Epidemiology and Medical Statistics

Fertility Determinants and Mathematical Model for the Timing of its Convergence to Replacement Level in Nigeria

2021-07-01T00:00:00Z

Fertility Determinants and Mathematical Model for the Timing of its Convergence to Replacement Level in Nigeria OLOWOLAFE, TUBOSUN ALEX High level of female fertility and accelerated population growth have been consistently reported in Nigeria. Population growth stability is achieved when fertility converges to a Replacement Level (RL) attained when the Total Fertility Rate (TFR) is on average of 2.1 children per woman. The unrestraint population growth can lead to a population explosion that might constitute a challenge to achieving sustainable development goals (SDGs). Shifts in age pattern of fertility are central to modelling fertility convergence to RL. However, poor quality of fertility data from the vital registration system in Nigeria is a major limitation to the estimates of the fertility pattern. Therefore, this study used indirect demographic techniques to examine fertility determinants and develop a mathematical model for the timing of its convergence to RL. Nigeria Demographic and Health Survey data sets of the weighted sample of 2003 (n1=7620), 2008 (n2=33385), 2013 (n3=38948) and 2018 (n4=41821) were analyzed. Each survey of the secondary data set was a cross-sectional population-based design and a two-stage cluster sampling technique was used to select women aged 15-49 years. Fertility was measured using the information on the history of the selected women’s full birth. Analyses were conducted using Bongaarts’ revised proximate determinants model with a focus on Postpartum Infecundity-(Ci), Sexual Exposure-(Cm), Contraceptive use-(Cc) and abortion rate-(Ca). Das Gupta five-factor and Oaxaca Blinder decomposition were used to examine the fertility determinants. Age Specific Fertility Rate (ASFR) was modelled with the assumption of uniformity in the percentage contribution of TFR by the observed and the standard ASFR. Annual changes in the age patterns of fertility were employed to develop a model that predict the timing of fertility convergence to replacement level. Mean children ever born per woman in Nigeria was 3.0±3.2, 3.1±3.1, 3.1±3.0 and 3.1±3.0 in 2003, 2008, 2013 and 2018, respectively. The adjusted estimate of TFR was highest in 2003 (6.1) and least in 2018 (5.6). In 2003 and 2018, Ci’s fertility-inhibiting effect (0.69 and 0.70) was highest, and the smallest was Ca (0.94 and 0.93). Decomposition analysis showed that the change observed in TFR between 2003 and 2018 was attributed to Cc-(63%) and Cm-(43%). Risk difference (RD) of high fertility between uneducated-educated women was highest in South-East (RD=56.9; 95%CI=49.1-64.8) and least in North-East (RD=15.0; 95%CI=9.9-20.1). For rural-urban differentials, South-West has the highest RD (12.7; 95%CI=10.2-15.3) and lowest in South-East (RD=1.9; 95%CI=-0.8-4.6). Also, Poor-Rich differentials, RD were highest in South-West (RD=15.9; 95%CI=11.5-20.4) and the least in the North-West (RD=15.9; 95%CI=11.5-20.4). The model developed for predicting the timing of fertility convergence to RL is f x  f x  t T o rep t ( ) ( ) The timing of fertility convergence to RL in Nigeria was projected as the year 2089. Nigeria might not attain fertility replacement level until the next seventy years (2020-2089) if the prevailing fertility pattern persists. Women’s education, sexual exposure and contraceptive use are pertinent to fertility reduction to replacement level in Nigeria. Increasing educational opportunities for girls and access to family planning services for women of reproductive age will facilitate quick achievement of replacement level fertility in Nigeria

MODEL-BASED SUB-POPULATION ESTIMATES OF MATERNAL MORTALITY RATES AND RATIO FROM SIBLINGS’ SURVIVORSHIP HISTORIES IN NIGERIA (2008 -2018)

