Prevalence of asthma among schoolchildren in Patras, Greece: four questionnaire surveys during 1978-2003

Prevalence and Characteristics of Self-Reported Adult Asthma in Cyprus: A Population-Based Observational Study

Purpose

To estimate the prevalence of asthma in adults, by gender and age, in urban and rural areas of Cyprus.

Patients and Methods

This was a population-based, random-digit dialing, telephone nation-wide survey to recruit patients with asthma. Among 8996 random landline-telephone contacted from the five major urban and rural regions of Cyprus, 1914 were finally met the age criterion of ≥18 years old and 572 completed valid screening for prevalence estimation. The participants filled a short screening questionnaire in order for asthma cases to be recognized. Then, asthma cases filled the main ECRHS II questionnaire and were evaluated by a pulmonary physician. All underwent spirometry. Data on demographic characteristics, educational level, profession, smoking status, Body Mass Index (BMI), Total IgE and Eosinophil Cationic Protein levels were measured.

Results

The overall prevalence of bronchial asthma in adults in Cyprus was 5.57% (61.1% men and 38.9% women). Among the participants with self-reported bronchial asthma 36.1% were current smokers, while 12.3% were obese (BMI >30). A total value of IgE >115 IU and Eosinophil Cationic Protein (ECP) >20 IU was found in 40% of the participants with established bronchial asthma. Wheezing and chest tightness were the most frequently reported symptoms in asthma patients (36.1% and 34.5%, respectively), while 36.5% experienced at least one exacerbation during the last year. Interestingly, most of the patients were under-treated (14.2% were on maintenance asthma treatment, and 18% used solely reliever medication).

Conclusion

This was the first study estimating asthma prevalence in Cyprus. Asthma affects almost 6% of the adult population, with higher prevalence in urban areas and in men compared to women. Interestingly, one-third of the patients were uncontrolled and under-treated. This study revealed that in Cyprus there is space for improvement in the management of asthma.

Does BMI Modify the Association between Vitamin D and Pulmonary Function in Children of the Mild Asthma Phenotype?

Vitamin D deficiency and obesity are global health problems that are associated with increased asthma risk in children. The purpose of this study was to investigate whether BMI modifies pulmonary function across vitamin D tertiles in pediatric asthma patients of the mild asthma phenotype. This cross-sectional study conducted from November 2016-September 2017 compared lung function variability as assessed by spirometry and nitric oxide in exhaled breath (FeNO) among 35 normal-weight and 26 overweight/obese Greek schoolchildren (5-12 years old) with mild asthma. Serum 25 (OH)D levels ≥ 30 ng/mL were defined as 'sufficient', 20-30 ng/mL 'insufficient', and <20 ng/mL 'deficient'. Stratification by BMI category, linear regression showed positive associations between D, % FVC (β = 0.49, 95%CI: 0.05, 0.94), and % FEV₁ (β = 0.48, 95%CI: -0.01, 0.95) in the normal-weight only, adjusted for age, sex, regular exercise, and medication. FEV₁ was 10% higher in the normal-weight D-sufficient group compared to those D-deficient (β = 10.43, 95%CI: 0.54, 20.32). No associations were observed for the overweight/obese group or FeNO. In conclusion, BMI modified associations of vitamin D on airway mechanics in children of the mild asthma phenotype. Serum 25 (OH)D concentrations ≥ 30 ng/mL were associated with higher ventilation in central airways of normal-weight asthmatic children.

Physical activity and quality of life in children with well-controlled asthma

Background: Asthma is the most common disease in childhood. Appropriate management and programs encouraging exercise enable children to enjoy a good quality of life (QoL).Objective: To assess the association between lung function, physical activity (PA), and QoL in children with well-controlled asthma.Methods: Fifty-four children aged 7 to 14 years attending a Pediatric Asthma Clinic were included. All children underwent spirometry and completed three self-administered validated questionnaires: The Godin Leisure-Time Exercise Questionnaire (GLTEQ), the ACT (Asthma Control Test), and the DISABKIDS for QoL.Results: Mean age of the study population was 11.43(±2.1), BMI, kg/m² (20.8 ± 3.9), FVCpp (97.1% ±12.4), and FEV1pp (99.7% ±12.43), ACT (23.4 ± 3). The GLTEQ revealed that only 3% of the studied population presented satisfactory activity, while 86% were sedentary. Both FEV1pp, and PA were significantly correlated to the children's QoL ((r²: 0.55, p:0.0001), and (r²:0.45, p:0.003), respectively).Conclusions: Despite reasonable asthma control, the children exhibited low physical activity levels, which negatively correlated to their QoL. Families of asthmatic children should be educated to highlight the benefits of exercise and increase the PA of their children.

