Estimate of the incidence of bladder cancer in Africa: A systematic review and Bayesian meta-analysis.

OBJECTIVES: To quantify the epidemiology of bladder cancer in Africa to guide a targeted public health response and support research initiatives. METHODS: We systematically searched publicly available sources for population-based registry studies reporting the incidence of bladder cancer in Africa between January 1980 and June 2017. Crude incidence rates of bladder cancer were extracted. A Bayesian network meta-analysis model was used to estimate incidence rates. RESULTS: The search returned 1328 studies. A total of 22 studies carried out across 15 African countries met our pre-defined selection criteria. Heterogeneity across studies was high (I2  = 98.9%, P < 0.001). The pooled incidence of bladder cancer in Africa was 7.0 (95% credible interval 5.8-8.3) per 100 000 population in men and 1.8 (95% credible interval 1.2-2.6) per 100 000 in women. The incidence of bladder cancer was consistently higher in North Africa in both sexes. Among men, we estimated a pooled incidence of 10.1 (95% credible interval 7.9-11.9) per 100 000 in North Africa and 5.0 (95% credible interval 3.8-6.6) per 100 000 in sub-Saharan Africa. In women, the pooled incidence was 2.0 (95% credible interval 1.0-3.0) per 100 000 and 1.5 (95% credible interval 0.9-2.0) per 100 000 in North Africa and sub-Saharan Africa, respectively. Incidence rates increased significantly among men from 5.6 (95% credible interval 4.2-7.2) in the 1990s to 8.5 (95% credible interval 6.9-10.1) per 100 000 in 2010. CONCLUSIONS: The present study suggests a growing incidence of bladder cancer in Africa in recent years, particularly among men and in North Africa. This study also highlights the lack of quality data sources and collection of essential clinical and epidemiological data in several African countries, and this hinders public health planning.

Global, regional, and national prevalence of asthma in 2019: a systematic analysis and modelling study.

Background: Asthma has a significant impact on people of all ages, particularly children. A lack of universally accepted case definition and confirmatory tests and a poor understanding of major risks interfere with a global response. We aimed to provide global estimates of asthma prevalence and cases in 2019 across four main epidemiological case definitions - current wheezing, ever wheezing, current asthma, and ever asthma. We further investigated major associated factors to determine regional and national distributions of prevalence and cases for current wheezing and ever asthma. Methods: We identified relevant population-based studies published between January 1, 1990, and December 31, 2019. Using a multilevel multivariable mixed-effects meta-regression model, we assessed the age- and sex-adjusted associations of asthma with study-level variables, including year, setting, region and socio-demographic index (SDI). Using a random-effects meta-analysis, we then identified risk factors for current wheezing and asthma. From a "risk factor-based model", which included current smoking, and biomass exposure for current wheezing, and rural setting, current smoking, biomass exposure, and SDI for ever asthma, we estimated case numbers and prevalence across regions and 201 countries and territories in 2019. Results: 220 population-based studies conducted in 88 countries were retained. In 2019, the global prevalence estimates of asthma in people aged 5-69 years by various definitions, namely current wheezing, ever wheezing, current asthma, and ever asthma were 11.5% (95% confidence interval (CI) = 9.1-14.3), 17.9% (95% CI = 14.2-22.3), 5.4% (95% CI = 3.2-9.0) and 9.8% (95% CI = 7.8-12.2), respectively. These translated to 754.6 million (95% CI = 599. 7-943.4), 1181.3 million (95% CI = 938.0-1,471.0), 357.4 million (95% CI = 213.0-590.8), 645.2 million (95% CI = 513.1-806.2) cases, respectively. The overall prevalence of current wheezing among people aged 5-69 years was the highest in the African Region at 13.2% (95% CI = 10.5-16.5), and the lowest in the Americas Region at 10.0% (95% CI = 8.0-12.5). For ever asthma, the estimated prevalence in those aged 5-69 years was also the highest in the African Region at 11.3% (95% CI = 9.0-14.1), but the lowest in South-East Asia Region (8.8, 95% CI = 7.0-11.0). Conclusions: Although varying approaches to case identification in different settings make epidemiological estimates of asthma very difficult, this analysis reaffirms asthma as a common global respiratory condition before the COVID-19 pandemic in 2019, with higher prevalence than previously reported in many world settings.