Wheeze, asthma diagnosis and medication use: a national adult survey in a developing country

A model-based approach to estimating the prevalence of disease combinations in South Africa

BACKGROUND

The development of strategies to better detect and manage patients with multiple long-term conditions requires estimates of the most prevalent condition combinations. However, standard meta-analysis tools are not well suited to synthesising heterogeneous multimorbidity data.

METHODS

We developed a statistical model to synthesise data on associations between diseases and nationally representative prevalence estimates and applied the model to South Africa. Published and unpublished data were reviewed, and meta-regression analysis was conducted to assess pairwise associations between 10 conditions: arthritis, asthma, chronic obstructive pulmonary disease (COPD), depression, diabetes, HIV, hypertension, ischaemic heart disease (IHD), stroke and tuberculosis. The national prevalence of each condition in individuals aged 15 and older was then independently estimated, and these estimates were integrated with the ORs from the meta-regressions in a statistical model, to estimate the national prevalence of each condition combination.

RESULTS

The strongest disease associations in South Africa are between COPD and asthma (OR 14.6, 95% CI 10.3 to 19.9), COPD and IHD (OR 9.2, 95% CI 8.3 to 10.2) and IHD and stroke (OR 7.2, 95% CI 5.9 to 8.4). The most prevalent condition combinations in individuals aged 15+ are hypertension and arthritis (7.6%, 95% CI 5.8% to 9.5%), hypertension and diabetes (7.5%, 95% CI 6.4% to 8.6%) and hypertension and HIV (4.8%, 95% CI 3.3% to 6.6%). The average numbers of comorbidities are greatest in the case of COPD (2.3, 95% CI 2.1 to 2.6), stroke (2.1, 95% CI 1.8 to 2.4) and IHD (1.9, 95% CI 1.6 to 2.2).

CONCLUSION

South Africa has high levels of HIV, hypertension, diabetes and arthritis, by international standards, and these are reflected in the most prevalent condition combinations. However, less prevalent conditions such as COPD, stroke and IHD contribute disproportionately to the multimorbidity burden, with high rates of comorbidity. This modelling approach can be used in other settings to characterise the most important disease combinations and levels of comorbidity.

Urinary metabolites of polycyclic aromatic hydrocarbons and short-acting beta agonist or systemic corticosteroid asthma medication use within NHANES

BACKGROUND

Within cross-sectional studies like the U.S. National Health and Nutritional Examination Survey (NHANES), researchers have observed positive associations between polycyclic aromatic hydrocarbon (PAH) exposure and asthma diagnosis. It is unclear whether similar relationships exist for measures of acute asthma outcomes, including short-term asthma medication use to alleviate symptoms. We examined the relationship between markers of recent PAH exposure and 30-day short-acting beta agonist (SABA) or systemic corticosteroid use, an indicator for recent asthma symptoms.

MATERIALS AND METHODS

For 16,550 children and adults across multiple waves of NHANES (2005-2016), we fit quasi-Poisson multivariable regression models to describe the association between urinary 1-hydroxypyrene (a metabolite of PAH) and SABA or systemic corticosteroid use. We assessed for effect modification by age group and asthma controller medication use. All models were adjusted for urinary creatinine, age, female/male designation, race/ethnicity, poverty, insurance coverage, and serum cotinine.

RESULTS

After controlling for confounding, an increase of one standard deviation of 1-hydroxypyrene was associated with greater prevalence of recent SABA or systemic corticosteroid use (PR: 1.06, 95% CI: 1.03-1.10). The results were similar among those with ever asthma diagnosis and across urine creatinine dilution methods. We did not observe effect modification by age group (p-interaction = 0.22) or asthma controller medication use (p-interaction = 0.73).

CONCLUSION

Markers of recent PAH exposure was positively associated with SABA or systemic corticosteroid use, across various urine dilution adjustment methods. It is important to ensure appropriate temporality between exposures and outcomes in cross-sectional studies.

Chronic diseases of lifestyle risk factor profiles of a South African rural community

Globally, chronic diseases of lifestyle account for millions of dollars spent annually on health. These diseases share similar risk factors including: physical inactivity, obesity, cigarette smoking, and hypertension among others. This study sought to assess risk factors for chronic diseases of lifestyle of a rural community in South Africa. This study used a survey design with data randomly collected using the WHO STEPS Instrument for Chronic Disease Risk Factor Surveillance from participants who attended routine checks from February to October 2018 from a trained healthcare practitioner. Informed consent was sought from all participants before the administration of the instrument. The research setting was the community Primary Health Center. About 54.0% of participants presented with no family history of hypertension but 19.7% had a family history of type II diabetes mellitus. More women were found to be hypertensive, with the majority (93.4%) monitoring their blood pressure. The study revealed that more men were current smokers. A large number of participants were engaged in a sedentary lifestyle with about one-third of the participants reported being obese. Physical inactivity, sedentary lifestyle, and hypertension were among the lifestyle-related risk factors for chronic diseases among residents of this rural community.

Estimating the number of averted illnesses and deaths as a result of vaccination against an influenza pandemic in nine low- and middle-income countries

BACKGROUND

During the 2009 influenza A(H1N1)pdm09 pandemic, 77 countries received donated monovalent A(H1N1)pdm09 vaccine through the WHO Pandemic Influenza A(H1N1) Vaccine Deployment Initiative. However, 47% did not receive their first shipment until after the first wave of virus circulation, and 8% did not receive their first shipment until after the WHO declared the end of the pandemic. Arguably, these shipments were too late into the pandemic to have a substantial effect on virus transmission or disease burden during the first waves of the pandemic.