Parental education moderates the association between indoor moisture environment and asthma in adolescents: the Greek Global Asthma Network (GAN) cross-sectional study

Objective

Asthma is a major contributor to childhood morbidity. Several environmental and socioeconomic status (SES) factors have been implicated in its etiopathogeneses such as indoor moisture and parental education level. Our study examined the association between exposure to indoor dampness and/or mould (IDM) with adolescent asthma and how parental education could modify or mediate this relationship.

Method

A total of 1934 adolescents (boys: 47.5%, mean age (standard variation): 12.7(0.6) years) and their parents were voluntarily enrolled and completed a validated questionnaire on adolescents’ asthma status, parental educational level, and adolescents’ indoor exposure to IDM during three different lifetime periods, i.e., pregnancy, the first year of life and the current time.

Results

There was a significant modification effect of parental education only for the current exposure; higher parental education lowered almost 50% the odds of IDM and asthma (adjusted odds ratio (aOR): 1.96, 95% Confidence Intervals (CI): (1.05–3.68) and aOR:1.55, 95% CI (1.04–2.32), for primary/secondary and tertiary parental education, respectively).

Conclusion

Adolescents whose parents had a higher education level had lesser odds to have asthma, even if they were exposed to a moisture home environment. This could be attributed to the increased knowledge about asthma risk factors and the improved measures for the amelioration of moisture-home environment that highly educated parents are more likely to take. Further research is needed in order to elucidate the interweaved role of family SES in the aforementioned relation.

Changing trends in the prevalence of childhood asthma over 40 years in Greece

BACKGROUND

A series of repeated questionnaire surveys among 8- to 9-year-old school children in the city of Patras, Greece, demonstrated a continuous rise in the prevalence of wheeze/asthma from 1978 to 2003, with a plateau between 2003 and 2008. We further investigated wheeze/asthma trends within the same environment over the last decade.

METHODS

Two follow-up surveys were conducted in 2013 (N = 2554) and 2018 (N = 2648). Physician-diagnosed wheeze and asthma were analyzed in relation to their occurrence (recent-onset: within the last 2 years; noncurrent: before 2 years; persistent: both prior and within the last 2 years). In 2018, spirometry was also performed in participants reporting symptoms and in a sample of healthy controls.

RESULTS

The prevalence of current wheeze/asthma declined from 6.9% in 2008% to 5.2% in 2013% and 4.3% in 2018. The persistent and noncurrent wheeze/asthma groups followed this overall trend (P-for-trend <0.001), while the prevalence of recent-onset wheeze/asthma remained unchanged (P-for-trend >0.05). Persistent and noncurrent wheezers were also more frequently diagnosed with asthma, in contrast to those with recent-onset wheeze. The FEV₁ z-score was less than -1 in 32.1% of children with recent-onset and in 22.4% of those with persistent wheeze/asthma; both rates were higher than those of the Noncurrent wheeze/asthma group (7.1%; p < .05) and of healthy controls (3.5%; p < .001).

CONCLUSIONS

The prevalence of childhood wheeze/asthma has declined significantly during the last decade in Greece. The reversing trend may in part be attributed to changing asthma perceptions among physicians and/or parents, especially in the case of younger children with troublesome respiratory symptoms.

Prevalence of asthma symptoms and association with obesity, sedentary lifestyle and sociodemographic factors: data from the Hellenic National Action Plan for the assessment, prevention and treatment of childhood obesity (MIS301205)

