The Performance of The Lee-Carter Model on Heterogeneous Adult Mortality Data in a Limited Data Situation

Adult mortality in developing Countries remains one of the greatest challenges for monitoring, analyzing and projecting the health situation of a large proportion of the world's population. Because of limited resources, many developing Countries, especially in sub-Saharan Africa lack vital registration systems that could reliably and continuously collect information on adult mortality. However, periodic reviews of mortality rate and pattern using mortality models could show new trends and may provide information for the planning of a Country’s health care delivery services and a host of other programs.   Previous studies have found that the Lee-Carter model works well with homogenous mortality data. In this current study, we want to see the performance of the model on heterogenous adult mortality data in a limited data situation. A modified version of the Lee-Carter method is used to model sex-combined adult mortality data of Nigerians aged 15-84 years for the time periods 1990, 2000 and 2012. The model's parameters are estimated using the approach proposed by Lee and Carter (1992) based on the singular value decomposition technique, while the mortality index is predicted using the approach developed by Li et al. (2002). Our results show that on the overall, the model follows the mortality pattern very well for most of the ages despite the heterogonous nature of the data used. Forecast values of the mortality index show a gradual decline in mortality from 2013-2025 in Nigeria. KEYWORDS: Adult mortality; Age; Lee-Carter model; Nigeria

Comparison of Optimality Criteria of Reduced Models for Response Surface Designs with Restricted Randomization

In this work, $D-$, $G-$, and $A-$ efficiencies and the scaled average prediction variance, $IV$ criterion, are computed and compared for second-order split-plot central composite design. These design optimality criteria are evaluated across the set of reduced split-plot central composite design models for three design variables under various ratios of the variance components (or degrees of correlation $d$). It was observed that $D$, $A$, $G$, and $IV$ for these models strongly depend on the values of $d$; they are robust to changes in the interaction terms and vary dramatically with the number of, and changes in the squared terms

A Three-Parameter Gompertz-Lindley Distribution: Its Properties and Applications

This research proposed a three-parameter probability distribution called Gompertz-Lindley distribution using Gompertz generalized (Gompertz-G) family of distributions. The mathematical properties of the distribution such as moment, moment generating function, survival function and hazard function were derived. The parameters of the distribution were estimated using the method of maximum likelihood and the distribution was applied to model the strength of glass fibres. Gompertz-Lindley distribution performed best (AIC = 62.8537) when compared with other generalizations of the Lindley distribution. Keywords: Gompertz distribution, Lindley distribution, moment, survival function, hazard function DOI: 10.7176/MTM/9-4-04 Publication date: April 30th 2019

GAMMA-NORMAL VERSION OF THE LEE-CARTER MODEL FOR FORECASTING MORTALITY

The Lee-Carter model was primarily designed for the mortality pattern of the United States and has been used by many developed Countries as a gold standard to model their mortality pattern. Despite its merits, it is observed from  literature that the Lee and Carter (1992) and some of its variants have problems capturing a good fit when mortality rate has an increasing trend for some ages while decreasing for others or a fluctuating increase and decrease especially with respect to mortality data from developing Countries. In this study, based on the contributions of Zografos and Balakrishnan (2009) and Lima et al. (2015), we propose a Gamma-normal version of the Lee-Carter model which addresses the distribution of the error term inherent in the Lee-Carter approach. It is hoped that this new model will give a better fit and account for peculiarities at different ages without any loss of generality. Keywords:  Lee-Carter model, mortality, Gamma-normal, Age, developing Countries

Community Scientist Program Provides Bi-directional Communication and Co-learning Between Researchers and Community Members

Community involvement in research is key to translating science into practice, and new approaches to engaging community members in research design and implementation are needed. The Community Scientist Program, established at the MD Anderson Cancer Center in Houston in 2018 and expanded to two other Texas institutions in 2021, provides researchers with rapid feedback from community members on study feasibility and design, cultural appropriateness, participant recruitment, and research implementation. This paper aims to describe the Community Scientist Program and assess Community Scientists\u27 and researchers\u27 satisfaction with the program. We present the analysis of the data collected from 116 Community Scientists and 64 researchers who attended 100 feedback sessions, across three regions of Texas including Northeast Texas, Houston, and Rio Grande Valley between June 2018 and December 2022. Community Scientists stated that the feedback sessions increased their knowledge and changed their perception of research. All researchers (100%) were satisfied with the feedback and reported that it influenced their current and future research methods. Our evaluation demonstrates that the key features of the Community Scientist Program such as follow-up evaluations, effective bi-directional communication, and fair compensation transform how research is conducted and contribute to reducing health disparities

Is renal medullary carcinoma the seventh nephropathy in sickle cell disease? A multi-center Nigerian survey

