الفهرس 
Bronchial Asthma
Effects of Obesity on Children and AdolescentsOnly 14 pages are availabe for public view
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Abstract
During the past two decades, the prevalence of obesity in children has risen greatly worldwide. Obesity in childhood causes a wide range of serious complications, and increases the risk of premature illness and death later in life, raising public-health concerns. Results of research have provided new insights into the physiological basis of bodyweight regulation. However, treatment for childhood obesity remains largely ineffective. . Implications for the future can be gathered from longitudinal studies. Combined cohort studies indicate that relative body weight is sustained from childhood to adulthood and, once children or adolescents are overweight or obese, their weight is unlikely to track backwards. .Unfortunately, for more than 100 years, the incidence of obesity has increased in both developed and developing countries, a reflection of an affluent society with an increasingly sedentary life combined with high caloric foods.
Asthma is also a chronic inflammation of the airways with reversible episodes of obstruction, caused by an increased reaction of the airways to various stimuli. Asthma breathing problems usually happen in “episodes” or attacks but the inflammation underlying asthma is continuous. Asthma is the most common chronic disorder in childhood, currently affecting an estimated 6.2 million children under 18 years; of which 4 million suffered from an asthma attack or episode in 2004.Much of the focus of childhood asthma research has been on atopy and the development of allergic responses to common indoor allergens; however, atopic pathways do not appear to contribute to a substantial portion of cases, and other etiologic pathways that involve non allergic mechanisms are likely to be involved.
It has long been recognized that obesity is more common among children with asthma, and associations between asthma and high body mass index (BMI) (weight (kg)/height (m)2 have been observed in cross-sectional studies of adults and children. These associations have been explained as evidence that asthma causes obesity due to a lack of physical activity among children with asthma; however, this interpretation has been challenged by the results of longitudinal studies. Obesity is associated with an increased risk of asthma in prospective studies, especially among school girls. In girls, becoming overweight or obese between the ages of 6 and 11 years was found to increase the risk of developing new asthma and to increase bronchial responsiveness during adolescence. Obesity may directly affect the asthma phenotype by direct mechanical effects (alterations in tidal stretch leading to latch, gastrosophageal reflux), by enhancing the immune response, through related genetic mechanisms, and by sex specific influences (hormones). Alternatively, obesity may be closely related to other environmental factors such as physical activity, diet, and birth weight. These environmental influences, in combination with genetic susceptibility, may then lead to enhanced susceptibility to asthma.
So, this study was carried out in order to determine the relation between obesity and bronchial asthma among primary school children in Alexandria.
The study was conducted upon 360 students in the primary schools aged 6-12 years that were divided into two groups, the first one contains 120 asthmatic students and the second one contains 240 non asthmatic students. Pre-designed interview questionnaire to collect data including personal data, family history of asthma, medical history, dietary data and physical activity then severity of asthma was classified into high, moderate and low .
The weight and height for each child was measured and then BMI was calculated from which BMI percentiles for age and sex were recorded.
Asthmatic students was subjected to lung function measurement using available computer based electronic pulmonary function test apparatus (Shift graph H1-710) and after feeding the device with the birth date, the weight and the height of every child, every asthmatic child was asked to take a very deep inspiration and catch it then give a maximum expiration inside the changeable mouth piece of the device. The % predicted of FEV1, FVC and FEV1/ FVC ratio for age, weight and height was taken.
The age of the studied students ranged from 6-12 ,with the highest percent (47.5%) were aged (10-<12), (53.3%) among asthmatics and (44.6%) among non asthmatics. Age category (12+) showed (5.3%) in both groups, (5.8%) among asthmatics and (5%) among non asthmatics.
As regard sex of the studied students, (51.4%) were boys and (48.6%) were girls, (60%) of the boys were asthmatics and (47.1%) were non-asthmatics, (40%) of the girls were asthmatics and (52.9%) were non-asthmatics.
As regard the school type all non asthmatic students were in governmental schools while 90% only of asthmatic students were in governmental schools. There was no statistical difference between asthmatics and non-asthmatics as regards school performance. (X2 =5.373 p =0.068).
Concerning parents education, (41%) of fathers of both groups had middle qualification, (25%) of them among fathers of asthmatics and (49.2%) of them among fathers of non-asthmatics .Also (13%) of fathers of both groups had high qualification, (25%) of them among fathers of asthmatics and (6.3%) among fathers of non-asthmatics. There was statistical difference between asthmatics and non-asthmatics. (X2 =34.754 p=0.000). (40%) of mothers of both groups had middle qualification, (30%) of them among mothers of asthmatics and (45.4%) of them among mothers of non asthmatics Also (10%) of mothers of both groups had high qualification, (20%) of them among mothers of asthmatics and (5.4%) among mothers of non asthmatics. There was statistical difference between asthmatics and non asthmatics(X2 =33.852 p=0.000). There was no statistical difference between asthmatics and non-asthmatics concerning parents occupation. (X21 =5.768 p1=0.123) (X22=o.122 p2=0.727).