Objectives: To evaluate the prevalence of asthma symptoms in a representative sample of Greek schoolchildren and to evaluate its association with overweight/obesity as well as other socioeconomic, demographic, and lifestyle factors. Methods: This is a cross-sectional study conducted from 10/2012 to 12/2013 on a pre-selected, representative elementary school cohort. Parents completed standardized questionnaires evaluating among others socioeconomic and sedentary activity habits. Students were measured with high sensitivity methods. Socioeconomic status (SES) index (range: 0-13) was calculated on years of parental education, rented versus owned residence, size of residence evaluated as meters squared per person (m²/person), and number of vehicles. Asthma was defined according to the approved Greek version of the International Study on Allergies and Asthma in Childhood (ISAAC) criteria. Results: The prevalence of any asthma symptoms was documented in 31% of population. The odds of presenting any asthma symptoms decreased with increase in age (odds ratio: 0.96, 95% CI: 0.94-0.98) and increased with overweight (odds ratio: 1.13, 95% CI: 1.03-1.25), obesity (odds ratio: 1.27, 95% CI: 1.11-1.46) and sedentary lifestyle. Conclusion: This is the first representative survey of prevalence of asthma symptoms in children and adolescents in Greece indicating its continuous increase. A strong association between presence of asthma symptoms and obesity and sedentary activities was documented irrespectively of socioeconomic and regional factors. The findings stress the importance of public health policies toward obesity prevention and enhancement of physical activities in pediatric populations.

Antioxidant foods consumption and childhood asthma and other allergic diseases: The Greek cohorts of the ISAAC II survey

BACKGROUND

Antioxidant intake changes have been implicated with the increase in asthma and allergies outcomes, but no clear association has been revealed. In this cross sectional study, the overall effect of antioxidants on asthma and allergic diseases was studied.

METHODS

Data from the cohorts of the phase II ISAAC survey (2023 children 9-10 years old) in two metropolitan Greek cities were analysed. Using a semi-quantitative food frequency questionnaire, an Antioxidant Eating Index (AEI, range 0-6) was created with the pro-antioxidant (vegetables, fruits, fresh juice, fish) and the non-antioxidant (meat, burgers) food intake and was evaluated with allergic diseases. Higher values of the score suggest closer to an "antioxidant" and lesser to a "saturated fatty" diet.

RESULTS

Prevalence of lifetime and current asthma, current rhinitis and sensitisation were higher in Thessaloniki compared to Athens. The AEI score of the entire cohort was 4.2 ± 1.2 (median 4.0) and was higher in Athens compared to Thessaloniki (4.3 ± 1.2 vs. 4.0 ± 1.2, p=0.001) and in girls than boys (4.3 ± 1.1 vs. 4.0 ± 1.2, p=0.001). AEI was inversely associated with lifetime asthma (OR: 0.87, 95%CI 0.77, 0.99) in either cities independently of other cofounders such as family history, sensitisation, exercise, house smoking, breast feeding, pet or dampness in houses. No association with other allergic disease or sensitisation was detected.

CONCLUSION

Antioxidant foods seem to be a non-pharmacological, protective dietary pattern for asthma development in children irrespectively of atopy or heredity; AEI was a rough indicator and the role of antioxidants in allergic diseases is still under consideration.

The prevalence of asthma diagnosis and symptoms is still increasing in early adolescents in Turkey

BACKGROUND

This study was performed to evaluate the time trends in prevalence of asthma and related factors in Denizli, Turkey.

METHODS

Two cross-sectional surveys were performed, 6 years apart (2002 and 2008) using the ISAAC protocol, in the 13-14 age groups and comparisons were made between the results.

RESULTS

Lifetime prevalence of wheeze, 12 month prevalence of wheeze, and the prevalence of wheeze after exercise in the previous 12 months were significantly increased respectively from 10.2% to 13.4% (POR = 1.37, 95%CI = 1.18-1.58, p < 0.001), from 5.0% to 6.2% (POR = 1.26, 95%CI = 1.02-1.55, p = 0.016) and from 9% to 10.2% (POR = 1.15, 95%CI = 0.98-1.35, p = 0.046) in 2008 study. Doctor diagnosed asthma prevalence also increased significantly from 2.1% to 12.9 (POR = 6.80, 95%CI = 5.22-8.85, p < 0.001). Prevalence of sleep disturbed by wheeze in the last 12 months; but, never woken with wheezing (POR = 1.62, 95%CI = 1.26-2.09, p = < 0.001) and less than one night per week (POR = 1.58, 95%CI = 1.06-2.36, p = 0.013) were significantly increased in 2008 study. Severe attacks of wheeze limiting speech in the last year was increased from 1.3% to 2.2% (POR = 1.67, 95%CI = 1.14-2.43, p = 0.004). The number of wheeze attacks in the previous 12 months was increased significantly for 4-to-12 attacks (POR = 1.54, 95%CI = 1.03-2.32, p = 0.02) in 2008 study. However, prevalence of waking with cough in the last 12 months did not change. While history of family atopy and domestic animal at home were found as significant risk factors for asthma in 2002 study, male gender, history of family atopy and stuffed toys were found significant in 2008.

