Original article
Vol. 153 No. 3 (2023)
Prevalence of childhood cough in epidemiological studies depends on the question used: findings from two population-based studies
- Maria Christina Mallet
- Rebeca Mozun
- Eva S. L. Pedersen
- Cristina Ardura-Garcia
- Erol A. Gaillard
- Philipp Latzin
- Alexander Moelller
- Claudia E. Kuehni
- on behalf of the LUIS study group
Summary
BACKGROUND: Epidemiological studies use different questions to assess recurrent cough in children. In two independent population-based studies, we assessed how prevalence estimates of cough vary depending on the questions parents are asked about their child’s cough and how answers to the different questions overlap.
METHODS: We analysed cross-sectional data from two population-based studies on respiratory health: LuftiBus in the School (LUIS), conducted in 2013-2016 among 6- to 17-year-school children in the Canton of Zurich, Switzerland, and the 1998 Leicester Respiratory Cohort (LRC) study, UK where we used data from 6- to 8-year-old children from the 2003 follow-up survey. Both studies used parental questionnaires that included the same three questions on the child’s cough, namely cough without a cold, dry cough at night and coughing more than others. We assessed how the prevalence of cough varied depending on the question and how answers to the different questions on cough overlapped. We also assessed how results were influenced by age, sex, presence of wheeze and parental education.
RESULTS: We included 3457 children aged 6–17 years from LUIS and 2100 children aged 6–8 years from LRC. All respiratory outcomes – cough, wheeze and physician-diagnosed asthma – were reported twice as often in the LRC as in LUIS. We found large differences in the prevalence of parent-reported cough between the three cough questions. In LUIS, 880 (25%) parents reported cough without a cold, 394 (11%) dry night cough, and 159 (5%) reported that their child coughed more than other children. In the LRC, these numbers were 1003 (48%), 527 (25%) and 227 (11%). There was only partial overlap of answers, with 89 (3%) answering yes to all questions in LUIS and 168 (8%) in LRC. Prevalence of all types of cough and overlap between the cough questions was higher in children with current wheeze.
CONCLUSION: In both population-based studies prevalence estimates of cough depended strongly on the question used to assess cough with only partial overlap of responses to different questions. Epidemiological studies on cough can only be compared if they used exactly the same questions for cough.
References
- Sennhauser FH , Kühni CE . Prevalence of respiratory symptoms in Swiss children: is bronchial asthma really more prevalent in boys? Pediatr Pulmonol. 1995 Mar;19(3):161–6. https://doi.org/10.1002/ppul.1950190304
DOI: https://doi.org/10.1002/ppul.1950190304
- Hermann C , Westergaard T , Pedersen BV , Wohlfahrt J , Høst A , Melbye M . A comparison of risk factors for wheeze and recurrent cough in preschool children. Am J Epidemiol. 2005 Aug;162(4):345–50. https://doi.org/10.1093/aje/kwi212
DOI: https://doi.org/10.1093/aje/kwi212
- Boudewijn IM , Savenije OE , Koppelman GH , Wijga AH , Smit HA , de Jongste JC , et al. Nocturnal dry cough in the first 7 years of life is associated with asthma at school age. Pediatr Pulmonol. 2015 Sep;50(9):848–55. https://doi.org/10.1002/ppul.23092
DOI: https://doi.org/10.1002/ppul.23092
- Jurca M , Goutaki M , Latzin P , Gaillard EA , Spycher BD , Kuehni CE . Isolated night cough in children: how does it differ from wheeze? ERJ Open Res. 2020 Oct;6(4):00217-2020. https://doi.org/10.1183/23120541.00217-2020
DOI: https://doi.org/10.1183/23120541.00217-2020
- Asher MI , Rutter CE , Bissell K , Chiang CY , El Sony A , Ellwood E , et al.; Global Asthma Network Phase I Study Group . Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional study. Lancet. 2021 Oct;398(10311):1569–80. https://doi.org/10.1016/S0140-6736(21)01450-1
DOI: https://doi.org/10.1016/S0140-6736(21)01450-1
- Brodlie M , Graham C , McKean MC . Childhood cough. BMJ. 2012 Mar;344 mar06 1:e1177. https://doi.org/10.1136/bmj.e1177
DOI: https://doi.org/10.1136/bmj.e1177
- Ferris BG . Epidemiology Standardization Project (American Thoracic Society). Am Rev Respir Dis. 1978 Dec;118(6 Pt 2):1–120.