OBJECTIVES

In order to evaluate the potential benefits of earlier vaccine availability, we estimated the number of illnesses and deaths that could be averted during a 2009-like influenza pandemic under five different vaccine-availability timing scenarios.

METHODS

We adapted a model originally developed to estimate annual influenza morbidity and mortality burden averted through US seasonal vaccination and ran it for five vaccine availability timing scenarios in nine low- and middle-income countries that received donated vaccine.

RESULTS

Among nine study countries, we estimated that the number of averted cases was 61-216,197 for actual vaccine receipt, increasing to 2,914-283,916 had vaccine been available simultaneously with the United States.

CONCLUSIONS

Earlier delivery of vaccines can reduce influenza case counts during a simulated 2009-like pandemic in some low- and middle-income countries. For others, increasing the number of cases and deaths prevented through vaccination may be dependent on factors other than timely initiation of vaccine administration, such as distribution and administration capacity.

Prevalence and determinants of current asthma in Cameroon

INTRODUCTION

The prevalence of asthma varies from one country to another due to differences in ethnicity, socio-economics status, environmental and climatic risk factors. The aim of this study was to determine the prevalence and determinants of current asthma in Cameroonian adults.

MATERIAL AND METHODS

Data from 4 cross-sectional community-based studies from 2014 to 2018 were analyzed. Participants aged 19 years and above were selected through multilevel stratified random sampling methods across 2 urban areas, 2 semi-urban areas and 1 rural area. Current asthma was defined as "wheezing in the last 12 months in a subject with self-reported asthma or having used drugs for asthma treatment". Logistic regression was used to investigate the determinants of current asthma.

RESULTS

A total of 10,707 adults [median age (interquartile range)=36 (26-52) years, 44.5% of men] were definitively enrolled in the study. The overall prevalence [95% confidence interval (CI)] of current asthma was 3.9% (3.5-4.3)%. Determinants [odd's ratio (OR), (95%CI)] of current asthma were: Sudanese ethnicity [1.9(1.4-2.7)], rural area [1.5(1.1-2.1)], urban area [1.6(1.2-2.2)], past history of pneumonia [1.9(1.1-3.4)], allergic rhino-conjunctivitis [6.5(4.7-8.9)], atopic eczema [2.3(1.5-3.6)], body mass index (BMI)≥40kg/m² [1.9(1.0-3.4)] and BMI<18kg/m² [1.8(1.2-2.9)].

CONCLUSION

The prevalence of current asthma is close to the low value of the Sub-Saharan African range. Sudanese ethnicity, rural area, urban area, history of pneumonia, allergic disease, severe obesity and underweight were determinants of current asthma in Cameroon. More research is surely warranted to understand the mechanisms underlying the association of asthma with Sudanese ethnicity.

Urbanisation and asthma in low-income and middle-income countries: a systematic review of the urban-rural differences in asthma prevalence

BACKGROUND

Urbanisation has been associated with temporal and geographical differences in asthma prevalence in low-income and middle-income countries (LMICs). However, little is known of the mechanisms by which urbanisation and asthma are associated, perhaps explained by the methodological approaches used to assess the urbanisation-asthma relationship.

OBJECTIVE

This review evaluated how epidemiological studies have assessed the relationship between asthma and urbanisation in LMICs, and explored urban/rural differences in asthma prevalence.

METHODS

Asthma studies comparing urban/rural areas, comparing cities and examining intraurban variation were assessed for eligibility. Included publications were evaluated for methodological quality and pooled OR were calculated to indicate the risk of asthma in urban over rural areas.

RESULTS

Seventy articles were included in our analysis. Sixty-three compared asthma prevalence between urban and rural areas, five compared asthma prevalence between cities and two examined intraurban variation in asthma prevalence. Urban residence was associated with a higher prevalence of asthma, regardless of asthma definition: current-wheeze OR:1.46 (95% CI:1.22 to 1.74), doctor diagnosis OR:1.89 (95% CI:1.47 to 2.41), wheeze-ever OR:1.44 (95% CI:1.15 to 1.81), self-reported asthma OR:1.77 (95% CI:1.33 to 2.35), asthma questionnaire OR:1.52 (95% CI:1.06 to 2.16) and exercise challenge OR:1.96 (95% CI:1.32 to 2.91).

CONCLUSIONS

Most evidence for the relationship between urbanisation and asthma in LMICs comes from studies comparing urban and rural areas. These studies tend to show a greater prevalence of asthma in urban compared to rural populations. However, these studies have been unable to identify which specific characteristics of the urbanisation process may be responsible. An approach to understand how different dimensions of urbanisation, using contextual household and individual indicators, is needed for a better understanding of how urbanisation affects asthma.

PROSPERO REGISTRATION NUMBER

CRD42017064470.

Prevalence of chronic respiratory disease in urban and rural Uganda

Objective

To determine the prevalence of chronic respiratory diseases in urban and rural Uganda and to identify risk factors for these diseases.

Methods

The population-based, cross-sectional study included adults aged 35 years or older. All participants were evaluated by spirometry according to standard guidelines and completed questionnaires on respiratory symptoms, functional status and demographic characteristics. The presence of four chronic respiratory conditions was monitored: chronic obstructive pulmonary disease (COPD), asthma, chronic bronchitis and a restrictive spirometry pattern.

