scholarly journals Time to first birth and its Predictors among reproductive-age women in Ethiopia: inverse Weibull gamma shared frailty model

2020 ◽  
Author(s):  
Reta Dewau ◽  
Fantahun Ayenew Mekonnen ◽  
Wullo Sisay Seretew
Keyword(s):  
Frailty Model ◽  
Education Level ◽  
Reproductive Age ◽  
Early Age ◽  
Age Difference ◽  
Age At First Birth ◽  
First Birth ◽  
Reproductive Age Women ◽  
Shared Frailty Model ◽  
Shared Frailty

Abstract Background: High maternal and child death with high fertility rate have been reported in Ethiopia. Extreme age at first birth is linked with both maternal and child morbidity and mortality. However, literatures showed there were limited studies on the timing of the first birth and its predictors in the area so far. Therefore, determining the time to first birth and its predictors will help to design strategies to improve maternal and child survival. Methods: A community-based cross-sectional study was conducted among reproductive-age women in Ethiopia using the Ethiopian demographic health survey (EDHS), 2016 data. Stratified two-stage cluster sampling technique was used for sampling. The Kaplan-Meier (KM) method was used to estimate time to first birth. Inverse Weibull gamma shared frailty model applied to model the data at 95% confidence interval (CI), adjusted hazard ratio (AHR) and median hazard ratio (MHR) were reported as effect size. Proportional hazard assumption checked using Schoenfeld residual test. Information Criteria were applied to select a parsimonious model. Stratified analysis performed for the interaction terms and statistical significance was declared at p value<0.05. Results: The overall median age at first birth was found to be 20 years (IQR, 16-24 years). The independent predictors of time to first birth were: married 15-17 years (AHR=2.33,95% CI:2.08-2.63),secondary education level (AHR=0.84,95% CI:0.78-0.96), higher education level (AHR=0.75, 95% CI:0.65-0.85), intercourse before 15 years in the married stratum (AHR=23.81, 95% CI:22.22-25.64), intercourse 15-17 years in married stratum (AHR=5.56, 95% CI:5.26-5.88),spousal age difference (AHR=1.11, 95% CI:1.05-1.16),and use of contraceptives (AHR=0.91, 95% CI: 0.86-0.97). The median increase in the hazard of early childbirth in a cluster with higher early childbirth is 16% (MHR=1.16, 95% CI: 1.13-1.20) than low risk clusters adjusting for other factors.Conclusion:In this study, first birth was found to be at an early age. Early age at first marriage, at first sexual intercourse and their interaction, high spousal age difference, being Muslim were found to increase early motherhood. Conversely, living in the most urban region, secondary and higher women education were identified to delay the first birth. Investing on women education and protecting them from early marriage is required to optimize time to first birth. The contextual differences in time to first birth are an important finding which requires more study and interventions.

scholarly journals Time to first birth and its predictors among reproductive-age women in Ethiopia: inverse Weibull gamma shared frailty model

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Reta Dewau ◽  
Fantahun Ayenew Mekonnen ◽  
Wullo Sisay Seretew
Keyword(s):  
Frailty Model ◽  
Education Level ◽  
Reproductive Age ◽  
Early Age ◽  
Age Difference ◽  
Age At First Birth ◽  
First Birth ◽  
Reproductive Age Women ◽  
Shared Frailty Model ◽  
Shared Frailty