- Asher MI , Keil U , Anderson HR , Beasley R , Crane J , Martinez F , et al. International Study of Asthma and Allergies in Childhood (ISAAC): rationale and methods. Eur Respir J. 1995 Mar;8(3):483–91. https://doi.org/10.1183/09031936.95.08030483
DOI: https://doi.org/10.1183/09031936.95.08030483
- Clifford RD , Radford M , Howell JB , Holgate ST . Prevalence of respiratory symptoms among 7 and 11 year old schoolchildren and association with asthma. Arch Dis Child. 1989 Aug;64(8):1118–25. https://doi.org/10.1136/adc.64.8.1118
DOI: https://doi.org/10.1136/adc.64.8.1118
- Doull IJ , Williams AA , Freezer NJ , Holgate ST . Descriptive study of cough, wheeze and school absence in childhood. Thorax. 1996 Jun;51(6):630–1. https://doi.org/10.1136/thx.51.6.630
DOI: https://doi.org/10.1136/thx.51.6.630
- Pearce N , Aït-Khaled N , Beasley R , Mallol J , Keil U , Mitchell E , et al.; ISAAC Phase Three Study Group . Worldwide trends in the prevalence of asthma symptoms: phase III of the International Study of Asthma and Allergies in Childhood (ISAAC). Thorax. 2007 Sep;62(9):758–66. https://doi.org/10.1136/thx.2006.070169
DOI: https://doi.org/10.1136/thx.2006.070169
- Vlaski E , Stavrikj K , Kimovska M , Cholakovska VC , Lawson JA . Divergent trends in the prevalence of asthma-like symptoms and asthma in a developing country: three repeated surveys between 2002 and 2016. Allergol Immunopathol (Madr). 2020;48(5):475–83. https://doi.org/10.1016/j.aller.2019.11.003
DOI: https://doi.org/10.1016/j.aller.2019.11.003
- Mozun R , Kuehni CE , Pedersen ES , Goutaki M , Kurz JM , de Hoogh K , et al.; On Behalf Of The Luis Study Group . LuftiBus in the school (LUIS): a population-based study on respiratory health in schoolchildren. Swiss Med Wkly. 2021 Aug;151(3132):w20544. https://doi.org/10.4414/smw.2021.20544
DOI: https://doi.org/10.4414/smw.2021.20544
- Kuehni CE , Brooke AM , Strippoli MP , Spycher BD , Davis A , Silverman M . Cohort profile: the Leicester respiratory cohorts. Int J Epidemiol. 2007 Oct;36(5):977–85. https://doi.org/10.1093/ije/dym090
DOI: https://doi.org/10.1093/ije/dym090
- Burr ML , Anderson HR , Austin JB , Harkins LS , Kaur B , Strachan DP , et al. Respiratory symptoms and home environment in children: a national survey. Thorax. 1999 Jan;54(1):27–32. https://doi.org/10.1136/thx.54.1.27
DOI: https://doi.org/10.1136/thx.54.1.27
- Jurca M , Ramette A , Dogaru CM , Goutaki M , Spycher BD , Latzin P , et al. Prevalence of cough throughout childhood: A cohort study. PLoS One. 2017 May;12(5):e0177485. https://doi.org/10.1371/journal.pone.0177485
DOI: https://doi.org/10.1371/journal.pone.0177485
- Brunekreef B , Groot B , Rijcken B , Hoek G , Steenbekkers A , de Boer A . Reproducibility of childhood respiratory symptom questions. Eur Respir J. 1992 Sep;5(8):930–5. https://doi.org/10.1183/09031936.93.05080930
DOI: https://doi.org/10.1183/09031936.93.05080930
- Patel SP , Järvelin MR , Little MP . Systematic review of worldwide variations of the prevalence of wheezing symptoms in children. Environmental health : a global access science source. 2008;7:57. https://doi.org/10.1186/1476-069X-7-57
DOI: https://doi.org/10.1186/1476-069X-7-57
- Mölter A , Simpson A , Berdel D , Brunekreef B , Custovic A , Cyrys J , et al. A multicentre study of air pollution exposure and childhood asthma prevalence: the ESCAPE project. Eur Respir J. 2015 Mar;45(3):610–24. https://doi.org/10.1183/09031936.00083614
