Cohort Effects in the Prevalence of Caries in Child Populations in Tanzania

1989 ◽  
Vol 68 (12) ◽  
pp. 1777-1780 ◽  
Author(s):  
J.E. Frencken ◽  
M.A. Van't Hof ◽  
G.-J. Truin ◽  
B.S. Lembariti ◽  
K.G. König
Keyword(s):  
Longitudinal Study ◽  
Oral Health ◽  
Longitudinal Studies ◽  
Developing Country ◽  
Cohort Analysis ◽  
Cohort Effect ◽  
Cohort Effects ◽  
External Information ◽  
Upward Trend ◽  
Period Effects

In 1984, a four-year mixed-longitudinal study of oral health was begun in Morogoro Town and Morogoro District, Tanzania. Its main goal was to detect a possible upward trend in prevalence of caries in child cohorts in this developing country. The sample consisted of 722 seven-to nine-year-olds in 1984, 833 seven- to 11-year-olds in 1986, and 989 seven- to 13-year-olds in 1988. Mixed-longitudinal studies provide the opportunity for application of the Age-Period-Cohort analysis. On the basis of external information, either age and/or cohort and/or period effects can thus be isolated. Apart from significant age and period effects, a cohort effect was found, indicating that the prevalence of caries has decreased in these child populations between 1984 and 1988.

scholarly journals Age period cohort analysis of chewing ability in Korea from 2007 to 2018

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nam-Hee Kim ◽  
Ichiro Kawachi
Keyword(s):  
Cohort Analysis ◽  
Cohort Effect ◽  
Cohort Effects ◽  
Period Effect ◽  
The Past ◽  
Health And Nutrition ◽  
Period Effects ◽  
Chewing Ability ◽  
Main Variable ◽  
Observation Period

AbstractThere have been marked improvements in oral health in Korea during the past 10 years, including chewing ability. We sought to disentangle age, period, and cohort effects in chewing ability between 2007 and 2018. We analyzed data from the Korea National Health and Nutrition Examination Survey. The main variable was chewing difficulty, which was assessed among participants aged 20 years and older. APC analysis revealed three trends in chewing difficulty: (1) there was an increase in chewing difficulty starting at around 60 years of age (age effect), (2) there was a steady decrease in chewing difficulty during the observation period (period effect), and (3) chewing ability improved with each successive generation born after 1951 (cohort effect). Regarding recent improvements in chewing ability, cohort effects were somewhat more important than period effects.

scholarly journals Getting a Grip on Secular Changes: Age-Period-Cohort modeling of grip strength in the English Longitudinal Study of Ageing

2021 ◽  
Author(s):  
Patrick O’Keefe ◽  
Frank D Mann ◽  
Sean Clouston ◽  
Stacey Voll ◽  
Graciela Muniz-Terrera ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Grip Strength ◽  
Careful Analysis ◽  
Cohort Effects ◽  
Functional Capabilities ◽  
Aging Period ◽  
Biomarkers Of Aging ◽  
Period Effects ◽  
Effects Of Aging ◽  
English Longitudinal Study

Abstract Background Grip strength is a popular and valuable measure in studies of physical functional capabilities in old-age. The influence of historical trends and differential period-specific exposures can complicate the interpretation of biomarkers of aging and health and requires careful analysis and interpretation of ageing, birth cohort, and period effects. The current study evaluates the effects of aging, period, and cohort on grip strength in a population of adults and older adults. Methods We use >27,000 observations for individuals ≥50 years of age, born in approximately 1910-1960, from the English Longitudinal Study of Aging to examine a variety of multilevel and cross-classified modeling approaches to evaluate age, period, and cohort effects. Our results extended Hierarchical Age Period Cohort modeling and compared our results with a set of nine sub-models with explicit assumptions to determine the most reliable modeling approach. Results Findings suggest grip strength is primarily related to age, with minimal evidence of either period and/or cohort effects. Each year’s increase in a person’s age was associated with a 0.40-kilogram decrease in grip strength, though this decline differs by gender. Conclusions We conclude that as a population ages, grip strength declines at a systematic and predictable rate equal to -0.40-kilograms per year (approximately -.50-kg for men and -.30-kg for women) in residents of England aged 50 and older. Age-effects were predominant and most consistent across methodologies. While there was some evidence for cohort effects, such effects were minimal and therefore indicative that grip strength is a consistent physiological biomarker of aging.

