Determinants of severe exercise-induced bronchoconstriction in Nigerian children with asthma.

BACKGROUND/PURPOSE: Asthmatics with severe exercise-induced bronchoconstriction (EIB) are at high risk of exacerbations. The purpose of this study was to determine the prevalence, phenotypic, and laboratory determinants of severe EIB in Nigerian children with asthma. METHODS: Children with controlled asthma (n = 101) underwent characterization and free-running exercise bronchoprovocation at a center in Nigeria. Lung function was measured before, then 5, 10, 15, and 30 minutes after 6 to 8 minutes exercise. Severe EIB was defined as ≥50% decrease in forced expired volume in 1 second (FEV1 ) from preexercise. Serum vitamin D and total antioxidant capacity were measured chromatographically. Factors predicting severe EIB were tested by logistic regression. RESULT: The sample was enriched in children with corticosteroid-naïve, mild intermittent asthma (71%). Thirteen percent had no EIB, 22% had severe and 65% nonsevere EIB. Children with severe EIB had higher preexercise FVC (105% vs 96%; P = .03) and FEV1 (98% vs 90%; P = .07), greater obesity (13.6% vs 1.3%; P = .02), more allergic rhinitis (AR) (63.6% vs 35.4%; P = .03), but less exposure to household pets (31.8% vs 72.2%; P = .003) compared to children with nonsevere EIB. Significant determinants (odds ratios/confidence intervals) for severe EIB were obesity = 12.3 (1.2-125.1), AR = 3.18 (1.19-8.52), blood eosinophilia = 1.005 (1.001-1.009), and hypovitaminosis D = 0.87 (0.81-0.93). CONCLUSION: In Nigerian children with asthma, severe EIB is common and associated with remediable comorbidities including type 2 pattern inflammation and vitamin D deficiency.

Serum Zinc, Selenium and Total Antioxidant Contents of Nigerian Children with Asthma: Association with Disease Severity and Symptoms Control.

BACKGROUND: Micronutrients and antioxidants may ameliorate oxidative stress. This study aimed to determine the serum Zinc (Zn), Selenium (Se) and Total Antioxidant Contents (TAC) of Nigerian children with asthma and relate these to disease severity and symptoms control. METHODS: Children aged 2-15 years with asthma and age and sex matched controls were consecutively recruited. The children's serum Zn, Se and TAC were assayed and compared. RESULTS: Eighty children each with asthma and controls participated in the study. Serum Zn (71.0 ± 30.3 µg/dl vs. 84.2 ± 31.7 µg/dl; p = 0.008), Se (67.3 ± 29.8 µg/l vs. 80.0 ± 31.7 µg/l; p = 0.033) and TAC [median (interquartile range) 5.2 (3.8-6.8) ng/dl vs. 6.2 (4.3-8.0) ng/dl; p = 0.019] were lower in children with asthma. Serum Se (65.7 ± 29.1 µg/l vs. 92.4 ± 28.6 µg/l; p = 0.001) was lower in those with moderate/severe than mild disease, but no association with symptoms control (p > 0.05). CONCLUSION: Micronutrient supplementation may be beneficial in Nigerian children with asthma as they have relatively lower antioxidant micronutrients than nonasthmatics.

Prevalence and factors associated with exercise-induced bronchospasm among rural school children in Ilesa, Nigeria.

