Chronic obstructive pulmonary disease in sub-Saharan Africa: a systematic review.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major global health problem. Although COPD is the sixth most common cause of mortality in low- and middle-income countries, most research comes from high-income countries. We set out to systematically review existing published research on COPD in sub-Saharan Africa to identify knowledge gaps and opportunities for further research. METHODS: A literature search of MEDLINE, EMBASE and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases, published reviews, reference lists from included publications and abstracts from major thoracic medicine conference proceedings within the previous 2 years was performed using a protocol-driven search strategy. Texts were screened for inclusion by two independent reviewers. Studies were included if they met the following criteria: 1) COPD was an outcome, and 2) the population included people from sub-Saharan Africa. There were no language restrictions. FINDINGS: Our search identified 688 studies: 41 were duplicates, 638 were excluded, and 9 met our inclusion criteria. Included studies were all cross-sectional, and included 3673 people from four sub-Saharan African countries. Estimates of COPD prevalence varied between 4% and 25%. Only one study used population-based representative sampling and an adequate case definition. Assessment of risk factors was limited. CONCLUSIONS: There is little existing research on COPD in sub-Saharan Africa. Prevalence estimates varied, reflecting the range of populations studied, inconsistent diagnostic criteria and variable methods and methodological quality. Population-representative studies using appropriate case definitions are needed to define the epidemiology of COPD in sub-Saharan Africa and to inform the development of prevention and management strategies for the future.

Experimental hookworm infection: a randomized placebo-controlled trial in asthma.

BACKGROUND: Epidemiological studies suggest that hookworm infection protects against asthma, and therefore that hookworm infection may have a direct or an indirect therapeutic potential in this disease. We now report the first clinical trial of experimental hookworm infection in people with allergic asthma. OBJECTIVES: To determine the effects of experimental hookworm infection in asthma. METHODS: Thirty-two individuals with asthma and measurable airway responsiveness to adenosine monophosphate (AMP) were randomized and double blinded to cutaneous administration of either ten Necator americanus larvae, or histamine solution (placebo), and followed for 16 weeks. The primary outcome was the change in provocation dose of inhaled AMP required to reduce forced expiratory volume in 1 s by 20% (PD(20)AMP) from baseline to week 16. Secondary outcomes included change in several measures of asthma control and allergen skin sensitivity and the occurrence of adverse effects. RESULTS: Mean PD(20)AMP improved in both groups, more in the hookworm [1.49 doubling doses (DD)] than the placebo group (0.98 DD), but the difference between groups was not significant (0.51 DD; 95% confidence interval: -1.79 to 2.80; P=0.65). There were no significant differences between the two groups for other measures of asthma control or allergen skin sensitization. Infection was generally well tolerated. CONCLUSIONS: Experimental infection with ten hookworm larvae in asthma did not result in significant improvement in bronchial responsiveness or other measures of asthma control in this study. However, infection was well tolerated and resulted in a non-significant improvement in airway responsiveness, indicating that further studies that mimic more closely natural infection are feasible and should be undertaken.