across Europe.

The effect of pneumococcal conjugate vaccines on otitis media from 2005 to 2013 in children aged ≤5 years: a retrospective cohort study in two Swedish regions

Seven-valent pneumococcal conjugate vaccine (PCV7) was introduced to Sweden in 2009 and replaced by pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) or 13-valent PCV (PCV13) from late 2009. A retrospective cohort study assessed the impact of PCVs on otitis media/acute otitis media (OM) in children aged ≤5 years (NCT02742753) living in Skåne (PCV7 then PHiD-CV) or Västra Götalandsregionen (PCV7 then PCV13) between 2005 and 2013 using linked regional and national databases. Time-series analyses described differences between pre-PCV and post-PCV eras. Adjusted age-period-cohort (APC) predictive models estimated vaccine effectiveness and OM incidence ratios between PCV cohorts. Time-to-first OM diagnosis was estimated in ≤2 year-olds by survival analysis using a Cox proportional hazards model. Descriptive interrupted time-series analyses showed OM incidence in ≤2 year-olds declined by 42% (Skåne) and 25% (Västra Götalandsregionen) after PHiD-CV/PCV13, respectively, versus pre-PCV, but baseline OM incidence and duration of PCV7 use differed between regions. In adjusted APC models, OM incidence decreased after PHiD-CV by 9.9% (95% confidence interval [CI]: 4.4; 15.1, p < .001) and PCV13 by 2.3% (95%CI: −3.2; 7.6, p = .401) compared with pre-PCV. Both PHiD-CV and PCV13 decreased the risk of first OM diagnosis: hazard ratio (95%CI) for PHiD-CV relative to pre-PCV 0.67 (0.65; 0.69); 0.87 (0.85; 0.89) for PCV13 relative to pre-PCV; p < .001 for both comparisons. Within the limitations of this study conducted in two large Swedish regions, descriptive time-series analyses showed that OM incidence rates declined following the introduction of PHiD-CV and PCV13; however, this reduction only reached statistical significance for PHiD-CV in the adjusted APC models.

The influence of birth cohort and calendar period on global trends in ovarian cancer incidence

Ovarian cancer is the eighth most common cancer in women worldwide and incidence rates vary markedly by world region. Our study provides a comprehensive overview of ovarian cancer incidence trends globally, examining the influence of birth cohort and period of diagnosis on changing risk. We presented current patterns and trends of ovarian cancer incidence until 2012 using data from successive volumes of Cancer Incidence in Five Contents. The incidence of ovarian cancer is highest in northern and eastern European countries and in northern America. Declining trends were observed in most countries with the exception of a few central and eastern Asian countries. Marked declines were seen in Europe and North America for women aged 50-74 where rates have declined up to 2.4% (95% CI: -3.9, -0.9) annually in Denmark (DNK) over the last decade. Additionally, declines in the incidence rate ratio (IRR) were observed for generations born after the 1930s, with an additional strong period effect seen around 2000 in United States and DNK. In contrast, IRRs increased among younger generations born after the 1950s in Japan and Belarus. Overall, the favorable trends in ovarian cancer incidence is likely due to the increase use of oral contraceptive pills, and changes in the prevalence of other reproductive risk and protective factors for ovarian cancer over the years studied. Changes in disease classifications and cancer registry practices may also partially contribute to the variation in ovarian cancer incidence rates. Thus, continuous cancer surveillance is essential to detect the shifting patterns of ovarian cancer.

Fact or artefact? Childhood adversity and adulthood trauma in the U.S. population-based Health and Retirement Study

Background: Despite the well-known deleterious health effects of childhood adversity (CA) and adulthood trauma (AT) and ageing of the global population, little is known about self-reported CA and AT in older populations. Existing findings are mixed due to methodological and sampling artefacts, in particular, recall and selection biases, and due to age-period-cohort effects. Objectives: We aim to first, provide data on the prevalence of retrospective self-reported CA and AT in a large population-based sample of older adults and, second, to discuss the data in the context of major methodological and sampling artefacts, and age-period-cohort effects. Method: Data are derived from the U.S. population-based Health and Retirement Study (N = 19,547, mean age = 67.24 ± 11.33, 59% female). Seven birth-cohorts were included (<1924, 1924-1930, 1931-1941, 1942-1947, 1948-1953, 1954-1959, >1959). Results: Overall, 35% of participants reported CA and 62% AT, with strong variability among birth-cohorts. Opposing trends were observed regarding prevalence of CA and AT. As age of cohorts increased, prevalence of CAs decreased while that of ATs increased. Investigating the distributions of incidence of specific ATs across age and period per cohort revealed incidence of exposure was associated with (1) age (e.g. having lost a child), (2) time-period (e.g. major disaster), and (3) cohort (e.g. military combat). Conclusions: Retrospective self-reported CA and AT in older samples should be interpreted with caution and with regard to major methodological challenges, including recall and selection biases. Untangling fact from artefact and examining age, period, and cohort effects will help elucidate profiles of lifetime exposures in older populations.

