Results
Participant characteristics
Participants’ characteristics are presented in Table 1. Out of 837
children who underwent skin examinations, 7.3% (61/837) presented with
AD lesions at the time of clinic visits. Amongst 61 children diagnosed
with AD, 23% (14/61) presented with moderate-to-severe AD lesions while
77% (47/61) had mild AD lesions. The mean (SD) SCORAD scores for mild
and moderate-to-severe AD cases were 17.2 (4.6) and 37.86 (12.7),
respectively.
Of these 837 participants, 181 children (21.6%) did not undergo oral
examination at 3-years due to logistic/manpower constraints, with no
significant differences in socio-demographic characteristics, except for
monthly household income, between those who received oral examination vs
those who did not (Appendix Table 1). Although the AD severity profile
of children who underwent oral examination significantly differed from
those who did not, no differences in SCORAD scores were observed for
both moderate-to-severe AD and mild AD groups (p>0.05).
Oral examinations for ECC detection were performed in 656 participants
at the 3-year visit. ECC lesions were observed in 85.7% (6/7), 36.8%
(14/38) and 42.8% (262/611) children in moderate-to-severe AD, mild AD
and non-AD groups, respectively. Furthermore, the mean (SD) decayed
surfaces in moderate-to-severe, mild and non-AD groups were 5.4 (4.6),
2.2 (4.1) and 2.4 (5.1), respectively. Three examiners performed oral
examinations, with mean inter- and intra-examiner reliability scores of
0.80 and 0.80, respectively (for ICDAS code 2) and 0.80 and 0.90,
respectively (for ICDAS codes 3-6).
AD severity and early childhood caries
A significant difference in number of decayed surfaces across the AD
severity groups was observed (P=0.04). On subgroup analysis after
Bonferroni correction, significantly higher decayed surfaces were found
in moderate-to-severe AD group compared to those without AD (p=0.03),
while no difference was found between mild AD and the reference group
(p=0.62) (Table 1). After adjusting for potential confounders (Model-1),
children in the moderate-to-severe AD group were at higher risk of ECC
(aIRR 2.30 [95% confidence interval (CI) 1.04-5.06]; p=0.03),
compared to non-AD group. However, no differences in ECC risk was
observed between mild AD and reference group (aIRR 0.89 [95% CI
0.47-1.70]; p=0.74) (Table 2). Other significant risk factors for ECC
included Chinese ethnicity (aIRR 2.91 [95%CI 1.82-4.66];
p<0.001), Malay ethnicity (aIRR 2.31 [95%CI 1.37-3.89];
p=0.002) and lower household income level (aIRR 1.94 [95%CI
1.15-3.26]; p=0.01), detailed in Table 2.
Potential confounding effect of postnatal dietary and oral hygiene
factors
On adjusting for additional postnatal dietary factors such as duration
of breastfeeding and frequency of child’s daily sweet snack intake
(Model-2), children with moderate-to-severe AD also showed a 2-fold
increase in ECC risk (aIRR 2.41 [95%CI 1.08-5.37]; p=0.03) compared
to non-AD, similar to Model-1 (Table 3). On further inclusion of oral
hygiene factors such as child’s daily tooth-brushing frequency
(Model-3), strength of the association remained robust (aIRR 2.31
[95%CI 1.06-5.03]; p=0.03). For both Models-2 and 3, no association
was seen between mild AD and ECC, similar to Model 1 where no
dietary/oral hygiene factors were controlled in the regression model.
Comparative evaluation of different diagnostic systems for AD estimation
Using physician diagnosis as the gold standard, caregiver-report of
doctor-diagnosed AD demonstrated high specificity (86.6%) and negative
predictive value (NPV=95.5%), but low sensitivity (51.9%) and positive
predictive value (PPV=24.8%), in identifying true AD cases (Table 4).
Single use of SPT performed similar to the caregiver-report of
doctor-diagnosed AD with sensitivity, specificity, PPV and NPV of
40.3%, 88.2%, 22.6% and 94.6%, respectively. In contrast, combined
criteria of caregiver-reported doctor-diagnosed AD and a positive SPT
demonstrated 2-fold higher PPV values (45.4%), compared to individual
criteria, although other parameters such as sensitivity (44.1%),
specificity (96.3%) and NPV (96.2%) remained similar.