Showing 6 results for Period
M Moradi Lakeh, M Montazer, M Moradi, Smh Mahmoodi, Sap Alemzadeh Bahreini, S Askari,
Volume 5, Issue 3 (12-2009)
Abstract
Background & objectives: The trend of stunting indicates of long term health status and the efficacy of different health interventions for chronic malnutrition in children. The objective of this study was to investigate the trends of stunting prevalence in preschool children living in rural area of Robat-Karim.
Methods: The method of Age-Period-Cohort analysis was utilized. Existing height data of all children whom registered in health houses of Robat-Karim health network were converted to Standard Deviation Scores (SDS) using Anthro2005 software The SDS≤ -2 for height-for-age was defined to be the moderate/severe forms of stunting. Age-Period-Cohort analysis was done with two graphical and statistical methods. The statistical method was based on logistic regression modeling in which stunting was assumed to be the dependent variable and age, birth cohort and time period were independent variables.
Results: Growth data of 970 (51.9%) boys and 898 (48.1%) girls were analyzed. The overall stunting prevalence was estimated 8.0%. This estimation by Logistic regression models (P<0.001) and graphical analyses were similar and showed that the prevalence of stunting has a decreasing trend in different birth cohorts and time periods. The prevalence of stunting was higher in the 2nd and 5th-6th years of life. The stunting prevalence was significantly higher in boys (9.3%) and non-Iranian children (9.5%) (P<0.001).
Conclusions: The prevalence of stunting appears to be decreasing in the investigated population. Appropriate interventions is thought to be essential for reducing stunting of 2nd and 5th-6th years of life, boys, and non-Iranian children.
Mr Aflatoonian, I Sharifi, A Nadim, B Aflatoonian,
Volume 9, Issue 4 (3-2014)
Abstract
Background & Objectives: Bam is one of the old CL centers and this study aimed to determine and compare the period prevalence among its population and housing units in two periods of 1990-92 and 2010-2012.
Methods: In this descriptive–analytical study, data were collected in the questionnaires through door-to-door visits environmental hygiene, and inquiring the history of the CL disease. A questionnaire was completed for each household, the data were analyzed using SPSS software and t- and X2 tests. P<0.05 was considered significant.
Results: The prevalence rates in the periods 1998-1999 and 2010-2012 were 10.3% and 2.1%, in the study population and 33.6% and 5.5% in the residential units in the period of the last 3 years, respectively with a very significant difference (P<0.0001). The environmental hygiene of the houses in terms of vector breeding was significantly lower in the period 1990-1992 than 2010-2012 (P<0.0001). The mean score of environmental hygiene was 11.5 and 16.6 out of 20 during the two periods, respectively.
Conclusion: According to the results of this study, urban CL is extremely reflective of the environmental changes and probably the best preventive measure is to improve the environmental hygienic conditions in and around the households. Public participation and commitment of the health authorities in this regard could be an important measure for planning preventive programs.
A Motevalian, R Sahebi, A Rahimi Movaghar , M Yunesian,
Volume 11, Issue 2 (9-2015)
Abstract
Background & Objectives: The aim of the study was to determine age, period, and cohort effects on trend of alcohol and drug use in the students of Tehran University of Medical Sciences from 2006 to 2009.
Methods: Between 2006 and 2009, the students of Tehran University of Medical Sciences were surveyed annually using a structured self-administered and anonymous questionnaire. Intrinsic estimator, which is a new method for resolving linear dependency between age, period, and cohort in linear regression models, was used for data analysis.
Results: In the present study, in the descriptive method, the prevalence of alcohol consumption increased in males and females with an increase in age. The prevalence of illicit drug use was higher in 2007 in comparison with other periods for males and females. In the analytical method (intrinsic estimator), there were no age, period and cohort effects for alcohol and drug use for females. For males, the age effect exhibited an increasing-decreasing-increasing trend and period and cohort effects showed a decreasing trend for alcohol use. As for drug use, the age effect exhibited gradual increases. The period effect displayed an increasing-decreasing trend and the cohort effect exhibited an increasing-decreasing-increasing trend.
Conclusion: The IE method showed no age, period and cohort effects for alcohol and drug use in females. The prevalence of drug and alcohol use increased with an increase in age in males. The high prevalence of drug use could be due to easy accessibility and low price of drugs.
