Xu et al. BMC Pediatrics(2024) 24:533
https://doi.org/10.1186/s12887-024-04876-y

BMC Pediatrics

RESEARCH

Open Access

Associations between abnormal sleep
behavior and indoor environmental risk
factors among children with a chronic coughin Wuxi, China: a cross-sectional study
Shiyao Xu1†, Zhenzhen Pan1,2†, Yun Guo1, Qin Zhou1, Qian Wang1, Shanshan Pan1 and Ling Li1*
Abstract
Background Indoor environmental factors, such as pet ownership, presence of cockroaches, mattress quality, fuelusage (gas or electricity), use of biomass for cooking and heating, exposure to tobacco smoke or household molds
can significantly affect the sleep quality of children with chronic cough. However, data regarding the effects ofindoor environmental conditions on sleep in this population are limited. This study aimed to assess the prevalence ofabnormal sleep behaviors and to establish associations between indoor environmental factors and sleep behaviors
among children with chronic cough in Wuxi, China.
Methods A cross-sectional design was employed in this study, involving children aged 3–18 years. Data onsociodemographic factors, allergies, home environmental exposures, and sleep characteristics of the participants
were collected using paper-based questionnaires. The association between indoor environmental factors and sleep
behaviors in children with chronic cough was analyzed using logistic regression models.
Results The findings demonstrated that the prevalence of chronic cough among children in Wuxi was 15.50%.
The chronic cough group exhibited a significantly higher incidence of eczema, wheezing, rhinitis, food allergy, andnasosinusitis than the non-chronic cough group. In addition, children with chronic cough also tended to havea family history of sleep disorders and adenoid hypertrophy (P < 0.01). After adjusting for confounding factors, asignificant association was observed between bruxism (teeth grinding) and chronic cough (sometimes: odds ratio[OR] = 1.04; confidence interval [CI] = 1.01–1.08; always: OR = 1.11; CI = 1.04–1.19; P < 0.01). Among children withchronic cough, recent home decoration was associated with sleepwalking (OR = 1.04; CI = 1.00–1.07; P < 0.05), mold
exposure was associated with bruxism (OR = 1.15; CI = 1.0–1.31; P < 0.05), and carpet use at home was associated withapnea (OR = 1.09; CI = 1.02–1.17; P < 0.05), twitching during sleep (OR = 1.13; CI = 1.00–1.27; P < 0.01) and morning
headache (OR = 1.14; CI = 1.05–1.23; P < 0.01).

†

Shiyao Xu and Zhenzhen Pan contributed equally to this work.

*Correspondence:
Ling Lililing@njmu.edu.cn
Full list of author information is available at the end of the article© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0
International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you
give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified thelicensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to thematerial. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation
or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://
creativecommons.org/licenses/by-nc-nd/4.0/.

Xu et al. BMC Pediatrics(2024) 24:533

Page 2 of 10

Conclusion Children with chronic cough are more prone to some abnormal sleep behaviors than children without
chronic cough. Household decoration within a year, household mold exposure, and carpet use were all significantly
positively associated with abnormal sleep behaviors in children with chronic cough. Our study provides novel
insights into the impact of the indoor environment on children’s sleep and the occurrence of chronic cough, offering
guidance for tailored health promotion programs for families.
Keywords Chronic cough, Abnormal sleep behavior, Indoor environment, Children

Background
The Clinical Practice Guidelines for the Diagnosis andManagement of Children with Cough in China (v2021)
define chronic cough as persistent cough lasting > 4 weeks[1]. Unfortunately, many children with chronic cough andtheir families still make unnecessary medical visits, leading to significant financial and societal costs. In addition,
chronic cough can cause various adverse effects, such as
disrupting sleep quality, limiting participation in activities, causing emotional distress, and reducing overall
quality of life [2]. The prevalence of chronic cough amongchildren in China varies across different regions, withincidences ranging from 6 to 27% [3–5].
Quality sleep is crucial for a healthy childhood, but
sleep-disordered breathing (SDB) can interfere withproper ventilation and breathing patterns during sleep,
leading to a variety of physical and behavioral problems[6]. The International Classification of Sleep Disorders(ICSD), 3rd edition, categorizes sleep disorders into
seven groups: insomnia disorders, sleep-related breathing disorders, central disorders of hypersomnolence,circadian rhythm sleep-wake disorders, sleep-related
movement disorders, parasomnias, and other sleep disorders [7]. Sleep breathing disorders are relatively common, with approximately one in ten healthy children
habitually snoring during sleep. One in four children who
snore have obstructive sleep apnea syndrome (OSAS)[8]. Previous studies have explored the relationshipbetween OSAS and chronic cough, reporting an association between chronic cough and obstructive sleep apnea(OSA) in adults. These studies suggested that treating
OSA with continuous positive airway pressure can alleviate cough symptoms [9]. However, there is no evidence
to endorse the application of OSA-specific therapies for
managing chronic cough in children [10]. Furthermore,
many children without a clear diagnosis of OSAS areoften assumed to have sleep-breathing disorders. This
assumption arises because parents and guardians may not
fully understand the medical terminology, and instead
describe various abnormal sleep behaviors, including
somnolence, insomnia, snoring, open-mouth breathing, dyspnea, apnea, sleep disturbance, teething disorder,
sleep talking, sleepwalking, bedwetting, and hyperhidrosis. As such, the association between chronic cough andsleep disorders may have been underestimated.

In addition to the above, previous studies have highlighted the influence of indoor environments onchildhood sleep. A systematic review exploring therelationships between air pollution exposure and sleep
measures across different age groups revealed that children and adolescents exposed to higher environmental
and indoor pollutants had a higher risk of experiencing
respiratory sleep problems and other adverse sleep outcomes [11]. Moreover, studies have indicated that various indoor environmental factors, such as pet ownership,
exposure to environmental tobacco smoke [12], exposure
to household molds [13], the presence of cockroaches,
mattress quality [14], fuel usage (gas or electricity) [15],and usage of biomass for cooking and heating [16], canincrease the risk of persistent cough and intractable sputum in children. As such, it is reasonable to speculate thatindoor environmental factors may significantly affect thesleep quality of children with chronic cough. However,data regarding the effects of indoor environmental conditions on sleep in this population are limited. Consequently, this research aimed to assess the prevalence ofabnormal sleep behaviors and the associations between
indoor environmental factors and sleep behaviors in children with chronic cough in Wuxi, China.