Age, period and cohort effects in frequent cannabis use among US students: 1991-2018

BACKGROUND AND AIMS

As the legal status of cannabis changes across the United States and modes of administration expand, it is important to examine the potential impact on adolescent cannabis use. This study aimed to assess changes in prevalence of frequent cannabis use in adolescents in the United States and how far this varies by age and cohort.

DESIGN

Analysis of Monitoring the Future, a nationally representative annual survey of 8th-, 10th- and 12th-grade students in the United States conducted from 1991 to 2018.

SETTING

In-school surveys completed by US adolescents.

PARTICIPANTS

A total of 1 236 159 8th-, 10th- and 12th-graders; 51.5% female, 59.6% non-Hispanic white, 12.3% non-Hispanic black, 13.4% Hispanic and 14.7% other race/ethnicity.

MEASUREMENTS

Frequent cannabis use (FCU), defined as six or more occasions in the past 30 days, stratified by sex, race/ethnicity and parental education.

FINDINGS

FCU among US adolescents increased over the study period; the peak in 2010-18 was 11.4% among 18-year-old students. This increase was best explained by both period and cohort effects. Compared with respondents in 2005, adolescents surveyed in 2018 had period effects in FCU that were 1.6 times greater. Adolescents in younger birth cohorts (those born > 1988) had a lower increase in FCU than those born prior to 1988. Results were consistent across sex, parent education and race/ethnicity, with period effects indicating increasing FCU after 2005 and cohort effects indicating a lower magnitude of increase in more recent birth cohorts. Age and parental education disparities in FCU have increased over time, whereas race/ethnicity differences have converged over time; black students were 0.67 [95% confidence interval (CI) = 0.64-0.70] times as likely to use cannabis frequently as white students from 1991 to 2000, and 1.03 (95% CI = 0.98-1.09) times as likely from 2011 to 2018 (P-value for time interaction < 0.001).

CONCLUSIONS

The prevalence of frequent cannabis use (FCU) increased from 1991 to 2018 among older adolescents in the United States. Racial/ethnic differences in FCU converged, whereas parental education differences have diverged.

Patterns of opioid use (codeine, morphine or meperidine) in the Canadian population over time: analysis of the Longitudinal National Population Health Survey 1994-2011

OBJECTIVE

This study aimed to investigate cohort effects in selected opioids use and determine whether cohort differences were associated with changes in risk factors for use over time.

DESIGN

This study presents secondary analyses of a longitudinal survey panel of the general population that collected data biannually.

SETTING

Data from the Canadian Longitudinal National Population Health Survey 1994-2011.

POPULATION

This study included 12 542 participants from the following birth cohorts: post-World War I (born 1915-1924), pre-World War II (born 1925-1934), World War II (born 1935-1944), Older Baby Boom (born 1945-1954), Younger Baby Boom (born 1955-1964), Older Generation X (born 1965-1974) and Younger Generation X (born 1975-1984).

MAIN OUTCOME

Responses to a single question asking about the use of codeine, morphine or meperidine in the past month (yes/no) were examined.

RESULTS

Over and above age and period effects, there were significant cohort differences in selected opioids use: each succeeding recent cohort had greater use than their predecessors (eg, Gen Xers had greater use than younger baby boomers). Selected opioids use increased significantly from 1994 to 2002, plateauing between 2002 and 2006 and then declining until 2011. After accounting for cohort and period effects, there was a decline in use of these opioids with increasing age. Although pain was significantly associated with greater selected opioids use (OR=3.63, 95% CI 3.39 to 3.94), pain did not explain cohort differences. Cohort and period effects were no longer significant after adjusting for the number of chronic conditions. Cohort differences in selected opioids use mirrored cohort differences in multimorbidity. Use of these opioids was significantly associated with taking antidepressants or tranquillisers (OR=2.52, 95% CI 2.27 to 2.81 and OR=1.60, 95% CI 1.46 to 1.75, respectively).