Cohort Trends in Youth Suicide in Australia 1964–1997

2000 ◽  
Vol 34 (3) ◽  
pp. 408-412
Author(s):  
Michael Lynskey ◽  
Louisa Degenhardt ◽  
Wayne Hall
Keyword(s):  
Cohort Analysis ◽  
Cohort Effect ◽  
Psychosocial Problems ◽  
Suicide Mortality ◽  
Youth Suicide ◽  
Birth Cohorts ◽  
Period Effects ◽  
Gender And Age ◽  
Males And Females ◽  
Australian Bureau Of Statistics

Objective: This paper examines trends in the rate of suicide among young Australians aged 15–24 years from 1964 to 1997 and presents an age-period-cohort analysis of these trends. Method: Study design consisted of an age-period-cohort analysis of suicide mortality in Australian youth aged between 15 and 24 for the years 1964–1997 inclusive. Data sources were Australian Bureau of Statistics data on: numbers of deaths due to suicide by gender and age at death; and population at risk in each of eight birth cohorts (1940–1944, 1945–1949, 1950–1954, 1955–1959, 1960–1964, 1965–1969, 1970–1974, and 1975–1979). Main outcome measures were population rates of deaths among males and females in each birth cohort attributed to suicide in each year 1964–1997. Results: The rate of suicide deaths among Australian males aged 15–24 years increased from 8.7 per 100 000 in 1964 to 30.9 per 100 000 in 1997, with the rate among females changing little over the period, from 5.2 per 100 000 in 1964 to 7.1 per 100 000 in 1997. While the rate of deaths attributed to suicide increased over the birth cohorts, analyses revealed that these increases were largely due to period effects, with suicide twice as likely among those aged 15–24 years in 1985–1997 than between 1964 and 1969. Conclusions: The rate of youth suicide in Australia has increased since 1964, particularly among males. This increase can largely be attributed to period effects rather than to a cohort effect and has been paralleled by an increased rate of youth suicides internationally and by an increase in other psychosocial problems including psychiatric illness, criminal offending and substance use disorders.

scholarly journals Sex-specific intergenerational trends in morbidity burden and multimorbidity status in Hong Kong community: an age-period-cohort analysis of repeated population surveys

BMJ Open ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. e023927 ◽  
Author(s):  
Francisco T T Lai ◽  
Bruce Guthrie ◽  
Samuel Y S Wong ◽  
Benjamin H K Yip ◽  
Gary K K Chung ◽  
...  
Keyword(s):  
Hong Kong ◽  
Relative Risk ◽  
Lower Risk ◽  
Cohort Analysis ◽  
Cohort Effect ◽  
Cohort Effects ◽  
Cross Sectional ◽  
Obesity Epidemic ◽  
Morbidity Burden ◽  
Drastic Increase

ObjectivesPrevalence of multimorbidity has been increasing worldwide. While population ageing undoubtedly contributes, secular trends have seldom been decomposed into age, period and cohort effects to investigate intergenerational differences. This study examines the birth cohort effect on morbidity burden and multimorbidity in Hong Kong community.DesignSex-specific age-period-cohort analysis with repeated cross-sectional surveys.SettingA territory-wide population survey database.Participants69 636 adults aged 35 or above who participated in the surveys in 1999, 2001, 2005 or 2008.Main outcome measuresMorbidity burden was operationalised as number of chronic conditions from a list of 14, while multimorbidity was defined as a dichotomous status of whether participants had two or more conditions.ResultsFor both sexes, there was an upward inflection (positive change) of risk of increased morbidity burden starting from cohort 1955–1959. For men born after 1945–1954, there was a trend of lower risk (relative risk=0.63, 95% CI 0.50 to 0.80 for 1950–1954 vs 1935–1939) which continued through subsequent cohorts but with no further declines. In women, there had been a gradual increase of risk, although only significant for cohort 1970–1974 (relative risk=1.90, 95% CI 1.08 to 1.34 vs 1935–1939). Similar results were found for dichotomous multimorbidity status.ConclusionsThe trend of lower risk starting from men born in 1945–1954 may be due to a persistent decline in smoking rates since the 1980s. On the other hand, the childhood obesity epidemic starting from the late 1950s coincided with the observed upward inflection of risk for both sexes, that is, notably more drastic increase of risk in women and the levelling-off of the decline of risk in men. These findings highlight that the cohort effects on morbidity burden and multimorbidity may be sex-specific and contextual. By examining such effects in different world populations, localised sex-specific and generation-specific risk factors can be identified to inform policy-making.