Methods
Setting, sampling, and participants

A cross-sectional design was employedin this study.
z2 P(1−P)
Based on statistical calculations ( n = α/2 2), a sampleδsize of 1,920 was determined, assuming a chronic coughprevalence of approximately 15% in children, a significance level of α = 0.05, a Zα/2 value of 1.96, and an acceptable error of 0.1 p. Considering a 20% non-response
rate, the sample size was fixed at 2,400. This study was
conducted between October 2020 and April 2022 acrossfive districts in Wuxi, Jiangsu, China. Schools and gradelevels were randomly selected using computer-generated
random numbers, considering the scale and distributionof schools in each region. Specifically, children aged 3–18
years were recruited as participants. School teachers distributed questionnaires to parents or guardians, and collected them after completion. The questionnaires werecompleted by the primary carers for children under 16
years old, and by both the primary carers and the children themselves for those aged 16–18 years. Before participant recruitment, approval for this study was obtained

Xu et al. BMC Pediatrics(2024) 24:533

from the Affiliated Wuxi Children’s Hospital of Nanjing
Medical University’s ethics committee (approval number
WXCH2019-8-002).
Questionnaires
Demographic data/characteristics

Demographic data encompassed a variety of factors,
including age, sex, weight (in kilograms), and height(in centimeters). Moreover, information was gatheredregarding their history of asthma, sleep disturbances,
exposure to maternal smoking during pregnancy, andcurrent smoking status within the family. Body massindex (BMI) was calculated as the weight (kg)/ height(m2), using values reported in the questionnaires.
Disease assessment

The definition of chronic cough used in this study alignedwith the Clinical Practice Guidelines for the Diagnosis and Management of Children with Cough in China[1], which has achieved consensus in the country. It wascharacterized by a positive response to the question, “Hasyour child ever experienced a cough lasting longer than 4
weeks in the last year?” An experienced physician re-confirmed the diagnosis of chronic cough after excluding thepresence of respiratory illnesses, such as pneumonia andbronchitis, during chronic cough by checking electronicor paper medical records. Another interesting aspect of
this study was the assessment of allergic comorbidities
based on self-reported information provided by guardians regarding physician-diagnosed conditions at any
point in the child’s life. The definitions for various comorbidities were as follows. Eczema: Affirmative responseto the query, “Has your child ever received a physician’s
diagnosis of eczema?” Wheezing: Positive response to thequestion, “Has your child ever experienced whistling or
wheezing in the chest at any time in the past?” Rhinitis:
Confirmation of physician-diagnosed rhinitis or recurring symptoms of sneezing, blocked or runny nose notassociated with a cold or flu. Food allergy: Validation ofa clinician’s diagnosis of food allergy. Nasosinusitis: Physician-confirmed diagnosis of nasosinusitis. Urticaria:
Physician-confirmed diagnosis of urticaria. Adenoid
hypertrophy: Diagnosis of adenoid hypertrophy throughnasopharyngeal lateral radiographs or electronic nasopharyngoscopy. Please refer to Additional file 1 for further details.
Home environmental exposure

The inquiries on home environmental exposure in thisstudy were classified into three distinct groups: (1)Household renovation: These encompassed aspects
such as recent decoration within a year, floor level, wallmaterials, floor materials, wall painting materials, furniture material, door material, pillow materials, and quilt

Page 3 of 10

materials. (2) Cooling method, heating method, andcooking fuel: This category focused on the specific techniques employed for cooling and heating, as well as thetype of fuel used for cooking within the participants’ residences. (3) Household exposure to molds, pet ownership,presence of carpets, plants, and tobacco: This group ofquestions explored factors such as the presence of household molds, keeping of pets, utilization of carpets, presence of indoor plants, and exposure to tobacco smoke
within the home environment. For further details, pleaserefer to Additional file 1.
Pediatric sleep questionnaire

A retrospective parental report was used as the sleep
questionnaire to assess sleep problems in children. The
questionnaire evaluated various sleep behaviors and difficulties, including sleep gestures, duration, and abnormal
sleep behaviors. Abnormal sleep behaviors encompassed
several categories: (1) Night waking: waking during
sleep and sleepwalking. (2) Parasomnias: This category
encompassed twitching, bedwetting, restless sleep, sleep
talking, bruxism (teeth grinding), and sweating. (3)Sleep-disordered breathing: Behaviors such as snorting,mouth opening, and dyspnea (difficulty breathing) fell
under this category. (4) Daytime sleepiness: This included
taking a long time to become alert, experiencing headaches, morning thirst, and napping. The participants’parents were requested to indicate the frequency of theirchildren’s sleep behaviors for each item over a typicalrecent week, using a three-point scale (never = 0 times/
week; sometimes = 1–2 times/week; and always = 3–7
times/week). The Children’s Sleep Habits Questionnaire(CSHQ), which served as the foundation for this questionnaire, was initially designed to screen problematic
sleep behaviors in children aged 4–10 years [17], andwas later validated for its applicability in toddlers andpreschool-aged children, irrespective of their medical
condition [18]. The CSHQ has been commonly appliedin China, and has demonstrated acceptable internal consistency, reliability, and validity. The Cronbach’s α coefficient for the Chinese version of the full scale was 0.73,
while the sub-scale coefficients ranged from 0.42 to 0.69
[19].
Statistical analysis

Statistical tests were conducted using the R program
v3.6.2 (http://www.r-project.org/). Normally distributed
data are presented as the mean ± standard deviation,
whereas non-normally distributed data are expressed as
the median and interquartile range. The t-test and Mann–
Whitney U test were used for continuous variables. The
Chi-squared or Fisher’s exact test was employed for
categorical variables. Logistic regression models wereconstructed to explore the association between each

Xu et al. BMC Pediatrics(2024) 24:533

Page 4 of 10

Table 1 Characteristics of study participants (n = 2,026)

AgeSex, female (%)
BMI (kg/m2)
Diseases, n/N (%)
Eczema, yes
Wheeze, yes
Rhinitis, yes
Food allergy, yes
Nasosinusitis, yes
Urticaria, yes
Family asthma history, yes
Family history of sleep disturbance, yes
Adenoid hypertrophy, yes
Sleep duration
Sleep behaviors
Snorting
Never
Sometimes
AlwaysMouth opening
Never
Sometimes
AlwaysRestless sleep
Never
Sometimes
AlwaysTwitching
Never
Sometimes
AlwaysSleep talking
Never
Sometimes
Always
Bruxism
Never
Sometimes
AlwaysSweating
Never
Sometimes
AlwaysWaking during sleep
Never
Sometimes
AlwaysChronic
cough(n = 316)
8.15 ± 3.01
179 (56.65)
17.49 ± 5.38