CONCLUSIONS

The findings underscore the need to consider multimorbidity including possible psychological disorders and associated medications when prescribing opioids (codeine, morphine, meperidine), particularly for recent birth cohorts. Continued efforts to monitor prescription patterns and develop specific opioid use guidelines for multimorbidity appear warranted.

The Risk of Hypertension Doubles Every 10 Years in China: Age, Period, and Birth Cohort Effects on the Prevalence of Hypertension From 2004 to 2013

BACKGROUND

Hypertension is a growing problem worldwide and can often result in a variety of negative health outcomes. The aim of this study was to assess the effects of age at diagnosis, calendar period, and birth cohort on the change in the prevalence rate of hypertension in Guangzhou from 2004 to 2013.

METHODS

We used data from the Guangzhou Community Health Survey, a population-based study designed by the National Health and Family Planning Commission of the PRC every 5 years. A total of 27,299, 23,467, and 18,362 participants aged 15-79 years completed the survey in 2004, 2009, and 2013, respectively.

RESULTS

Age effects increased slowly before the age of 42 years but increased rapidly after the age of 42 years, peaking at 79 years. Cohort effects grew slowly before the end of the 1960s but grew quickly after the end of the 1960s. The risk of suffering from hypertension among people born in 1962, 1972, 1982, and 1992 was 1.39, 2.68, 5.55, and 11.53 times, respectively, than that of people born in 1952. The period effects increased 25% from 2004 to 2009 and later declined 27% from 2009 to 2013 in the entire population. There was no gender difference in age effects and period effects, but strong cohort effects on hypertension were observed among males compared with females.

CONCLUSIONS

For Chinese individuals, the later one is born, the higher the risk is of suffering from hypertension. Strong cohort effects for hypertension were observed among males compared with females, indicating that males are more easily affected by hypertension based on the change in birth cohort.

Using weighted regression model for estimating cohort effect in age-period contingency table data

Background

Recently, the multiphase method was proposed to estimate cohort effects after removing the effects of age and period in age-period contingency table data. Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and is strongly associated with cirrhosis, due to both alcohol and viral etiologies. In epidemiology, age-period-cohort (APC) model can be used to describe (or predict) the secular trend in HCC mortality.

Results

The confidence interval (CI) of the weighted estimates was found to be relatively narrow (compared to unweighted estimates). Moreover, for males, the mortality trend reverses itself during 2006-2010 was found from an increasing trend into a slightly deceasing trend. For females, the increasing trend reverses (earlier than males) itself during 2001-2005.

Conclusions

The weighted estimation of the regression model is recommended for the multiphase method in estimating the cohort effects in age-period contingency table data.

Impact

The regression model can be modified through the weighted average estimate of the effects with narrower CI of each cohort.

Methods

After isolating the residuals during the median polish phase, the final phase is to estimate the magnitude of the cohort effects using the regression model of these residuals on the cohort category with the weight equal to the occupied proportion according to the number of death of HCC in each cohort.

Trends and age, period and cohort effects for marijuana use prevalence in the 1984-2015 US National Alcohol Surveys

BACKGROUND AND AIMS

Epidemiological trends show marijuana use in the United States to have increased in recent years. Previous research has identified cohort effects as contributing to the rising prevalence, in particular birth cohorts born after 1945. However, given recent policy efforts to regulate marijuana use at the state level, period effects could also play a contributory role. This study aimed to examine whether cohort or period effects play a larger role in explaining trends in marijuana use.

DESIGN

Using data from seven National Alcohol Surveys, we estimated age-period-cohort decomposition models for marijuana use, controlling for socio-demographic measures.

SETTING

United States.

PARTICIPANTS

US general population aged 18 and older from 1984 to 2015.

MEASUREMENTS

Any past-year marijuana use.

FINDINGS

Results indicated that period effects were the main driver of rising marijuana use prevalence. Models including indicators of medical and recreational marijuana policies did not find any significant positive impacts.

