Decreased prevalence and severity of asthma symptoms among adolescents in Ibadan, Nigeria, 1995-2018.

BACKGROUND: Phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) documented increased asthma symptoms among Nigerian 13-14-year old adolescents. We investigated the trend further using the Global Asthma Network (GAN) surveillance.METHODS: Using ISAAC methodology, GAN Phase I data on symptoms and risk factors for asthma and asthma management were obtained from February to July 2018.RESULTS: There were 2,897 adolescents from 23 secondary schools. For current wheeze, there was an absolute prevalence fall per decade of -1.4 with -1 standard error (SE) in 16 years from 2002 (ISAAC Phase III) to 2018 (GAN Phase I). This pattern was evident for prevalence of reported asthma ever, severe asthma symptoms and night cough with ≥1 SE. During the 23-year interval between ISAAC Phase I and GAN Phase I, there was a fall (≥1 SE) in the absolute prevalence of reported asthma ever, severe asthma symptoms and night cough, except for severe asthma symptoms (-0.2 SE). Respectively 36% and 43% of symptomatic adolescents purchased and used salbutamol and prednisolone.CONCLUSION: The prevalence and severity of asthma symptoms remain high among adolescents in Ibadan. This could be mitigated by improved access to affordable and effective asthma treatments.

The relationship between second-hand smoke and wheezing in infants from Córdoba, Argentina

Background: Wheezing constitutes a common respiratory symptom in children, and several risk factors have been associated with the prevalence of recurrent wheezing (RW) and its severity, especially viral respiratory infections and second-hand smoke (SHS) exposure. Objective: To analyze the relationship between smoking patterns in the home and wheezing, in infants from the city of Córdoba, Argentina, during their first year of life. Methods: Parents of infants were invited to complete a standardized questionnaire voluntarily and anonymously (WQ-P1-EISL). Wheezing in the first 12 months of life was classified as occasional wheezing (OW) when having one or two episodes during the first 12 months of life; recurrent wheezing (RW) if having three or more, and more frequent wheezing (MFW) ≥ 6 episodes. Results: 409 infants (39.0%) had one or more episodes of wheezing in the first 12 months. Of these, 214 infants (52.3%) presented occasional wheezing (OW), 135 (33%) had recurrent wheezing (RW), and 60 (14.7%) more frequent wheezing (MFW). SHS was significantly related to MFW, especially if the mother smoked (OR = 2.7; IC 95%: 1.4-5.18; p = 0.0009) or if she smoked during pregnancy (OR = 4; IC 95%: 1.8-8.5; p = 0.0001). This group of MFW was also associated with SHS as well as having been to the emergency room for wheezing (40.87%, p = 0.0056). Conclusion: The results indicate that second-hand tobacco smoke is a significant risk factor for the presence of wheezing in infants, and for its severity. Our findings have significant implications for public health, as smoking is a modifiable behavior

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The relationship between second-hand smoke and wheezing in infants from Córdoba, Argentina.

BACKGROUND: Wheezing constitutes a common respiratory symptom in children, and several risk factors have been associated with the prevalence of recurrent wheezing (RW) and its severity, especially viral respiratory infections and second-hand smoke (SHS) exposure. OBJECTIVE: To analyze the relationship between smoking patterns in the home and wheezing, in infants from the city of Córdoba, Argentina, during their first year of life. METHODS: Parents of infants were invited to complete a standardized questionnaire voluntarily and anonymously (WQ-P1-EISL). Wheezing in the first 12 months of life was classified as occasional wheezing (OW) when having one or two episodes during the first 12 months of life; recurrent wheezing (RW) if having three or more, and more frequent wheezing (MFW) ≥6 episodes. RESULTS: 409 infants (39.0%) had one or more episodes of wheezing in the first 12 months. Of these, 214 infants (52.3%) presented occasional wheezing (OW), 135 (33%) had recurrent wheezing (RW), and 60 (14.7%) more frequent wheezing (MFW). SHS was significantly related to MFW, especially if the mother smoked (OR=2.7; IC 95%: 1.4-5.18; p=0.0009) or if she smoked during pregnancy (OR=4; IC 95%: 1.8-8.5; p=0.0001). This group of MFW was also associated with SHS as well as having been to the emergency room for wheezing (40.87%, p=0.0056). CONCLUSION: The results indicate that second-hand tobacco smoke is a significant risk factor for the presence of wheezing in infants, and for its severity. Our findings have significant implications for public health, as smoking is a modifiable behavior.