The housing conditions of both groups showed no statistical difference except for exposure to sun(X2 =9.618p =.008) being better in houses of asthmatic. There was positive family history for asthma and obesity among asthmatic students and also positive history for other allergies in asthmatic students (p=0.000).
The highest mean BMI (24.81) for asthmatic boys was for those aged(10-<12) while for asthmatic girls, it was(25.39). For those aged (12+). The highest mean BMI(23.28) for non asthmatic boys was for those aged(12+)while for non asthmatic girls ,it was(21.21) for those aged (10-<12).
The overall prevalence of obesity was (39.1%) in asthmatic students versus (18.7%) in non asthmatic while the overall prevalence of overweight was (26.7%) in asthmatic students versus (22.5%) in non asthmatic.
Concerning the relation of obesity to severity of asthma, The present study shows that (85%) of the studied asthmatic students had high score of severity of asthma. The children with high score of severity were (42.1%) among obese,(27.5%) among overweight and (30.4%)among normal weight children. (x2 =7.394 p =0.025).
Concerning the relation of obesity to lung functions, the present study found that there is a highly significant relation (p=0.000) between obesity (BMI≥85th percentile)and reduction in pulmonary functions .As regards FEV1 the normal weight children had better readings (0.91±0.07) compared to the obese children(0.7±0.1) and overweight children (0.72±0.1) % of predicted values for age and sex. As regards FVC the normal weight children had better readings (0.98±0.06) compared to the obese children (0.75±0.09) and overweight children (0.77±0.1) % of predicted values for age and sex. As regards FEV1/FVC ratio the normal weight children had better readings (1.02±0.05) compared to the obese children (0.94±0.09) and overweight children (0.93±0.06) % of predicted values for age and sex. ( x2 =0.626 p value =0.000)
Concerning tolerance to exercise, in the present study,(24%) of asthmatic students do practice sports versus (76%) who don’t practice sports . Among obese students 25.5 % and 12.5% of overweight versus 29.3% of normal weight practice sports. There is no statistical difference as regards practicing sports between obese, overweight and normal weight students. (x2 =3.034 p value =0.219). Of those who practice sports, all obese students (100%) play football versus 75% of overweight students and 50% of normal weight students. There is a statistical difference as regards playing football between overweight and normal weight students. (x2 =7.182 p value =0.018)
As regards attendance of physical education lessons at school, 82.1% of obese students and 75.9 % 0f overweight students versus 90% 0f normal weight students attend these lessons at schools. There was no statistical difference between obese and normal weight students as regards attendance of physical education lessons at school. (x2 =2.492 p value =0.288)
This may be attributed to the social level of the students which make sports available only in schools and playing football in front of their homes.
The mean daily consumption of macronutrients, antioxidants by asthmatic boys and girls was calculated. The mean intakes combined for both boys and girls under the age of 11 years, and differentiated for older children. Among asthmatic children, obese children consume more carbohydrates, fats and proteins than normal children at all ages and in both sexes and the intakes by girls are higher than that of boys. As a result the energy intakes by obese children are higher than that by the non obese particularly by girls and the differences in the intakes are statistically significant.
The same patterns in the intakes of antioxidants (vitamin A and E) was seen as there was a statistically significant difference between non obese and obese boys and girls in the intakes of these nutrients at all ages , being higher in the obese. The intakes of the antioxidant (vitamin C) was lower among both boys and girls ≥11years. there was also a high statistically significant difference between non obese and obese boys and girls in intake along all years being higher in obese.
Lastly, a stepwise logistic regression was done .the regression model included age, sex, mother’s education, house aeration, family history of asthma, family history of obesity ,presence of allergies other than asthma , indoor smoking of students’ fathers ,intake of snacks and obesity as a predictor variables for asthma among primary school children.
Among the included variables; (age, sex , ,house aeration, family history of asthma, family history of obesity and obesity) were found to be the significant predictors. Regarding sex ,boys were found to have about doubled risk to develop asthma compared to girls.(p=0.000)
Regarding house aeration , children with bad aerated houses had 2.6 more risk to develop asthma compared to those with good aerated houses. (p=0.000) Regarding age ,the increase in age by one year is associated with decrease in the risk of asthma by about 30%.(p=0.000) Regarding obesity, obese children were found to be 3.6 times more likely to be asthmatic compared to those of normal weight. (p=0.000) Regarding family history of asthma, children with positive family history of asthma ,have 15 times more risk to develop asthma compared to those with negative family history of asthma. (p=0.000)
Regarding family history of obesity, children with positive family history of obesity ,have 64 times more risk to develop asthma compared to those with negative family history of obesity. (p=0.000)
Collectively, the present study revealed a highly significant relation between obesity and bronchial asthma in children . The increase in weight was related to sex and asthma severity and reduction in pulmonary function. These results should be considered in the future for the management of childhood asthma with consideration to their body weight.