Non-chroniccough(n = 1,710)
9.10 ± 3.15
889 (51.99)
17.67 ± 4.76

P-value

143 (45.25)
77 (24.37)
133 (42.09)
40 (12.66)
28 (8.87)
51 (16.14)
6 (1.90)89 (28.16)

518 (30.29)
143 (8.36)
416 (24.32)
118 (6.90)
80 (4.67)
210 (12.28)
50 (2.92)
330 (19.29)< 0.001***< 0.001***< 0.001***< 0.001***
0.0036**0.070
0.40
0.0014**25 (7.91)
8.94 ± 0.73

67 (3.92)
8.84± 0.95

0.0027**0.037*< 0.001***
0.14
0.59

< 0.001***146 (46.20)
145 (45.89)
25 (7.91)

982 (57.4)
672 (39.30)
56 (3.27)
0.0022**147 (46.52)
131 (46.46)
38 (12.03)

952 (55.67)
629 (36.78)
129 (7.54)

144 (45.57)
148 (46.84)
24 (7.59)

1,053 (61.58)
584 (34.15)
73 (4.27)< 0.001***< 0.001***266 (84.18)
45 (14.24)
5 (1.58)

1,560 (91.22)
139 (8.13)
11 (0.64)< 0.001***108 (34.18)
200 (63.29)
8 (2.53)788 (46.08)
892 (52.16)30 (1.75)

138 (43.67)
151 (47.78)
27 (8.54)987 (57.72)
646 (37.78)
77 (4.50)< 0.001***< 0.001***
121 (38.29)
132 (41.77)
63 (19.94)

908 (53.10)
629 (36.78)
173 (10.12)< 0.001***230 (72.78)
84 (26.58)
2 (0.63)

1,401 (81.93)
302 (17.66)
7 (0.41)never = 0 times/week; sometimes = 1 to 2 times/week; usually = 3 to 7 times/
week. *P value < 0.05, **P value < 0.01, ***P value < 0.001

abnormal sleep behavior, chronic cough and indoor
environmental factors. In order to reduce the confounding bias, the logistic regression models were adjusted
for confounding factors (such as age, sex, BMI, former
diseases, family history of asthma, etc.). Estimated odds
ratios (eOR) and adjusted OR with corresponding 95%
confidence intervals (CI) were computed to identify theseassociations. Statistical significance was set at P < 0.05.

Results
Questionnaire and participant characteristics

In total, 2,310 parents/caregivers completed the questionnaires for this study. Some questionnaires were considered invalid due to incomplete data, duplicates, or
false information, leaving 2,026 valid responses (response
rate, 87.7%).
Overall, as shown in Tables 1 and 316 valid questionnaires were completed by the chronic cough group,
whereas 1,710 were completed by children without
chronic cough. The survey-weighted prevalence of children with chronic cough was 15.50% (n = 316). Overall, the average ages of chronic and non-chronic coughgroups were 8.15 and 9.10 years (P < 0.01), respectively.
However, there were no significant differences in terms ofsex (56.60% vs. 51.90%, P = 0.14) or BMI (17.49 vs. 17.67,
P = 0.59) between the chronic and non-chronic coughgroups.
The chronic cough group exhibited significantly higher
incidences of eczema (45.25% vs. 30.29%), wheezing(24.37% vs. 143%), rhinitis (42.09% vs. 24.32%), foodallergy (12.66% vs. 6.90%) and nasosinusitis (8.87% vs.
4.67%) than controls. Children in the chronic coughgroup were also more likely to have a family history of
sleep disorders (28.16% vs. 19.29%) and adenoid hypertrophy (7.91% vs. 3.92%) (P < 0.01) compared with the
non-chronic cough group. The average sleep duration
was 8.95 h for children with chronic cough, and 8.85 h forcontrols (P = 0.03).
No significant differences were detected between thetwo groups in terms of home environmental exposure
variables, including floor type, household renovations(walls, furniture, doors, pillows, and quilt materials), useof air conditioners, fuel burning for cooking and heating,tobacco smoke exposure, carpet, flower, and pet exposure at home (Additional file 2). However, a higher percentage of children with chronic cough reported living inenvironments with a perception of moldy air comparedwith controls (21.2% vs. 15.1%; P < 0.001).
Sleep behavior and indoor environment of children withand without chronic coughTable 2 presents the relationship between chronic coughand sleep behavior. In the unadjusted models, snoring (sometimes: OR = 1.05; CI = 1.02–1.08; P < 0.01;

Xu et al. BMC Pediatrics(2024) 24:533

Page 5 of 10

Table 2 Association between chronic cough and sleep behaviors
Sleep status
Sleep duration
Snorting
Never
Sometimes
AlwaysApnea
NeverSometimes
AlwaysRestless sleep
Never
Sometimes
AlwaysTwitching
Never
Sometimes
AlwaysSleep talking
Never
Sometimes
Always
Bruxism
Never
Sometimes
AlwaysSweating
Never
Sometimes
AlwaysWaking during sleep
Never
Sometimes
AlwaysLong to waking
Never
Sometimes
AlwaysFamily history of sleep disturbance, yes
Adenoid hypertrophy

Unadjusted model
OR (95% CI)
1.01 (0.99, 1.03)

P-value
0.080

Adjusted model
OR (95% CI)
1.00 (0.98, 1.02)

P-value
0.90

Ref.
1.05 (1.02, 1.08)
1.20 (1.10, 1.30)

0.0038**< 0.001***

Ref.
1.01 (0.98, 1.05)
1.12 (1.04, 1.21)

0.37
0.0037**Ref.
1.06 (0.93, 1.21)
1.67 (1.11, 2.52)

0.38
0.015*

Ref.
1.02 (0.90, 1.16)
1.69 (1.15, 2.50)

0.70
0.0078**Ref.
1.08 (1.05, 1.12)
1.13 (1.05, 1.22)< 0.001***< 0.001***

Ref.
1.06 (1.02, 1.09)
1.07 (0.99, 1.15)< 0.001***
0.05

Ref.
1.10 (1.04, 1.17)
1.18 (0.99, 1.41)< 0.001***
0.06

Ref.
1.09 (1.03, 1.15)
1.17 (0.99, 1.39)