Abstract Background High maternal and child death with high fertility rate have been reported in Ethiopia. Extreme age at first birth is linked with both maternal and child morbidity and mortality. However, literatures showed there were limited studies on the timing of the first birth and its predictors in the area so far. Therefore, determining the time to first birth and its predictors will help to design strategies to improve maternal and child survival. Methods A community-based cross-sectional study was conducted among reproductive-age women in Ethiopia using the Ethiopian demographic health survey, 2016 data. Stratified two-stage cluster sampling technique was used for sampling. The Kaplan–Meier method was used to estimate time to first birth. Inverse Weibull gamma shared frailty model applied to model the data at 95% confidence interval (CI), adjusted hazard ratio (AHR) and median hazard ratio (MHR) were reported as effect size. Proportional hazard assumption checked using Schoenfeld residual test. Information Criteria were applied to select a parsimonious model. Stratified analysis performed for the interaction terms and statistical significance was declared at p value < 0.05. Results The overall median age at first birth was found to be 20 years (IQR, 16–24 years). The independent predictors of time to first birth were: married 15–17 years (AHR = 2.33, 95% CI 2.08–2.63), secondary education level (AHR = 0.84, 95% CI 0.78–0.96), higher education level (AHR = 0.75, 95% CI 0.65–0.85), intercourse before 15 years in the married stratum (AHR = 23.81, 95% CI 22.22–25.64), intercourse 15–17 years in married stratum (AHR = 5.56, 95% CI 5.26–5.88), spousal age difference (AHR = 1.11, 95% CI 1.05–1.16),and use of contraceptives (AHR = 0.91, 95% CI 0.86–0.97). The median increase in the hazard of early childbirth in a cluster with higher early childbirth is 16% (MHR = 1.16, 95% CI 1.13–1.20) than low risk clusters adjusting for other factors. Conclusion In this study, first birth was found to be at an early age. Early age at first marriage, at first sexual intercourse and their interaction, high spousal age difference, being Muslim were found to increase early motherhood. Conversely, living in the most urban region, secondary and higher women education were identified to delay the first birth. Investing on women education and protecting them from early marriage is required to optimize time to first birth. The contextual differences in time to first birth are an important finding which requires more study and interventions.

scholarly journals Time to first birth and its Predictors among reproductive-age women in Ethiopia: inverse Weibull gamma shared frailty model

2020 ◽  
Author(s):  
Reta Dewau Yimer ◽  
Fantahun Ayenew Mekonnen ◽  
Wullo Sisay Seretew
Keyword(s):  
Frailty Model ◽  
Reproductive Age ◽  
Early Age ◽  
Age Difference ◽  
Age At First Birth ◽  
First Birth ◽  
Interaction Terms ◽  
Reproductive Age Women ◽  
Shared Frailty Model ◽  
Shared Frailty

Abstract Background: High maternal and child death with high fertility rate have been reported in Ethiopia. Extreme age at first birth is linked with both maternal and child morbidity and mortality. However, literatures showed there are limited studies on timing of first birth and its predictors in the area so far. Therefore, determining time to first birth and its predictors will help to design strategies to improve maternal and child survival. Methods: A survey-based study was conducted among reproductive-age women in Ethiopia using Ethiopian demographic health survey (EDHS), 2016 data. Stratified two-stage cluster sampling technique was used for sampling. The Kaplan-Meier (KM) method was used to estimate time to first birth. Inverse Weibull gamma shared frailty model applied to model the data at 95% confidence interval (CI), adjusted hazard ratio (AHR) and median hazard ratio (MHR) were reported as effect size. Proportional hazard assumption checked using Schoenfeld residual test. Information Criteria was applied to select parsimonious model. Stratified analysis performed for interaction terms and statistical significance declared at p value<0.05. Results: The overall median age at first birth found to be 20 years (IQR, 16-24years). The independent predictors of time to first birth were: marriage 15-17 years (AHR=2.33,95% CI:2.08-2.63),secondary education level (AHR=0.84,95% CI:0.78-0.96), higher education level (AHR=0.75, 95% CI:0.65-0.85), intercourse before 15 years in the married stratum (AHR=23.81, 95% CI:22.22-25.64), intercourse 15-17 years in married stratum (AHR=5.56, 95% CI:5.26-5.88),spousal age difference (AHR=1.11, 95% CI :1.05-1.16),and use of contraceptives (AHR=0.91, 95% CI [0.86-0.97]). The median increase in the hazard of early childbirth at a cluster with higher early childbirth is 16% (MHR=1.16, 95% CI [1.13-1.20]) than low risk clusters.Conclusion: In this study, first birth found to be at an early age. Early age at first marriage, at first sexual intercourse and their interaction terms, high spousal age difference, being Muslim were found to increase early motherhood. Conversely, living in most urban region, secondary and higher women education were identified to delay first birth. Investing on women education and protecting them from early marriage are required to optimize time to first birth. The contextual differences in time to first birth are a novel finding which requires more study and interventions.