Findings

In total, 1502 participants (average age: 46.9 years) had acceptable, reproducible spirometry results: 837 (56%) in rural Nakaseke and 665 (44%) in urban Kampala. Overall, 46.5% (698/1502) were male. The age-adjusted prevalence of any chronic respiratory condition was 20.2%. The age-adjusted prevalence of COPD was significantly greater in rural than urban participants (6.1 versus 1.5%, respectively; P < 0.001), whereas asthma was significantly more prevalent in urban participants: 9.7% versus 4.4% in rural participants (P < 0.001). The age-adjusted prevalence of chronic bronchitis was similar in rural and urban participants (3.5 versus 2.2%, respectively; P = 0.62), as was that of a restrictive spirometry pattern (10.9 versus 9.4%; P = 0.82). For COPD, the population attributable risk was 51.5% for rural residence, 19.5% for tobacco smoking, 16.0% for a body mass index < 18.5 kg/m² and 13.0% for a history of treatment for pulmonary tuberculosis.

Conclusion

The prevalence of chronic respiratory disease was high in both rural and urban Uganda. Place of residence was the most important risk factor for COPD and asthma.

Prevalence and factors associated with asthma among adolescents and adults in Uganda: a general population based survey

Background

Recent large-scale population data on the prevalence of asthma and its risk factors are lacking in Uganda. This survey was conducted to address this data gap.

Methods

A general population based survey was conducted among people ≥12 years. A questionnaire was used to collect participants socio-demographics, respiratory symptoms, medical history, and known asthma risk factors. Participants who reported wheeze in the past 12 months, a physician diagnosis of asthma or current use of asthma medications were classified as having asthma. Asthmatics who were ≥ 35 years underwent spirometry to determine how many had fixed airflow obstruction (i.e. post bronchodilator forced expiratory volume in one second/forced vital capacity (FEV₁/FVC) ratio < lower limit of normal (LLN). Descriptive statistics were used to summarize participants’ characteristics. Prevalence of asthma was calculated as a proportion of asthmatics over total survey population. To obtain factors independently associated with asthma, a random-effects model was fitted to the data.

Results

Of the 3416 participants surveyed, 61.2% (2088) were female, median age was 30 years (IQR, 20–45) and 323 were found to have asthma. Sixteen people with asthma ≥35 years had fixed airflow obstruction. The prevalence of asthma was 11.0% (95% CI:8.9–13.2; males 10.3%, females 11.4%, urban 13.0% and rural 8.9%. Significantly more people with asthma smoked than non-asthmatics: 14.2% vs. 6.3%, p < 0.001, were exposed to biomass smoke: 28.0% vs. 20.0%, p < 0.001, had family history of asthma: 26.9% vs. 9.4%, p, < 0.001, had history of TB: 3.1% vs. 1.30%, p = 0.01, and had hypertension: 17.9% vs. 12.0%, p = 0. 003. In multivariate analysis smoking, (adjusted odds ratio (AOR), 3.26 (1.96–5.41, p < 0.001) family history of asthma, AOR 2.90 (98–4.22 p- < 0.001), nasal congestion, AOR 3.56 (2.51–5.06, p < 0.001), biomass smoke exposure, AOR 2.04 (1.29–3.21, p = 0.002) and urban residence, AOR 2.01(1.23–3.27, p = 0.005) were independently associated with asthma.

Conclusion

Asthma is common in Uganda and is associated with smoking, biomass smoke exposure, urbanization, and allergic diseases. Health care systems should be strengthened to provide asthma care. Measures to reduce exposure to the identified associated factors are needed.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6562-2) contains supplementary material, which is available to authorized users.

Factors Associated with Persistent Lower Respiratory Symptoms or Asthma among Residents Exposed to a Sulphur Stockpile Fire Incident

Introduction: Residents of Macassar, South Africa, were exposed to sulphur dioxide vapours (SO₂) caused by an ignited sulphur stockpile, which produced peak hourly SO₂ levels of 20–200 ppm. The aim of this study was to assess the risk factors associated with persistent lower respiratory symptoms (LRS) or asthma six years after acute exposure to high SO₂ levels. Methods: A case-control study of residents that presented for a health evaluation six years after the incident was conducted. Survey instruments included a questionnaire, clinical examination and medical record review by an expert panel. A “case” was defined as a resident with persistent LRS/asthma. The Industrial Source Complex Short Term Model (ISCST 3) was used to predict time-averaged hourly SO₂ levels. Results: A previous history of pulmonary tuberculosis (PTB) was associated with persistent LRS/asthma (OR_udj: 3.49, CI: 1.46–8.35). Cases were more likely to report chest tightness (OR_udj: 9.93; CI: 5.15–19.11) at the time of the incident. Peak exposure at hour 15 was associated with persistent LRS/asthma (OR_adj: 1.04; CI: 1.01–1.07). Conclusion: LRS/asthma persisted in some individuals six years after acute SO₂ exposure_. Aside from peak exposures, initial chest tightness and a previous history of PTB were the strong predictors of persistent LRS/asthma.

Relationship between Serum Omega-3 Fatty Acid and Asthma Endpoints

Recent studies have highlighted the potential protective role of omega-3 polyunsaturated fatty acids (n-3 PUFA) in asthma. This study aimed at determining the association between seafood intake, serum PUFA composition and clinical endpoints of asthma in adults. A cross-sectional study of 642 subjects used the European Committee Respiratory Health Survey (ECRHS) questionnaire, skin prick tests, spirometry and methacholine challenge tests following ATS guidelines. Sera was analysed for n-3 and n-6 PUFA composition. Subjects had a mean age of 34 years, were largely female (65%) and 51% were current smokers. While 99% reported fish consumption, rock lobster, mussels, squid and abalone were also consumed less frequently. The prevalence of asthma symptoms was 11%, current asthma (ECRHS definition) was 8% and non-specific bronchial hyperresponsiveness (NSBH) was much higher (26%) In adjusted models the n-3 PUFAs 20:5 (EPA) and 22:5 (DPA) were significantly associated with a decreased risk of having NSBH. Total n-3 PUFA composition was associated with decreased NSBH risk (OR = 0.92), while high n-6 PUFA composition was associated with an increased risk (OR = 1.14).