2021-04-01T00:00:00Z

MODEL-BASED SUB-POPULATION ESTIMATES OF MATERNAL MORTALITY RATES AND RATIO FROM SIBLINGS’ SURVIVORSHIP HISTORIES IN NIGERIA (2008 -2018) BABAJIDE, Opeyemi Oluwatosin Despite several interventions, Maternal Mortality (MM) remains high in Nigeria. This is further complicated by lack of reliable estimates of MM for subnational levels such as states and geopolitical regions. A plausible estimate of MM levels is essential to provide evidence based national and state-level planning, resource allocation and monitoring of progress. It will reflect the population diversity in the country and assist in closing MM gaps. This study was designed to adapt sisterhood method and small area estimation techniques to derive plausible estimates of MM rates and ratios for subnational populations in Nigeria. Survivorship history data of 293,769 female siblings provided by 114,154 women in the Nigeria Demographic and Health Surveys conducted in 2008, 2013 and 2018 were analysed. The dataset from each survey was reconstructed into a panel data structure such that each reported sibling was captured as an observation. The MM Rates (maternal deaths per women-years of exposure to childbearing) and Ratios (maternal deaths per 100,000 live births) were estimated using direct and indirect sisterhood methods. Empirical Bayesian technique for small area demographic estimates was used to obtain MM rates and ratios at state-levels. The James-Stein estimator was used to shrink the estimates closer to the population mean values at 95% Confidence Interval (CI). Zero-inflated Poisson regression model was fitted to investigate association between selected covariates and maternal death counts at the community levels. Incident Risk Ratio (IRR) was reported as measures of effect. All analyses were weighted to adjust for the effects of clustering. MM rates in 2008 were high in rural areas and North-West region at 1.21 and 1.65 per 1,000 women-exposure years and lowest in South-West at 0.45 per 1,000 women-exposure years. Levels of MM Ratios were highest in the rural areas and South-South region at 624 and 679 respectively and lowest in South-West (281 per 100,000 live births). In 2013, the levels of MM Ratio were highest in North-Central (712) and lowest in South-West (367 per 100,000 livebirths) and for 2018, it was higher in rural areas (548) compared to urban (523); highest in North-West (901) and lowest in the South-East (268). MM Ratio was consistently lower in the South-West (2008=281; 2013=367; 2018=392) and higher among the Northern regions of the country, particularly the North-East (2008=654; 2013=612; 2018=901). Overall, Kebbi, Adamawa and Taraba states had high MM Ratio across the three surveys. From 2008 to 2018, MM Ratio declined by 18% in the North-West and 54.2% in the South East region. However, there was a 4.8% increase in MM Ratio for South-West from 2008 to 2018. At the community levels, geopolitical zone, knowledge (IRR=1.33, CI=0.98-6.1) and actual use of family planning (IRR=1.92, CI=1.1-9.1) were associated with maternal death counts. This study has derived and shown differentials in subnational estimates of maternal mortality in Nigeria and has identified geopolitical region, the knowledge and use of family planning as major covariates of maternal mortality. This has produced a baseline upon which improvements in maternal mortality in states and geopolitical zones in Nigeria can be based.

DEVELOPMENT, DIAGNOSTIC ACCURACY AND FEASIBILITY OF A SCREENING TOOL FOR EARLY DETECTION OF BLINDING EYE DISEASES AMONG INFANTS IN IBADAN, NIGERIA

2021-03-01T00:00:00Z

DEVELOPMENT, DIAGNOSTIC ACCURACY AND FEASIBILITY OF A SCREENING TOOL FOR EARLY DETECTION OF BLINDING EYE DISEASES AMONG INFANTS IN IBADAN, NIGERIA OLUSANYA, BOLUTIFE AYOKUNNU Approximately seventy per 100,000 children are blind worldwide. Early detection and prompt treatment play vital roles in prevention of blindness from cataract and other eye diseases in children. However, there are no established screening programmes for blinding eye diseases among infants in Nigeria. This has contributed to delayed presentation to hospital among children with blinding eye diseases. Therefore, this study was conducted to develop and validate a simple screening tool for the early detection of blinding eye diseases among infants as well as assess the perceptions of health care workers regarding the feasibility of using the tool. This cross-sectional study was conducted in 3 phases. The first phase was the development and validation of a screening checklist. This entailed a literature review, expert opinion, stakeholders’ input, content validation and pretesting of the checklist. The second phase was a diagnostic accuracy study which compared the newly developed checklist to a gold standard, which was eye examination by an ophthalmologist. This phase was carried out on 1214 infants receiving immunisation in eight primary health care centres located in four urban Local Government Areas in Ibadan metropolis. Each infant was first screened by a primary health worker (immunisation staff) using the checklist and subsequently examined by the ophthalmologist. The sensitivity, specificity, positive and negative predictive values as well as reliability indices of the checklist were determined. The third phase was a questionnaire survey to assess the perceptions of all the participating immunisation staff (38 in number) about the feasibility of using the checklist. Data were analysed using descriptive statistics. Level of significance was set at α0.05. A checklist with two sections and 11 items was developed. The first section consisted of six questions that the health workers asked the infants’ mothers or caregivers; while the second section contained five questions that were answered by the health workers after a quick examination of the children’s eyes. The mean age of the infants was 5.2±3.8 months and 52.5% were males. The screening checklist had a sensitivity of 70.0% for detection of blinding eye disease. In addition, it had a specificity of 94.8% for detection of blinding eye disease. The inter-observer agreement was 96.6% (Kappa = 0.71); while test-retest reliability showed an intra-class correlation coefficient of 0.90. All the immunisation staff were females, with a mean age of 43.1±7.6 years. They all reported that the checklist was useful in screening for eye diseases among infants. Majority (81.6%) reported that the checklist was very easy to use. About one-third (34.2%) experienced challenges, such as poor cooperation from mother or child, while using the checklist. A screening tool with good sensitivity, high specificity and high reliability was developed for the early detection of blinding eye diseases in infants. Primary health care workers found the checklist to be easy to administer and useful for screening. Adoption of this checklist as a screening tool at the primary health care level could be instrumental in the establishment of screening programmes and early detection of blinding eye diseases among children.

