Life-course effects of air pollution (LEAP) on cardio-respiratory morbidity in the MRC National Survey of Health and Development

Most of the epidemiological studies of long term exposure to air pollution showed increased risk of death from cardio-respiratory diseases. However the effect of long-term exposure to air pollution on morbidity is less clear. Additionally, questions as to which stage of life is more important in the effect of air pollution on health in adulthood are still unanswered. This project investigates the relationship between long-term exposure to air pollution and cardio-respiratory morbidity using the National Survey for Health and Development (NSHD) with consideration to lifestyle and socioeconomic factors. A comparison between early life and more recent exposures to air pollution will also be made. Finally, the effect of cumulative and change in air pollution over the life course will be explored. Lung function was measured and self-reported chronic bronchitis (CB) symptoms and ischaemic heart disease (IHD) were collected in 1989, 1999 and 2006/10 for more than 3000 participants. A residential history of the NSHD participants from 1962 onwards was constructed using addresses and/or postcodes and was geocoded and linked to model black smoke (BS) sulphur dioxide (SO2) in 1962, 1971, 1981 and 1991 and nitrogen dioxide (NO2) air pollution in 1991, 2001 and 2010-11. Earlier childhood exposures to air pollutants were assessed using the Douglas and Waller index. Relationships to air pollution were investigated using various statistical models. Contrary to expectations, some results suggested protective effects of air pollution on lung function and symptoms of CB. BS showed positive associations with lung function particularly from 1999 follow-up; 10 µg/m3 of BS in 1971 and 10 µg/m3 in 1991 were associated with 19.2ml (95%CI: 3.5-34.9) and 82.9ml (95%CI: 21.2-144.5) increase in Forced Vital Capacity (FVC) respectively. SO2 showed some positive (protective) associations; 10 µg/m3 of SO2 in 1962 was associated with 3.9 ml (95%CI: 0.1-7.9) increase in Forced Expiratory Volume in 1 second (FEV1) and 5.4 ml (95%CI: 0.2-10.7) increase in Forced Vital Capacity (FVC) in 1989. BS and SO2 both showed positive (protective) associations with lung function decline where 10 µg/m3 of BS in 1981 was associated with 80 ml (95%CI: 16-150) less decline in FVC ; and 10 µg/m3 of SO2 in 1991 was associated with 70 ml (95%CI: 22-120 ) less decline in FVC over the 20 year period. Change and cumulative BS did not show a clear pattern in generalized analyses, however results from stratified analyses suggested positive effects on men that indicate higher BS exposure was associated with better lung function. These protective effects were more consistently observed in SO2 analyses; 10 µg/m3 change (decrease) in SO2 between 1962 and 1991 was associated with 4.3ml (95%CI: 0.4-8.2) higher FEV1 in 1989, 6.1 ml (95%CI: 0.6-11.5) higher FVC in 1989, and 8.4ml (95% CI: 3.0-13.9) higher FVC in 1999. Higher cumulative exposure of 10 µg/m3 of SO2 was associated with 0.5 ml (95% CI: 0.1-0.9) increase in FVC in 1999. Air pollution was not associated with prevalence of CB, results indicated some protective effects. Air pollution was not associated with IHD prevalence; however detrimental effects were suggested. A healthy survivor effect would explain the findings for CB and lung function whereby the most exposed individuals who potentially experience more ill health are under-represented in the study and were differentially lost to follow up. Some evidence was found to suggest greater drop-out in individuals with higher exposure in more deprived areas. However, positive association between decline in air pollution and lung function may be related to the large falls in air pollution levels over the time period of study.Open Acces

Hepatitis C Virus Infection in Populations With Liver-Related Diseases in the Middle East and North Africa.