Asthma and its related socioeconomic factors: The Shiraz Adult Respiratory Disease Study 2015

OBJECTIVE

This study aimed to explore the association between the prevalence of asthma and the socioeconomic factors using data from the Shiraz Adult Respiratory Disease Study, 2015(SARDS).

METHODS

The SARDS was conducted from June to October 2015 among adult subjects of the general population of Shiraz, Iran. Current asthma was defined as the presence of at least 1 of the following factors in the preceding 12 months: (1) being awakened by an attack of shortness of breath, coughing, or chest tightness without any identifiable cause; (2) having an asthma attack; (3) currently using medication for asthma; or (4) having wheezing or whistling in the chest not associated with a cold or the flu. Information on individual socioeconomic status was derived from self-reported education level, occupation, income, and residence location. A value of P < .05 was considered statistically significant.

RESULTS

A total of 4582 respondents aged 20-60 years were included in the analysis. The overall prevalence of adult asthma was 7.8%. The prevalence of asthma was higher significantly among female and subjects with higher body mass index, allergic rhinitis, smokers, jobless, and individuals who live in suburban areas. In the adjusted logistic regression model, being jobless (odds ratio [OR], 2.256; 95% confidence interval [CI], 1.123-4.535) and living in a suburban area (OR, 1.735; 95% CI, 1.058-2.845) were the most significant socioeconomic predictive factors for adult current asthma.

CONCLUSIONS

It can be concluded that lower socioeconomic status is associated with higher adult current asthma prevalence. Target interventions are necessary to reduce disparities in healthcare systems.

Asthma and Allergic Disorders in Uganda: A Population-Based Study Across Urban and Rural Settings

BACKGROUND

Allergic diseases are increasing in sub-Saharan Africa, but few studies have characterized the burden among adults.

OBJECTIVE

We conducted a study to evaluate the prevalence and risk factors of allergic disorders in urban and rural Uganda.

METHODS

We present a cross-sectional analysis of enrollment data from a population-based cohort study of adults aged ≥35 years in urban and rural Uganda. Sociodemographic and both lifetime and 12-month respiratory symptoms data were collected and spirometry was conducted following standard guidelines.

RESULTS

In 1,308 adults (median age 43.8 years and 52.3% female), we found an age-adjusted prevalence of 6.8% for asthma (9.8% urban, 4.3% rural; P < .001), 11.9% for allergic rhinitis (16.4% urban, 7.8% rural; P < .001), and 8.2% for eczema (9.9% urban, 7.8% rural; P = .15). Urbanization was the primary driver of asthma, accounting for 61.4% of cases (95% confidence interval [CI] 22.0% to 83.4%), and was the strongest risk factor for any allergic illness (odds ratio [OR] = 1.87, 95% CI 1.39-2.51). Parental asthma was not associated with allergic illness. Asthma was associated with a lower forced expiratory volume in 1 second (FEV₁) by 0.56 z scores (95% CI 0.33-0.80). We found a dose-response association between lower quintiles of the FEV₁/forced vital capacity ratio and both hospitalization (OR = 1.77, 95% CI 1.21-2.59) and impairment in daily activities (1.65, 1.20-2.27).

CONCLUSIONS

Asthma and allergic rhinitis were twice as prevalent in urban settings. Asthma was associated with greater impairment and worse lung function outcomes. We identified a high prevalence of allergic disorders in Uganda, which can be expected to increase due to urbanization and resultant exposures throughout early development.

Clinico-Radiologic and Spirometric Profile of an Indian Population with Post-Tuberculous Obstructive Airway Disease

INTRODUCTION

Tuberculosis is a public health problem in developing countries and in spite of receiving adequate anti-tuberculous therapy, patients often continues to have several post-tuberculous sequelae, especially airflow limitation.

AIM

To evaluate pulmonary function by spirometry among post-tuberculosis cases with airway obstruction and their relationship with smoking.

MATERIALS AND METHODS

All patients who presented to the pulmonary medicine Outpatient Department (OPD) with symptoms of obstructive airway disease and had completed adequate anti-tuberculous therapy for pulmonary tuberculosis were taken up for study. They were initially evaluated with sputum smear for Acid Fast Bacilli (AFB) and chest X-ray. Patients without evidence of active tuberculosis underwent spirometry and those having post-bronchodilator Forced Expiratory Volume in first second (FEV1)/ Forced Vital Capacity (FVC) FEV1/FVC<0.7 were taken up for final analysis. Spirometric parameters were compared between smokers and non-smokers.

RESULTS

Out of 138 finally selected cases, 84.06% were male and 71.01% were within age range of 40-69 years. Significant positive association was found between extent of radiologic lesion and severity of airflow obstruction. Purely obstructive pattern was found in 27.54% cases and 72.46% showed mixed pattern. Patients with mixed ventilatory abnormality had worse pulmonary function and poorer bronchodilator reversibility than patients with pure obstruction. Comparison of post-bronchodilator FEV1, FVC, Peak Expiratory Flow (PEF) and Forced Expiratory Flow (FEF) 25-75 between smokers and non-smokers did not show statistically significant difference.

CONCLUSION

Majority of patients with post-tuberculous obstructive airway disease have associated restrictive component. But smoking did not cause significant alteration in pulmonary function among such patients.