BACKGROUND: Exercise-induced bronchospasm (EIB) assessed using changes in peak expiratory flow rates (PEFRs) to free range exercise is a relatively cheap way of screening for asthma in resource-poor centres where children with asthma are often undiagnosed and poorly managed. This study sets out to determine the prevalence and factors associated with EIB among rural schoolchildren in Ilesa, Nigeria. SUBJECTS AND METHODS: Children aged 8-16 years from two middle schools in rural Ilesa were selected by multistage sampling. Their sociodemographic characteristics and personal/family history of asthma and allergies were obtained. The children had their PEFR measured before, 5, 10 and 15 min after 6-8 min of free running exercise to achieve 80% of their maximal pulse rate. EIB was defined as change in PEFR expressed as a percentage of the pre-exercise value ≥15%. The prevalence and factors associated with EIB were determined. RESULTS: The mean (standard deviation) age of the 250 study participants was 12.5 (1.5) years (M: F 0.9:1) None of the children had previously been diagnosed with asthma. The prevalence of EIB was 9.2%, 6.4% and 4.0% at 5, 10 and 15 min post-exercise, respectively. Household poultry birds, personal history of allergies, wheeze in the past 12 months and family history of asthma were associated with EIB (P < 0.05); only wheezing in the past 12 months independently predicted EIB (odds ratio = 6.343; 95% confidence interval = 2.040-8.798; P= 0.020). CONCLUSION: The prevalence of EIB among rural schoolchildren in Ilesa was 9.2%. EIB was associated with the history of allergies and wheeze and presence of household poultry birds. We recommend routine screening of these children for early diagnosis and good asthma symptom control.

Rural-urban disparity in lung function parameters of Nigerian children: effects of socio-economic, nutritional and housing factors.

INTRODUCTION: The effect of socio-demographic and nutritional factors on lung functions of African children is poorly studied. This study set out to determine the effects of these factors on lung functions of Nigerian school children. METHODS: Rural and urban secondary schools students in Ilesa, Nigeria were selected by multistage sampling. The socio-demographic, nutritional status as well as lung function parameters measured using incentive Spirometry (MIR Spirolab III srl, Italy) of the children were obtained and compared among the rural and urban children. RESULTS: A total of 250 children (128 rural and 122 urban) aged 9 to 17 years participated in the study over a 12 month period. Mean (SD) age was 12.6 (1.9) years and Male: Female 1:1.1. The urban children were heavier, taller and have larger lung volumes than their age and sex matched rural counterpart. Stunted rural males [Mean (SD) FVC 1.8 (0.3) L vs. 2.2 (0.6) L t-test = 2.360; p = 0.022], underweight females [Mean (SD) FVC 1.8 (0.4) L vs. 2.2 (0.6) L; t-test = 2.855; p = 0.006] and those exposed to unclean fuel [Mean (SD) FVC 2.1 (0.6) L vs. 2.4 (0.5) L; t-test = 2.079; p = 0.041] had significantly lower lung volumes compared to their counterparts without these conditions. CONCLUSION: Undernutrition, low socio-economic class and use of unclean fuels adversely affect the lung functions of Nigerian children. Improved standard of living, use of clean fuel and adequate nutrition may ensure better lung health among these children.

Factors associated with childhood asthma control in a resource-poor center.

INTRODUCTION: Optimal asthma control is a major aim of childhood asthma management. This study aimed to determine factors associated with suboptimal asthma control at the pediatric chest clinic of a resource-poor center. METHODS: Over a 12-month study period, children aged 2-14 years with physician-diagnosed asthma attending the pediatric chest clinic of the Wesley Guild Hospital (WGH), Ilesa, Nigeria were consecutively recruited. Asthma control was assessed using childhood asthma control questionnaire. Partly and uncontrolled asthma was recorded as a suboptimal control. Relevant history and examinations findings were compared between children with good and suboptimal asthma control. Binary logistic regression analysis was used to determine the predictors of suboptimal asthma control. RESULTS: A total of 106 children participated in the study with male:female ratio of 1.5:1, and majority (83.0%) had mild intermittent asthma. Suboptimal asthma control was observed in 19 (17.9%) of the children. Household smoke exposure, low socioeconomic class, unknown triggers, concomitant allergic rhinoconjunctivitis, and poor parental asthma knowledge, were significantly associated with suboptimal control (P < 0.05). Low socioeconomic class (odds ratio [OR] =6.231; 95% confidence interval [CI] =1.022-8.496; P = 0.005) and poor parental asthma knowledge (OR = 7.607; 95% CI = 1.011-10.481; P = 0.007) independently predict suboptimal control. CONCLUSION: Approximately, one in five asthmatic children attending the WGH pediatric chest clinic who participated in the study had suboptimal asthma control during the study. More comprehensive parental/child asthma education and provision of affordable asthma care services may help improve asthma control among the children.