CONCLUSIONS

The prevalence of asthma symptoms were increased in Denizli. History of family atopy, male gender and stuffed toys were important risk factors for asthma in 2008.

Health effects of ozone focusing on childhood asthma: what is now known--a review from an epidemiological point of view

Protecting the health of children and the environment is an essential objective for the health policies of any modern society, being also crucial for a sustainable development, according to the World Health Organization. Evaluating the risk of developing childhood asthma is one of the four priority issues identified by the European Commission, according to the European Union Environment and Health Action Plan. Accordingly, this review aimed to update information concerning the effects of exposure to ozone on childhood asthma, thus helping in the development of strategies for further research. Studies have been demonstrating strong associations between the exposure to ozone and asthma. However, the complexity of exposure patterns, the changes in the vulnerability of children at various stages of development, and the practical limitations of research, lead to a still incomplete understanding of the ozone impact on the health of children. Difficulties on the interpretation of epidemiological studies to evaluate chronic effects are mainly due to an absence of studies designed specifically to address this question and to inherent limitations in characterizing exposure. The more rigorous studies provided new evidences for chronic effects of ozone on small airway function and possibly on asthma, but substantial uncertainties remain.

The 2002-2007 trends of prevalence of asthma, allergic rhinitis and eczema in Irish schoolchildren

BACKGROUND

Irish adolescents have the third highest asthma prevalence in the world. Few data examine trends of prevalence of asthma and allergic disorders in younger Irish children. We compared the prevalence of asthma, allergic rhinitis and eczema in school children, aged 6-9 in 2002 and 2007.

METHODS

In two cross-sectional studies, parents of children aged 6-9, completed identical ISAAC-based questionnaires in the same 24 Cork City schools in 2002 (n = 1474, response rate = 74.8%) and in 2007 (n = 1535, response rate = 76.2%).

RESULTS

The prevalence of asthma in our study population of schoolchildren, aged 6-9 remained stable in 2007 (23.5%) since the 2002 finding of 21.7% (p = 0.27). Significant increases were found in the prevalence of rhino-conjunctivitis (7.6-10.6%, p = 0.005) and eczema (8.9-13.5%, p < 0.001). In 2007, male preponderance for suffering the symptoms of current asthma existed (M:F 1.2:1, p = 0.075), although it had lost its significance since 2002 (M:F 1.5:1, p < 0.001). M:F ratio for most allergic rhinitis related symptoms moved from equal sex distribution to male predominance (nasal problems ever: 2002 - M:F, 1.1:1, p = 0.117; 2007 - M:F, 1.2:1, p = 0.012, current rhinitis: 2002 - M:F 1.2:1, p = 0.98; 2007 M:F 1.3:1, p = 0.009, hay fever ever: 2002 - M:F 1:1, p = 0.57; 2007 - M:F 1.5:1, p = 0.007). The sex-specific prevalence of rhino-conjunctivitis and the severity of symptoms suffered, remained equally sex distributed in both timeframes. From 2002 to 2007, the prevalence of all the reported symptoms of eczema were equally distributed between the sexes, while lifetime prevalence of eczema moved from male predominance to equal distribution.

CONCLUSION

The prevalence of asthma in 6-9 yr old Cork schoolchildren remained static between 2002 and 2007; however, rhino-conjunctivitis and eczema have become increasingly prevalent. Co-morbidity of allergic conditions continues to pose a considerable health burden in this young population. We also demonstrated an alteration in the sex-specific profile of current asthma and lifetime allergic rhinitis towards equalization in distribution.

Time trend of asthma in children and adolescents in Brazil, 1998-2008

OBJECTIVE

To analyze the trends in asthma prevalence in children and adolescents between 1998 and 2008 in Brazil.

METHODS

Data on asthma prevalence from the 1998, 2003 and 2008 National Household Sample Surveys were analyzed. The sample was comprised of 141,402, 144,443 and 134,032 individuals in 1998, 2003 and 2008, respectively, and the analysis was adjusted for the sample design. Trends in asthma prevalence were described for sex, Brazilian regions and place of residence of children (zero to nine years of age) and adolescents (ten to 19 years of age).