Global Asthma Network survey suggests more national asthma strategies could reduce burden of asthma

BACKGROUND: Several countries or regions within countries have an effective national asthma strategy resulting in a reduction of the large burden of asthma to individuals and society. There has been no systematic appraisal of the extent of national asthma strategies in the world. METHODS: The Global Asthma Network (GAN) undertook an email survey of 276 Principal Investigators of GAN centres in 120 countries, in 2013-2014. One of the questions was: "Has a national asthma strategy been developed in your country for the next five years? For children? For adults?". RESULTS: Investigators in 112 (93.3%) countries answered this question. Of these, 26 (23.2%) reported having a national asthma strategy for children and 24 (21.4%) for adults; 22 (19.6%) countries had a strategy for both children and adults; 28 (25%) had a strategy for at least one age group. In countries with a high prevalence of current wheeze, strategies were significantly more common than in low prevalence countries (11/13 (85%) and 7/31 (22.6%) respectively, p < 0.001). Interpretation. In 25% countries a national asthma strategy was reported. A large reduction in the global burden of asthma could be potentially achieved if more countries had an effective asthma strategy

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Global Asthma Network survey suggests more national asthma strategies could reduce burden of asthma.

BACKGROUND: Several countries or regions within countries have an effective national asthma strategy resulting in a reduction of the large burden of asthma to individuals and society. There has been no systematic appraisal of the extent of national asthma strategies in the world. METHODS: The Global Asthma Network (GAN) undertook an email survey of 276 Principal Investigators of GAN centres in 120 countries, in 2013-2014. One of the questions was: "Has a national asthma strategy been developed in your country for the next five years? For children? For adults?". RESULTS: Investigators in 112 (93.3%) countries answered this question. Of these, 26 (23.2%) reported having a national asthma strategy for children and 24 (21.4%) for adults; 22 (19.6%) countries had a strategy for both children and adults; 28 (25%) had a strategy for at least one age group. In countries with a high prevalence of current wheeze, strategies were significantly more common than in low prevalence countries (11/13 (85%) and 7/31 (22.6%) respectively, p<0.001). INTERPRETATION: In 25% countries a national asthma strategy was reported. A large reduction in the global burden of asthma could be potentially achieved if more countries had an effective asthma strategy.

Can geodata be used to determine the distribution of fast food outlets in relation to the prevalence and severity of asthma? A novel methodology

Research question: Can the distribution of fast food outlets be obtained and effectively used to identify if there is a relationship between the placement of these and the prevalence and severity of asthma, rhinoconjunctivitis and eczema (ARE) in children and adolescents? METHOD: Fast food restaurant location data was obtained for seven countries. Data from the International Study of Asthma and Allergies in Childhood (ISAAC) was used from 53 centres in the same seven countries. Each ISAAC centre provided a detailed map of the study area. The location of restaurants and ISAAC centres were overlaid using the ArcMap software, and the number of restaurants within each ISAAC centre counted. Bivariate regression analysis was used to compare outlet density with ARE prevalence and severity. RESULTS: The results from the analyses showed a positive (non-significant) trend on a regression plot between outlet density and ARE severity. This project has shown that it is practical to systematically obtain and map fast food outlets and compare their distribution worldwide with the prevalence and severity of diseases, in this case ARE. The devised methodology has proven to be an efficient way to obtain restaurant distribution data in a form that is manageable and suitable to compare with area based disease prevalences. This project has shown that a larger scale investigation is both feasible and warranted

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Can geodata be used to determine the distribution of fast food outlets in relation to the prevalence and severity of asthma? A novel methodology.