A MULTI-LEVEL INTERVENTION ON THE PHYSICAL ACTIVITY BEHAVIOURS OF IN-SCHOOL ADOLESCENTS IN OYO STATE, NIGERIA

2018-07-01T00:00:00Z

A MULTI-LEVEL INTERVENTION ON THE PHYSICAL ACTIVITY BEHAVIOURS OF IN-SCHOOL ADOLESCENTS IN OYO STATE, NIGERIA OLUWASANU, Mojisola Morenike Physical inactivity is on the increase among Nigerian adolescents and it remains a key risk factor for noncommunicable diseases. Although multi-level, school-based intervention may offer opportunities for promoting Physical Activity (PA), its effects have not been well investigated. This study was conducted to evaluate the effects of a 12-week multi-level intervention on the PA behaviours of adolescents in secondary schools, Oyo State. A cluster randomised experimental design was adopted with measurements at baseline and post-intervention. Ibadan North-west and Ogbomosho North Local Government Areas (LGAs) were randomly selected and allocated to the Experimental Group (EG) and Control Group (CG) respectively. Twenty-two of the 72 schools in both LGAs were randomly selected. A total of 1,318 respondents (EG= 666; CG= 652) participated in the baseline assessments and 995 (EG =493; CG=502) did so at post-evaluation. A pre-tested, self-administered questionnaire, comprising a10-point knowledge, 90-point attitude, 50-point self-efficacy and 5-point Self-reported PA (SPA) scales was used for data collection. Knowledge Score (KS), Self-Efficacy Score (SES) and Attitude Score (AS) were dichotomised into “poor” and “good”, using 50th percentile as the cut-off. The SPA score was categorised as low (<1 to ≤1.9), moderate (>1.9 to ≤3.9) and vigorous (>3.9). Seven key informant interviews and six focus group discussions were held with principals and teachers, respectively. Baseline findings guided the design and implementation of the intervention which comprised the following: dialogue meetings with officials of the Ministry of Education and school authorities; health education and medical screening for teachers; teacher-led sessions on PA, and provision of educational and sporting materials for students in EG. Quantitative data were analysed using descriptive statistics, Student's t-test, Chi-square and mixed-effects linear regression. Level of significance was α0.05. Qualitative data were analysed using thematic approach. Ages in EG and CG were 13.4±2.1 and 14.3±1.9 years, respectively. Baseline KS increased significantly from 8.4±1.3 to 8.7±1.2 in the EG but decreased slightly in the CG (8.6±1.1 to 8.5±1.3). Attitude score increased significantly from 65.3±13.4 to 69.3±11.3 in EG but decreased among the CG (66.7±11.2 to 64.3±12.4), while SES increased from 39.6±7.2 to 40.5±6.7 in EG but decreased in CG (39.6±6.4 to 39.4±6.1). At baseline, the moderate and vigorous SPA levels of the EG were 72.2% and 1.7% respectively; among the CG, the proportions were 72.9% and 0.8%, respectively. This increased significantly post-intervention to 89.2% and 3.7% in EG and 88.8% and 1.0% in CG. Exposure to intervention (β=0.10, CI=0.01-0.18), having a positive attitude (β=0.11;CI=0.06-0.15) and high self-efficacy (β=0.16, CI=0.11-0.21) were positively associated with increased SPA score at post-evaluation, while being a female (β= -0.22; CI= -0.27- -0.17) and being in the 15-19 years age range (β = -0.13; CI=-0.19-0.08) were negatively associated. Qualitative data revealed inconsistent PA policy implementation due to inadequate human, sporting resources and facilities and increasing time-demand for academic activities. School-based multi-level intervention could improve adolescents’ attitude, self-efficacy and physical activity behaviours. It is therefore recommended for adoption and scale-up in schools in the study location.