ABSTRACT
The IL4 gene is located on chromosome 5q23.3-31.2. Polymorphisms within this cytokine gene, like the derivative allele T of IL4-590, have been reported as being associated to elevated IgE serum levels and asthma. In the present work, the allelic and genotypic frequency of the IL4-590 and IL4 RP2 polymorphisms was carried out in 599 individuals from Madeira, Azores, Portugal mainland, Cape Verde and Guinea-Bissau and in a sample of 101 asthmatics from Madeira population. In all populations the polymorphisms were in LD and presented a significant dissimilar allelic and genotypic distribution (p<0.05) except between mainland Portugal and Madeira when compared to Azores. Significant differences regarding both loci were found between Madeira population and the group of asthmatics. Genotype 183183TT frequency is higher for African populations while 253253CC prevails in Caucasian populations. The existence of a Hardy-Weinberg Disequilibrium in Guinea-Bissau population not observed in neutral markers leads to the hypothesis of natural selection occurring in these loci probably associated to a rapid population growth an hypothesis strengthened by neutral STRs D5S818 and CSF1PO gene diversity.
ABSTRACT
Bronchial asthma is related to a high morbidity rate, leading to an increasing frequency of emergency room visits and hospital admissions. The aim of this study was to identify severity risk factors for childhood asthma related to hospitalization. The authors studied 124 children admitted to the hospital for asthma, during a 2-year period, correlating the obtained data with a sample of outpatients with asthma matched by age, gender, and socioeconomic status. A standardized questionnaire and skin-prick tests (SPTs) were performed on all children. The significant and independent risk factors identified for hospital admission were prior asthma hospitalization (OR = 7.63; 95% CI = 1.5-39.6; p = 0.01) and last-year admission (OR = 3.18; 95% CI = 1.1-8.9; p = 0.02), environmental tobacco-smoke exposure (OR = 6.63; 95% CI = 2.5-17.8; p = 0.002), allergen sensitization (OR = 3.86; 95% CI = 1.4-10.7; p = 0.009), family history of maternal asthma (OR = 3.58; 95% CI = 1.3-9.6; p = 0.01), and onset of symptoms before 12 months of age (OR = 2.76; 95% CI = 1.0-7.9; p = 0.06). Attendance at day care or kindergarten (OR = 0.38; 95% CI = 0.2-0.9; p = 0.04) and large family size (OR = 0.25; 95% CI = 0.1-0.8; p = 0.01) could be protective factors. Our results stress the importance of early diagnosis and specialized medical care of childhood asthma, mainly in high-risk children, with emphasis on medication planning and the establishment of preventive measures such as environmental tobacco smoke avoidance and limitation of aeroallergen exposure.