RESEARCH QUESTION: Can the distribution of fast food outlets be obtained and effectively used to identify if there is a relationship between the placement of these and the prevalence and severity of asthma, rhinoconjunctivitis and eczema (ARE) in children and adolescents? METHOD: Fast food restaurant location data was obtained for seven countries. Data from the International Study of Asthma and Allergies in Childhood (ISAAC) was used from 53 centres in the same seven countries. Each ISAAC centre provided a detailed map of the study area. The location of restaurants and ISAAC centres were overlaid using the ArcMap software, and the number of restaurants within each ISAAC centre counted. Bivariate regression analysis was used to compare outlet density with ARE prevalence and severity. RESULTS: The results from the analyses showed a positive (non-significant) trend on a regression plot between outlet density and ARE severity. This project has shown that it is practical to systematically obtain and map fast food outlets and compare their distribution worldwide with the prevalence and severity of diseases, in this case ARE. The devised methodology has proven to be an efficient way to obtain restaurant distribution data in a form that is manageable and suitable to compare with area based disease prevalences. This project has shown that a larger scale investigation is both feasible and warranted.

Respiratory effects in children from passive smoking of cigarettes and narghile: ISAAC Phase Three in Syria.

BACKGROUND: The association between environmental tobacco smoke (ETS) and asthma symptoms is well documented, but a causal relationship is inconclusive. International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three was the first to report a dose-response relationship between current wheezing and exposure to parental cigarette smoke. As exposure of children to water pipe (narghile) smoke is of concern in Syria, in the ISAAC Phase Three Tartous Centre we also examined the role of parental smoking of the narghile. METHODS: Parents of children aged 6-7 years completed core written questionnaires about the prevalence of symptoms, and an environmental questionnaire for other risk factors, including parental cigarette smoking. We added questions about narghile to the questionnaire. RESULTS: Among 2 734 pupils (49% females) surveyed, we found an association between exposure to ETS of the mother smoking cigarette or narghile and ever wheezing, nocturnal cough and severe wheeze; however, the strongest association was found when the mother smoked narghile. Mother smoking narghile was also associated with exercise wheeze. Father smoking narghile, but not cigarettes, was associated with nocturnal cough, severe wheeze and exercise wheeze. The association with current wheeze became significant when mother smoked both cigarettes and narghile; however, the effect was addititive and not synergic. CONCLUSION: We recommend that international studies investigating ETS include questions on narghile smoking.

How are ‘urban’ and ‘rural’ defined in publications regarding asthma and related diseases?

BACKGROUND: Global variations in the prevalence of asthma and related diseases have suggested that environmental factors are causative, and that factors associated with urbanisation are of particular interest. A range of definitions for 'urban' and 'rural' have been used in articles on asthma and related diseases, making it difficult to assess their importance as aetiological factors. This study sets out to examine such definitions used in the literature. METHODS: Medical and social science databases were searched for articles that made distinctions of 'urban' and/or 'rural' in the context of asthma and related diseases. RESULTS: The search identified 73 articles and categorised four types of definitions. A specific definition of urban or rural was used in 19 (26%) articles. Nine (12%) articles used non-specific and/or administrative definitions. There were 23 (32%) articles that described locations as 'urban' or 'rural' but did not indicate if the description defined 'urban' or 'rural'. Distinctions were made between urban and rural locations without a description or definition in 22 (30%) articles. CONCLUSIONS: There is substantial variation in the definitions of 'urban' and 'rural' in articles regarding asthma and related diseases. It would be advantageous to have clearer and more precise definitions of 'urban' and 'rural' which could facilitate aetiological research and also comparisons between locations, especially in international studies

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How are 'urban' and 'rural' defined in publications regarding asthma and related diseases?