We investigated hepatitis C virus (HCV) epidemiology in populations with liver-related diseases (LRDs) in the Middle East and North Africa. The data source was standardized databases of HCV measures populated through systematic reviews. Random-effects meta-analyses and meta-regressions were performed, and genotype diversity was assessed. Analyses were based on 252 HCV antibody prevalence measures, eight viremic rate measures, and 30 genotype measures on 132,358 subjects. Pooled mean prevalence in LRD populations was 58.8% (95% confidence interval [CI], 51.5%-66.0%) in Egypt and 55.8% (95% CI, 49.1%-62.4%) in Pakistan; these values were higher than in other countries, which had a pooled prevalence of only 15.6% (95% CI, 12.4%-19.0%). Mean prevalence was highest in patients with hepatocellular carcinoma at 56.9% (95% CI, 50.2%-63.5%) and those with cirrhosis at 50.4% (95% CI, 40.8%-60.0%). Type of LRD population and country were the strongest predictors of prevalence, explaining 48.6% of the variation. No evidence for prevalence decline was found, but there was strong evidence for prevalence increase in Pakistan. A strong, positive association was identified between prevalence in the general population and that in LRD populations; the Pearson correlation coefficient ranged between 0.605 and 0.862. The pooled mean viremic rate was 75.5% (95% CI, 61.0%-87.6%). Genotype 4 was most common (44.2%), followed by genotype 3 (34.5%), genotype 1 (17.0%), genotype 2 (3.5%), genotype 6 (0.5%), and genotype 5 (0.3%). Conclusion: HCV appears to play a dominant role in liver diseases in Egypt and Pakistan and has a growing role in Pakistan. Testing and treatment of LRD populations are essential to reduce disease burden and transmission and to reach HCV elimination by 2030

Individual-level key associations and modes of exposure for hepatitis C virus infection in the Middle East and North Africa: a systematic synthesis.

PURPOSE: To identify, map, and synthesize the individual-level key associations and modes of exposure for hepatitis C virus (HCV) infection in the Middle East and North Africa (MENA), the most affected region by HCV. METHODS: Source of data was the MENA HCV Epidemiology Synthesis Project database, populated through systematic literature searches. Risk factors determined to be statistically significant after adjustment for confounders were extracted and categorized into key associations or modes of exposure. RESULTS: In total, 329 risk factors were identified from 109 articles in 14 of 24 MENA countries. Among key associations, age was most frequently reported (n = 39; 34.2%), followed by other infections/diseases (n = 20; 17.5%), and incarceration (n = 17; 14.9%). Among modes of exposure, health care-related exposures were most frequently reported (n = 127; 59.5%), followed by injecting drug use exposures (n = 45; 20.9%), community-related exposures (n = 34; 15.8%), and sexual-related exposures (n = 8; 3.7%). Blood transfusion, hemodialysis, surgical and other medical procedures, dental work, and medical injections were identified as key health care-related exposures. CONCLUSIONS: Health care appears to be the primary driver of prevalent (and possibly incident) infections in MENA, followed by injecting drug use. HCV screening should target the identified modes of exposure. Commitment to prevention should be an integral component of HCV response to achieve HCV elimination by 2030, with focus on strengthening infection control in health care facilities, improving injection safety and blood screening, and expanding harm reduction services for people who inject drugs

Key associations for hepatitis C virus genotypes in the Middle East and North Africa.

This study aimed to investigate the epidemiology of hepatitis C virus (HCV) genotypes in the Middle East and North Africa (MENA) through an analytical and quantitative meta-regression methodology. For the most common genotypes 1, 3, and 4, country/subregion explained more than 77% of the variation in the distribution of each genotype. Genotype 1 was common across MENA, and was more present in high-risk clinical populations than in the general population. Genotype 3 was much more present in Afghanistan, Iran, and Pakistan than the rest of countries, and was associated with transmission through injecting drug use. Genotype 4 was broadly disseminated in Egypt in all populations, with overall limited presence elsewhere. While genotype 2 was more present in high-risk clinical populations and people who inject drugs, most of the variation in its distribution remained unexplained. Genotypes 5, 6, and 7 had low or no presence in MENA, limiting the epidemiological inferences that could be drawn. To sum up, geography is the principal determinant of HCV genotype distribution. Genotype 1 is associated with transmission through high-risk clinical procedures, while genotype 3 is associated with injecting drug use. These findings demonstrate the power of such analytical approach, which if extended to other regions and globally, can yield relevant epidemiological inferences

Hepatitis C virus genotypes in the Middle East and North Africa: Distribution, diversity, and patterns.

