Background: Atopic dermatitis (AD) is a chronic skin disease characterized by dry skin, severe itching, inflammation and impaired quality of life. Moisturizing is an integral part of treatment for AD, but its potential for prevention of AD is unclear. Objective: To evaluate whether the early use of emollients in infancy can prevent later development of AD. Methods: We searched Medline, Embase, Web of Science, PubMed, Cochrane Library and other databases to collect randomized controlled trials on early use of emollients in infants for a meta-analysis. Results: Nine articles were included. The OR value for incidence rate was 0.7 (95% CI: 0.48–1.01). No significant publication bias was found by Egger’s test. The sensitivity analysis indicated that the final conclusion was reliable. Conclusions: We found that the difference in incidence rate of AD between the experimental and control groups was not statistically significant. However, due to different methods of using emollients, different follow-up times and different sample sizes included in this meta-analysis, a definitive conclusion could not be reached in this study. In the future, it is still necessary to carry out randomized controlled, multicenter, large-sample trials with an excellent study design and high methodological quality on early application of emollients in high-risk infants to prevent AD.

Atopic dermatitis (AD), a chronic inflammatory skin disease, can affect the quality of life of patients and their families. Most children with AD present with pruritus, dry skin, and eczematous rash before they are 1 year old [1]. At present, it is not clear whether early use of skin emollients in infants can effectively prevent AD [2‒6]. We therefore carried out a meta-analysis to evaluate whether the use of skin emollients in infants can prevent the later development of AD.

This meta-analysis was performed strictly in accordance with the requirements of the PRISMA statement. Medline, Embase, Web of Science, PubMed and Cochrane Library were searched from their inception to October 2020. Among them, the detailed retrieval strategies for PubMed were: ("Emollients"[Mesh]) OR (Emollient)) AND ("Dermatitis, Atopic"[Mesh]) OR (Atopic Dermatitides) OR (Atopic Dermatitis) OR (Dermatitides, Atopic) OR (Neurodermatitis, Atopic) OR (Atopic Neurodermatitides) OR (Atopic Neurodermatitis) OR (Neurodermatitides, Atopic) OR (Neurodermatitis, Disseminated)) OR (Disseminated Neurodermatitides) OR (Disseminated Neurodermatitis) OR (Neurodermatitides, Disseminated) OR (Eczema, Atopic)) OR (Atopic Eczema) OR (Eczema, Infantile) OR (Infantile Eczema) AND (“Infant”[Mesh]) OR (Infants). No language restrictions were implemented in the literature search. We only extracted available data from published articles.

Inclusion criteria: (1) the type of study: randomized controlled trial (RCT); (2) the subject populations: infants (0–12 months); (3) intervention: the experimental groups were subjected to daily use of emollients, while the control groups received no regular administration of emollients.

Exclusion criteria: (1) any publication type other than RCT; (2) republished papers; (3) the study populations other than infants; (4) papers containing incomplete information.

Two researchers read the abstracts of literature and excluded papers according to the criteria. Papers that met the inclusion criteria were used for further analysis. Consensus was required for inclusion, and in cases of dissenting assessment papers were discussed by all the authors until consensus was reached.

The Cochrane risk of bias assessment tool was used to evaluate the quality of the included literature. There were no significant factors affecting the meta-analysis (Fig. 1).

Fig. 1.

The Cochrane risk bias assessment.

Fig. 1.

The Cochrane risk bias assessment.

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We used STATA version 14.0 to calculate a 95% confidence interval (CI) for the incidence of AD of the included patients. The heterogeneity of the literature was tested according to the Cochrane Handbook requirements, and an I2 >50% was considered indicative of high heterogeneity. If the heterogeneity was high, we would use the random-effect model for the meta-analysis. Conversely, we would use the fixed-effect model for the meta-analysis. We used Egger’s test to assess publication bias. Sensitivity analysis was realized by a one-by-one exclusion method. For analysis of combined effects, p < 0.05 was used to indicate significant differences between the experimental and control groups.