BACKGROUND: Global variations in the prevalence of asthma and related diseases have suggested that environmental factors are causative, and that factors associated with urbanisation are of particular interest. A range of definitions for 'urban' and 'rural' have been used in articles on asthma and related diseases, making it difficult to assess their importance as aetiological factors. This study sets out to examine such definitions used in the literature. METHODS: Medical and social science databases were searched for articles that made distinctions of 'urban' and/or 'rural' in the context of asthma and related diseases. RESULTS: The search identified 73 articles and categorised four types of definitions. A specific definition of urban or rural was used in 19 (26%) articles. Nine (12%) articles used non-specific and/or administrative definitions. There were 23 (32%) articles that described locations as 'urban' or 'rural' but did not indicate if the description defined 'urban' or 'rural'. Distinctions were made between urban and rural locations without a description or definition in 22 (30%) articles. CONCLUSIONS: There is substantial variation in the definitions of 'urban' and 'rural' in articles regarding asthma and related diseases. It would be advantageous to have clearer and more precise definitions of 'urban' and 'rural' which could facilitate aetiological research and also comparisons between locations, especially in international studies.

The challenges of replicating the methodology between Phases I and III of the ISAAC programme.

BACKGROUND: The International Study of Asthma and Allergies in Childhood (ISAAC) used standardised methods to examine symptom prevalence of asthma, rhinitis and eczema in adolescents and children between Phases I and III. Centres followed essential rules to ensure comparability of methodology, examined by a centralised data centre. METHODS: Centre reports (CRs) were compared for both phases and age groups. Methodological differences were categorised under major deviations (centres excluded), minor deviations (deviations identified in published tables) and very minor deviations (deviations not identified). RESULTS: There were 112 CRs for adolescents and 70 for children. Six centres for adolescents and four for children had major deviations and were excluded. Minor deviations (35 for adolescents and 20 for children) were identified in the publications. Very minor deviations (92 for adolescents and 51 for children) were not identified. The odds ratios for having any differences in methodology between phases with a change in Principal Investigator were 0.80 (95%CI 0.36-1.81) for adolescents and 0.91 (95%CI 0.32-2.62) for children. CONCLUSION: The majority of the centres replicated the ISAAC methodology to a high standard. Careful documentation of methodology using standardised tools with careful checks allows the full potential of studies such as ISAAC to be realised.

The impact of the method of consent on response rates in the ISAAC time trends study.

BACKGROUND: Centres in Phases I and III of the International Study of Asthma and Allergies in Childhood (ISAAC) programme used the method of consent (passive or active) required by local ethics committees. METHODS: Retrospectively, relationships between achieved response rates and method of consent for 13-14 and 6-7-year-olds (adolescents and children, respectively), were examined between phases and between English and non-English language centres. RESULTS: Information was obtained for 113 of 115 centres for adolescents and 72/72 centres for children. Both age groups: most centres using passive consent achieved high response rates (>80% adolescents and >70% children). English language centres using active consent showed a larger decrease in response rate. Adolescents: seven centres changed from passive consent in Phase I to active consent in Phase III (median decrease of 13%), with five centres showing lower response rates (as low as 34%). Children: no centre changed consent method between phases. Centres using active consent had lower median response rates (lowest response rate 45%). CONCLUSION: The requirement for active consent for population school-based questionnaire studies can impact negatively on response rates, particularly English language centres, thus adversely affecting the validity of the data. Ethics committees need to consider this issue carefully.

Translation of questions: the International Study of Asthma and Allergies in Childhood (ISAAC) experience.

OBJECTIVE: To explore the consequences of translating the International Study of Asthma and Allergies in Childhood (ISAAC) English core questionnaires on asthma, rhinitis and eczema symptoms into other languages. DESIGN: ISAAC Phase III developed 49 language translations for adolescents and 42 for children following standardised guidelines, which included back-translating the questionnaires into English to check their accuracy and meaning. Language deviations were categorised and analysed with regard to influences on the reported symptom prevalence. RESULTS: Category 1 deviations for one or more questions were found in seven translations (14%) for adolescents and in three translations (7%) for children. Data for these questions were excluded from the worldwide analyses. Category 2 deviations were identified in the publications, and Category 3 deviations were ignored. CONCLUSIONS: Translations of questionnaires should follow a consistent protocol in global epidemiological research. Cultural norms need to be considered when evaluating back-translations into English, as disease labels are not available in every language, nor are they understood in the same way. Deviations from literal translations of English should be permitted if the intent of the original meaning is retained. A web-based tool of medical terminology would be useful for international research requiring the use of translations.

