Differential effect of residual oil fly ash (ROFA), ambient particulate matter and diesel exhaust particle (DEP) on the human pulmonary alveolar epithelium

Epidemiological studies have shown that exposure to particulate matter (PM) contributes to cardiopulmonary morbidity and mortality. Evidence suggests that the diesel exhaust in ambient air in major cities mediates a significant proportion of the adverse health effects. However, it has been speculated that these effects might be increased in cities within the oil and gas producing countries as a result of a combined effect of inhaling both diesel exhaust particles (DEP) and residual oil fly ash (ROFA) It is hypothesised that the nature and degree of alveolar epithelial reactivity will depend on the physico-chemistry of the particles, and that DEP/ROFA mixture will result in greater bio-reactivity compared to the same amount of DEP and ROFA alone. The specific aim is to determine the physico-chemical characteristics of ambient PM, DEP, ROFA and DEP/ROFA mixture and to compare their cellular reactivity/effects on human alveolar epithelium in vitro. The physico-chemical composition of the particles was determined using transmission electron microscope and energy dispersive x-ray spectrometer (TEM/EDX) analysis. Primary human alveolar type 2 epithelial cells (AT2) and a transformed human alveolar type 1 (TT1) epithelial cell line were exposed to ambient particles, ROFA, DEP and a ROFA/ DEP (1:1) mixture. Reactive oxygen species (ROS) production and cell viability were evaluated using the dichlorofluorescin (DCFDA) and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium (MTT) assay respectively. Enzyme-linked immunosorbent assay (ELISA) was used to quantify release of CXCL8, IL-6, and CCL2. TEM/EDX results revealed that transition metals and other reactive elements were present in the samples. The result also showed that ambient PM has an amorphous structure which made particle size difficult to determine. The estimated average diameters of ROFA and DEP were 74 ±17nm and 65 ± 2nm respectively. When mixed, it was 76 ± 24nm. Morphologically, these particles have large spherical, agglomerate and crystalline structures. Cellular exposures to PM were associated with significant increases in cytokine and chemokine release compared to non-treated controls (P< 0.002). At high concentrations (50 and 100μg/ml) the ROFA/DEP mixtures caused a significant increase in IL-6, CXCL8, and CCL2 release by TT-1 cells compared to exposure to an equivalent amount of DEP or ROFA alone (P<0.05). Ambient PM induced a higher level of mediator release compared to those observed with DEP while the DEP/ROFA mixture reduced cell viability and also triggerd rapid intracellular ROS release greater than that observed with ambient PM, DEP or ROFA alone. All these changes are concentration- and exposure time-dependent. However, the results are not statistically significant. In conclusion, DEP/ROFA mixture resulted in significant changes in cytokines/chemokines induction, ROS release and reduction in cell viability compared to DEP and ROFA alone (as well as PM). There was very little difference in particle size and shape, suggesting that differences between the reactivity of the test materials could be related to surface chemistry, for example elemental composition, although this could not be deduced in the current study. Other organic components might also be important, although they were not analysed in this investigation. Consequently, future work is needed to unravel the specific role of transition metals, as well as the organic and other inorganic components of the particles, in their cellular reactivity. It is also possible that mixing of ROFA and DEP causes reactions between volatile chemical components that enhances their cellular reactivity. These unique findings are of significance to those who live or work in cities where there are likely to be high levels of both types of emissions, which might have significant health effects

Estimating the uptake of brain imaging and 30-days stroke mortality in Nigeria : a meta-analysis of hospital-based studies