Increase in the Risk of Respiratory Disorders in Adults and Children Related to Crop-Growing in Niger

Background and Objective. Environmental factors are an increasing concern for respiratory health in developing countries. The objective of this study was to investigate whether Nigerien people living in cultivated areas have more respiratory symptoms than those living in pastoral areas. Method. A cross-sectional study was conducted in 2013 in two populations during the rainy season when land is cultivated. Environmental factors including pesticide use and respiratory symptoms were collected in adults and children during face-to-face interviews. Multivariate analysis between exposures and symptoms was performed in children and in adults separately. Results. The study included 471 adults and 229 children. Overall, none of the households reported the use of pesticides for agricultural purposes. However, 87.2% reported the use of insecticides at home. Multivariate analysis showed that people living in agricultural areas compared to those in pastoral areas had an increased risk of respiratory symptoms in adults (wheezing, dyspnea, sudden shortness of breath, and cough without fever) and in children (cough without fever). The use of insecticides showed no effect on respiratory symptoms after adjustment. Conclusion. This first epidemiological study on the environment and respiratory health conducted in Niger demonstrates a significant relationship between respiratory manifestations and the agricultural characteristics of the living area. However only the effect of insecticides in the home on respiratory health was observed.

Distribution and etiology of chronic respiratory diseases in primary healthcare departments in Cape Verde

BACKGROUND AND OBJECTIVE

Data on chronic respiratory diseases (CRD) are scarce or unavailable in most African countries. We aimed to determine the prevalence of CRD and associated risk factors in Cape Verde, at the primary healthcare level.

METHODS

In the frame of the Global Alliance Against Chronic Respiratory Diseases, a cross-sectional study was carried out in October 2006 in 3256 outpatients (2142 women) (median age of 30 years) seeking care at primary healthcare departments, through a standardized interview questionnaire during two weeks.

RESULTS

The prevalence of emphysema, tuberculosis, chronic bronchitis, rhinoconjunctivitis and asthma were 0.7%, 2%, 4.5%, 12.3% and 6.2%, respectively. Current smoking was associated with emphysema (OR: 3.36; 95% CI: 0.97-11.40) and tuberculosis (OR: 2.14; 95% CI: 1.07-4.30), ever exposed to a dusty workplace with chronic bronchitis (OR: 2.20; CI 95%: 1.50-3.21) and rhinoconjunctivitis (OR: 1.56; CI 95%: 1.23-1.98) and cooking or heating using an open fire with asthma (OR: 1.59; CI 95%: 1.16-2.19). The estimates of attributable risks percent indicated that, in the sample, a noticeable part of CRD could be attributed to active smoking, exposure to dust and biomass. Results varied according to gender, particularly regarding current smoking which was more important for men.

CONCLUSIONS

Tobacco smoking, exposure to dust at work and using an open fire were important risk factors for CRD. Our results suggest that if actions were taken in order to reduce the aforementioned exposures, an important CRD decrease could be achieved.

Prevalence, risk factors and underdiagnosis of asthma and wheezing in adults 40 years and older: A population-based study

OBJECTIVE

There are differences in the prevalence and risk factors of asthma around the world. The epidemiological situation of adults 40 years and older is not well established. Our aim was to determine the prevalence, underdiagnosis and risk factors of asthma and wheezing in adults in Colombia.

METHODS

A cross-sectional, population-based study including 5539 subjects from 40 to 93 years selected by a probabilistic sampling technique in five cities was conducted.

MEASUREMENTS

respiratory symptoms and risk factors questionnaire and spirometry.

DEFINITIONS

(a) Wheezing: Affirmative answer to the question "have you ever had two or more attacks of "wheezes" causing you to feel short of breath?" (b) Asthma: Wheezing definition and FEV1/FVC post-bronchodilator ≥ 70%. (c) Underdiagnosis: Asthma definition without a physician-diagnosis. Logistic regression was used for exploring risk factors.

RESULTS

Prevalence of asthma was 9.0% (95% CI: 8.3-9.8) and wheezing 11.9% (95% CI: 11.0-12.8). Asthma underdiagnosis was 69.9% and increased to 79.0% in subjects 64 years or older. The risk factors related to asthma and/or wheezing were: living in Bogota or Medellin, female gender, first degree relative with asthma, respiratory disease before 16 years of age, obesity, no education, indoor wood smoke exposure and occupational exposure to dust particles, gases or fumes.

CONCLUSION

We described the epidemiologic situation of asthma in adults 40 years and older in Colombia. In addition to some recognized risk factors, our data supports the association of indoor wood smoke and occupational exposures with asthma and wheezing. Underdiagnosis of asthma in adults was high, particularly in older subjects.

Prevalence of asthma and allergic rhinitis among adults in Yaounde, Cameroon

BACKGROUND

Population-based estimates of asthma and allergic rhinitis in sub-Saharan African adults are lacking. We assessed the prevalence and determinants of asthma and allergic rhinitis in urban adult Cameroonians.

METHODS

A community-based survey was conducted from December 2013 to April 2014 among adults aged 19 years and above (N = 2,304, 57.3% women), selected through multilevel stratified random sampling across all districts of Yaounde (Capital city). Internationally validated questionnaires were used to investigate the presence of allergic diseases. Logistic regressions were employed to investigate the determinants of allergic conditions.