0.0013**0.06

Ref.
1.06 (1.03, 1.10)
1.09 (0.97, 1.23)< 0.001***
0.13

Ref.
1.03 (1.00, 1.06)
1.04 (0.93, 1.16)

0.044*
0.49

Ref.
1.07 (1.03, 1.10)
1.15 (1.07, 1.23)< 0.001***< 0.001***

Ref.
1.04 (1.01, 1.08)
1.11 (1.04, 1.19)

0.0058**0.0022**

Ref.
1.06 (1.02, 1.09)
1.16 (1.10, 1.22)

0.0012**< 0.001***

Ref.
1.02 (0.99, 1.05)
1.10 (1.05, 1.16)

0.25< 0.001***

Ref.
1.08 (1.04, 1.12)
1.08 (0.86, 1.37)< 0.001***
0.50

Ref.
1.05 (1.01, 1.10)
1.17 (0.93, 1.46)

0.0068**0.17

Ref.
1.03 (0.99, 1.06)
1.13 (1.03,1.25)
1.07 (1.03, 1.11)
1.13 (1.05, 1.22)

0.12
0.013*< 0.001***< 0.001***

Ref.
1.02 (0.99, 1.06)
1.10 (1.01, 1.21)
1.05 (1.01, 1.09)
1.02 (0.95, 1.10)

0.18
0.034*
0.0084**0.63

Models were adjusted for age, sex, BMI, former diseases, family history of asthma, eczema, wheeze, rhinitis, food allergy, nasosinusitis and urticaria. never = 0 times/
week; sometimes = 1 to 2 times/week; always = 3 to 7 times/week. *P value < 0.05, **P value < 0.01, ***P value < 0.001

always: OR = 1.20; CI = 1.10–1.30; P < 0.001), restlesssleep (sometimes: OR = 1.08; CI = 1.05–1.12; P < 0.001;
always: OR = 1.13; CI = 1.05–1.22; P < 0.001), bruxism (sometimes: OR = 1.07; CI = 1.03–1.10; P < 0.001;
always: OR = 1.15; CI = 1.07–1.23; P < 0.001), and sweating (sometimes: OR = 1.06; CI = 1.02–1.09; P < 0.01;
always: OR = 1.16; CI = 1.10–1.22; P < 0.001) were significantly associated with a high risk of chronic cough.
After adjusting for confounding factors, chronic
cough was still significantly associated with bruxism(sometimes: OR = 1.04; CI = 1.01–1.08; always: OR = 1.11;
CI = 1.04–1.19; P < 0.01). In the unadjusted analysis, afamily history of sleep disturbance was significantly
associated with the risk of chronic cough (OR = 1.07;
CI = 1.03–1.11; P < 0.001). This significant difference
was still detected even after adjusting for age and othercovariates (OR = 1.05; CI = 1.01–1.09; P < 0.01). However,
the adjusted analysis found no notable difference for the
adenoid hypertrophy subset (OR = 1.02; CI = 0.95–1.10).

Xu et al. BMC Pediatrics(2024) 24:533

Page 6 of 10

Table 3 Association between chronic cough and indoor
environment
Indoor environment
Decoration
No
Yes
Mold exposure
No
Yes
CarpetNo
Yes
Flower
No
Yes
Pet
No
Yes
Former smoker
No
Yes
Current smoker
No
Yes

Unadjusted model
Adjusted model
OR (95% CI)
P-value OR (95% CI)
P-valueRef.
0.94 (0.73, 1.21) 0.62

Ref.
0.78 (0.60, 1.01) 0.060

Ref.
0.68 (0.50, 0.92) 0.010*

Ref.
1.40 (1.02, 1.90) 0.030*

Ref.
0.88 (0.61, 1.26) 0.49

Ref.
1.07 (0.74, 1.55) 0.71

Ref.
0.91 (0.69, 1.19) 0.49

Ref.
1.19 (0.90, 1.56) 0.22

Ref.
1.14 (0.80, 1.63) 0.47

Ref.
0.86 (0.60, 1.24) 0.42

Ref.
0.73 (0.53, 1.00) 0.050

Ref.
1.24 (0.97, 1.59) 0.090

Ref.
1.33 (0.97, 1.84) 0.080

Ref.
1.04 (0.81, 1.33) 0.78

Models were adjusted for age, sex, BMI, former diseases, family history ofasthma, eczema, wheeze, rhinitis, food allergy, nasosinusitis and urticaria. *Pvalue < 0.05, **P value < 0.01, ***P value < 0.001

Table 3 shows the association between chronic coughand indoor environment. Mold exposure (OR = 1.40;
CI = 1.02– 1.90; P 0.05) was found to be a high-risk factor for chronic cough after adjusting for age, sex, BMI,
eczema, wheezing, rhinitis, food allergies, nasosinusitis, and urticaria. Furthermore, carpet use at home
(OR = 1.07; CI = 0.74–1.55), growing flowers at home
(OR = 1.19; CI = 0.90–1.56), pregnancy and perinatal
smoke exposure (OR = 1.24; CI = 0.97–1.59), and current
smoke exposure (OR = 1.04; CI = 0.81–1.33) were all positively associated with chronic cough, but the differenceswere not statistically significant.
Associations between the indoor environment andabnormal sleep behavior among children with chronic
coughLogistic regression analysis conducted among children with chronic cough, before and after adjusting forconfounders (Tables S3 and 4), identified several associations. Home decoration within a year was positively
associated with sleepwalking (OR = 1.04; CI = 1.00–1.07;
P < 0.05); mold exposure was positively associated withbruxism (OR = 1.15; CI = 1.0–1.31; P < 0.05); and carpet
use at home was significantly positively associated withapnea (OR = 1.09; CI = 1.02–1.17; P < 0.05), twitching during sleep (OR = 1.13; CI = 1.00–1.27; P < 0.01), and morning headache (OR = 1.14; CI = 1.05–1.23; P < 0.01).
In the non–chronic cough group, pet ownership was
found to be significantly positively associated with several sleep-related factors, such as open-mouth breathing(OR = 1.48; CI = 1.10–1,98; P < 0.01), dyspnea (OR = 2.64;

Table 4 Associations between the indoor environment and abnormal sleep behavior after adjusted analysis among chronic coughchildren (n = 316, multivariate)
Variable