scholarly journals Time to first antenatal care visit among pregnant women in Ethiopia: secondary analysis of EDHS 2016; application of AFT shared frailty models

2021 ◽  
Vol 79 (1) ◽  
Author(s):  
Kenaw Derebe Fentaw ◽  
Setegn Muche Fenta ◽  
Hailegebrael Birhan Biresaw ◽  
Solomon Sisay Mulugeta
Keyword(s):  
Antenatal Care ◽  
Pregnant Women ◽  
Frailty Model ◽  
Information Criterion ◽  
Education Level ◽  
Outcome Variable ◽  
Inverse Gaussian ◽  
Shared Frailty Model ◽  
The World ◽  
Shared Frailty

Abstract Background The survival of pregnant women is one of great interest of the world and especially to a developing country like Ethiopia which had the highest maternal mortality ratios in the world due to low utilization of maternal health services including antenatal care (ANC). Survival analysis is a statistical method for data analysis where the outcome variable of interest is the time to occurrence of an event. This study demonstrates the applications of the Accelerated Failure Time (AFT) model with gamma and inverse Gaussian frailty distributions to estimate the effect of different factors on time to first ANC visit of pregnant women in Ethiopia. Methods This study was conducted by using 2016 EDHS data about factors associated with the time to first ANC visit of pregnant women in Ethiopia. A total of 4328 women from nine regions and two city administrations whose age group between 15 and 49 years were included in the study AFT models with gamma and inverse Gaussian frailty distributions have been compared using Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) to select the best model. Results The factors residence, media exposure, wealth index, education level of women, education level of husband and husband occupation are found to be statistically significant (P-value < 0.05) for the survival time of time to first ANC visit of pregnant women in Ethiopia. Inverse Gaussian shared frailty model with Weibull as baseline distribution is found to be the best model for the time to first ANC visit of pregnant women in Ethiopia. The model also reflected there is strong evidence of the high degree of heterogeneity between regions of pregnant women for the time to first ANC visit. Conclusion The median time of the first ANC visit for pregnant women was 5 months. From different candidate models, Inverse Gaussian shared frailty model with Weibull baseline is an appropriate approach for analyzing time to first ANC visit of pregnant women data than without frailty model. It is essential that maternal and child health policies and strategies better target women’s development and design and implement interventions aimed at increasing the timely activation of prenatal care by pregnant women. The researchers also recommend using more powerful designs (such as cohorts) for the research to establish timeliness and reduce death.

Determinants of Time-to-Under-Five Mortality in Ethiopia

2018 ◽  
Vol 7 (1) ◽  
pp. 1-24
Author(s):  
Abebe Argaw Wogi ◽  
Shibru Temesgen Wakweya ◽  
Yohannes Yebabe Tesfay
Keyword(s):  
Economic Status ◽  
Frailty Model ◽  
Information Criterion ◽  
Demographic Variables ◽  
Age At First Birth ◽  
Under Five ◽  
Shared Frailty Model ◽  
Shared Frailty ◽  
Major Factors ◽  
Best Fit

This article describes how under-five mortality rate is one of the critical indicators of development of a country. This rate tells of children's access to basic health interventions such as vaccinations, medical treatment and adequate nutrition. This article proposes to identify the determinants of time to under-five mortality in Ethiopia based on the 2014 data taken from the Ethiopian Mini Demographic and Health Survey of women of the age group15-49 years. In this survival quantitative analysis, this article considers relevant socioeconomic, demographic variables and environmental factors. Various parameters shared among frailty models are employed to identify the determinants of Time-To-Under-Five Mortality of Ethiopia. The selection of the best-fit survival model is done by applying the Akaike information criterion (AIC). The AIC prevailed that the Weibull-gamma multivariable-shared frailty model is relatively the best-fit model. The estimation result of the Weibull-gamma multivariable-shared frailty model predicted that the major factors identified for under-five mortality in Ethiopia were mothers' educational level, mothers' age at first birth, place of residence, household size, sex of child born, preceding birth interval, economic status of family, place of delivery, marital status of family, and source of drinking water. The result implied that vast work is expected from governmental and non-governmental bodies to reduce the under-five mortality in the country by considering the identified factors.