CONCLUSIONS

The steep rise in marijuana use in the United States since 2005 occurred across the population and is attributable to general period effects not linked specifically to the liberalization of marijuana policies in some states.

Commentary on Kerr et al. (2018): Marijuana, drug use, and mental health in the United States-a tale of two generations

Adults and adolescents in the United States are experiencing unprecedented increases in depression and suicide, yet while marijuana and other drug use are increasing among adults, they are decreasing among adolescents. The causes and, therefore the remedies, of this public health burden may be fundamentally different between the two generations.

Age-period-cohort analysis of trends in blood pressure and body mass index in children and adolescents in Hong Kong

BACKGROUND

The declining or fluctuating trend in blood pressure (BP) despite the rising trend in body mass index (BMI) during childhood and adolescence is unexplained. We decomposed trends in BP and BMI to identify the relevance of early-life and contemporaneous factors.

METHODS

We assessed the relative contribution of age, period and cohort to secular trends in BP in children and adolescents (9-18 years) from 1999 to 2014 and BMI (6-18 years) from 1996 to 2014 in Hong Kong, China.

RESULTS

After accounting for age, period effects contributed more than cohort effects to the overall fluctuating BP trend and the rising BMI trend observed in this Chinese population. For both sexes, BP fell from the start of period to a low point in 2003-2005 but then rose. BMI rose strongly across the period before levelling off in 2009-2010. Earlier cohorts (born in 1983-1984) had higher BP and BMI than later cohorts.

CONCLUSION

With globalisation and associated lifestyle changes, successive generations of children and adolescents in a recently developed Chinese setting had lower BP and BMI, but this fall was offset until recently by population-wide increase in BMI. School-based health promotion efforts could have partly mitigated the population-wide rise in child and adolescent BMI, while socioeconomic transition or other factors could be relevant to changes in BP between generations. Explaining these trends will help identify early-life factors that may contribute to a healthier start as well as contemporaneous factors that may protect against rising trends in adiposity.

The great sleep recession: changes in sleep duration among US adolescents, 1991-2012

BACKGROUND

Average nightly sleep times precipitously decline from childhood through adolescence. There is increasing concern that historical shifts also occur in overall adolescent sleep time.

METHODS

Data were drawn from Monitoring the Future, a yearly, nationally representative cross-sectional survey of adolescents in the United States from 1991 to 2012 (N = 272 077) representing birth cohorts from 1973 to 2000. Adolescents were asked how often they get ≥7 hours of sleep and how often they get less sleep than they should. Age-period-cohort models were estimated.

RESULTS

Adolescent sleep generally declined over 20 years; the largest change occurred between 1991-1995 and 1996-2000. Age-period-cohort analyses indicate adolescent sleep is best described across demographic subgroups by an age effect, with sleep decreasing across adolescence, and a period effect, indicating that sleep is consistently decreasing, especially in the late 1990s and early 2000s. There was also a cohort effect among some subgroups, including male subjects, white subjects, and those in urban areas, with the earliest cohorts obtaining more sleep. Girls were less likely to report getting ≥7 hours of sleep compared with boys, as were racial/ethnic minorities, students living in urban areas, and those of low socioeconomic status (SES). However, racial/ethnic minorities and adolescents of low SES were more likely to self-report adequate sleep, compared with white subjects and those of higher SES.

CONCLUSIONS

Declines in self-reported adolescent sleep across the last 20 years are concerning. Mismatch between perceptions of adequate sleep and actual reported sleep times for racial/ethnic minorities and adolescents of low SES are additionally concerning and suggest that health education and literacy approaches may be warranted.

Benefits gained, benefits lost: comparing baby boomers to other generations in a longitudinal cohort study of self-rated health

POLICY POINTS: Despite beliefs that baby boomers are healthier than previous generations, we found no evidence that the health of baby boomers is substantially different from that of the previous or succeeding cohorts. The effects of increased education, higher income, and lower smoking rates on improving self-rated health were nearly counterbalanced by the adverse effect of increasing body mass index (BMI). Assumptions that baby boomers will require less health care as they age because of better education, more prosperity, and less propensity to smoke may not be realized because of increases in obesity.

CONTEXT

Baby boomers are commonly believed to be healthier than the previous generation. Using self-rated health (SRH) as an indicator of health status, this study examines the effects of age, period, and birth cohort on the trajectory of health across 4 generations: World War II (born between 1935 and 1944), older baby boomers (born between 1945 and 1954), younger baby boomers (born between 1955 and 1964), and Generation X (born between 1965 and 1974).