RESULTS

The prevalence of asthma in children was 7.7% in 1998, 8.1% in 2003 and 8.5% in 2008, with an annual increase of 1%. The highest annual increase was observed in the Southeast and North regions (1.4%). Among adolescents, the prevalence of asthma was 4.4% in 1998, 5.0% in 2003 and 5.5% in 2008, with an increase of 2.2% per year. In the Northeast region, the annual increase in the prevalence of asthma was 3.5%. The greatest increases were observed in boys and in residents of rural areas.

CONCLUSIONS

Although asthma has decreased in some developing countries, the results found in Brazil point to an increase in this disease in children and adolescents between 1998 and 2008, especially in rural areas.

Temporal changes in the prevalence of childhood asthma and allergies in urban and rural areas of Cyprus: results from two cross sectional studies

BACKGROUND

The prevalence of childhood asthma and allergies in Cyprus was significantly higher in urban compared to rural areas back in the year 2000, against a background of an overall low prevalence (e.g. current wheeze 6.9%) by comparison to northern European countries. In this study we aimed to assess temporal changes in the prevalence of asthma and allergies in Cyprus after an 8-year interval and to examine whether any differential changes have occurred in urban and rural parts of the island.

METHODS

During the academic years 1999-2000 and 2007-2008, the parents of 7-8 year old children residing in the same set of urban and rural areas completed the ISAAC core questionnaire. In addition to providing prevalence estimates of allergic diseases in 2000 and 2008, changes between the two periods were expressed as odds ratios estimated in multiple logistic regression models adjusting for survey participants' characteristics.

RESULTS

The prevalence of current wheeze was higher in 2008 (8.7%, 95% confidence interval 7.5%-9.9%, n = 2216) than the previously recorded figure in 2000 (6.9%, 95% CI 6.2%-7.6%, OR = 1.25, 95% CI: 1.02-1.53, n = 4944). Significant increases were also seen in the prevalence of lifetime asthma (11.3% vs. 17.4%, OR = 1.59, CI: 1.36-1.86), eczema (6.8% vs. 13.5%, OR = 1.91, CI: 1.59-2.29) and allergic rhinoconjuctivitis (2.6% vs. 5.2%, OR = 1.82, CI: 1.39-2.41). The prevalence of current wheeze nearly doubled between 2000 and 2008 in rural areas (5.4% vs. 9.7%, OR 1.81, CI: 1.24-2.64) while no significant change was observed in urban areas (7.5% vs. 8.4%, OR 1.08, CI: 0.84-1.37); p value for effect modification = 0.04. Rises in asthma and rhinitis prevalence, but not eczema were also more pronounced in rural compared to urban areas.

CONCLUSIONS

The prevalence of allergic diseases in Cyprus is still on the rise; recent increases appear more pronounced among children living in rural areas possibly indicating recent environmental and lifestyle changes in these communities.

Comparison in asthma and allergy prevalence in the two major cities in Greece: the ISAAC phase II survey

BACKGROUND

Variability in the prevalence of allergic diseases has been detected not only between different countries, but also between cities with similar national and different socio-economic or climatic characteristics. The aim of this study was to determine the prevalence of childhood asthma and allergies and which factors are associated with them, in the two largest Greek cities, Athens and Thessaloniki.

METHODS

Two thousand and twenty-three Greek 9-10-year-old schoolchildren from Athens (Central Greece) and Thessaloniki (North Greece, more humid), were included in ISAAC-II study. All participants followed the ISAAC-II protocol by questionnaire, skin prick testing and flexural dermatitis examination.

RESULTS

Compared with Athens, the prevalence of current wheezing (8.4% vs. 5.7%, p=0.002), lifetime asthma (11.5% vs. 7.7%, p=0.004), atopic current asthma (3.2% vs. 1.6%, p=0.02), allergic rhinitis (8.2% vs. 5.2%, p=0.007), and hay fever (21.7% vs. 12.5%, p<0.001) were higher in Thessaloniki. The overall sensitisation rate was also higher in Thessaloniki than in Athens (25.2% vs. 16%, p<0.001) with more prevalent sensitising due to the perennial allergens (D. pteronyssinus, D. farinae, Alternaria tenuis) and cat dander. Perennial allergens sensitisation was a risk factor for current asthma in both cities.

CONCLUSION

A higher prevalence of asthma symptoms, allergic rhinitis, and sensitisation rate was detected in Greek schoolchildren living in Thessaloniki compared to those in Athens. Allergy to mites and mould was more prevalent in Thessaloniki. The more humid weather of Thessaloniki may be implicated.