Purpose This study aims to estimate the computed tomography (CT) and Magnetic resonance imaging (MRI) uptake, stroke subtypes and 30-days case-fatality in Nigeria. Methods Stroke diagnosis and mortality data were identified from relevant databases. A random effect meta-analysis was conducted to obtain the pooled percentage uptake of CT/MRI, including 30-days case fatality and a meta-regression-like epidemiological model was applied on all data points. Findings A total of 24 studies involving 5874 stroke patients conducted in predominantly tertiary referral hospitals met the inclusion criteria. The pooled CT/MRI uptake in the last seven years was 46.66% (95% CI  = 15.35 to 77.98, 8 studies). There were significant variations in the prevalence of stroke subtypes. The pooled prevalence ischemic stroke was highest (55.32%, 95% CI 48.67 to 61.97, 16 studies), followed by intracerebral haemorrhage (ICH) (32.69%, 95% CI 25.54 to 39.83, 16 studies), subarachnoid haemorrhage (SAH) (3.76%, 95% CI 2.30 to 5.22, 14 studies). In addition, the stroke of undetermined aetiology was found to be 16.57% (95% CI, 7.44–25.70, 8 studies). Overall, the 24-h, one-week and 30-days case-fatality from stroke were 10.84% (95% CI, 4.48–17.20), 24.62% (95% CI, 17.20–32.04) and 33.28% (95% CI, 27.80–38.77), respectively. There was a moderate negative correlation between prevalence of brain imaging uptake and ischaemic stroke, albeit not statistically significant (Spearman rho = 0.333, p-value = .412). Conclusion Uptake of CT/MRI procedure for stroke is poor in Nigeria. Although poverty, inaccessibility and influence of major risk factors remain pronounced, scaling up of effective strategies for stroke prevention and management should be a major public health policy priority in Nigeria

Secular trends in the prevalence of female genital mutilation/cuttings among girls: a systematic analysis

Background Current evidence on the decline in the prevalence of female genital mutilation or cutting (FGM/C) has been lacking worldwide. This study analyses the prevalence estimates and secular trends in FGM/C over sustained periods (ie, 1990–2017). Its aim is to provide analytical evidence on the changing prevalence of FGM/C over time among girls aged 0–14 years and examine geographical variations in low-income and middle-income countries. Methods Analysis on the shift in prevalence of FGM/C was undertaken using the Demographic Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) data sets from Africa and Middle East. A random-effects model was used to derive overall prevalence estimates. Using Poisson regression models, we conducted time trends analyses on the FGM/C prevalence estimates between 1990 and 2017. Findings We included 90 DHS and MICS data sets for 208 195 children (0–14 years) from 29 countries spread across Africa and two countries in Western Asia. The prevalence of FGM/C among children varied greatly between countries and regions and also within countries over the survey periods. The percentage decline in the prevalence of FGM/C among children aged 0–14 years old was highest in East Africa, followed by North and West Africa. The prevalence decreased from 71.4% in 1995 to 8.0% in 2016 in East Africa. In North Africa, the prevalence decreased from 57.7% in 1990 to 14.1% in 2015. In West Africa, the prevalence decreased from 73.6% in 1996 to 25.4% in 2017. The results of the trend analysis showed a significant shift downwards in the prevalence of FGM/C among children aged 0–14 years in such regions and subregions of East Africa, North Africa and West Africa. East Africa has experienced a much faster decrease in the prevalence of the practice (trend=−7.3%, 95% CI −7.5% to −7.1%) per year from 1995 to 2014. By contrast, the decline in prevalence has been much slower in North Africa (trend=−4.4%, 95% CI −4.5% to −4.3%) and West Africa (trend=−3.0%, 95% CI −3.1% to −2.9%). Conclusion The prevalence of FGM/C among children aged 0–14 years varied greatly between countries and regions and also within countries over the survey periods. There is evidence of huge and significant decline in the prevalence of FGM/C among children across countries and regions. There is a need to sustain comprehensive intervention efforts and further targeted efforts in countries and regions still showing high prevalence of FGM/C among children, where the practice is still pervasive

Estimating morbidity due to stroke in Nigeria: a systematic review and meta-analysis

The response to stroke in Nigeria is impaired by inadequate epidemiologic information. We sought to collate available evidence and estimate the incidence of stroke and prevalence of stroke survivors in Nigeria. Using random effects meta-analysis, we pooled nationwide and regional incidence and prevalence of stroke from the estimates reported in each study. Eleven studies met our selection criteria. The pooled crude incidence of stroke in Nigeria was 26.0 (12.8-39.0) /100,000 person-years, with this higher among men at 34.1 (9.7-58.4) /100,000, compared to women at 21.2 (7.4-35.0) /100,000. The pooled crude prevalence of stroke survivors in Nigeria was 6.7 (5.8-7.7) /1000 population, with this also higher among men at 6.4 (5.1-7.6) /1000, compared to women at 4.4 (3.4-5.5) /1000. In the period 2000-2009, the incidence of stroke in Nigeria was 24.3 (95% CI: 11.9-36.8) per 100,000, with this increasing to 27.4 (95% CI: 2.2-52.7) per 100,000 from 2010 upwards. The prevalence of stroke survivors increased minimally from 6.0 (95% CI: 4.6-7.5) per 1000 to 7.5 (95% CI: 5.8-9.1) per 1000 over the same period. The prevalence of stroke survivors was highest in the South-south region at 13.4 (9.1-17.8) /100,000 and among rural dwellers at 10.8 (7.5-14.1) /100,000. Although study period does not appear to contribute substantially to variations in stroke morbidity in Nigeria, an increasing number of new cases compared to survivors may be due in part to limited door-door surveys, or possibly reflects an increasing mortality from stroke in the country. [Abstract copyright: Copyright © 2019 Elsevier B.V. All rights reserved.