Decoration
OR (95% CI)
Sleep duration
0.89 (0.76, 1.06)
Snorting
0.92 (0.82, 1.03)
Mouth opening
1.04 (0.93, 1.17)
Dyspnea
0.99 (0.95, 1.04)
Apnea
0.98 (0.92, 1.02)
Restless sleep
0.92 (0.82, 1.03)
Twitching
0.99 (0.91, 1.08)
Sleep talking
0.97 (0.87, 1.08)
Sleep walking
1.04 (1.00, 1.07)*
Bruxism
1.01 (0.90, 1.13)
Sweating
0.96 (0.86, 1.07)
Bed wetting
0.91 (0.83, 0.99)
Waking during sleep 0.95 (0.86, 1.06)
Long to waking
0.99 (0.89, 1.10)
Headache in morning 1.02 (0.97, 1.07)
Thirsting
0.96 (0.86, 1.07)
Napping
1.07 (0.97, 1.19)

Mold exposure
OR (95% CI)
1.16 (0.95, 1.41)
1.16 (1.02, 1.33)*
0.93 (0.81, 1.06)
0.98 (0.93, 1.04)
1.02 (0.98, 1.07)
1.13 (0.99, 1.29)
1.03 (0.93, 1.13)
1.02 (0.89, 1.60)
0.98 (0.94, 1.01)
1.15 (1.00, 1.31)*
0.92 (0.81, 1.05)
1.05 (0.94, 1.16)
0.98 (0.87, 1.10)
0.97 (0.85, 1.10)
1.05 (0.99, 1.12)
0.98 (0.86, 1.11)
0.96 (0.85, 1.09)

CarpetOR (95% CI)
1.08 (0.85, 1.37)
1.10 (0.93, 1.29)
1.10 (0.94, 1.30)
1.09 (1.02, 1.16)*
1.05 (1.00, 1.11)
0.98 (0.83, 1.15)
1.13 (1.00, 1.27)*
1.04 (0.89, 1.21)
1.01 (0.96, 1.05)
0.95 (0.81, 1.12)
1.15 (0.98, 1.34)
0.95 (0.84, 1.08)
1.10 (0.85, 1.27)
1.15 (0.98, 1.34)
1.13 (1.04, 1.22)*
1.03 (0.88, 1.21)
1.08 (0.93, 1.26)

FlowerOR (95% CI)
1.04 (0.87, 1.24)
0.96 (0.85, 1.08)
1.03 (0.91, 1.07)
1.00 (0.95, 1.00)
1.02 (0.98, 1.06)
1.05 (0.93, 1.18)
1.07 (0.98, 1.17)
1.00 (0.89, 1.13)
1.01 (0.98, 1.04)
1.11 (0.98, 1.25)
1.01 (0.89, 1.14)
0.92 (0.84, 1.01)
0.93 (0.83, 1.04)
1.17 (1.04, 1.31)
1.06 (0.99, 1.12)
1.06 (0.94, 1.20)
1.12 (1.00, 1.25)

Pet
OR (95% CI)
1.06 (0.84, 1.34)
1.08 (0.92, 1.27)
1.08 (0.92, 1.27)
0.98 (0.91, 1.04)
1.02 (0.97, 1.08)
1.04 (0.89, 1.22)
1.18 (1.05, 1.33)
1.02 (0.87, 1.19)
1.00 (0.96, 1.05)
0.94 (0.80, 1.10)
1.01 (0.87, 1.18)
1.08 (0.96, 1.23)
1.01 (0.87, 1.16)
1.02 (0.87, 1.19)
0.98 (0.91, 1.06)
1.11 (0.95, 1.29)
1.07 (0.92, 1.24)

Former smoker
OR (95% CI)
1.08 (0.92, 1.28)
1.11 (0.99, 1.24)
1.12 (1.00, 1.25)
0.98 (0.93, 1.02)
1.00 (0.97, 1.04)
1.11 (0.99, 1.24)
1.03 (0.95, 1.11)
1.17 (1.06, 1.30)
1.00 (0.97, 1.03)
0.98 (0.88, 1.10)
1.04 (0.93, 1.16)
1.01 (0.92, 1.10)
1.03 (0.93, 1.13)
1.11 (1.00, 1.23)
1.03 (0.97, 1.08)
1.01 (0.91, 1.12)
1.04 (0.93, 1.15)

Current smoker
OR (95% CI)
0.96 (0.82, 1.13)
1.01 (0.90, 1.12)
0.97 (0.87, 1.09)
0.96 (0.91, 1.00)
1.00 (0.97, 1.04)
1.02 (0.91, 1.14)
1.01 (0.94, 1.10)
1.11 (1.00, 1.23)
0.99 (0.96, 1.02)
0.97 (0.87, 1.09)
0.98 (0.88, 1.09)
0.99 (0.91, 1.08)
1.00 (0.90, 1.10)
1.06 (0.96, 1.18)
0.97 (0.92, 1.03)
1.00 (0.90, 1.11)
0.97 (0.88, 1.08)

Models were adjusted for age, sex, BMI, eczema, wheeze, rhinitis, food allergy, nasosinusitis and urticaria. *P value < 0.05, **P value < 0.01, ***P value < 0.001

Xu et al. BMC Pediatrics(2024) 24:533

CI = 1.38–5.56; P < 0.01), apnea (OR = 2.90; CI = 1.07–
7.87; P < 0.05), sleepwalking (OR = 2.77; CI = 1.37–5.60;
P < 0.01), morning headache (OR = 2.01; CI = 1.38–3.40;
P < 0.05), and thirst (OR = 1.90; CI = 1.41–2.57; P < 0.001)
both before and after adjusting for variables (Additional
file 3 and 4).

