Leptin: does it have any role in childhood asthma?
BACKGROUND
Although there is evidence of a positive association between asthma and obesity in adults and children, very little is known about the role of leptin in asthmatic children.


OBJECTIVE
The aims of this study were to evaluate the relation between leptin and parameters of atopy and asthma in children.


METHODS
Body mass index (BMI) and serum leptin levels were measured in 102 (37 female, 65 male; mean age, 5.9 +/- 3.4 years) asthmatic and 33 (14 female, 19 male; mean age, 6.1 +/- 3.4 years) healthy children. Skin prick tests, total serum IgE, and pulmonary function tests were performed and were completed.


RESULTS
A significant difference was observed in serum leptin levels between asthmatic and healthy children. Median (interquartile range) levels were 3.53 (2.06-7.24) ng/mL and 2.26 (1.26-4.71) ng/mL, respectively (P=.008). Subgroup analysis revealed that this difference in leptin levels was confined entirely to boys: 3.09 (1.99-7.51) ng/mL in boys with asthma versus 1.52 (1.06-3.17) ng/mL in boys without asthma (P=.003). By logistic regression analysis, we found that leptin was a predictive factor for having asthma (odds ratio, 1.98; CI, 1.10-3.55; P=.021), whereas sex, age, or BMI were not. In a stepwise multiple regression analysis including sex (P=.001), age (P=.016), BMI (P <.001), and asthma (P=.022), all of these variables were found to affect log leptin levels (R2=0.404). There was no significant sex difference in serum leptin levels among asthmatic children, whereas healthy boys had significantly lower leptin levels than healthy girls (P=.019). Atopic asthmatic subjects had significantly higher leptin levels than nonatopic asthmatic subjects (P=.038) with similar BMI. A significant, but weak, correlation was observed between leptin levels and IgE in the overall group of asthmatic children (r=0.231; P=.019). Again, this correlation was confined entirely to boys (r=0.319; P=.010). There was no relation between leptin levels and skin prick tests, pulmonary function tests, passive smoking, birth weight, and duration of breast-feeding.


CONCLUSIONS
Our findings suggest that leptin may play a role in atopic asthma. High serum leptin levels in asthmatic boys may partly explain the higher prevalence of childhood asthma in male sex.
Department of Pediatrics, Division of Allergy and Chest Diseases, Istanbul Medical Faculty, Turkey. eztamay@yahoo.com
Nermin
N
Guler
Emel
E
Kirerleri
Ulker
U
Ones
Zeynep
Z
Tamay
Nihal
N
Salmayenli
Feyza
F
Darendeliler
D001249:Asthma / Q000097:blood / Q000209:etiology*; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D015850:Interleukin-6 / Q000096:biosynthesis; D020738:Leptin / Q000097:blood / Q000502:physiology*; D008297:Male; D012737:Sex Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D015850:Interleukin-6; D020738:Leptin; D014409:Tumor Necrosis Factor-alpha; D007073:Immunoglobulin E