3 | RESULTS
3.1 | Participant characteristics and prevalence of
habitual
snorers
Of the 1721 children enrolled, 197 questionnaires were excluded because:
(1) the questionnaire was completed irregularly; (2) the child had a
history of neuromuscular disease, craniofacial syndrome, cerebral palsy,
sickle cell disease, mucopolysaccharide storage disease, or
immunodeficiency; (3) the child had a mental or physical impairment
severe enough to cause abnormal behaviors (including congenital disease,
intellectual disability, or psychiatric disorder). The final 1524
questionnaires used for analyses represented a response rate of 88.56%.
The survey included 926 boys and 622 girls. The sample’s average age was
7.11 ± 5.25 years, ranging from 2–14 years. Among these participants,
730, 282, 314, 119, and 103 lived in a city, a suburb, a county seat, a
town, and a countryside village, respectively. Overall, there were 463
habitual snorers (30.38%), 683 occasional snorers (44.82%), and 402
non-snorers (26.38%).
3.2 | Risk factors for
HS
3.2.1 | Social
demography
Social demographic risk factors were tabulated for each group and are
shown in Table 1. HS morbidity was significantly higher in preschool
children (<7 years old) than in school children (≥7 years
old). Though boys (31.53%, 292/926) had a slightly higher rate of HS
than girls (27.49%, 171/622), this difference was not statistically
significant.
Fewer minority nationality children (2.6%) than Han (97.4%)
participated, though there was no race difference in HS prevalence. Nor
did HS morbidity differ based on living district (Table 1).
BMI scores were 16.62 (15.12–19.80), 16.63 (15.08–19.72), and 16.59
(15.15–19.96) for the HS group, occasional snoring group, and
non-snoring group, respectively. Adjusting for age and gender, BMI did
not differ among the snoring groups.
3.2.2 | Socioeconomic
factors
According to the average household income statistics of Sichuan Province
in 2019, we divided family monthly earning into six groups. No
significant difference was found between the prevalence of HS and family
monthly earning (p = .21).
Paternal education did not differ between snoring groups (p =
.119). Higher maternal education was associated with greater HS
prevalence (p = .023); maternal college and undergraduate degrees
were related to an increase in HS morbidity (2.3; 95% CI, 1.1–4.7).
3.2.3 | Birth and heredity
information
Neither delivery method (natural labor vs. cesarean section) nor
gestational age (premature, full-term, or post-term birth) was related
to HS prevalence (p = .75 and .11, respectively). Nor were
maternal or paternal ages at the child’s birth related to HS prevalence
(p = .123 and .373, respectively).
In our sample, 77 mothers had pregnancy complications, including three
highly prevalent diseases: diabetes, hypertension, and hypothyroidism.
Interestingly, the prevalence of HS in children born to mothers with
triple pregnancy complications was significantly lower compared with
occasional and non-snoring (Table 2).
The average breastfeeding duration for the overall sample was 6.92 ±
5.51 months. The between-groups difference in average breastfeeding
duration was statistically significant (p = .019). Breastfeeding
duration (6.07 ± 5.22 months) in the HS group was significantly shorter
than in the occasional snoring group (8.25 ± 5.91 months) and the
non-snoring group (7.92 ± 6.12 months).
Parental loud snoring (considered a hereditary factor) was related to
the HS prevalence (p < .001) (1.16; 95% CI,
1.29–1.61).
3.2.4 | History of upper respiratory
inflammation
The prevalence of AR, nasosinusitis, and tonsillitis symptoms in the
past six months for the HS, occasional, and non-snoring groups are
listed in Table 3. AR symptoms (1.24; 95% CI, 1.10–1.77),
nasosinusitis symptoms (17.62; 95% CI, 6.41–48.80), tonsillitis
symptoms (19.66; 95% CI, 9.51–55.38), and pneumonia/bronchitis
symptoms (14.22; 95% CI, 5.42–38.01) within the past six months were
related to HS incidence. However, only 20 (1.3%) of the children had
been diagnosed with asthma, which was unrelated to HS prevalence.
3.2.5 | Passive smoking
exposure
In the HS group, the proportion of mothers with a history of smoking
during pregnancy (43.1%) was markedly higher than that in the
non-snoring (4.7%) and occasional snoring (2%) groups. Both maternal
exposure to secondhand smoke during pregnancy and child exposure were
related to HS prevalence (p < .00) (Table 4). To
further investigate the relation between passive smoking and other
factors and snoring, multivariate logistic regression analysis was
undertaken, controlling for the potential confounders of age, gender,
and upper respiratory inflammation in the fully adjusted model. Maternal
smoking during pregnancy (1.95; 95% CI, 1.63–2.34), maternal exposure
to secondhand smoke during pregnancy (1.61; 95% CI, 1.08–2.39), and
child exposure to secondhand smoke (1.89; 95% CI, 1.56–2.23) were
significant risk factors for HS.