Discussion
This study was the first to investigate the prevalence ofchronic cough among children aged 3–18 years in Wuxi,
finding an overall incidence of 15.5%. Moreover, certain factors, such as household decoration within a year,
household mold exposure, and carpet use, were identified as risk factors for abnormal sleep behaviors in children with chronic cough. Coughing serves as a defensive
mechanism to prevent the intake of excessive fluids andforeign objects [20]; however, it can also significantly
reduce quality of life and impose a substantial social andfinancial burden on society. In children, cough that persists for ≥ 4 weeks is classified as chronic [21, 22]. Chronic
cough incurs an annual expenditure of approximately$360 million on over-the-counter drugs in the UnitedStates alone, with global costs exceeding $10 billion [23].
The economic burden of chronic cough has not been specifically investigated in China; however, we speculate thatthe situation is likely similar to that in the United States.
One meta-analysis conducted in 2022 indicated thatthe prevalence of chronic cough in southern cities was
lower than that in northern cities [24], which suggeststhat regional factors and unique environmental andeconomic conditions may influence the prevalence ofchronic cough. The higher prevalence observed in ourstudy could be attributed to these factors. Wuxi, locatedin southern China, has experienced rapid industrialization, and has emerged as a major economic center in
the Yangtze River Delta, with Shanghai at its core, sincethe 1980s. In 2022, Wuxi recorded a per capita GDP of
RMB 199,015.7 billion, ranking third highest in Jiangsu
province. Moreover, the city has undergone substantial
urbanization, which could contribute to the increase inchronic cough diagnoses [25].
In our study, we observed that children with chronic
cough were more likely to experience wheezing, eczema,
rhinitis, or nasosinusitis than those in the control group,
which aligns with previous studies [26, 27]. This increase
may largely be attributed to shared underlying conditions such as airway hyper-responsiveness and atopy.
A chart study focusing on children with sinusitis andchronic cough revealed that 65% of children with persistent cough displayed sinus abnormalities on radiography[28]. It is believed that nasal secretions, whether reaching
the pharynx alone or in conjunction with the larynx, canstimulate nerve endings and trigger coughing [29]. The
pathogenesis of chronic cough is complex and involves a

Page 7 of 10

variety of factors, including nasobronchial reflex, upper
airway inflammation, exposure to cold and dry air, andthe propagation of inflammatory mediators through thesystemic circulation [30]. In addition, other etiologicalfactors, such as central and peripheral neuroplasticity,
may also contribute [31]. However, a definitive explanation has not yet been provided. Allergic diseases rarely
occur in isolation, and must be considered alongsidevarious comorbid conditions, including sinusitis, asthma,
disrupted sleep, lymphoid hypertrophy causing obstructive sleep apnea, and subsequent behavioral effects [32].
Sleep is vital to children’s health and overall wellbeing. Previous research has confirmed that patientswith chronic cough often complain of sleep disorders[33]. Moreover, another study found that the relationship between psychological distress and allergic disease is mediated by sleep disruption, highlighting theimportance of assessing the sleep health of children withallergic conditions [34]. In the present study, sleep disturbances such as snoring, restless sleep, bruxism, andsweating were all found to besignificantly associated witha high risk of chronic cough, although some associations did not reach statistical significance. Most of these
symptoms are consistent with the clinical presentation of
OSA. Notably, multiple adult studies have demonstrated
the association between OAS and chronic cough, withmechanisms including airway inflammatory responses,
esophageal-tracheobronchial reflexes, airway wall edema,and sleep deprivation [35]. The muscular movements
associated with coughing can lead to teeth grinding andarousal from sleep. Nocturnal hyperhidrosis can contribute to sympathetic nerves and acetylcholine neurotransmitters [36]. However, investigations into the association
between chronic cough and sleep disorders in children
are limited, and further investigations are require toassess if the underlying processes differ between children
and adults.
Despite the well-documented impact of the indoor
environment on children’s respiratory systems in numerous countries [37–39], only a few studies have examined
the relationships between indoor environments and sleep
disorders. Our study found that the use of carpets athome was associated with morning apnea, convulsions,and headaches in children with chronic cough. Carpets
are known to be repositories of allergens, and considering that modern societies spend a significant amount oftime indoors [40], it is crucial to examine their potential
impact. Feline allergen I (feld I) [41], a common and significant feline allergen, has an 11-fold higher average concentration per unit area on carpeted floors than on othersurfaces. This allergen can attach to surfaces, including
fur, and tends to persist on carpets for extended periods. It can also bind to small dust particles (1–20 μm insize), enabling allergens to remain suspended in the air

Xu et al. BMC Pediatrics(2024) 24:533

for longer durations [42]. A cross-sectional study conducted in four Swedish cities found a higher prevalenceof snoring among individuals who reported humidity andair pollution in their homes [43]. However, in our study,
no statistical significance was observed after adjustment. Tiesler et al. previously reported that visible moldor moisture in the home might have a negative impact
on children’s sleep, although the specific sleep problems
were not categorized. This study suggested an association between home moisture and bruxism [44]. Generally, indoor air pollutants, such as total volatile organic
compounds, formaldehyde, plasticizers, carbon monoxide, carbon dioxide, particulate matter (PM2.5, PM10etc.), and ultrafine particles, are significantly higher inbedrooms that have undergone home decoration or are
exposed to smoke [45, 46]. Considering that decorationmaterials, indoor humidity, and smoking exposure areassociated with allergic diseases [47], we hypothesizedthat indoor environments could negatively affect sleep
through allergic inflammation. Nevertheless, further
research is necessary to validate this finding and explore
its underlying biological mechanisms.
This study identified the prevalence of chronic coughin Wuxi for the first time, and it concentrated on indoor
environmental factors, which are relatively easy to modify among the variables which affect children’s life andhealth and have more guiding significance in the dailycare of children by their guardians. The present study has
several limitations that should be acknowledged. First,
the assessment of clinical symptoms relied on questionnaires completed by parents and guardians. This subjective reporting of whether children snore, experience
difficulty breathing, grind their teeth, or experiencenight-time convulsions may introduce biases influenced
by parental anxiety and lack of professional judgment,
potentially impacting the reported prevalence of chronic
cough and sleep disorders. As the variables required inour study were all provided by the children themselves
and/or the primary caregivers, recall bias may haveexisted. However; we asked older children and their primary caregivers to complete the questionnaires together
to minimize the risk of recall bias. Second, due to thestudy’s cross-sectional design, establishing causal relationships between variables was not possible. Finally,
the influence of residual confounding factors cannot be
entirely ruled out.

Conclusion
This study revealed a prevalence of 15.5% for chronic
cough among children aged 3–18 years in Wuxi. Children
with chronic cough are more prone to exhibiting someabnormal sleep behaviors than those without chronic
cough. Household decoration within a year, household mold exposure, and carpet use were significantly

Page 8 of 10

positively associated with abnormal sleep behaviors inchildren with chronic cough. These results suggest thatclinicians and parents should carefully consider thesefactors. Overall, our study provides novel insights into
the impact of the indoor environment on children’s sleep
and the occurrence of chronic cough, offering guidance
for tailored health promotion programs for families.
Abbreviations
BMI	Body mass index
CI	Confidence interval
CSHQ	Children’s Sleep Habits Questionnaire
Fel d I	Felis domesticus allergen I
GER	Gastroesophageal reflux disease
ICSD	International Classification of Sleep Disorders
OR	Odds ratio
OSA	Obstructive sleep apnea
OSAS	Obstructive sleep apnea syndrome
SDB	Sleep-disordered breathing

