Life-course of atopy and allergy-related disease events in tropical sub-Saharan Africa: A birth cohort study.

BACKGROUND: In high-income countries, allergy-related diseases (ARDs) follow a typical sequence, the 'Atopic March'. Little is known about the life-course of ARDs in the markedly different, low-income, tropical environment. We describe ARDs in a tropical, African birth cohort. METHODS: Ugandan children were followed from birth to 9 years. ISAAC questionnaires were completed at intervals; doctor-diagnosed ARDs were recorded throughout follow-up. Skin prick tests (SPTs) were performed at 3 and 9 years. Atopy was defined as ≥1 positive SPT. RESULTS: Of the 2345 live-born children, 1214 (52%) were seen at 9 years. Wheeze and eczema were common in infancy, but by 9 years, only 4% reported recent wheeze, 5% eczema and 5% rhinitis. Between 3 and 9 years, atopy prevalence increased from 19% to 25%. Atopy at 3 or 9 years was associated with reported ARD events at 9 years, for example OR = 5.2 (95% CI 2.9-10.7) for atopy and recent wheeze at 9 years. Reported or doctor-diagnosed ARD events in early childhood were associated with the same events in later childhood, for example OR = 4.4 (2.3-8.4) for the association between reported wheeze before 3 years with reported recent wheeze at 9 years, but progression from early eczema to later rhinitis or asthma was not observed. CONCLUSION: Allergen sensitization started early in childhood and increased with age. Eczema and wheeze were common in infancy and declined with age. Atopy was strongly associated with ARD among the few affected children. The typical Atopic March did not occur. Environmental exposures during childhood may dissociate atopy and ARD.

Asthma control and management among schoolchildren in urban Uganda: results from a cross-sectional study.

Background: Children from low- and middle-income countries have poor asthma control, mainly because of poor management. The extent of this problem in Uganda is not well known, but such information would be useful to guide policy and practice. We therefore conducted a cross-sectional study among schoolchildren with asthma in urban Uganda, to assess the level of asthma control and management. Methods: Schoolchildren aged 5-17 years were enrolled, asthma was diagnosed by the study medical team. Asthma control was assessed using the Asthma Control Test and the childhood Asthma Control Test. Data on previous asthma management was obtained using interviewer-led questionnaires. Data were analysed using multiple linear and multiple logistic regression. Results: We enrolled 561 children with asthma, of whom only 56% had ever had an asthma diagnosis. We categorised asthma as well-controlled (55.5%), partly-controlled (29.5%) and poorly-controlled (15.0%). Poor asthma control was associated with increasing age (adjusted regression coefficient [95% confidence interval], p-value: -1.07 [-1.20, -0.94], p<0.0001), concurrent allergic rhinitis (-1.33 [-2.28, -0.38], p=0.006), and city residence in early life (-1.99 [-3.69, -0.29], p=0.06). Regular use of inhaled asthma medication in the last 12 months was very low; 18.1% for salbutamol and 6.7% for inhaled corticosteroids. The main barriers to inhaled asthma medication use were lack of prescription (47.6%) and inaccurate diagnosis (38.8%). Increased inhaler use was associated with tertiary education of the fathers (adjusted odds ratio [95% confidence interval], p-value: 5.19 [2.39-11.28], p<0.0001), city residence in early life (4.66 [1.79-12.43], 0.002) and an asthma diagnosis prior to enrolment (11.39 [6.35-20.43], p<0.0001). Conclusions: This study confirms that children with asthma in Uganda generally have inadequate asthma control, which is attributable to poor asthma management. This could be improved through re-training of medical workers and patient education, and by increasing availability and affordability of essential asthma medications.

Risk factors for asthma among schoolchildren who participated in a case-control study in urban Uganda.

Data on asthma aetiology in Africa are scarce. We investigated the risk factors for asthma among schoolchildren (5-17 years) in urban Uganda. We conducted a case-control study, among 555 cases and 1115 controls. Asthma was diagnosed by study clinicians. The main risk factors for asthma were tertiary education for fathers (adjusted OR (95% CI); 2.32 (1.71-3.16)) and mothers (1.85 (1.38-2.48)); area of residence at birth, with children born in a small town or in the city having an increased asthma risk compared to schoolchildren born in rural areas (2.16 (1.60-2.92)) and (2.79 (1.79-4.35)), respectively; father's and mother's history of asthma; children's own allergic conditions; atopy; and cooking on gas/electricity. In conclusion, asthma was associated with a strong rural-town-city risk gradient, higher parental socio-economic status and urbanicity. This work provides the basis for future studies to identify specific environmental/lifestyle factors responsible for increasing asthma risk among children in urban areas in LMICs.