Sex-specific trends in prevalence of childhood asthma over 30 years in Patras, Greece

AIM

 According to four surveys conducted during 1978-2003, the prevalence of childhood asthma and wheezing has risen in the city of Patras, Greece, albeit at a decelerating rate. We examined sex-specific wheeze and asthma prevalence in the same urban environment in 2008.

METHODS

A cross-sectional parental questionnaire survey was performed in 2008 among third and fourth grade schoolchildren (8-9 year old), which was identical to previously conducted surveys in 1978 (n = 3003), 1991 (n = 2417), 1998 (n = 3076) and 2003 (n = 2725).

RESULTS

The prevalence of current wheeze and asthma in 1978, 1991, 1998, 2003 and 2008 (n = 2688) was 1.5%, 4.6%, 6.0%, 6.9% and 6.9%, respectively (p for trend <0.001). Respective values for lifetime (ever had) wheeze and asthma in the 1991-2008 surveys were 8.0%, 9.6%, 12.4% and 12.6% (p for trend <0.001). The male:female ratio of current and lifetime wheeze and asthma increased during the 30-year surveillance period (p for trend <0.001). Irrespective of sex, diagnosed asthma declined among current wheezers by 17% (p < 0.001), but not among non-current ones (6.7%, p = 0.16) during 2003-2008.

CONCLUSIONS

Childhood wheeze and asthma have reached a plateau in an urban environment in Greece, while the male:female ratio increased. Asthma diagnosis declined among schoolage but not preschool wheezers during 2003-2008.

Trends in asthma prevalence and incidence in Ontario, Canada, 1996-2005: a population study

In the 1980s and early 1990s, asthma prevalence increased significantly in most Westernized countries. In more recent years, asthma trends have been less clear, with some studies suggesting that they are still rising and others suggesting that they have stabilized or decreased. A population-based cohort study was conducted to estimate asthma prevalence and incidence trends in one large Canadian province, Ontario. All individuals with asthma living in Ontario, a province of Canada with a multicultural population of approximately 12 million, were identified in universal, population health administrative databases by using a validated health administrative case definition of asthma. Annual asthma prevalence, incidence, and all-cause mortality rates were estimated from 1996 to 2005. During this time, the prevalence of asthma increased by 70.5%. The age- and sex-standardized asthma prevalence increased from 8.5% in 1996 to 13.3% in 2005, a relative increase of 55.1% (P < 0.0001). Asthma incidence rates increased in children by 30.0% and were relatively stable in adults. Overall all-cause mortality decreased. Asthma prevalence in Ontario, Canada, has increased significantly. This is attributable, in part, to an increase in the incidence of asthma in children. Effective clinical and public health strategies are needed to prevent and manage asthma in the population.

A telehealth integrated asthma-COPD service for primary care: a proposal for a pilot feasibility study in Crete, Greece

Background

Chronic obstructive pulmonary disease (COPD) and asthma are considered underdiagnosed and misdiagnosed chronic diseases. In The Netherlands, a COPD-asthma telemedicine service has been developed to increase GPs' ability to diagnose and manage COPD and asthma. A telemedicine COPD-asthma service may benefit Greece as it is a country, partly due to its geography, that does not have easy access to pulmonologists.

Findings

Therefore, a pilot feasibility study has been designed in Greece in order to establish this telemedicine service. Ten rural practices, in the island of Crete, with an average population of 2000 patients per practice will pilot the project supported by three pulmonologists. This paper presents the translated interfaces, the flowcharts and the steps that are considered as necessary for this feasibility study in Crete, Greece.

Is the prevalence of asthma declining? Systematic review of epidemiological studies

Asthma prevalence has increased very considerably in recent decades such that it is now one of the commonest chronic disorders in the world. Recent evidence from epidemiological studies, however, suggests that the prevalence of asthma may now be declining in many parts of the world, which, if true is important for health service planning and also because this offers the possibility of generating and testing new aetiological hypotheses. Our objective was to determine whether the prevalence of asthma is declining worldwide. We undertook a systematic search of EMBASE, Medline, Web of Science and Google Scholar, for high quality reports of cohort studies, repeat cross-sectional studies and analyses of routine healthcare datasets to examine international trends in asthma prevalence in children and adults for the period 1990-2008. There were 48 full reports of studies that satisfied our inclusion criteria. The large volume of data identified clearly indicate that there are, at present, no overall signs of a declining trend in asthma prevalence; on the contrary, asthma prevalence is in many parts of the world still increasing. The reductions in emergency healthcare utilization being reported in some economically developed countries most probably reflect improvements in quality of care. There remain major gaps in the literature on asthma trends in relation to Africa and parts of Asia. There is no overall global downward trend in the prevalence of asthma. Healthcare planners will for the foreseeable future, therefore, need to continue with high levels of anticipated expenditure in relation to provision of asthma care.