DOI: https://doi.org/10.1183/09031936.00083614
- Asher MI , García-Marcos L , Pearce NE , Strachan DP . Trends in worldwide asthma prevalence. Eur Respir J. 2020 Dec;56(6):2002094. https://doi.org/10.1183/13993003.02094-2020
DOI: https://doi.org/10.1183/13993003.02094-2020
- Woodcock A , Custovic A . ABC of allergies. Avoiding exposure to indoor allergens. BMJ. 1998 Apr;316(7137):1075–8. https://doi.org/10.1136/bmj.316.7137.1075
DOI: https://doi.org/10.1136/bmj.316.7137.1075
- Sheikh A , Hurwitz B , Sibbald B , Barnes G , Howe M , Durham S . House dust mite barrier bedding for childhood asthma: randomised placebo controlled trial in primary care [ISRCTN63308372] [ISRCTN63308372]. BMC Fam Pract. 2002 Jun;3(1):12. https://doi.org/10.1186/1471-2296-3-12
DOI: https://doi.org/10.1186/1471-2296-3-12
- Strachan DP , Flannigan B , McCabe EM , McGarry F . Quantification of airborne moulds in the homes of children with and without wheeze. Thorax. 1990 May;45(5):382–7. https://doi.org/10.1136/thx.45.5.382
DOI: https://doi.org/10.1136/thx.45.5.382
- Eguiluz-Gracia I , Mathioudakis AG , Bartel S , Vijverberg SJ , Fuertes E , Comberiati P , et al. The need for clean air: the way air pollution and climate change affect allergic rhinitis and asthma. Allergy. 2020 Sep;75(9):2170–84. https://doi.org/10.1111/all.14177
DOI: https://doi.org/10.1111/all.14177
- Bayer-Oglesby L , Grize L , Gassner M , Takken-Sahli K , Sennhauser FH , Neu U , et al. Decline of ambient air pollution levels and improved respiratory health in Swiss children. Environ Health Perspect. 2005 Nov;113(11):1632–7. https://doi.org/10.1289/ehp.8159
DOI: https://doi.org/10.1289/ehp.8159
- Perez L , Rapp R , Künzli N . The Year of the Lung: outdoor air pollution and lung health. Swiss Med Wkly. 2010 Nov;140:w13129. https://doi.org/10.4414/smw.2010.13129
DOI: https://doi.org/10.4414/smw.2010.13129
- Schraufnagel DE , Balmes JR , De Matteis S , Hoffman B , Kim WJ , Perez-Padilla R , et al. Health Benefits of Air Pollution Reduction. Ann Am Thorac Soc. 2019 Dec;16(12):1478–87. https://doi.org/10.1513/AnnalsATS.201907-538CME
DOI: https://doi.org/10.1513/AnnalsATS.201907-538CME
- Beloconi A , Vounatsou P . Substantial Reduction in Particulate Matter Air Pollution across Europe during 2006-2019: A Spatiotemporal Modeling Analysis. Environ Sci Technol. 2021 Nov;55(22):15505–18. https://doi.org/10.1021/acs.est.1c03748
DOI: https://doi.org/10.1021/acs.est.1c03748
- Dales RE , White J , Bhumgara C , McMullen E . Parental reporting of childrens’ coughing is biased. Eur J Epidemiol. 1997 Jul;13(5):541–5. https://doi.org/10.1023/A:1007311912777
DOI: https://doi.org/10.1023/A:1007311912777
- Lindenhofer M , Roth L , Mädel C , Götzinger F , Kainz K , Lex C , et al. Wheeze and cough measurements at night in children with respiratory symptoms. BMC Pediatr. 2020 Dec;20(1):556. https://doi.org/10.1186/s12887-020-02455-5
DOI: https://doi.org/10.1186/s12887-020-02455-5
- Cane RS , McKenzie SA . Parents’ interpretations of children’s respiratory symptoms on video. Arch Dis Child. 2001 Jan;84(1):31–4. https://doi.org/10.1136/adc.84.1.31
DOI: https://doi.org/10.1136/adc.84.1.31
- Michel G , Silverman M , Strippoli MP , Zwahlen M , Brooke AM , Grigg J , et al. Parental understanding of wheeze and its impact on asthma prevalence estimates. Eur Respir J. 2006 Dec;28(6):1124–30. https://doi.org/10.1183/09031936.06.00008406
DOI: https://doi.org/10.1183/09031936.06.00008406