Ethnic differences in time trends in asthma prevalence in New Zealand: ISAAC Phases I and III.

SETTING: The International Study of Asthma and Allergies in Childhood (ISAAC) Phase III survey, New Zealand. OBJECTIVE: To assess the prevalence of asthma symptoms and time trends by ethnicity between ISAAC Phase I (1992-1993) and Phase III (2001-2003). DESIGN: Information on asthma symptoms and environmental exposures was collected in children aged 6-7 years (n = 10,873) and adolescents aged 13-14 years (n = 13,317). RESULTS: In children, the prevalence of current wheeze was 28.5% in Maori (prevalence odds ratio [POR] = 1.49, 95%CI 1.32-1.68), and 25.2% in Pacific Islanders (POR 1.28, 95%CI 1.07-1.54) compared with 20.7% in Europeans/Pakeha. In adolescents, 29.9% of Maori (POR = 1.13, 95%CI 1.03-1.23) and 20.8% of Pacific Islanders (POR 0.74, 95%CI 0.62-0.87) experienced current wheeze compared to 28.6% of Europeans/Pakeha. Between Phases I and III, the prevalence of current wheeze increased significantly by 0.49%/year in Pacific Islanders, increased non-significantly by 0.12%/year in Maori, and decreased significantly by 0.25%/year in Europeans/Pakeha children. In adolescents, the prevalence of current wheeze increased by 0.05%/year in Pacific Islanders and decreased by 0.33%/year in Europeans/Pakeha and by 0.07%/year in Maori. CONCLUSION: Ethnic differences in asthma symptom prevalence in New Zealand have increased. The reasons for this are unclear, but may reflect inequalities in access to health services.

Global map of the prevalence of symptoms of rhinoconjunctivitis in children: The International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three.

BACKGROUND: Phase One of the International Study of Asthma and Allergies in Childhood (ISAAC) measured the global patterns of prevalence and severity of symptoms of rhinoconjunctivitis in children in 1993-1997. METHODS: International Study of Asthma and Allergies in Childhood Phase Three was a cross-sectional survey performed 5-10 years after Phase One using the same methodology. Phase Three covered all of the major regions of the world and involved 1 059 053 children of 2 age groups from 236 centres in 98 countries. RESULTS: The average overall prevalence of current rhinoconjunctivitis symptoms was 14.6% for the 13- to 14-year old children (range 1.0-45%). Variation in the prevalence of severe rhinoconjunctivitis symptoms was observed between centres (range 0.0-5.1%) and regions (range 0.4% in western Europe to 2.3% in Africa), with the highest prevalence being observed mainly in the centres from middle and low income countries, particularly in Africa and Latin America. Co-morbidity with asthma and eczema varied from 1.6% in the Indian sub-continent to 4.7% in North America. For 6- to 7-year old children, the average prevalence of rhinoconjunctivitis symptoms was 8.5%, and large variations in symptom prevalence were also observed between regions, countries and centres. DISCUSSION: Wide global variations exist in the prevalence of current rhinoconjunctivitis symptoms, being higher in high vs low income countries, but the prevalence of severe symptoms was greater in less affluent countries. Co-morbidity with asthma is high particularly in Africa, North America and Oceania. This global map of symptom prevalence is of clinical importance for health professionals.

The effects of illumination and focal distance on light-induced fluorescence images in vitro.

When using quantitative light-induced fluorescence a number of factors can influence illumination level. The purpose of this study was to investigate, using a high-resolution camera and fibre-optic light source, the impact of illumination level and focal distance on common quantitative light-induced fluorescence outcomes. Twenty-four extracted teeth were examined using 6 illumination levels and 4 focal distances. Analysis was conducted using multiple linear regression models fitted to log DeltaQ, log DeltaF and log area with clustering of teeth and robust standard errors. Separate models were used for the different light and focal levels. The regression coefficients were significant for both DeltaQ and DeltaF but not area. Despite the significant regressions the actual effect was very small, and unlikely to confound clinical trial or practice results.