METHODS

We analyzed Canada's longitudinal National Population Health Survey 1994-2010 (n = 8,570 at baseline), using multilevel growth models to estimate the age trajectory of SRH by cohort, accounting for period and incorporating the influence of changes in education, household income, smoking status, and body mass index (BMI) on SRH over time.

FINDINGS

SRH worsened with increasing age in all cohorts. Cohort differences in SRH were modest (p = 0.034), but there was a significant period effect (p = 0.002). We found marked cohort effects for increasing education, income, and BMI, and decreasing smoking from the youngest to the oldest cohorts, which were much reduced (education and smoking) or removed (income and BMI) once period was taken into account. At the population level, multivariable analysis showed the benefits of increasing education and income and declines in smoking on the trajectory of improving SRH were almost counterbalanced by the effects of increasing BMI (obesity).

CONCLUSIONS

We found no evidence to support the expectation that baby boomers will age more or less healthily than previous cohorts did. We also found that increasing BMI has likely undermined improvements in health that might have otherwise occurred, with possible implications for the need for health care. Period effects had a more profound effect than birth cohort effects. This suggests that interventions to improve health, such as reducing obesity, can be targeted to the entire, or a major portion of the, population and need not single out particular birth cohorts.

Breast and prostate cancer: an analysis of common epidemiological features in mortality trends in Spain

BACKGROUND

Breast cancer in women and prostate cancer are the first and second leading tumour respectively in terms of incidence world-wide. Our objective is to ascertain the similarities and differences between mortality trends in breast cancer among women and prostate cancer in Spain using age-period-cohort models, and analyse the correlation between incidence of breast and prostate cancer at cancer registries locally and world-wide.

METHODS

We analysed the independent effects of age, period of death and birth cohort on mortality rates for breast cancer in women and prostate cancer in Spain across the period 1952-2011. Segmented regression analyses were performed to detect and estimate changes in period and cohort curvatures. Correlation among age-adjusted incidence rates at 246 population cancer registries world-wide was analysed for the period 2003-2007.

RESULTS

The mortality trend displayed common characteristics in terms of the annual number of deaths due to these tumours, their adjusted mortality rates and the change points detected in the cohort and period effects. The trend in incidence was very different to that in mortality, due to early detection and progressive improvement in survival. Correlation between the incidence rates of both tumours recorded by registries around the world proved to be a generalised phenomenon.

CONCLUSIONS

This study shows that breast cancer mortality in women and prostate cancer mortality and their trends in Spain display visible similarities in terms of the number of deaths due to these tumours, their adjusted mortality rates and the changes experienced by mortality over time. The effects of advances in the diagnosis of both tumours correspond to a decline in mortality which becomes evident after a lag of approximately eight years. Correlation between breast and prostate cancer incidence rates is very high in Spain and at registries on all continents.

Taking time seriously: a call to action in mental health research

Sociological research on mental health focuses on a multitude of dynamic processes, including changes in psychological symptoms or the onset of a mental disorder, the course and outcome of mental health problems, and the associations of mental health with a wide variety of time-varying social risk and protective factors. I argue that scholars studying mental health have, thus far, only scratched the surface of the temporal dynamics upon which mental health and illness rest. Two broad research issues are reviewed to illustrate important temporal issues that have been neglected or understudied in mental health research: (1) specific dimensions of temporality, which focus on dynamic processes at the individual level, and (2) the age-period-cohort model, which focuses on mental health at the population level. Priority topics for future research that takes time seriously are recommended.

Brain cancer mortality in an agricultural and a metropolitan region of Rio de Janeiro, Brazil: a population-based, age-period-cohort study, 1996-2010

BACKGROUND

Individuals who live in rural areas are at greater risk for brain cancer, and pesticide exposure may contribute to this increased risk. The aims of this research were to analyze the mortality trends and to estimate the age-period-cohort effects on mortality rates from brain cancer in two regions in Rio de Janeiro, Brazil.

METHODS

This descriptive study examined brain cancer mortality patterns in individuals of both sexes, >19 years of age, who died between 1996 and 2010. They were residents of a rural (Serrana) or a non-rural (Metropolitan) area of Rio de Janeiro, Brazil. We estimated mortality trends using Joinpoint Regression analysis. Age-period-cohort models were estimated using Poisson regression analysis.