Our objective was to characterize the distribution, diversity and patterns of hepatitis C virus (HCV) genotypes in the Middle East and North Africa (MENA). Source of data was a database of HCV genotype studies in MENA populated using a series of systematic literature searches. Pooled mean proportions were estimated for each genotype and by country using DerSimonian-Laird random-effects meta-analyses. Genotype diversity within countries was assessed using Shannon Diversity Index. Number of chronic infections by genotype and country was calculated using the pooled proportions and country-specific numbers of chronic infection. Analyses were conducted on 338 genotype studies including 82 257 genotyped individuals. Genotype 1 was dominant (≥50%) in Algeria, Iran, Morocco, Oman, Tunisia, and UAE, and was overall ubiquitous across the region. Genotype 2 was common (10-50%) in Algeria, Bahrain, Libya, and Morocco. Genotype 3 was dominant in Afghanistan and Pakistan. Genotype 4 was dominant in Egypt, Iraq, Jordan, Palestine, Qatar, Saudi Arabia, and Syria. Genotypes 5, 6, and 7 had limited or no presence across countries. Genotype diversity varied immensely throughout MENA. Weighted by population size, MENA's chronic infections were highest among genotype 3, followed by genotype 4, genotype 1, genotype 2, genotype 5, and genotype 6. Despite ubiquitous presence of genotype 1, the vast majority of chronic infections were of genotypes 3 or 4, because of the sizable epidemics in Pakistan and Egypt. Three sub-regional patterns were identified: genotype 3 pattern centered in Pakistan, genotype 4 pattern centered in Egypt, and genotype 1 pattern ubiquitous in most MENA countries

Hepatitis C virus viremic rate in the Middle East and North Africa: Systematic synthesis, meta-analyses, and meta-regressions.

OBJECTIVES: To estimate hepatitis C virus (HCV) viremic rate, defined as the proportion of HCV chronically infected individuals out of all ever infected individuals, in the Middle East and North Africa (MENA). METHODS: Sources of data were systematically-gathered and standardized databases of the MENA HCV Epidemiology Synthesis Project. Meta-analyses were conducted using DerSimonian-Laird random-effects models to determine pooled HCV viremic rate by risk population or subpopulation, country/subregion, sex, and study sampling method. Random-effects meta-regressions were conducted to identify predictors of higher viremic rate. RESULTS: Analyses were conducted on 178 measures for HCV viremic rate among 19,593 HCV antibody positive individuals. In the MENA region, the overall pooled mean viremic rate was 67.6% (95% CI: 64.9-70.3%). Across risk populations, the pooled mean rate ranged between 57.4% (95% CI: 49.4-65.2%) in people who inject drugs, and 75.5% (95% CI: 61.0-87.6%) in populations with liver-related conditions. Across countries/subregions, the pooled mean rate ranged between 62.1% (95% CI: 50.0-72.7%) and 70.4% (95% CI: 65.5-75.1%). Similar pooled estimates were further observed by risk subpopulation, sex, and sampling method. None of the hypothesized population-level predictors of higher viremic rate were statistically significant. CONCLUSIONS: Two-thirds of HCV antibody positive individuals in MENA are chronically infected. Though there is extensive variation in study-specific measures of HCV viremic rate, pooled mean estimates are similar regardless of risk population or subpopulation, country/subregion, HCV antibody prevalence in the background population, or sex. HCV viremic rate is a useful indicator to track the progress in (and coverage of) HCV treatment programs towards the set target of HCV elimination by 2030

Air pollution and cardiovascular mortality with over 25years follow-up : a combined analysis of two British cohorts

Adverse effects of air pollution on cardiovascular disease (CVD) mortality are well established. There are comparatively fewer studies in Europe, and in the UK particularly, than in North America. We examined associations in two British cohorts with >25years of follow-up.; Annual average NO2, SO2 and black smoke (BS) air pollution exposure estimates for 1991 were obtained from land use regression models using contemporaneous monitoring data. From the European Study of Cohorts and Air Pollution (ESCAPE), air pollution estimates in 2010-11 were obtained for NO2, NOx, PM10, PMcoarse and PM2.5. The exposure estimates were assigned to place of residence 1989 for participants in a national birth cohort born in 1946, the MRC National Study of Health and Development (NSHD), and an adult multi-ethnic London cohort, Southall and Brent Revisited (SABRE) recruited 1988-91. The combined median follow-up was 26years. Single-pollutant competing risk models were employed, adjusting for individual risk factors.; Elevated non-significant hazard ratios for CVD mortality were seen with 1991 BS and SO2 and with ESCAPE PM10 and PM2.5 in fully adjusted linear models. Per 10μg/m(3) increase HRs were 1.11 [95% CI: 0.76-1.61] for BS, 1.05 [95% CI: 0.91-1.22] for SO2, 1.16 [95% CI: 0.70-1.92] for PM10 and 1.30 [95% CI: 0.39-4.34] for PM2.5, with largest effects seen in the fourth quartile of BS and PM2.5 compared to the first with HR 1.24 [95% CI: 0.91-1.61] and 1.21 [95% CI: 0.88-1.66] respectively. There were no consistent associations with other ESCAPE pollutants, or with 1991 NO2. Modelling using Cox regression led to similar results.; Our results support a detrimental long-term effect for air pollutants on cardiovascular mortality