RESULTS

Prevalence rates were 2.7% (95% CI: 2.1-3.4) for asthma-ever, 6.9% (5.9-7.9) for lifetime wheezing, 2.9% (92.2-3.6) for current wheezing and 11.4% (10.1-12.7) for self-reported lifetime allergic rhinitis; while 240 (10.4%) participants reported current symptoms of allergic rhinitis, and 125 (5.4%) had allergic rhino-conjunctivitis. The prevalence of current asthma medication use and self-reported asthma attack was 0.8 (0.4-1.2) and 1 (0.6-1.4) respectively. Multivariable adjusted determinants of current wheezing were signs of atopic eczema [2.91 (1.09-7.74)] and signs of allergic rhinitis [3.24 (1.83-5.71)]. Age group 31-40 years [0.27(0.09-0.78), p = 0.016] was an independent protective factor for wheezing. Determinants of current rhinitis symptoms were active smoking [2.20 (1.37-3.54), p<0.001], signs of atopic eczema [2.84 (1.48-5.46)] and current wheezing [3.02 (1.70-5.39)].

CONCLUSION

Prevalence rates for asthma and allergic rhinitis among adults in this population were at the lower tails of those reported in other regions of the world. Beside the classical interrelation between allergic diseases found in this study, active smoking was an independent determinant of allergic rhinitis symptoms. Nationwide surveys are needed to investigate regional variations.

An estimate of asthma prevalence in Africa: a systematic analysis

Aim

To estimate and compare asthma prevalence in Africa in 1990, 2000, and 2010 in order to provide information that will help inform the planning of the public health response to the disease.

Methods

We conducted a systematic search of Medline, EMBASE, and Global Health for studies on asthma published between 1990 and 2012. We included cross-sectional population based studies providing numerical estimates on the prevalence of asthma. We calculated weighted mean prevalence and applied an epidemiological model linking age with the prevalence of asthma. The UN population figures for Africa for 1990, 2000, and 2010 were used to estimate the cases of asthma, each for the respective year.

Results

Our search returned 790 studies. We retained 45 studies that met our selection criteria. In Africa in 1990, we estimated 34.1 million asthma cases (12.1%; 95% confidence interval [CI] 7.2-16.9) among children <15 years, 64.9 million (11.8%; 95% CI 7.9-15.8) among people aged <45 years, and 74.4 million (11.7%; 95% CI 8.2-15.3) in the total population. In 2000, we estimated 41.3 million cases (12.9%; 95% CI 8.7-17.0) among children <15 years, 82.4 million (12.5%; 95% CI 5.9-19.1) among people aged <45 years, and 94.8 million (12.0%; 95% CI 5.0-18.8) in the total population. This increased to 49.7 million (13.9%; 95% CI 9.6-18.3) among children <15 years, 102.9 million (13.8%; 95% CI 6.2-21.4) among people aged <45 years, and 119.3 million (12.8%; 95% CI 8.2-17.1) in the total population in 2010. There were no significant differences between asthma prevalence in studies which ascertained cases by written and video questionnaires. Crude prevalences of asthma were, however, consistently higher among urban than rural dwellers.

Conclusion

Our findings suggest an increasing prevalence of asthma in Africa over the past two decades. Due to the paucity of data, we believe that the true prevalence of asthma may still be under-estimated. There is a need for national governments in Africa to consider the implications of this increasing disease burden and to investigate the relative importance of underlying risk factors such as rising urbanization and population aging in their policy and health planning responses to this challenge.

The impact of asthma and COPD in sub-Saharan Africa

BACKGROUND

Many countries in sub-Saharan Africa have the highest risk of developing chronic diseases and are the least able to cope with them.

AIMS

To assess the current knowledge of the prevalence and impact of asthma and chronic obstructive pulmonary disease (COPD) in sub- Saharan Africa.

METHODS

A literature search was conducted using Medline (1995-2010) and Google Scholar.

RESULTS

Eleven studies of the prevalence of asthma in sub-Saharan Africa were identified, all of which showed a consistent increase, particularly in urban regions. The data on asthma show a wide variation (5.7-20.3%), with the highest prevalence in 'westernised' urban areas. Only two studies of the prevalence of COPD in sub-Saharan Africa have been performed. Nevertheless, COPD has become an increasing health problem in sub-Saharan Africa due to tobacco smoking and exposure to biomass fuels. In most countries of sub-Saharan Africa, 90% of the rural households depend on biomass fuel for cooking and heating, affecting young children (acute lower respiratory infections) and women (COPD). This is the cause of significant mortality and morbidity in the region.

CONCLUSIONS

Asthma and COPD in sub-Saharan Africa are under-recognised, under-diagnosed, under-treated, and insufficiently prevented. A major priority is to increase the awareness of asthma and COPD and their risk factors, particularly the damage caused by biomass fuel. Surveys are needed to provide local healthcare workers with the possibility of controlling asthma and COPD.

Burden of obstructive lung disease in a rural setting in the Philippines

BACKGROUND AND OBJECTIVE

The aim of this study was to determine the prevalence of and risk factors associated with COPD in a rural setting in the Philippines.

METHODS

The study was conducted in two municipalities in Nueva Ecija province in the Philippines. Using the Burden of Obstructive Lung Disease (BOLD) protocol and study design, non-hospitalized men or women, aged 40years or older, were recruited by multi-stage random sampling procedures. Participants completed questionnaires on respiratory symptoms and exposure to potential risk factors for COPD, including smoking, occupation and exposure to burning of biomass fuel. Spirometry was performed according to American Thoracic Society criteria.