The international study of asthma and allergies in childhood (ISAAC): phase three rationale and methods.

The International Study of Asthma and Allergies in Childhood (ISAAC) programme commenced in 1991 to study the aetiology of asthma, allergic rhinoconjunctivitis and atopic eczema in children in different populations using standardised methodology and facilitating international collaboration. ISAAC Phase One (1992-1996) found marked differences in the prevalence of symptoms of asthma and allergic disease throughout the world which have not been explained by the current understanding of these diseases. ISAAC Phase Two (1998-2004) uses intensive investigations to further examine the potential role of risk and protective factors that may contribute to the international difference observed in Phase One. Phase Three (2000-2003) essentially represents a repeat of Phase One, in which more detailed standardised data are obtained to enable the time trends of symptom prevalence to be determined as well as the development of a more comprehensive 'world map'. The ISAAC Phase Three rationale and methods are described in this paper. With over 280 centres in 106 countries, we anticipate that ISAAC Phase Three will comprehensively determine the prevalence of symptoms of asthma and allergic disease worldwide, explore recent time trends in the prevalence of these symptoms and cast new light on the aetiology of asthma and allergic disease.

Diet and asthma, allergic rhinoconjunctivitis and atopic eczema symptom prevalence: an ecological analysis of the International Study of Asthma and Allergies in Childhood (ISAAC) data. ISAAC Phase One Study Group.

Several studies have suggested that the increasing prevalence of symptoms of asthma, rhinitis and eczema, could be associated with dietary factors. In the present paper, a global analysis of prevalence rates of wheeze, allergic rhinoconjunctivitis and atopic eczema was performed in relation to diet, as defined by national food intake data. Analyses were based on the International Study of Asthma and Allergies in Childhood (ISAAC) data for 6-7 and 13-14 yr old children. Symptoms of wheeze, allergic rhinoconjunctivitis and atopic eczema symptom prevalence were regressed against per capita food intake, and adjusted for gross national product to account for economic development. Dietary data were based on 1995 Food and Agriculture Organisation of the United Nations data for 53 of the 56 countries that took part in ISAAC phase I (1994/1995). The 13-14 year age group showed a consistent pattern of decreases in symptoms of wheeze (current and severe), allergic rhinoconjunctivitis and atopic eczema, associated with increased per capita consumption of calories from cereal and rice, protein from cereals and nuts, starch, as well as vegetables and vegetable nutrients. The video questionnaire data for 13-14 yr olds and the ISAAC data for 6-7 yr olds showed similar patterns for these foods. A consistent inverse relationship was seen between prevalence rates of the three conditions and the intake of starch, cereals, and vegetables. If these findings could be generalised, and if the average daily consumption of these foods increased, it is speculated that an important decrease in symptom prevalence may be achieved.

The burden of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema in children and adolescents in six New Zealand centres: ISAAC Phase One.

AIM: To describe the burden of symptoms of asthma, allergic rhinoconjunctivitis and atopic eczema in children in six New Zealand centres. METHODS: The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One was undertaken in Auckland, Bay of Plenty, Hawke's Bay, Wellington, Nelson and Christchurch during 1992-1993. In each centre, approximately 3,000 six to seven year old children and 3,000 thirteen to fourteen year old adolescents were studied, a total of 37,592 participants. Both age groups answered written questionnaires and the adolescents a video questionnaire about asthma symptoms. RESULTS: The prevalences of symptoms were high, for asthma 25% and 30%, allergic rhinoconjunctivitis 10% and 19%, and atopic eczema 15% and 13% in each age group respectively. More than 40% of participants had symptoms in the last year of at least one condition, most commonly asthma. There were no significant differences among regions, except for six to seven year olds in Nelson who had significantly lower prevalences of some symptoms of asthma and allergic rhinoconjunctivitis. CONCLUSIONS: Asthma and allergies are common in New Zealand, with resultant morbidity and cost. However, there is little regional variation with the exception of lower rates in Nelson children. Explanations for these findings will be the subject of further studies.