Introduction: Previous studies had enlisted renal medullary carcinoma (RMC) as the seventh nephropathy in sickle cell disease (SCD). Clinical experience has contradicted this claim and this study is targeted at refuting or supporting this assumption.Objective: To estimate the prevalence of RMC and describe other renal complications in SCD.Materials and methods: 14 physicians (haematologists and urologists) in 11 tertiary institutions across the country were collated from patients’ case notes and hospital SCD registers.Results: Of the 3,596 registered sickle patients, 2 (0.056%) had been diagnosed with RMC over a ten year period, thereby giving an estimated prevalence rate of 5.6 per 100,000. The most common renal complication reported by the attending physicians was chronic kidney disease (CKD). The frequency of routine renal screening for SCD patients varied widely between centres – most were done at diagnosis, annually or bi-annually.Conclusion: The ten year prevalence of RMC in Nigerian SCD patients was determined to be 5.6 (estimated incidence of 0.56). RMC is not more common in SCD patients and therefore cannot be regarded as a “Seventh Sickle nephropathy”. Most of the managing physicians reported that the commonest nephropathy observed in their SCD patients was chronic kidney disease.Keywords: Renal medullary carcinoma, seventh nephropathy, sickle cell disease, Nigerian surve

Reported Barriers to Healthcare Access and Service Disruptions Caused by COVID-19 in Burkina Faso, Ethiopia, and Nigeria: A Telephone Survey.

The coronavirus disease 2019 (COVID-19) pandemic may have short-term and long-term impacts on health services across sub-Saharan African countries. A telephone survey in Burkina Faso, Ethiopia, and Nigeria was conducted to assess the effects of the pandemic on healthcare services from the perspectives of healthcare providers (HCPs) and community members. A total of 900 HCPs (300 from each country) and 1,797 adult community members (approximately 600 from each country) participated in the study. Adjusted risk ratios (ARRs) and 95% confidence intervals (CIs) were computed using modified Poisson regression. According to the HCPs, more than half (56%) of essential health services were affected. Child health services and HIV/surgical/other services had a slightly higher percentage of interruption (33%) compared with maternal health services (31%). A total of 21.8%, 19.3%, and 7.7% of the community members reported that their family members and themselves had difficulty accessing childcare services, maternal health, and other health services, respectively. Nurses had a lower risk of reporting high service interruptions than physicians (ARR, 0.85; 95% CI, 0.56-0.95). HCPs at private facilities (ARR, 0.71; 95% CI, 0.59-0.84) had a lower risk of reporting high service interruptions than those at governmental facilities. Health services in Nigeria were more likely to be interrupted than those in Burkina Faso (ARR, 1.38; 95% CI, 1.19-1.59). Health authorities should work with multiple stakeholders to ensure routine health services and identify novel and adaptive approaches to recover referral services, medical care, maternal and child health, family planning, immunization and health promotion, and prevention during the COVID-19 era

COVID-19 Knowledge, Perception, Preventive Measures, Stigma, and Mental Health Among Healthcare Workers in Three Sub-Saharan African Countries: A Phone Survey.

The coronavirus disease 2019 (COVID-19) pandemic is an unprecedented public health crisis globally. Understanding healthcare providers' (HCPs') knowledge and perceptions of COVID-19 is crucial to identifying effective strategies to improve their ability to respond to the pandemic in sub-Saharan Africa. A phone-based survey of 900 HCPs in Burkina Faso, Ethiopia, and Nigeria (300 per country) was conducted to assess knowledge, perceptions, COVID-19 prevention measures, stigma, and mental health of HCPs. Modified Poisson regression models were used to evaluate predictors of knowledge, perceptions, and prevention measures; adjusted risk ratios (ARRs) and 95% confidence intervals (CIs) were calculated. Three-fourths of the HCPs had adequate knowledge, and over half had correct perceptions of risk and high levels of self-reported prevention measures. The majority of the HCPs (73.7%) reported self-perceived social stigma. There was relatively low prevalence of depression (6.6%), anxiety (6.6%), or psychological distress (18%). Compared with doctors, being a nurse was associated with lower levels of knowledge (ARR: 0.83; 95% CI: 0.77-0.90) and was also negatively associated with having correct perceptions toward COVID-19 (AOR: 0.82; 95% CI: 0.73-0.92). HCPs treating COVID-19 patients had higher likelihood of having high levels of prevention measures (AOR: 1.37; 95% CI: 1.23-1.53). Despite high levels of knowledge among HCPs in sub-Saharan Africa, there is a need to improve COVID-19 perceptions and compliance with prevention measures as well as address social stigma toward HCPs to better ensure their safety and prepare them to deliver health services