scholarly journals Age-period-cohort effects in half a century of motor vehicle theft in the United States

Crime Science ◽  
2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony Dixon ◽  
Graham Farrell
Keyword(s):  
United States ◽  
Motor Vehicle ◽  
Cohort Effect ◽  
The United States ◽  
Cohort Effects ◽  
Period Effect ◽  
Motor Vehicle Theft ◽  
Birth Cohorts ◽  
Vehicle Theft ◽  
Period Effects

AbstractAdopting and refining O’Brien’s S-constraint approach, we estimate age-period-cohort effects for motor vehicle theft offences in the United States for over half a century from 1960. Taking the well-established late-teen peak offending age as given, we find period effects reducing theft in the 1970 s, and period, but particularly cohort effects, reducing crime from the 1990s onwards. We interpret these effects as consistent with variation in the prevailing level of crime opportunities, particularly the ease with which vehicles could be stolen. We interpret the post-1990s cohort effect as triggered by a period effect that operated differentially by age: improved vehicle security reduced juvenile offending dramatically, to the extent that cohorts experienced reduced offending across the life-course. This suggests the prevailing level of crime opportunities in juvenile years is an important determinant of rates of onset and continuance in offending in birth cohorts. We outline additional implications for research and practice.

scholarly journals Party Identification in an Encapsulated Party System: The Case of Postauthoritarian Chile

2018 ◽  
Vol 10 (1) ◽  
pp. 29-68 ◽  
Author(s):  
Matías A. Bargsted ◽  
Luis Maldonado
Keyword(s):  
Political Parties ◽  
Party System ◽  
Party Identification ◽  
Cohort Analysis ◽  
Cohort Effects ◽  
Period Effects ◽  
Negative Effect ◽  
Large Period ◽  
Partisan Identification ◽  
Positive Effect

Since the return of democracy, party identification has been declining sharply among the Chilean public. We seek to understand this process by applying an age-period-cohort analysis to survey data from 1994 to 2014. In light of the elite-driven and socially uprooted character, or what we call the encapsulated nature, of the Chilean party system, we hypothesize that cumulative electoral experience has had a negative effect on party identification and not the positive effect that Converse's (1969) social-learning model would predict. Our findings support these expectations but also reveal large period effects that have shrunk the overall level of partisan identification and significant cohort effects whereby generations born after the 1950s have become less partisan. We also uncover important nuances that occur across the various mainstream political parties. We conclude that all three sources of social change are leading toward the extinction of mass partisanship from Chilean society.

scholarly journals Addressing the Younger Age at Onset in Breast Cancer Patients in Asia: An Age-Period-Cohort Analysis of Fifty Years of Quality Data from the International Agency for Research on Cancer

ISRN Oncology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Seyed Houssein Mousavi-Jarrrahi ◽  
Amir Kasaeian ◽  
Kamyar Mansori ◽  
Mehdi Ranjbaran ◽  
Mahmoud Khodadost ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Cohort Analysis ◽  
Age At Onset ◽  
Cohort Effect ◽  
Asian Population ◽  
Cohort Effects ◽  
International Agency ◽  
Breast Cancer Patients ◽  
Younger Age