Estimating the prevalence of overweight and obesity in Nigeria in 2020: a systematic review and meta-analysis

Background Targeted public health response to obesity in Nigeria is relatively low due to limited epidemiologic understanding. We aimed to estimate nationwide and sub-national prevalence of overweight and obesity in the adult Nigerian population. Methods MEDLINE, EMBASE, Global Health, and Africa Journals Online were systematically searched for relevant epidemiologic studies in Nigeria published on or after 01 January 1990. We assessed quality of studies and conducted a random-effects meta-analysis on extracted crude prevalence rates. Using a meta-regression model, we estimated the number of overweight and obese persons in Nigeria in the year 2020. Results From 35 studies (n = 52,816), the pooled crude prevalence rates of overweight and obesity in Nigeria were 25.0% (95% confidence interval, CI: 20.4–29.6) and 14.3% (95% CI: 12.0–15.5), respectively. The prevalence in women was higher compared to men at 25.5% (95% CI: 17.1–34.0) versus 25.2% (95% CI: 18.0–32.4) for overweight, and 19.8% (95% CI: 3.9–25.6) versus 12.9% (95% CI: 9.1–16.7) for obesity, respectively. The pooled mean body mass index (BMI) and waist circumference were 25.6 kg/m2 and 86.5 cm, respectively. We estimated that there were 21 million and 12 million overweight and obese persons in the Nigerian population aged 15 years or more in 2020, accounting for an age-adjusted prevalence of 20.3% and 11.6%, respectively. The prevalence rates of overweight and obesity were consistently higher among urban dwellers (27.2% and 14.4%) compared to rural dwellers (16.4% and 12.1%). Conclusions Our findings suggest a high prevalence of overweight and obesity in Nigeria. This is marked in urban Nigeria and among women, which may in part be due to widespread sedentary lifestyles and a surge in processed food outlets, largely reflective of a trend across many African settings

The prevalence of hypertension and stroke survivors in the polluted environment : a case study of rural Niger Delta.

Background The risk of hypertension and/or stroke and prolonged exposure to crude oil pollution and gas flares remains unexplored. This was examined in the rural Niger Delta communities where decades of rampant oil and gas pollution and institutional neglect have been linked to increased cardiovascular diseases, poverty, and underdevelopment. Study aim and Objectives The aim of the study was to assess the prevalence of hypertension and stroke in the Niger Delta region. The overall objectives were to conduct a systematic review and meta-analysis of the prevalence of hypertension in Niger Delta region and the prevalence of stroke in low- and middle-income countries (LMICs) including Nigeria; and to conduct a survey to evaluate the relative prevalence and correlates of both hypertension and stroke. Methods Relevant databases were searched and articles reporting hypertension and stroke prevalence were systematically reviewed to obtain a pooled prevalence estimates and secular trends based on the random-effect model. In the cross-sectional survey, 2,028 resident adults (aged 18-80) were recruited in both oil/gas polluted and non-polluted communities. Prevalence of hypertension and stroke and other important measures were examined and compared between the two communities. Results The review found a continuous increase in the prevalence of hypertension in the region such that the estimates have been increasing by 8.31% every 5 years. For stroke, the lowest prevalence was found in sub-Saharan Africa including Nigeria (3.5 per 1000, 95% CI, 1.9-5.7). However, the only study conducted in the rural Niger Delta found a higher prevalence compared to other areas in Nigeria and in sub-Saharan Arica (8.51 per 1000 95% CI, 3.9-16.1). In the cross-sectional survey, the study found that one-third of participants were hypertensive (37.4%) while 27 stroke with a crude prevalence of 13.31/1000 persons (95% CI, 8·32-18·31) were found. In the adjusted model, participants living in oil-polluted areas were almost 5 times as likely to have developed hypertension (adjusted odds ratio (aOR) = 4.85, 95% confidence interval (CI): 1.84-112.82) compared to participants in non-polluted areas. Age-adjusted prevalence of stroke was 14.6/1000 person, which is about 7-folds higher than outside the Niger Delta region, and is the highest ever recorded in Africa as a whole. The study also found that participant’s age, education attainment, and obesity modify the association between pollution status and risk of hypertension. In particular, age modifies the association between pollution status and risk of hypertension. Conclusion The increased prevalence of hypertension and stroke is consistent with ongoing epidemiological and environmental transitions. The study findings have huge socioeconomic implications in the Niger Delta population particularly in the rural oil and gas hosts-host communities suggesting a potential interplay between socioeconomic, lifestyle and environmental factors. The findings could be useful for screening purposes to identify high-risk population before a diagnosis is made and to target interventions appropriately. The study findings need to be investigated further in longitudinal studies. The influence of other extrinsic factors underscores the need for improved surveillance and better management of undetected or uncontrolled high blood pressure