Pregnancy and the Risk of Rheumatoid Arthritis in a Highly Predisposed North American Native Population

2012 ◽  
Vol 39 (12) ◽  
pp. 2253-2260 ◽  
Author(s):  
CHRISTINE A. PESCHKEN ◽  
DAVID B. ROBINSON ◽  
CAROL A. HITCHON ◽  
IRENE SMOLIK ◽  
DONNA HART ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
North American ◽  
Shared Epitope ◽  
Reproductive History ◽  
Early Age ◽  
Age At First Birth ◽  
Native Population ◽  
First Birth ◽  
Pregnancy Smoking ◽  
First Time

Objective.To examine reproductive history and rheumatoid arthritis (RA) risk in a highly predisposed population of North American Natives (NAN) with unique fertility characteristics.Methods.The effect of pregnancy on the risk of RA was examined by comparing women enrolled in 2 studies: a study of RA in NAN patients and their unaffected relatives; and NAN patients with RA and unrelated healthy NAN controls enrolled in a study of autoimmunity. All participants completed questionnaires detailing their reproductive history.Results.Patients with RA (n = 168) and controls (n = 400) were similar overall in age, education, shared epitope frequency, number of pregnancies, age at first pregnancy, smoking, and breastfeeding history. In multivariate analysis, for women who had ≥ 6 births the OR for developing RA was 0.43 (95% CI 0.21–0.87) compared with women who had 1–2 births (p = 0.046); for women who gave birth for the first time after age 20 the OR for developing RA was 0.33 (95% CI 0.16–0.66) compared with women whose first birth occurred at age ≤ 17 (p = 0.001). The highest risk of developing RA was in the first postpartum year (OR 3.8; 95% CI 1.45–9.93) compared with subsequent years (p = 0.004).Conclusion.In this unique population, greater parity significantly reduced the odds of RA; an early age at first birth increased the odds, and the postpartum period was confirmed as high risk for RA onset. The protective effect of repeated exposure to the ameliorating hormonal and immunological changes of pregnancy may counterbalance the effect of early exposure to the postpartum reversal of these changes.

scholarly journals Training Load and Baseline Characteristics Associated With New Injury/Pain Within an Endurance Sporting Population: A Prospective Study

2019 ◽  
Vol 14 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Richard Johnston ◽  
Roisin Cahalan ◽  
Laura Bonnett ◽  
Matthew Maguire ◽  
Alan Nevill ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Frailty Model ◽  
Training Load ◽  
Moving Averages ◽  
Shared Frailty Model ◽  
Shared Frailty ◽  
History Of ◽  
Baseline Characteristics ◽  
A Prospective Study ◽  
Exponentially Weighted

Purpose: To determine the association between training-load (TL) factors, baseline characteristics, and new injury and/or pain (IP) risk in an endurance sporting population (ESP). Methods: Ninety-five ESP participants from running, triathlon, swimming, cycling, and rowing disciplines initially completed a questionnaire capturing baseline characteristics. TL and IP data were submitted weekly over a 52-wk study period. Cumulative TL factors, acute:chronic workload ratios, and exponentially weighted moving averages were calculated. A shared frailty model was used to explore time to new IP and association to TL factors and baseline characteristics. Results: 92.6% of the ESP completed all 52 wk of TL and IP data. The following factors were associated with the lowest risk of a new IP episode: (a) a low to moderate 7-d lag exponentially weighted moving averages (0.8–1.3: hazard ratio [HR] = 1.21; 95% confidence interval [CI], 1.01–1.44; P = .04); (b) a low to moderate 7-d lag weekly TL (1200–1700 AU: HR = 1.38; 95% CI, 1.15–1.65; P < .001); (c) a moderate to high 14-d lag 4-weekly cumulative TL (5200–8000 AU: HR = 0.33; 95% CI, 0.21–0.50; P < .001); and (d) a low number of previous IP episodes in the preceding 12 mo (1 previous IP episode: HR = 1.11; 95% CI, 1.04–1.17; P = .04). Conclusions: To minimize new IP risk, an ESP should avoid high spikes in acute TL while maintaining moderate to high chronic TLs. A history of previous IP should be considered when prescribing TLs. The demonstration of a lag between a TL factor and its impact on new IP risk may have important implications for future ESP TL analysis.