R Sahebi, Sa Motevalian, L Sahebi, H Sharifi,
Volume 13, Issue 2 (9-2017)
Abstract
Background and Objectives: The aim of this study was to compare the intrinsic estimator method and the age, period and cohort accounting model used for identifying age, period, and cohort trends in incidence, prevalence, and mortality rates.
Methods: The data of 2 studies " Age, Period, and Cohort Effects on Alcohol and Drug use Among Students of Tehran University of Medical Sciences from 2006 to 2009" and "The Role of Age, Period, and Cohort Effects on Smoking among the Students of Tehran University of Medical Science "were used. First the age, period and cohort accounting model and then The IE method are explained, their advantages and disadvantages are discussed, and their results are compared.
Results: Both methods showed an increasing, decreasing, and increasing trend for age, cohort, and cohort effect for the prevalence of smoking. IE could predict a preventing effect for an early age factor for smoking. In the descriptive model, a decreasing trend was seen from old cohorts to younger cohorts in nearly all age groups. However, the IE method did not show any cohort effects for alcohol consumption in female studnets.
Conclusion: Currently, the IE method is the best method for solving linear dependence between three variables of age, birth cohort, and period in this type of studies. However, researchers should use it with caution because it has many pitfalls.
S Ebrahimi Kebria , Ss Hashemi Nazari, Y Mdehrabi, B Nazparvar , A Shojaei, Sd Mirtorabi,
Volume 15, Issue 1 (5-2019)
Abstract
Background and Objectives: Suicide is one of the psychosocial problems in Lorestan Province due to its socio-cultural and economic structure. The aim of this study was to investigate the effect of age group, time period, and birth cohort on the suicide incidence in Lorestan Province during the 2006-2015.
Methods: In this study, to overcome the identifiability problem, the Carstensen approach and natural cubic smoothing character were used in age-period-cohort models (APC). Cohort effect was calculated as the relative rate from the 1984 reference cohort for men and 1987 cohort for women. The period effect in both sexes constrained to be relative to 1390 and to be 0 on average with 0 slope. The best APC model for both sexes was the models with "AC-P" parameter, 7 knots, and natural splines for men and B splines for women. All analyses were performed using the R software with Epi package.
Results: The age effect showed that the highest suicide incidence rate was seen in the elderly. Two strong birth cohort effects were observed, one increasing one in the 1980 cohort and one decreasing one in 1991 cohort. The most significant period effect was seen in men in 2011.
Conclusion: The effects of 1991 and 1980 birth cohorts could be due to the consequences of imposed war in Iran. The three economic phenomena, oil price change, increased divorce rate, and increased unemployment rate can be effective in the emergence of the period effect in year 2011.
Rasoul Gholamiveis, Fatemeh Heydarpour, Mehdi Moradinazar,
Volume 21, Issue 4 (3-2026)
Abstract
Background and Objectives: Prostate cancer is one of the most common cancers among Iranian men and has shown a marked increase in both incidence and mortality over recent decades. This study aimed to analyze temporal trends in prostate cancer incidence and mortality in Iran using an Age–Period–Cohort (APC) analytical framework.
Methods: Data were extracted from the Global Burden of Disease Study 2021 for Iranian males aged 45 years and older during 1992–2021. Data were stratified into eight 5-year age groups and six 5-year time periods. APC analysis was conducted using the second-order difference method, and Joinpoint regression was employed to assess temporal trends in risk factors.
Results: In 2021, the age-standardized incidence rate reached 30.05 per 100,000 population, and the mortality rate reached 10.66 per 100,000 representing increases of 105.96% and 14.99%, respectively, compared to 1992. Age effects were positively associated with both incidence and mortality. The period effect peaked during 2002–2006. Cohort analysis revealed that younger birth cohorts exhibited a slower acceleration in incidence rates. Among risk factors, the disease burden attributable to smoking increased by 17.1%, while the protective effects of low calcium intake and low milk consumption diminished over time.
Conclusion: Rising incidence and mortality are shaped by age, period, and cohort effects. The relative decline in younger cohorts underscores the need for targeted prostate cancer screening programs. Strengthening public health education policies and improving access to diagnostic services can reduce the disease burden.