RESULTS

The estimated annual percentage change in mortality caused by brain cancer was 3.8% in the Serrana Region (95% confidence interval (CI): 0.8-5.6) and -0.2% (95% CI: -1.2-0.7) in the Metropolitan Region. The results indicated that the relative risk was higher in the rural region for the more recent birth cohorts (1954 and later). Compared with the reference birth cohort (1945-49, Serrana Region), the relative risk was four times higher for individuals born between 1985 and 1989.

CONCLUSIONS

The results of this study indicate that there is an increasing trend in brain cancer mortality rates in the rural Serrana Region in Brazil. A cohort effect occurred in the birth cohorts born in this rural area after 1954. At the ecological level, different environmental factors, especially the use of pesticides, may explain regional disparities in the mortality patterns from brain cancers.

Targeted vaccination programme successful in reducing acute hepatitis B in men having sex with men in Amsterdam, the Netherlands

BACKGROUND & AIMS

In the Netherlands, transmission of hepatitis B virus occurs mainly within behavioural high-risk groups, such as in men who have sex with men. Therefore, a vaccination programme has targeted these high-risk groups. This study evaluates the impact of the vaccination programme targeting Amsterdam's large population of men who have sex with men from 1998 through 2011.

METHODS

We used Amsterdam data from the national database of the vaccination programme for high-risk groups (January 1, 1998 to December 31, 2011). Programme and vaccination coverage were estimated with population statistics. Incidence of acute hepatitis B was analyzed with notification data from the Amsterdam Public Health Service (1992-2011). Mathematical modelling accounting for vaccination data and trends in sexual risk behaviour was used to explore the impact of the programme.

RESULTS

At the end of 2011, programme coverage was estimated at 41% and vaccination coverage from 30% to 38%. Most participants (67%) were recruited from the outpatient department for sexually transmitted infections and outreach locations such as saunas and gay bars. Incidence of acute hepatitis B dropped sharply after 2005. The mathematical model in which those who engage most in high-risk sex are vaccinated, best explained the decline in incidence.

CONCLUSIONS

Transmission of hepatitis B virus among Amsterdam's men who have sex with men has decreased, despite ongoing high-risk sexual behaviour. Vaccination programmes targeting men who have sex with men do not require full coverage; they may be effective when those who engage most in high-risk sex are reached.

Pleural cancer mortality in Spain: time-trends and updating of predictions up to 2020

BACKGROUND

A total of 2,514,346 metric tons (Mt) of asbestos were imported into Spain from 1906 until the ban on asbestos in 2002. Our objective was to study pleural cancer mortality trends as an indicator of mesothelioma mortality and update mortality predictions for the periods 2011-2015 and 2016-2020 in Spain.

METHODS

Log-linear Poisson models were fitted to study the effect of age, period of death and birth cohort (APC) on mortality trends. Change points in cohort- and period-effect curvatures were assessed using segmented regression. Fractional power-link APC models were used to predict mortality until 2020. In addition, an alternative model based on national asbestos consumption figures was also used to perform long-term predictions.

RESULTS

Pleural cancer deaths increased across the study period, rising from 491 in 1976-1980 to 1,249 in 2006-2010. Predictions for the five-year period 2016-2020 indicated a total of 1,319 pleural cancer deaths (264 deaths/year). Forecasts up to 2020 indicated that this increase would continue, though the age-adjusted rates showed a levelling-off in male mortality from 2001 to 2005, corresponding to the lower risk in post-1960 generations. Among women, rates were lower and the mortality trend was also different, indicating that occupational exposure was possibly the single factor having most influence on pleural cancer mortality.

CONCLUSION

The cancer mortality-related consequences of human exposure to asbestos are set to persist and remain in evidence until the last surviving members of the exposed cohorts have disappeared. It can thus be assumed that occupationally-related deaths due to pleural mesothelioma will continue to occur in Spain until at least 2040.

Birth cohort effects on abdominal obesity in the United States: the Silent Generation, Baby Boomers and Generation X

BACKGROUND

Abdominal obesity predicts a wide range of adverse health outcomes. Over the past several decades, prevalence of abdominal obesity has increased markedly in industrialized countries like the United States No previous analyses, however, have evaluated whether there are birth cohort effects for abdominal obesity. Estimating cohort effects is necessary to forecast future health trends and understand the past population-level trends.