scholarly journals A time-varying shared frailty model with application to infectious diseases

2014 ◽  
Vol 8 (1) ◽  
pp. 430-447 ◽  
Author(s):  
Doyo G. Enki ◽  
Angela Noufaily ◽  
C. Paddy Farrington
Keyword(s):  
Infectious Diseases ◽  
Frailty Model ◽  
Time Varying ◽  
Shared Frailty Model ◽  
Shared Frailty

Determinants of Time-to-recovery from Hypertension using a Comparison of Various Parametric Shared Frailty Models: In Case of Felege Hiwot Refral Hospital.

2021 ◽  
Author(s):  
Nigist Mulu ◽  
Yeshambel Kindu ◽  
Abay Kassie
Keyword(s):  
Survival Time ◽  
Blood Urea Nitrogen ◽  
Normal Condition ◽  
Recovery Time ◽  
Frailty Model ◽  
Frailty Models ◽  
Inverse Gaussian ◽  
Urea Nitrogen ◽  
Shared Frailty Model ◽  
Shared Frailty

Abstract Background: Hypertension is a major public health problem that is responsible for morbidity and mortality. In Ethiopia hypertension is becoming a double burden due to urbanization. The study aimed to identify factors that affect time-to-recovery from hypertension at Felege Hiwot Referral Hospital. Retrospective study design was used at FHRH. Methods: The data was collected in patient’s chart from September 2016 to January 2018. Kaplan-Meier survival estimate and Log-Rank test were used to compare the survival time. The AFT and parametric shared frailty models were employed to identify factors associated with the recovery time of hypertension patients. All the fitted models were compared by using AIC and BIC. Results: Eighty one percent of sampled patients were recovered to normal condition and nineteen percent of patients were censored observations. The median survival time of hypertensive patients to attain normal condition was 13 months. Weibull- inverse Gaussian shared frailty model was found to be the best model for predicting recovery time of hypertension patients. The unobserved heterogeneity in residences as estimated by the Weibull-Inverse Gaussian shared frailty model was θ=0.385 (p-value=0.00). Conclusion: The final model showed that age, systolic blood pressure, related disease, creantine, blood urea nitrogen and the interaction between blood urea nitrogen and age were the determinants factors of recovery status of patients at 5% level of significance. The result showed that patients creantine >1.5 Mg/dl compared to creantine ≤1.5 Mg/dl and SBP were prolonged the recovery time of patients whereas patients having kidney disease, other disease and had no any disease compared to diabetic patients and the interaction BUN and age were shorten recovery status of hypertension patients.

scholarly journals A bivariate power generalized Weibull distribution: A flexible parametric model for survival analysis

2019 ◽  
Vol 29 (8) ◽  
pp. 2295-2306 ◽  
Author(s):  
MC Jones ◽  
Angela Noufaily ◽  
Kevin Burke
Keyword(s):  
Survival Analysis ◽  
Weibull Distribution ◽  
Survival Data ◽  
Frailty Model ◽  
Weibull Model ◽  
Flexible Parametric Model ◽  
Shared Frailty Model ◽  
Shared Frailty ◽  
Power Variance ◽  
Parametric Survival

We are concerned with the flexible parametric analysis of bivariate survival data. Elsewhere, we argued in favour of an adapted form of the ‘power generalized Weibull’ distribution as an attractive vehicle for univariate parametric survival analysis. Here, we additionally observe a frailty relationship between a power generalized Weibull distribution with one value of the parameter which controls distributional choice within the family and a power generalized Weibull distribution with a smaller value of that parameter. We exploit this relationship to propose a bivariate shared frailty model with power generalized Weibull marginal distributions linked by the BB9 or ‘power variance function’ copula, then change it to have adapted power generalized Weibull marginals in the obvious way. The particular choice of copula is, therefore, natural in the current context, and the corresponding bivariate adapted power generalized Weibull model a novel combination of pre-existing components. We provide a number of theoretical properties of the models. We also show the potential of the bivariate adapted power generalized Weibull model for practical work via an illustrative example involving a well-known retinopathy dataset, for which the analysis proves to be straightforward to implement and informative in its outcomes.

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