Association of nutrient intake and wheeze or asthma in a Greek pre-school population

The rise of asthma prevalence in children observed the last years might be related to several dietary factors/components as suggested by several researchers. We aimed to evaluate the potential relationship between certain nutrients intake and asthma occurrence in a population of pre-school children. In the framework of the cross-sectional study 'Growth, Exercise and Nutrition Epidemiological Study In pre-schoolers', data were collected from 1964 children, aged 24-72 months, living in five different counties in Greece. The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma related outcomes. Dietary intake was assessed with 3 days diet records. The prevalence of ever wheeze, current wheeze and diagnosed asthma was 37.7%, 27.5% and 10.5% respectively. Dietary intake of magnesium had a 0.5% and 0.6% increase in the reported risk of current wheeze and diagnosed asthma respectively. On the contrary a decrease in the prevalence of ever (OR: 0.997, 95% CI: 0.995-1.000) and current wheeze (OR: 0.996, 95% CI: 0.993-0.999) was associated with vitamin C intake. Calcium intake slightly decreased the risk of current wheeze (OR: 0.999, 95% CI: 0.998-0.999). An increase of 2% of the risk of reporting ever or current wheeze was associated with mono-unsaturated fatty acid intake. Magnesium intake was the only independent predictor for doctor's diagnosed asthma. We conclude that dietary intake of vitamin C and calcium seem to have a protective effect on the incidence of wheeze in pre-school children, whereas magnesium and mono-unsaturated fatty acid may have a harmful role.

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.

Prevalence of asthma symptoms and atopic disorders in preschool children and the trend over a decade

OBJECTIVES

Over the last few decades, there have been substantial publications on the prevalence and trends of asthma in school-age children and adolescents. There has been a scarcity of reports on asthma prevalence and trends in preschool children. This study was performed to measure the prevalence of symptoms of asthma, allergic rhinitis, and eczema in preschool (4- and 5-year-old) children and the trend over a decade.

STUDY DESIGN

A cross-sectional questionnaire based survey using the International Study of Asthma and Allergy in Childhood (ISAAC) was performed on South Australian preschool children in 2006. The results were compared to a previous survey conducted in 1993.

RESULTS

The 12-month period prevalence of reported wheeze, allergic rhinitis, and eczema was 23.7%, 20.8%, and 18.8%, respectively. The prevalence of wheeze symptoms was higher in males than females. There was a decline in the prevalence of "wheeze in the last 12 months" (25.2% to 23.7%) and in "asthma ever" (22.5% to 19.0%, p < 0.05) from 1993 to 2006.

CONCLUSION

There is a burden in the symptoms of asthma, allergic rhinitis, and eczema in preschool children. There is a declining trend in the prevalence of "current wheeze" and "asthma ever" in South Australian preschool children over a decade.

Can we be optimistic about asthma in childhood? A Greek cohort study

OBJECTIVE

To examine the prevalence and natural course of asthma from childhood to adolescence in a population-based, Greek birth cohort and to identify associated factors.

METHODS

Longitudinal information on asthma symptoms, physician diagnosed and treated, was available for 2133 children at 7 and 18 years of age.

RESULTS

The prevalence of current asthma was 9.0% and 5.0% at 7 and 18 years, respectively. The prevalence of lifetime asthma was 26.3% at 18 years. More than half of the children (58.2%) with early onset asthma were asymptomatic at 7 years and only 7.6% continued to have symptoms during adolescence. However, in 48.2% of those with late onset asthma, symptoms persisted up to 18 years. Logistic regression analyses showed that male gender, family history of atopy, active adolescent smoking and maternal smoking were significantly positively associated with lifetime asthma at 18 years. In addition, smoking during pregnancy was associated with an increased risk for persistence of asthma symptoms at 18 years. Asthma during childhood and active adolescent smoking were positively associated, and daily consumption of fruit and vegetables was negatively associated with current asthma at 18 years of age. Finally, children who were breastfed had a lower risk for lifetime asthma at 7 years.