METHODS

This analysis evaluated whether there were birth cohort effects for abdominal obesity for the Silent Generation (born 1925-1945), children of the Great Depression; Baby Boomers (born 1946-1964); or Generation X (born 1965-1980). Cohort effects for prevalence of abdominal obesity were estimated using the median polish method with data collected from the National Health and Nutrition Examination Survey (NHANES) between 1988 and 2008. Respondents were aged 20-74 years.

RESULTS

After taking into account age effects and ubiquitous secular changes, the Silent Generation and Generation X had higher cohort-specific prevalence of abdominal obesity than the Baby Boomers. Effects were more pronounced in women than men.

CONCLUSIONS

This work presents a novel finding: evidence that the birth cohorts of the post-World War II Baby Boom appeared to have uniquely low cohort effects on abdominal obesity. The growing prosperity of the post-World War II US may have exposed the baby-boom generation to lower levels of psychosocial and socioeconomic stress than the previous or subsequent generations. By identifying factors associated with the Baby Boomers' low cohort-specific sensitivity to the obesogenic environment, the obesity prevention community can identify early-life factors that can protect future generations from excess weight gain.

Assessing the effect of a guideline change on drug use prevalence by including the birth cohort dimension: the case of benzodiazepines

PURPOSE

The aim of this study was to investigate whether including the birth cohort dimension in time series analysis leads to a more accurate estimation of the (long-term) effect of a guideline change on the trend of benzodiazepine use.

METHODS

We calculated age-specific (20-84 years) and sex-specific prevalence of benzodiazepine use per 1000 population per quarter year (1998 to 2008) using a prescription database set in the Netherlands. We studied the prevalence over time by age group and within birth cohorts through interrupted time series analyses to estimate the effect of the guideline change in 2001.

RESULTS

From 1998 to 2008, the overall age-standardized prevalence of benzodiazepine use per 1000 population declined from ~54 for men and ~107 for women to ~45 for men and ~85 for women. The relative change increased significantly after 2001 for both sexes and for the majority of age groups. Within birth cohorts, the prevalence increased with age until the year 2001 and leveled thereafter. The age-period approach overall had worse model fit indicators than the within-cohort approach and predicted larger long-term effects than the within-cohort approach. The age-period projection estimated 36% decline in benzodiazepine use relative to 2008, whereas the birth-cohort projection estimated 8% decline.

CONCLUSION

Explicitly following birth cohort trajectories led to models with better fit; the conventional approach estimated a stronger long-term guideline effect. This has important implications for professional practice.

An age-period-cohort approach to analyzing trends in suicide in Quebec between 1950 and 2009

OBJECTIVE

Suicide rates in Quebec over the second half of the 20th century show a wide range of variation depending on age and time period. However, few studies have verified the presence of a cohort effect affecting trends in Quebec suicide rates. This study is designed to evaluate the potential effects of age, period and cohort (APC) on trends in suicide between 1950 and 2009 in Quebec.

METHOD

For these APC analyses, we used a multiphase approach combining a graphical inspection followed by an analysis that isolates the cohort effect from age and period effects (linear regression of the residuals from a median polish of the rates).

RESULTS

The graphical inspection of trends in rates points to combined effects of age, period and cohort among both men and women. However, the median polish analysis attributes primary importance to period effects, followed by age effects, but also shows weak cohort effects that are significant only among men born between 1950 and 1979.

CONCLUSION

The variation in Quebec suicide rates appears to be primarily a reflection of period, age and, to a lesser degree, birth cohort. Thus, in addition to sex, selection of risk groups should be based more on age and time period than on birth cohort.

An age-period-cohort approach to analyzing trends in suicide in Quebec between 1950 and 2009

OBJECTIVE

Suicide rates in Quebec over the second half of the 20th century show a wide range of variation depending on age and time period. However, few studies have verified the presence of a cohort effect affecting trends in Quebec suicide rates. This study is designed to evaluate the potential effects of age, period and cohort (APC) on trends in suicide between 1950 and 2009 in Quebec.

METHOD

For these APC analyses, we used a multiphase approach combining a graphical inspection followed by an analysis that isolates the cohort effect from age and period effects (linear regression of the residuals from a median polish of the rates).