RESULTS

Of the 1188 individuals selected for recruitment, 722 had acceptable post-bronchodilator spirometry and were classified according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. The overall prevalence of COPD for all stages was 20.8%. The prevalence of COPD at GOLD Stage I or higher was greater in men compared with women (26.5% vs 15.3%), and increased between the ages of 40 to >70years. Logistic regression analysis showed a significant association between all stages of COPD and farming for >40years (odds ratio (OR) 2.48, 95% confidence interval (CI): 1.43-4.30), use of firewood for cooking for >60years (OR 3.48, 95% CI: 1.57-7.71), a smoking history of ≥20 pack-years (OR 2.86; 95% CI: 1.78-4.60), and a history of tuberculosis (OR 6.31, 95% CI: 2.67-15.0).

CONCLUSIONS

The prevalence COPD in a rural community in Nueva Ecija, Philippines was 20.8% for GOLD Stage I or higher, and 16.7% for GOLD Stage II or higher. In addition to smoking history, the use of firewood for cooking, working on a farm and a history of tuberculosis were significantly associated with fixed airflow obstruction, as assessed by spirometry.

Socio-epidemiological Aspects of Respiratory Allergic Diseases in Southern Africa

The prevalence of respiratory allergic diseases has been increasing in Southern Africa both in urban and in rural environments. Various factors may contribute toward this situation, namely, exposure to aeroallergens, such as grass pollens and house dust mites. However, other irritant environmental triggers, such as exposure to tobacco smoke and certain indoor and outdoor fumes, may also play a relevant part. Furthermore, certain parasitic and mycobacterial infections may act as allergic disease risk modifiers, although such an influence should be confirmed. Finally, certain cultural and socioeconomic factors may also influence accessibility to healthcare and adherence to treatment of these diseases.

Prevalence of atopy, asthma and COPD in an urban and a rural area of an African country

The objectives of this study were to determine the prevalence of asthma, atopy and COPD in Rwanda and to identify risk factors. The survey was conducted in Kigali, the Capital of Rwanda, and in Huye District, a rural area located in southern Rwanda.

METHODS

A total of 2138 subjects were invited to participate in the study.1920 individuals (90%) answered to questionnaires on respiratory symptoms and performed spirometry, 1824 had acceptable spirograms and performed skin-prick test. In case of airflow obstruction (defined as pre-bronchodilator ratio FEV(1)/FVC < LLN) a post bronchodilator spirometry was performed. Reversibility was defined as an increase in FEV(1) of 200 ml and 12% above baseline FEV(1) after inhalation of 400 mcg of salbutamol.

RESULTS

The mean age was 38.3 years; 48.1% of participants were males and 51.9% females. Airflow obstruction was found in 256 participants (14%); 163(8.9%) subjects were asthmatics and 82 (4.5%) had COPD. COPD was found in 9.6% of participants aged 45 years and above. 484 subjects had positive skin-prick tests (26.5%); house dust mite and grass pollen mix were the main allergens. Risk factors for asthma were allergy, female gender and living in Kigali. COPD was associated with cigarette smoking, age and male sex.

CONCLUSION

this is the first study which shows the prevalence of atopy, asthma and COPD in Rwanda. Asthma and COPD were respectively diagnosed in 8.9% and 4.5% of participants. COPD was diagnosed in 9.6% of subjects aged ≥ 45 years.The prevalence of asthma was higher in urban compared to rural area.

The next generation of public health approaches to asthma in Asia and the Middle East

Chronic respiratory diseases now affect more than half a billion people worldwide and their importance as a global health problem has risen dramatically in recent years, prompting intense epidemiological investigation and the launch of numerous initiatives. Across Asia and the Middle East, a variety of environmental exposures increase the risk for the onset or exacerbation of chronic respiratory disease, resulting in a considerable burden of morbidity and mortality. This article outlines new possibilities for public health surveillance of environmental exposures and chronic respiratory disease built around an emerging model of participatory public health: a decentralized approach that involves citizens in the collection and analysis of data, harnesses pervasive technology such as mobile phones and distributed sensors, and provides an open platform for public-private collaboration.

The Jamaica asthma and allergies national prevalence survey: rationale and methods

Background

Asthma is a significant public health problem in the Caribbean. Prevalence surveys using standardized measures of asthma provide valid prevalence estimates to facilitate regional and international comparisons and monitoring of trends. This paper describes methods used in the Jamaica Asthma and Allergies National Prevalence Survey, challenges associated with this survey and strategies used to overcome these challenges.

Methods/Design

An island wide, cross-sectional, community-based survey of asthma, asthma symptoms and allergies was done among adults and children using the European Community Respiratory Health Survey Questionnaire for adults and the International Study of Asthma and Allergies in Children. Stratified multi-stage cluster sampling was used to select 2, 163 adults aged 18 years and older and 2, 017 children aged 2-17 years for the survey. The Kish selection table was used to select one adult and one child per household. Data analysis accounted for sampling design and prevalence estimates were weighted to produce national estimates.

Discussion

The Jamaica Asthma and Allergies National Prevalence Survey is the first population- based survey in the Caribbean to determine the prevalence of asthma and allergies both in adults and children using standardized methods. With response rates exceeding 80% in both groups, this approach facilitated cost-effective gathering of high quality asthma prevalence data that will facilitate international and regional comparison and monitoring of asthma prevalence trends. Another unique feature of this study was the partnership with the Ministry of Health in Jamaica, which ensured the collection of data relevant for decision-making to facilitate the uptake of research evidence. The findings of this study will provide important data on the burden of asthma and allergies in Jamaica and contribute to evidence-informed planning of comprehensive asthma management and education programs.

