Symptoms of asthma and atopic disorders in preschool children: prevalence and risk factors

BACKGROUND: Published epidemiological data suggested that asthma and allergies may be increasing in preschool children. Identification of the risk factors is important for planning possible early intervention to prevent asthma. This study was designed to measure the prevalence of, and risk factors for, asthma and atopic disorders in preschool children from Hong Kong. METHODS: Children aged 2-6 years living in Hong Kong were recruited through the local nurseries and kindergartens for this study to ascertain the presence of symptoms of asthma and various possible risk factors. The parental questionnaire was developed based on the International Study of Asthma and Allergies in Childhood questionnaire. RESULTS: A total of 3089 children (1506 boys) from 14 nurseries and kindergartens participated in this study. The prevalence of wheeze ever and current wheeze were 16.7% and 9.3%. Two hundred and thirty-four subjects were born in mainland China and migrated to Hong Kong subsequently. When compared with children born and raised in Hong Kong, children born in mainland China had significantly lower prevalence of current wheeze (3.4% vs. 9.6%, P<0.01). Two environmental factors in the first year of life were associated with wheezing attacks within the last 12 months. They were the use of foam pillow (Odds ratio: 1.45; 95% Confidence interval: 1.04-2.00) and the use of gas as cooking fuel (1.68; 1.03-2.75). Frequent use of paracetamol was also associated with wheezing attack in the past 12 months. CONCLUSIONS: This study confirms the high prevalence of symptoms of atopic disorders in preschool children from Hong Kong. Early environmental exposure factors are important determinants of subsequent development of asthma symptoms in the preschool years. Further studies are needed to evaluate the possible pathogenetic role of the identified risk factors.     

Time trends in asthma and wheeze in Swedish children 1996–2006: prevalence and risk factors by sex

Background:  Recent data suggest that the previously rising trend in childhood wheezing symptoms has plateaued in some regions. We sought to investigate sex-specific trends in wheeze, asthma, allergic conditions, allergic sensitization and risk factors for wheeze.
Methods:  We compared two population-based cohorts of 7 to 8-year olds from the same Swedish towns in 1996 and 2006 using parental expanded ISAAC questionnaires. In 1996, 3430 (97%) and in 2006, 2585 (96%) questionnaires were completed. A subset was skin prick tested: in 1996, 2148 (88%) and in 2006, 1700 (90%) children participated.
Results:  No significant change in the prevalence of current wheeze ( P  = 0.13), allergic rhinitis ( P  = 0.18) or eczema ( P  = 0.22) was found despite an increase in allergic sensitization (20.6–29.9%, P  < 0.01). In boys, however, the prevalence of current wheeze (12.9–16.4%, P  < 0.01), physician-diagnosed asthma (7.1–9.3%, P  = 0.03) and asthma medication use increased. In girls the prevalence of current symptoms and conditions tended to decrease. The prevalence of all studied risk factors for wheeze and asthma increased in boys relative to girls from 1996 to 2006, thus increasing the boy-to-girl prevalence ratio in risk factors.
Conclusions:  The previously reported increase in current wheezing indices has plateaued in Sweden. Due to increased diagnostic activity, physician diagnoses continue to increase. Time trends in wheezing symptoms differed between boys and girls, and current wheeze increased in boys. This was seemingly explained by the observed increases in the prevalence of risk factors for asthma in boys compared with girls. In contrast to the current symptoms of wheeze, rhinitis or eczema, the prevalence of allergic sensitization increased considerably.     

Psychosocial risk factors for tobacco use among adolescents with asthma

OBJECTIVE: To determine the prevalence of smoking among adolescents with asthma and smoking's psychosocial risk factors (environmental smoking exposure, autonomy, depression). METHOD: Participants were 2,039 adolescents with asthma and 2,039 matched controls from the Add Health study. RESULTS: The prevalence of ever smoking among adolescents with asthma was 56%. Among ever smokers with asthma, the prevalence of current smoking was 48%, and the prevalence of current smokers having made a recent attempt to stop smoking was 57%. Having parents who have smoked, exposure to friends who smoke, and depression were significant psychosocial risk factors for ever smoking. Asthma and exposure to friends who smoke were significantly associated with current smoking, and attempts to stop smoking were significantly associated with asthma and depression. CONCLUSIONS: Psychosocial risk factors for smoking among adolescents with and without asthma appear similar. Research on the role of illness in tobacco control is warranted.     