Supplementary Information

The online version contains supplementary material available at https://doi.
org/10.1186/s12887-024-04876-y.
Supplementary Material 1
Acknowledgements
We thank the Medical Innovation Team of Jiangsu Province and the Wuxi
Municipal Bureau on Science and Technology for their generous funding.
Author contributions
LL designed and supervised the research project. SYX drafted the initialmanuscript and contributed to its writing. ZZP meticulously revised thepaper. ZZP and YG analyzed the participants’ data. SSP, QW, and QZ diligently
collected and organized the data. The implementation of this study involved
contributions from all authors. All authors thoroughly reviewed and gave theirapproval for the final manuscript.
Funding
This study was funded by Wuxi Taihu Lake Talent Plan [grant number
DJTD202304], Major Program of Wuxi Health and Family Planning Commission[grant number Z202016], General project of Wuxi Health and Family Planning
Commission [grant number M202305], Youth Project of Wuxi Health andFamily Planning Commission [grant number Q201837], Wuxi Medical Talents[grant number QNRC071], Maternal and child health project of Wuxi HealthCommission [grant number FYKY202204], and Top Talent Support Program for
Young and Middle-aged People of the Wuxi Health Committee [grant number
HB2020088 and HB2023092].
Data availability
The datasets generated and/or analyzed in this study are not publicly available
due to the lack of consent from all participants to share their information
online. However, interested parties can obtain the datasets from thecorresponding author upon reasonable request.

Declarations
Ethics approval and consent to participate
Before participant recruitment, this research obtained approval from the
Ethics Committee of the Affiliated Wuxi Children’s Hospital of Nanjing Medical
University (Approval number. WXCH2019-8-002). The parents or guardians of
all children were informed regarding the purpose of this research and signed
written informed consent before the study’s commencement. All information
obtained was treated as confidential.
Consent for publication
Not applicable.

Xu et al. BMC Pediatrics(2024) 24:533

Competing interests
The authors declare no competing interests.
Author details
1
Department of Respiratory Medicine & Clinical Allergy Center, AffiliatedChildren’s Hospital of Jiangnan University (Wuxi Children’s Hospital), Wuxi,
China
2
Department of Respiratory Medicine, Children’s Hospital of Soochow
University, Suzhou, China
Received: 4 November 2023 / Accepted: 9 June 2024

References
1. Subspecialty Group of Pharmacology, The Society of Pediatrics, Chinese
Medical Association. Clinical practice guidelines for the diagnosis andmanagement of children with cough in China (version 2021). Zhonghua Er
Ke Za Zhi Chin J Pediatr. 2021;59:720–9. National Clinical Research Center forChild Health and Disorders, Subspecialty Group of Respiratory Diseases, The
Society of Pediatrics, Chinese Medical Association, Children′s Respiratory
Professional Committee, The Society of Pediatrics of Chinese Medical Doctor
Association, Editorial Board, Chinese Journal of Pediatrics.
2. Waring G, Kirk S, Fallon D. The impact of chronic non-specific cough onchildren and their families: a narrative literature review. J Child Health Care
Prof Work Child Hosp Community. 2020;24:143–60.
3. Gao K, Hu H, Zhang X. A controlled study on the prevalence and risk factorsof chronic cough in children. Zhejiang Prev Med. 2012;24:52–85.
4. Bergmann M, Haasenritter J, Beidatsch D, Schwarm S, Hörner K, Bösner S, etal. Coughing children in family practice and primary care: a systematic review
of prevalence, aetiology and prognosis. BMC Pediatr. 2021;21:260.
5. Leconte S, Degryse J. [Prolonged cough in children in the primary care
office]. Rev Med Brux. 2011;32:5–9.
6. Gipson K, Lu M, Kinane TB. Sleep-disordered breathing in children. Pediatr
Rev. 2019;40:3–13.
7. Sateia MJ. International classification of sleep disorders-third edition: highlights and modifications. Chest. 2014;146:1387–94.
8. Trachsel D, Datta AN. [Sleep-Disordered breathing in Childhood]. Praxis.
2019;108:97–102.
9. Sundar KM, Daly SE. Chronic cough and OSA: a New Association? J clin sleep
Med JCSM off Publ. Am Acad Sleep Med. 2011;7:669–77.
10. Teoh L, Hurwitz M, Acworth JP, van Asperen P, Chang AB. Treatment of
obstructive sleep apnoea for chronic cough in children. Cochrane Database
Syst Rev. 2011;:CD008182.
11. Liu J, Wu T, Liu Q, Wu S, Chen J-C. Air pollution exposure and adverse sleep
health across the life course: a systematic review. Environ Pollut Barking Essex
1987. 2020;262:114263.
12. Zhao Y, Liu Y, Liu M, Wang D, Ren W, Gao F, et al. [Interactive effects ofenvironmental tobacco smoke and pets ownership on respiratory diseases and symptoms in children]. Zhonghua Er Ke Za Zhi Chin J Pediatr.
2013;51:96–100.
13. Lombardi E, Simoni M, La Grutta S, Viegi G, Bisanti L, Chellini E, et al. Effectsof pet exposure in the first year of life on respiratory and allergic symptoms
in 7-yr-old children. The SIDRIA-2 study. Pediatr Allergy Immunol off Publ Eur
Soc Pediatr Allergy Immunol. 2010;21(2 Pt 1):268–76.
14. Roda C, Guihenneuc-Jouyaux C, Momas I. Environmental triggers of nocturnal dry cough in infancy: new insights about chronic domestic exposure toformaldehyde in the PARIS birth cohort. Environ Res. 2013;123:46–51.
15. Arku RE, Brauer M, Duong M, Wei L, Hu B, Ah Tse L, et al. Adverse healthimpacts of cooking with kerosene: a multi-country analysis within the prospective Urban and Rural Epidemiology Study. Environ Res. 2020;188:109851.
16. Uzun K, Ozbay B, Ceylan E, Gencer M, Zehir I. Prevalence of chronic bronchitis-asthma symptoms in biomass fuel exposed females. Environ Health Prev
Med. 2003;8:13–7.
17. Owens JA, Spirito A, McGuinn M. The children’s Sleep habits Questionnaire(CSHQ): psychometric properties of a survey instrument for school-aged
children. Sleep. 2000;23:1043–51.
18. Liu Z, Wang G, Geng L, Luo J, Li N, Owens J. Sleep patterns, sleep disturbances, and Associated factors among Chinese urban kindergarten children.
Behav Sleep Med. 2016;14:100–17.