CONCLUSION

The prevalence of asthma symptoms at 7 and 18 years of age was low throughout Greece. Our results suggest that, among others, nutrition is an important correlate of asthma in Greek children.

Increase in chronic or recurrent rhinitis, rhinoconjunctivitis and eczema among schoolchildren in Greece: three surveys during 1991-2003

The prevalence of allergic rhinitis, hay fever and eczema has risen worldwide during the last four decades but may have reached a plateau in some westernized societies. We examined time trends in the prevalence of childhood chronic or recurrent rhinitis, rhinoconjunctivitis and eczema in urban Greece. Using identical methodology, three population-based cross-sectional parental questionnaire surveys on current (last two years) and lifetime allergic symptoms of the nose, eyes and skin were performed among 8-10-yr-old children in 1991, 1998 and 2003 in Patras, Greece. Exactly 2417, 3006 and 2725 questionnaires were completed in 1991, 1998 and 2003, respectively. Prevalence rates of current (lifetime) symptoms of chronic or recurrent rhinitis were 5.1% (6.0%) for 1991, 6.5% (8.0%) for 1998 and 8.0% (9.8%) for 2003. Respective values for rhinoconjunctivitis were 1.8% (2.1%), 2.7% (3.4%) and 3.6% (4.6%) and for eczema 2.5% (4.5%), 3.4% (6.3%) and 5.0% (9.5%) (p for trend <0.001). Among current asthmatics there was an increase in lifetime rhinitis (p = 0.038), current (p = 0.025) and lifetime rhinoconjunctivitis (p = 0.007) and current (p = 0.001) and lifetime eczema (p < 0.001); male predominance increased throughout the study. The proportion of atopic asthma (current asthma with chronic or recurrent rhinitis and/or rhinoconjunctivitis and/or eczema) increased during the same period (p < 0.001). In conclusion, there is a continuous increase in the prevalence of allergic manifestations among preadolescent children in Patras, Greece during the period 1991-2003. In our population, boys have contributed to this increase more than girls and the increase of atopy is, at least partially, responsible for the increase of asthma.

Factors associated with asthma symptoms in schoolchildren from Greece: the Physical Activity, Nutrition and Allergies in Children Examined in Athens (PANACEA) study

To evaluate whether dietary habits and anthropometric and lifestyle characteristics are associated with the prevalence of asthma symptoms, a sample of 700 Greek schoolchildren were evaluated through a standardized questionnaire. Body height and weight were measured, and body mass index was calculated. Multiple logistic regression and multivariate techniques (principal components analysis) were performed. Overall lifetime prevalence for asthma symptoms was found to be 23.7%. Increased body weight, sedentary lifestyle, and consumption of sulphur-dioxide-enriched foods and beverages seem to promote asthma symptoms, while avoidance of this chemical preservative and physical activity was associated with reduced odds of reporting asthma symptoms.

Aims, methods and preliminary findings of the Physical Activity, Nutrition and Allergies in Children Examined in Athens (PANACEA) epidemiological study

BACKGROUND

To determine the prevalence of asthma symptoms in a sample of Greek children aged 10-12 years, and to evaluate these rates in relation to anthropometric, lifestyle characteristics and dietary habits.

METHODS

During 2006, 700 schoolchildren (323 male and 377 female), aged 10-12 years (4th to 6th school grade), were selected from 18 schools located in the greater Athens area. The schools were randomly selected from a list provided by the regional educational offices. To achieve a representative sample the schools enrolled were selected from various region of the Athens area. For each child a questionnaire was completed that was developed for the purposes of the study to retrieve information on: age, sex, school class, other socio-demographic characteristics, anthropometric measurements, dietary habits (through a semi-quantitative Food Frequency Questionnaire) and physical activity status; the presence of asthma and allergies was assessed by the standard ISAAC questionnaire.

RESULTS

The prevalence of wheezing in the past was 25% in boys and 19% in girls, while the prevalence of current wheezing was 9.0% in boys and 5.8% in girls. The prevalence of any asthma symptoms was 27.6% in boys and 20.4% in girls. Multiple logistic regression analysis revealed that increased body weight and sedentary lifestyle is associated with asthma symptoms only in boys.

CONCLUSION

The present cross-sectional study cannot establish causal relationships between asthma and increased body weight of schoolchildren; however, our findings underline the associations between asthma, increased body weight, and physical activity at population level, and urge for actions that should be taken by public health policy makers in order to prevent these conditions among children.