Stabilization of asthma prevalence among adolescents and increase among schoolchildren (ISAAC phases I and III) in Spain

BACKGROUND: Most studies show a steep increase in asthma prevalence in the last decades, although few studies had applied the same methodology. Recent reports point out the possibility that the epidemic has come to an end. We have studied the prevalence of asthma in a very large sample of children, repeating the study eight years apart. METHODS: Repeated cross-sectional studies using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol in a sample of Spanish schoolchildren 6-7 (parent-reported) and 13-14 (self-reported) years old in 1994-95 (phase I) and 2002-2003 (phase III). The number of participants was 42 417 in phase I and 42 813 in phase III. The participation rate was over 87% (13-14 years) and 70% (6-7 years). RESULTS: The prevalence of wheezing in the previous year in children aged 13-14 years was 9.0 and 9.3% for boys and 9.6 and 9.2% for girls for phases I and III, respectively. Children 6-7 years of age showed a substantial increase in wheezing in the previous year (7.0 and 10.7% for boys and 5.3 and 8.2% for girls). Other symptoms and severity indexes followed the same patterns. CONCLUSIONS: In the last 8 years, the prevalence of asthma has not changed in 13-14-year-old Spanish children but has increased substantially in 6-7-year olds.     

Brief report: social risk factors predict cigarette smoking progression among adolescents with asthma

OBJECTIVE: To compare smoking progression in adolescents with and without asthma and to compare their psychosocial risk factors. METHODS: Participants were 1,507 adolescents with asthma and 1,507 healthy matched controls from Waves I and II of the Add Health Project assessed at baseline and again 1 to 2 years later at follow-up. Three levels of smoking progression (defined as smoking more frequently and/or intensely over time) were identified: (a) Late Experimenters (never smokers at baseline, ever smokers at follow-up), (b) Early Experimenters (ever smokers at baseline, current/current frequent smokers at follow-up), and (c) Early Smokers (current smokers at baseline, current frequent smokers at follow-up). RESULTS: Twenty percent of adolescents experienced progression in their smoking behavior; those with and without asthma were equally likely to progress. Among adolescents who progressed, 37% were Late Experimenters, 42% were Early Experimenters, and 21% were Early Smokers. Exposure to friends who smoked was a consistent and powerful social risk factor for smoking progression among adolescents with asthma-more so than among adolescents without asthma. This effect was intensified among Late Experimenters by the presence of a positive history of parent smoking. CONCLUSIONS: Findings underscore the importance of addressing cigarette smoking behavior and its social risk factors among adolescents with asthma in both clinical and public health contexts, during early adolescence, and through research on this topic.     

Different pattern of risk factors for atopic and nonatopic asthma among children – report from the Obstructive Lung Disease in Northern Sweden Study

BACKGROUND: A cross-sectional study was performed among 78-year-old schoolchildren during the winter of 1996 in three municipalities in the most northern province of Sweden, Norrbotten. The study was the starting point of a longitudinal study of asthma, rhinitis, eczema, and type-1 allergy, and provided data on prevalence and risk factors for these conditions. The aim of the present study was to validate the classification of asthma based on a parental questionnaire, and to examine risk factors for atopic and nonatopic asthma. METHODS: The ISAAC questionnaire with additional questions was distributed by the schools to the parents. The response rate was 97%, and 3431 completed questionnaires were returned. The children in Kiruna and Lule? were also invited to be skin tested, and 2149 (88%) were tested with 10 common airborne allergens. A structured interview was administered by pediatricians in stratified samples of the children to test the validity of the diagnosis of asthma based on the questionnaire. RESULTS: After the validation study, the prevalence of "ever asthma" was estimated to be 8.0%. The specificity of the question, "Has your child been diagnosed as having asthma by a physician?", was high, >99%, while the sensitivity was around 70%. The strongest risk factor for "ever asthma" was a positive skin test (OR 3.9). Risk factors for asthma in the asthmatics who were not sensitized were family history of asthma, OR 3.6; breast-feeding less than 3 months, OR 1.8; past or present dampness at home, OR 1.8; smoking mother, OR 1.7; and male sex, OR 1.6. Among the sensitized asthmatics, only a family history of asthma was a significant risk factor (OR 3.0), while breast-feeding less than 3 months was not associated with an increased risk (OR 1.0). A synergistic effect between genetic and environmental factors was found especially in the nonatopic asthmatics; the children with a family history of asthma who had a smoking mother and past or present dampness at home had an OR for "ever asthma" of 13. CONCLUSIONS: Different risk-factor patterns were found for asthma and type-1 allergy. In addition, the risk factors for atopic or allergic asthma diverged from those for nonatopic asthma.     