Introduction. There is an established fact that Asian breast cancer patients are, on average, younger than their European counterparts. This study aimed to utilize the data from the Cancer Incidence in Five Continents I through XIII (published by the International Agency for Research on Cancer) to examine what contributes to the younger age at onset in the Asian population. Material and Methods. Data (number of breast cancer cases and corresponding population figures) for 29 registries in Europe and 9 registries in Asia for the period of 1953–2002 was accessioned and pooled to form two distinct populations, Asia and Europe. The age specific rates were defined and analyzed cross-sectionally (period wise) and longitudinally (cohort wise). The magnitude and the pattern of age specific rates were analyzed using the age-period-cohort analysis. The constrained generalized linear model with a priority assumption of cohort effect as contributing factor to changing rates was used to analyze the data. Result. During the last 50 years, the rate of breast cancer increased for both populations with an estimated annual percent change of 1.03% (with 95% CI of 1.029, 1.031) for Asia and 1.016% (95% CI of 1.015, 1.017) for Europe. There were stronger cohort effects in the magnitude of rates among the Asian population compared to the European population. The cohort effects, expressed as the rate ratio with cohort born in 1970 as reference, ranged from 0.06 (95% CI 0.05, 0.08) to 0.94 (95% CI 0.93, 0.96) for Asians and 0.35 (95% CI 0.33, 0.36) to 1.03 (95% CI 1.02, 1.04) for Europeans. The estimated longitudinal age specific rates (adjusted for cohort and period effects) showed similar patterns between the two populations. Conclusion. It was concluded that a strong cohort effect contributes to the younger age at onset among Asian breast cancer patients.

scholarly journals Mobile Phone Use and Brain Tumor: An Age-Period-Cohort Analysis of Brain Tumor Rates in the Nordic Population

2016 ◽  
Vol 1 (1) ◽  
pp. 19-29
Author(s):  
Mehdi Ranjbaran ◽  
Mahmood Khodadost ◽  
Kamyar Mansori ◽  
Seyed Houssien Mousavi Jarrahi ◽  
Erfan Ayubi ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Mobile Phone ◽  
Cohort Analysis ◽  
Latency Period ◽  
Cohort Effect ◽  
Positive Association ◽  
Incidence Rates ◽  
Cohort Effects ◽  
Mobile Phone Use ◽  
Study Results

Background: The association of the mobile phone use and risk of brain tumor remains controversial among radiation epidemiologists. Methods: We hypothesized if an association between brain tumor and mobile phone use exists, this association will be manifested as a cohort effect (as a proxy of association between mobile phone use and brain tumor) in the incidence rates of brain tumor during the period of 1990 to 2009. We used age-period-cohort methodology (generalized log-linear model) and compared the distribution of cohort effects in the observed rates of brain tumor from 1990 to 2009 to the cohort effects from rates driven based on epidemiological study results that reported a positive association between brain tumor and mobile phone use in the Nordic population. Three latency period of 1-4 years with odds ratio (OR) of 1.2, latency period of 5-9 years with OR of 1.3, and latency period of more than 10 years with OR of 2.7 were used to estimate expected rates. Results: The distribution of cohort effects between observed and expected rates were more similar among the males compared with females. A shorter latency was more con¬sistent to observed rates. Conclusion: Our study supports a possible a weak association between mobile phone use and brain tumor; further fueling the controversies in association.

Forecasting U.K. Population Mortality Allowing for Age, Period and Cohort Effects

2009 ◽  
Vol 15 (S1) ◽  
pp. 73-89 ◽  
Author(s):  
D. O. Forfar
Keyword(s):  
Cohort Effect ◽  
Cohort Effects ◽  
Mortality Data ◽  
Period Effect ◽  
Female Mortality ◽  
Mortality Experience ◽  
National Statistics ◽  
Period Effects ◽  
Males And Females ◽  
Population Mortality

ABSTRACTThe mortality data (registered deaths and population size) over the years 1961–2007 for the population of England and Wales and for Scotland were obtained from the Office for National Statistics (ONS) and from the Scottish Registrar General. This paper addresses the following questions:(i) Is there statistical evidence for a cohort effect (i.e. a generation effect separate from the period effect) being present in the data?(ii) Do both males and females exhibit similar cohort (generation) effects?(iii) Are period effects (i.e. the improvement in mortality with time) more significant than cohort effects?(iv) How should one allow, in forecasts of population mortality, for age, period and cohort effects?(v) Is it sensible to combine male and female mortality experience to determine the period effect and the cohort effect?(vi) How do the forecasts for the expectation of life at birth, using the Extended-Lee–Carter-Combined (ELCC) model (described in the paper) differ from the (2008 based) Office of National Statistics (ONS) forecasts of the expectation of life at birth?

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