Under-report and underdiagnosis of chronic respiratory diseases in an African country

BACKGROUND

Chronic respiratory diseases (CRD) are greatly underestimated. The aim of this study was to assess the burden associated with reported CRD and chronic obstructive pulmonary disease, as defined on the basis of various standardized criteria, by estimating their point prevalence in a sample of individuals attending the Primary Health Care (PHC) level and Emergency Room (ER) Departments in Cape Verde (CV) archipelago. The second aim of the study was to identify factors related to airways obstruction and reported CRD in this population.

METHODS

A cross-sectional study was carried out in CV during 2 weeks. Outpatients aged more than 20 years seeking care at PHC level and ER answered a standardized questionnaire and were subjected to spirometry, independently of their complaint. Two criteria for airways obstruction were taken into account: forced expiratory volume (FEV(1)) <80% of the predicted value and FEV(1)/forced vital capacity (FVC) ratio <0.70.

RESULTS

A total of 274 individuals with a satisfactory spirometry were included. 22% of the individuals had a FEV(1) < 80%. Individuals older than 46 years had a higher risk of having airways obstruction. Asthma diagnosis (11%) had a clear association with airways obstruction. Smoking was a risk factor for a lower FEV(1). Working in a dust place and cooking using an open fire were both related to chronic bronchitis and asthma diagnosis.

CONCLUSION

Under-report and underdiagnosis of chronic respiratory conditions seem to be a reality in CV just as in other parts of the world. To improve diagnosis, our results reinforce the need of performing a spirometry.

Asthma caused by occupational exposures is common - a systematic analysis of estimates of the population-attributable fraction

Background

The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures

Methods

We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review.

Results

The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%.

Conclusion

Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents.

Mycobacterium bovis Bacillus Calmette-Guérin suppresses inflammatory Th2 responses by inducing functional alteration of TSLP-activated dendritic cells

Allergic diseases such as atopic dermatitis and asthma develop as a consequence of dysregulated T(h)2 responses. Recently, it has been demonstrated that interaction between dendritic cells (DCs) and thymic stromal lymphopoietin (TSLP), an IL-7-like cytokine, is essential for evoking T(h)2 responses in allergy. In this study, we investigated whether Mycobacterium bovis Bacillus Calmette-Guérin (BCG), a strong T(h)1 response-inducing adjuvant, can alter the function of DCs activated by TSLP (TSLP-DCs). We demonstrated that BCG redirects TSLP-DCs away from inducing inflammatory T(h)2 cells that produce IL-4, IL-5, IL-13 and tumor necrosis factor (TNF)-alpha and toward regulatory T(h)1 cells that produce IFN-gamma and IL-10. We also demonstrated that this functional alteration of TSLP-DCs by BCG depended on both production of IL-12 from DCs and down-regulation of OX40 ligand, a member of the TNF family, on DCs. These findings suggest that BCG might be a useful adjuvant for the treatment of allergic diseases that are triggered by TSLP.

Nasobronchial interaction mechanisms in allergic airways disease

PURPOSE OF REVIEW

During the past few decades, the incidence of sensitization to inhaled allergens as well as allergic airways disease has grown steadily. Genetic and environmental factors are recognized as etiologic factors in the development of allergic airway disease, with allergic rhinitis often preceding the development of asthma. Allergic rhinitis is considered a risk factor for the development of asthma, and almost all allergic asthmatic patients have rhinitis. Insight into the risk factors responsible for allergic airways disease and the interaction between the involved organs results in a better diagnostic and therapeutic approach in global airway allergy syndrome.

RECENT FINDINGS

Recent studies have shown that local tissue factors, such as microbial stimuli and systemic inflammatory mechanisms, play a role in the clinical expression of the allergic airway syndrome. In addition, impaired nasal function affects the lower airways of asthmatic patients via different pathways. To date, most human and animal data point towards a systemic pathway linking the upper and lower airways, involving both bloodstream and bone marrow. Recent clinical trials and current guidelines underline the importance of an integrated treatment strategy involving both ends of the respiratory tract.

SUMMARY

This review provides an overview of recent epidemiological and immunopathologic evidence concerning the link between upper and lower airways in allergic disease and its therapeutic implications.

Prevalence of COPD in five Colombian cities situated at low, medium, and high altitude (PREPOCOL study)

BACKGROUND

The prevalence of COPD in Colombia is unknown. This study aimed to investigate COPD prevalence in five Colombian cities and measure the association between COPD and altitude.

METHODS

A cross-sectional design and a random, multistage, cluster-sampling strategy were used to provide representative samples of adults aged >or= 40 years. Each participant was interviewed (validated Spanish version of the Ferris Respiratory Questionnaire) and performed spirometry before and after 200 microg of inhaled salbutamol, using a portable spirometer according to American Thoracic Society recommendations. COPD definitions were as follows: (1) spirometric: fixed ratio (primary definition): FEV1/FVC < 70% after bronchodilator; (2) medical: a diagnosis of chronic bronchitis, emphysema, or COPD made by a physician; (3) clinical: cough and phlegm >or= 3 months every year during >or= 2 consecutive years (chronic bronchitis). Analysis was performed using statistical software.

RESULTS

A total of 5,539 orsubjects were included. The overall COPD prevalence using the primary definition (spirometric) was 8.9%, ranging from 6.2% in Barranquilla to 13.5% in Medellín. The prevalence measured by the spirometric definition was higher than medical (2.8%) and clinical (3.2%) definitions. After the logistic regression analysis, the factors related with COPD were age >or= 60 years, male gender, history of tuberculosis, smoking, wood smoke exposure >or= 10 years, and very low education level. There was a nonsignificant tendency toward larger prevalence with higher altitude.

CONCLUSION

COPD is an important health burden in Colombia. Additional studies are needed to establish the real influence of altitude on COPD prevalence.