Increasing prevalence of atopic eczema in Taiwanese adolescents from 1995 to 2001

BACKGROUND: The prevalence of atopic eczema in adolescents has recently been reported as increasing in many countries, a phenomenon yet to be fully explained. This study compared the prevalence of atopic eczema among Taiwanese adolescents with individual-level risk factors and community-level data of temperature, relative humidity, and air pollutants to determine whether changes in these factors could explain the observed change in prevalence. METHODS: We conducted two nationwide, cross-sectional surveys of atopic illness and symptoms among Taiwanese 12-15-year-old schoolchildren in 1995-1996 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with the prevalence difference of atopic eczema. RESULTS: A total of 42 919 adolescents from the 1995 to 1996 survey and 10 215 adolescents from the 2001 survey attended schools located within 1 km of 22 monitoring stations. The 12-month prevalence of atopic eczema increased significantly during this period [adjusted prevalence ratio (PR)=1.43, 95% confidence interval (CI) 1.21-1.70 in boys; PR=1.77, 95% CI 1.49-2.10 in girls]. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed the most, changes in personal and environmental factors might not explain the observed prevalence increases of atopic eczema. Temporal change in the relative humidity was significantly associated with prevalence increase among boys but its contribution was also small. CONCLUSION: Correlates of the investigated risk factors that have changed over time still underlie the prevalence increases of atopic eczema in Taiwanese adolescents. The exact reasons for the rising trends remain to be elucidated.     

Asthma-specific predictors of smoking onset in adolescents with asthma: a longitudinal study

Objective Despite even occasional smoking being more riskyfor adolescents with asthma, the smoking rate in this vulnerablepopulation remains high. This is the first longitudinal studyinvestigating asthma-specific predictors of smoking initiation. Methods Athree-wave longitudinal survey study (22 months) among 257 adolescentswith asthma was conducted. The effects of asthma-specific factors[symptom severity, medication adherence, coping, attitude towardsasthma, and quality of life (QOL)] on smoking onset were testedwith logistic regression models. Results Poorer self-reportedadherence and the maladaptive coping strategy of hiding asthmapredicted smoking onset. Poorer QOL predicted smoking in boysonly. Conclusions Our findings underscore the importanceof recognizing and addressing adherence problems during adolescenceas low adherence is a risk factor for smoking initiation. Moreover,psychosocial factors, such as coping and QOL for boys, wereassociated with smoking initiation. This highlights the importanceof attending to the psychosocial needs of youth with asthma.     

Prevalence and risk factors of oral HPV infection among a healthy Iranian population; Kurdistan,West of Iran

Human papillomavirus (HPV) infection has implicated in the development of some of the oral/oropharyngeal cancers. However, controversy still exists regarding the prevalence of oral HPV (OHPV) and its risk factors. This study aimed to determine the prevalence and variables of OHPV infection in a healthy Iranian population. This study evaluated 300 oral rinse samples. Following the oral and dental examination of participants and filling out a self-administered questionnaire; samples collected by swishing and gargling 0.09% saline. The viral DNA extraction, polymerase chain reaction and HPV genotyping then performed. Prevalence of OHPV DNA/OHPV+ infection and OHPV genotypes was 12% and 1% (two cases of HPV6 and one case of HPV53), respectively. Comparison of variables between OHPV+ and OHPV− groups revealed that only income (P = .045), number of cigarettes smoked per day (P = .002), and number of teeth in the mouth (P = .005) were significantly different between the two groups. In conclusion, prevalence of OHPV+ infection and its genotypes were very low in our healthy Iranian population, and its association was not significant with the majority of suggested risk factors. Further studies with a larger sample size are recommended to determine OHPV infection risk factors.     

The prevalence and risk factors of asthma and allergic diseases among working adolescents

Certain occupational groups are known to be at particularly high risk of developing allergic diseases. The objective of the present study was to evaluate the prevalence of allergic diseases among working adolescents. The International Study of Asthma and Allergies in Childhood questionnaire was used. Four hundred and thirty six adolescents working in motor, lathe-finish, coiffure and textile and 366 high school students as control group were enrolled to the study. Mean age was 16.8 +/- 1.2 years and 82.9% of them were male. There was no significant difference among groups for ever and current wheezing while doctor diagnosed asthma was higher in lathe- finish group (p = 0.036). Family history of allergy, history of allergic rhinitis, and active smoking were found to be risk factors for asthma and related symptoms. Working in coiffure (p = 0.054), and textile (p = 0.003) were significant risk factors for ever allergic rhinitis. Working in lathe finish (p = 0.023), coiffure (p = .002), and textile (p < 0.001) were associated with a higher risk for current allergic rhinitis. Working in coiffure was a risk factor for ever eczema (p = 0.008) and doctor diagnosed eczema (p = 0.014). It was concluded that working in lathe-finish was associated with doctor diagnosed asthma and active smoking was a risk factor for asthma and related symptoms. Working in coiffure, textile and lathe- finish were risk factors for rhinitis, and working in coiffure was a risk factor for eczema. Preventive measures should be taken at the onset of employment in order to prevent or reduce the detrimental effects of exposures in these occupational groups.     