Stroke survivors in low- and middle-income countries: a meta-analysis of prevalence and secular trends

Purpose To provide an up-to-date estimate on the changing prevalence of stroke survivors, and examines the geographic and socioeconomic variations in low and middle-income countries (LMICs). Methods We searched MEDLINE, EMBASE, SCOPUS and Web of Science databases and systematically reviewed articles reporting stroke prevalence and risk factors from inception to July 2015. Pooled prevalence estimates and secular trends based on random-effects models were conducted across LMICs, World Bank regions and income groups. Results Overall, 101 eligible community-based studies were included in the meta-analysis. The pooled crude prevalence of stroke survivors was highest in Latin America and Caribbean (21.2 per 1000, 95% CI 13.7 to 30.29) but lowest in sub-Saharan Africa (3.5 per 1000, 95% CI 1.9 to 5.7). Steepest increase in stroke prevalence occurred in low-income countries, increasing by 14.3% annually while the lowest increase occurred in lower-middle income countries (6% annually), and for every 10 years increase in participants' mean age, the prevalence of stroke survivors increases by 62% (95% CI 6% to 147%). Conclusion The prevalence estimates of stroke survivors are significantly different across LMICs in both magnitude and secular trend. Improved stroke surveillance and care, as well as better management of the underlying risk factors, primarily undetected or uncontrolled high blood pressure (HBP) are needed

The Burden of Hypertension in an Oil- and Gas-Polluted Environment: A Comparative Cross-Sectional Study

Background - Evidence of positive association between traffic-related air pollution and elevated blood pressure has been published widely. However, the risk of hypertension and prolonged exposure to crude oil pollution and gas flares remains unexplored. Methods - We recruited 2,028 residents (aged 18–80) in a cross-sectional survey of both oil/gas polluted and nonpolluted communities in the Niger Delta region of Nigeria. Prevalence and risk of hypertension, anthropometric indices, lifestyle and sociodemographic factors, and cardiovascular comorbidities were examined and compared between the 2 groups. Hypertension was defined as blood pressure ≥140/90mm Hg or on antihypertensive medication. Both univariate and multivariate logistic regression models were used to examine factors associated with hypertension. Model fits statistics were used to assess the parsimonious model and predictive power. Results - More than one-third of participants were hypertensive (37.4%). Half of the participants were from oil-polluted areas (51%). Only 15% of participants reported family history of hypertension. In the adjusted model, participants living in oil-polluted areas were almost 5 times as likely to have developed hypertension (adjusted odds ratio (aOR) = 4.85, 95% confidence interval (CI): 1.84–12.82) compared to participants in unpolluted areas. Age modifies the association between pollution status and risk of hypertension. For every 10 years increase in the age of the participants, the odds of developing hypertension increased by 108% (aOR = 2.08, 95% CI: 1.77–2.43). Conclusion - The results suggested that exposure to oil/gas pollution may be associated with an increased risk of hypertension. Our findings need to be further investigated in longitudinal studies