Page 9 of 10

19. Li S, Jin X, Shen X, Wu S, Jiang F, Yan C, et al. [Development and psychometricproperties of the Chinese version of children’s Sleep habits Questionnaire].
Zhonghua Er Ke Za Zhi Chin J Pediatr. 2007;45:176–80.
20. Spanevello A, Beghé B, Visca D, Fabbri LM, Papi A. Chronic cough in adults.
Eur J Intern Med. 2020;78:8–16.
21. Morice AH, Millqvist E, Bieksiene K, Birring SS, Dicpinigaitis P, Domingo Ribas
C, et al. ERS guidelines on the diagnosis and treatment of chronic cough in
adults and children. Eur Respir J. 2020;55:1901136.
22. Chang AB, Oppenheimer JJ, Irwin RS, CHEST Expert Cough Panel. Managing
chronic cough as a Symptom in Children and Management algorithms:
CHEST Guideline and Expert Panel Report. Chest. 2020;158:303–29.
23. Morice AH. Chronic cough: epidemiology. Chron Respir Dis. 2008;5:43–7.
24. Liang H, Ye W, Wang Z, Liang J, Yi F, Jiang M, et al. Prevalence of chronic
cough in China: a systematic review and meta-analysis. BMC Pulm Med.
2022;22:62.
25. Guidelines for the diagnosis and treatment of cough. (2015). Chin J Tuberc
Respir Dis. 2016;39:323–40.
26. Song W-J, Chang Y-S, Faruqi S, Kim J-Y, Kang M-G, Kim S, et al. The global epidemiology of chronic cough in adults: a systematic review and meta-analysis.
Eur Respir J. 2015;45:1479–81.
27. de Benedictis FM, Selvaggio D, de Benedictis D. Cough, wheezing andasthma in children: lesson from the past. Pediatr Allergy Immunol off Publ Eur
Soc Pediatr Allergy Immunol. 2004;15:386–93.
28. Nw W, Mb H, Cb H, K P. S B, V L, Sinusitis and chronic cough in children. J
Asthma Allergy. 2012;5.
29. O’Hara J, Jones NS. Post-nasal drip syndrome: most patients with purulent nasal secretions do not complain of chronic cough. Rhinology.
2006;44:270–3.
30. Braunstahl G-J, Fokkens W. Nasal involvement in allergic asthma. Allergy.
2003;58:1235–43.
31. Tatar M, Plevkova J, Brozmanova M, Pecova R, Kollarik M. Mechanisms of thecough associated with rhinosinusitis. Pulm Pharmacol Ther. 2009;22:121–6.
32. Ja SH. [Allergic rhinitis. Coexistent diseases and complications. A review andanalysis]. Rev Alerg Mex Tecamachalco Puebla Mex 1993. 2006;53.
33. Matricciani L, Paquet C, Galland B, Short M, Olds T. Children’s sleep and health:a meta-review. Sleep Med Rev. 2019;46:136–50.
34. Sherrey J, Biggs S, Dorrian J, Martin J, Gold M, Kennedy D, et al. Allergic
disease, sleep problems, and psychological distress in children recruitedfrom the general community. Ann Allergy Asthma Immunol off Publ Am Coll
Allergy Asthma Immunol. 2022;129:366–72.
35. Chan K, Ing A, Birring SS. Cough in obstructive sleep apnoea. Pulm Pharmacol
Ther. 2015;35:129–31.
36. Miki H, Minakuchi H, Miyagi M, Hara ES, Shigemoto S, Suzuki Y, et al. Association of masticatory muscle activity with sleep arousal and other concomitant
movements during sleep. J Oral Rehabil. 2020;47:281–8.
37. Siwarom S, Puranitee P, Plitponkarnpim A, Manuyakorn W, Sinitkul R, Arj-Ong
Vallipakorn S. Association of indoor air quality and preschool children’s respiratory symptoms. Asian Pac J Allergy Immunol. 2017;35:119–26.
38. Maung TZ, Bishop JE, Holt E, Turner AM, Pfrang C. Indoor air Pollution andthe health of vulnerable groups: a systematic review focused on Particulate
Matter (PM), volatile Organic compounds (VOCs) and their effects on children
and people with Pre-existing Lung Disease. Int J Environ Res Public Health.
2022;19:8752.
39. Vardoulakis S, Giagloglou E, Steinle S, Davis A, Sleeuwenhoek A, Galea KS, etal. Indoor exposure to selected air pollutants in the Home Environment: asystematic review. Int J Environ Res Public Health. 2020;17:E8972.
40. Cincinelli A, Martellini T. Indoor air Quality and Health. Int J Environ Res Public
Health. 2017;14:E1286.
41. Nastasi N, Renninger N, Bope A, Cochran SJ, Greaves J, Haines SR, et al. Persistence of viable MS2 and Phi6 bacteriophages on carpet and dust. Indoor Air.
2022;32:e12969.
42. Portnoy J, Kennedy K, Sublett J, Phipatanakul W, Matsui E, Barnes C, et al.
Environmental assessment and exposure control: a practice parameter–furry
animals. Ann Allergy Asthma Immunol off Publ Am Coll Allergy Asthma
Immunol. 2012;108:e2231–15.
43. Silverforsen D, Theorell-Haglöw J, Ljunggren M, Middelveld R, Wang J, Franklin K, et al. Snoring and environmental exposure: results from the Swedish
GA2LEN study. BMJ Open. 2021;11:e044911.
44. Tiesler CMT, Thiering E, Tischer C, Lehmann I, Schaaf B, von Berg A, et al. Exposure to visible mould or dampness at home and sleep problems in children:
results from the LISAplus study. Environ Res. 2015;137:357–63.

Xu et al. BMC Pediatrics(2024) 24:533

45. Canha N, Lage J, Coutinho JT, Alves C, Almeida SM. Comparison of indoor air
quality during sleep in smokers and non-smokers’ bedrooms: a preliminary
study. Environ Pollut Barking Essex 1987. 2019;249:248–56.
46. Xu X, Lian Z, Shen J, Cao T, Zhu J, Lin X, et al. Experimental study on sleep
quality affected by carbon dioxide concentration. Indoor Air. 2021;31:440–53.
47. Butland BK, Strachan DP, Anderson HR. The home environment and asthma
symptoms in childhood: two population based case-control studies 13 years
apart. Thorax. 1997;52:618–24.

Page 10 of 10

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.