RESULTS

The graphical inspection of trends in rates points to combined effects of age, period and cohort among both men and women. However, the median polish analysis attributes primary importance to period effects, followed by age effects, but also shows weak cohort effects that are significant only among men born between 1950 and 1979.

CONCLUSION

The variation in Quebec suicide rates appears to be primarily a reflection of period, age and, to a lesser degree, birth cohort. Thus, in addition to sex, selection of risk groups should be based more on age and time period than on birth cohort.

Depression and the sense of control: aging vectors, trajectories, and trends

Adulthood trajectories of outcomes such as depression and the sense of control measure aspects of the human condition that Americans may view as objects of change. Social science should provide information on that progress, or its absence. Whether these trajectories change their shape, and how and why if they do, is important theoretically too. A range of birth cohorts coexist in time, place, and social relationship. Each cohort, as it goes through adulthood, follows in aggregate a path left by older ones, reshaping that path as it goes. The shapes of the trajectories, and the trends reshaping them, represent two inseparable aspects of the same phenomenon. This report describes methods for mapping aging trajectories and intercohort trends, using linear latent-growth models of relatively brief follow-up data (six years in the examples). The author reviews shared research ideals that led to the model: put theory into modeling, go where the data lead, use what you have, go beyond where you have been, and risk being precisely wrong.

Educational Differences in U.S. Adult Mortality: A Cohort Perspective

We use hierarchical cross-classified random-effects models to simultaneously measure age, period, and cohort patterns of mortality risk between 1986 and 2006 for non-Hispanic white and non-Hispanic black men and women with less than a high school education, a high school education, and more than a high school education. We examine all-cause mortality risk and mortality risk from heart disease, lung cancer, and unpreventable cancers. Findings reveal that temporal reductions in black and white men's and women's mortality rates were driven entirely by cohort changes in mortality. Findings also demonstrate that disparate cohort effects between education groups widened the education gap in all-cause mortality risk and mortality risk from heart disease and lung cancer across this time period. Educational disparities in mortality risk from unpreventable cancers, however, did not change. This research uncovers widening educational differences in adult mortality and demonstrates that a cohort perspective provides valuable insights for understanding recent temporal changes in U.S. mortality risk.

Uncrossing the U.S black-white mortality crossover: the role of cohort forces in life course mortality risk

In this article, I examine the black-white crossover in U.S. adult all-cause mortality, emphasizing how cohort effects condition age-specific estimates of mortality risk. I employ hierarchical age-period-cohort methods on the National Health Interview Survey-Linked Mortality Files between 1986 and 2006 to show that the black-white mortality crossover can be uncrossed by factoring out period and cohort effects of mortality risk. That is, when controlling for variations in cohort and period patterns of U.S. adult mortality, the estimated age effects of non-Hispanic black and non-Hispanic white U.S. adult mortality risk do not cross at any age. This is the case for both men and women. Further, results show that nearly all the recent temporal change in U.S. adult mortality risk was cohort driven. The findings support the contention that the non-Hispanic black and non-Hispanic white U.S. adult populations experienced disparate cohort patterns of mortality risk and that these different experiences are driving the convergence and crossover of mortality risk at older ages.

Trends in breast cancer incidence in Hong Kong between 1973 and 1999: an age-period-cohort analysis

Hong Kong has the highest breast cancer incidence in Asia and studying secular changes in its rates may lead to hypotheses regarding disease aetiology and also predictions of future trends for China. We examined statistics from the Hong Kong Cancer Registry based on 26 566 cases of invasive breast cancer from 1973 to 1999. The trends in breast cancer incidence were studied using log-linear longitudinal models. We further analysed the independent effects of chronological age, time period and birth cohort on incidence trends using age-period-cohort modelling. The average annual per cent change of the age-standardised incidence was 3.6% during 1973-1999. Age-period-cohort modelling indicated the incidence development was predominantly a cohort effect, where the rise in relative risk was seemingly linear in successive birth cohorts, showing a 2-3-fold difference when comparing women born in the 1960's with those born around 1900. Our results suggest that direct and indirect consequences of westernisation may have been responsible for most of the observed increase in breast cancer incidence. As China moves towards a more westernised way of life, we can expect an emerging epidemic of breast cancer as Hong Kong's experience has demonstrated.