Trends in prevalence of asthma, allergic rhinitis and atopic dermatitis in 5-7-year old Swiss children from 1992 to 2001

BACKGROUND: Changing occurrence rates of asthma, allergic rhinitis and atopic dermatitis are of public health concern and require surveillance. Changes in prevalence rates of these atopic diseases were monitored during 10 years and their trend with time was determined taking into account the influence of personal and environmental risk factors. METHODS: Four cross-sectional surveys in 5-7-year old children were performed in seven different communities in Switzerland between 1992 and 2001. Prevalence of respiratory and allergic symptoms and of affecting risk factors including parental environmental concern were assessed using a standardized parental questionnaire. RESULTS: A total of 988 (74.1%), 1778 (79.0%), 1406 (82.6%) and 1274 (78.9%) children participated, respectively, in the 1992, 1995, 1998 and 2001 surveys. Prevalence rates of asthma and hay fever symptoms remained quite stable over time (wheeze/past year: 8.8%, 7.8%, 6.4% and 7.4%, sneezing attack during pollen season: 5.0%, 5.6%, 5.4% and 4.6%). Rates of reported atopic dermatitis symptoms (specific skin rash/past year: 4.6%, 6.5%,7.4% and 7.6%) showed an increase over time, but those of diagnosis of eczema did not show a clear pattern (18.4%, 15.7%, 14.0% and 15.2%). Stratified analysis by parental environmental concern and by parental atopy showed similar trends. Rates of atopic dermatitis symptoms showed significant increase in girls but stayed stable in boys. CONCLUSION: Results of these four consecutive surveys suggest that the increase in prevalence of asthma and hay fever in 5-7-year old children living in Switzerland may have ceased. However, symptoms of atopic dermatitis may still be on the rise, especially among girls.     

Rising trend of asthma prevalence among Turkish schoolchildren (ISAAC phases I and III)

BACKGROUND: Asthma is a common chronic illness in childhood. The aim of the study was to examine time trends in the prevalence of asthma using the ISAAC questionnaire in 6- to 12-year-old schoolchildren in Istanbul and factors affecting asthma prevalence. METHODS: Two cross-sectional surveys were performed, 9 years apart (1995 and 2004) using the ISAAC protocol. The survey conducted in 1995 was repeated in 2004 using the same questionnaire in the same age group, in the same schools in the same season. The 2500 questionnaires were distributed to the children to be completed by their parents at home. RESULTS: A total of 2387 children (response rate 95.5%) in the 2004 study and 2216 children (response rate 94.3%) in 1995 were included in the final analysis. The overall lifetime prevalence of wheeze increased from 15.1% to 25.3%; prevalence odds ratio (POR) = 1.91, 95% confidence interval (95% CI) = 1.64-2.21, and P < 0.001. The overall 12-month prevalence of wheeze increased from 8.2% to 11.3%; POR = 1.43, 95% CI = 1.18-1.75, and P < 0.001. The prevalence of asthma increased significantly from 9.8% to 17.8%; POR = 1.99, 95% CI = 1.67-2.36, and P < 0.001. In both 1995 and 2004, family history of asthma, eczema diagnosed by a physician, food allergy diagnosed by a physician, frequent otitis, frequent sinusitis were associated significantly with high risk for asthma. CONCLUSIONS: In the 9-year period from 1995 to 2004, the prevalence of asthma symptoms has increased in 6- to 12-year-old schoolchildren in Istanbul. Risk factors affecting asthma prevalence remained unchanged during the 9-year period.     

Stabilizing prevalence trends of eczema,asthma and rhinoconjunctivitis in Dutch schoolchildren (2001–2010)

In contrast to many countries, a decrease in childhood wheeze prevalence was previously reported for the Netherlands. In repeated cross‐sectional surveys in 2001, 2005 and 2010, we investigated whether this trend continued, and additionally examined prevalence trends of eczema, asthma and rhinoconjunctivitis among 8‐ to 11‐year‐old schoolchildren eligible for a routine physical examination. Overall, ~90% participated (mean age: 8.8 years in 2001 and 10.5 years in 2005 and 2010). Eczema, wheeze and asthma prevalence did not change significantly between 2001 and 2010, but rhinoconjunctivitis prevalence increased from 8.4% in 2001 to 12.3% in both 2005 and 2010 (P_trend < 0.01). In conclusion, after a decrease in wheeze prevalence among Dutch schoolchildren between 1989 and 2001, no further decrease was observed until 2010. Similarly, the prevalence of eczema and asthma remained stable, but rhinoconjunctivitis prevalence increased between 2001 and 2010. The latter may be an effect of older age and not a true increase over time.