SARS-CoV-2 infection hospitalization, severity, criticality, and fatality rates

AbstractBackgroundThis study aimed to estimate the age-stratified and overall morbidity and mortality rates of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection based on an analysis of the pervasive SARS-CoV-2 epidemic in Qatar, a country with &lt;9% of the population being ≥50 years of age.MethodsInfection disease outcomes were investigated using a Bayesian approach applied to an age-structured mathematical model describing SARS-CoV-2 transmission and disease progression in the population. The model was fitted to infection and disease time-series and age-stratified data. Two separate criteria for classifying morbidity were used: one based on actual recorded hospital admission (acute-care or intensive-care-unit hospitalization) and one based on clinical presentation as per World Health Organization classification of disease severity or criticality.ResultsAll outcomes showed very strong age dependence, with low values for those &lt;50 years of age, but rapidly growing rates for those ≥50 years of age. The strong age dependence was particularly pronounced for infection criticality rate and infection fatality rate. Infection acute-care and intensive-care-unit bed hospitalization rates were estimated at 13.10 (95% CI: 12.82-13.24) and 1.60 (95% CI: 1.58-1.61) per 1,000 infections, respectively. Infection severity and criticality rates were estimated at 3.06 (95% CI: 3.01-3.10) and 0.68 (95% CI: 0.67-0.68) per 1,000 infections, respectively. Infection fatality rate was estimated at 1.85 (95% CI: 1.74-1.95) per 10,000 infections.ConclusionsSARS-CoV-2 severity and fatality in Qatar was not high and demonstrated a very strong age dependence with &lt;4 infections in every 1,000 being severe or critical and &lt;2 in every 10,000 being fatal. Epidemic expansion in nations with young populations may lead to lower disease burden than previously thought.</jats:sec

COVID-19 risk score as a public health tool to guide targeted testing: A demonstration study in Qatar

We developed a Coronavirus Disease 2019 (COVID-19) risk score to guide targeted RTPCR testing in Qatar. The Qatar national COVID-19 testing database, encompassing a total of 2,688,232 RT-PCR tests conducted between February 5, 2020-January 27, 2021, was analyzed. Logistic regression analyses were implemented to derive the COVID-19 risk score, as a tool to identify those at highest risk of having the infection. Score cut-off was determined using the ROC curve based on maximum sum of sensitivity and specificity. The score's performance diagnostics were assessed. Logistic regression analysis identified age, sex, and nationality as significant predictors of infection and were included in the risk score. The ROC curve was generated and the area under the curve was estimated at 0.63 (95% CI: 0.63-0.63). The score had a sensitivity of 59.4% (95% CI: 59.1%-59.7%), specificity of 61.1% (95% CI: 61.1%-61.2%), a positive predictive value of 10.9% (95% CI: 10.8%- 10.9%), and a negative predictive value of 94.9% (94.9%-95.0%). The concept and utility of a COVID-19 risk score were demonstrated in Qatar. Such a public health tool can have considerable utility in optimizing testing and suppressing infection transmission, while maximizing efficiency and use of available resources. 2022 Abu-Raddad et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

SARS-CoV-2 infection hospitalization, severity, criticality, and fatality rates in Qatar.

The SARS-CoV-2 pandemic resulted in considerable morbidity and mortality as well as severe economic and societal disruptions. Despite scientific progress, true infection severity, factoring both diagnosed and undiagnosed infections, remains poorly understood. This study aimed to estimate SARS-CoV-2 age-stratified and overall morbidity and mortality rates based on analysis of extensive epidemiological data for the pervasive epidemic in Qatar, a country where < 9% of the population are ≥ 50 years. We show that SARS-CoV-2 severity and fatality demonstrate a striking age dependence with low values for those aged < 50 years, but rapidly growing rates for those ≥ 50 years. Age dependence was particularly pronounced for infection criticality rate and infection fatality rate. With Qatar's young population, overall SARS-CoV-2 severity and fatality were not high with < 4 infections in every 1000 being severe or critical and < 2 in every 10,000 being fatal. Only 13 infections in every 1000 received any hospitalization in acute-care-unit beds and < 2 in every 1000 were hospitalized in intensive-care-unit beds. However, we show that these rates would have been much higher if Qatar's population had the demographic structure of Europe or the United States. Epidemic expansion in nations with young populations may lead to considerably lower disease burden than currently believed