A total of 1,606 papers were retrieved. After screening, 9 papers meeting the inclusion criteria were included [7‒15]. The basic information of the included articles is shown in Table 1, and the specific paper screening process is shown in Figure 2. The comparison results of the incidence rate of AD between the experimental and control groups are shown in Figure 3. The odds ratio (OR) value for the incidence rate was 0.7 (95% CI: 0.48–1.01). The difference between the experimental and control groups was not statistically significant (z = 1.90, p = 0.057). No significant publication bias was found by Egger’s test (p > 0.05). We used the one-by-one exclusion method to perform the sensitivity analysis, which proved that the final conclusion was reliable (Fig. 4).

Table 1.

The information table for the articles

 The information table for the articles
 The information table for the articles
Fig. 2.

Article screening flow diagram.

Fig. 2.

Article screening flow diagram.

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Fig. 3.

Results of meta-analysis.

Fig. 3.

Results of meta-analysis.

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Fig. 4.

Results of sensitivity analysis.

Fig. 4.

Results of sensitivity analysis.

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Studies have found that regular use of emollients can alleviate clinical symptoms in patients with AD, delay flares, and reduce the dosage of topical corticosteroids [16‒20]. At present, however, it is not clear whether early use of skin emollients in infants can effectively prevent AD.

We included 9 RCTs in this meta-analysis (1,483 patients in the intervention group and 1,509 in the control group), and found the OR = 0.7 (95% CI: 0.48–1.01). The results of this meta-analysis suggest that the use of emollients in early life (before 1 year) in high-risk infants does not significantly prevent the development of AD. However, this result needs to be further verified by high-quality RCTs.

Of the 9 studies included, 6 supported the early use of emollients while 3 did not. The 3 studies that did not support the prevention of AD by early use of emollients, namely the studies by Chalmers et al. [14], Kataoka et al. [7], and Skjerven et al. [15], were more rigorous in design but lacked detailed information on the specific amount and frequency of emollient use in the experimental groups. The 6 studies supporting the prevention of AD by early use of emollients shared the common limitations of small sample size and short follow-up time. We believe that increasing the sample size and extending the follow-up time may ultimately lead to a conclusion that does not support the prevention of AD by early use of emollients. However, due to different methods of using emollients, different follow-up times and different sample sizes included in this meta-analysis, a definitive conclusion could not be reached in this study.

Heterogeneity in meta-analyses should always be paid attention to. In this study, the heterogeneity of the included literature was not high(I2 = 52.3%). The heterogeneity included the small sample sizes of most included studies, and different evaluated outcomes. The sensitivity test indicated that our conclusion was reliable.

At present, there are only few published papers in this field, and the conclusion of our study is therefore likely to be influenced by potential publication biases. We included articles written in English only because there were few articles on this topic written in other languages. However, in this meta-analysis, no significant publication bias was found by Egger’s test, and the stable OR value of our sensitivity test suggested that our final conclusion is reliable.

This study also has some limitations: not all the included articles mentioning random grouping provide the specific randomization methods. The subject populations of the included articles come from different regions, and the sample sizes of the included articles vary greatly. Different amounts and administration methods of the emollients were used in the included studies.

In conclusion, in the future, it is still necessary to carry out randomized controlled, multicenter, large-sample trials with an excellent study design and high methodological quality on the early application of emollients in high-risk infants to prevent AD. It is better to conduct a comprehensive study with a fixed type of emollients, a fixed amount of emollients, a fixed frequency of emollient administration, and multiple outcome evaluation indicators.

This meta-analysis shows that the application of emollients does not significantly reduce the later development of infantile AD.

No ethical approval was needed because data in our study came from previously published studies in which informed consent was obtained by the original investigators.

The authors have no conflicts of interest.

No funding was received for this study.

R.S. contributed to the conception of the study. X.D. and S.P. were responsible for data analysis and writing the first draft of the manuscript. All coauthors contributed to the writing of the manuscript. All coauthors have provided important intellectual input and approved the final version of the paper.

All data generated or analyzed during this study are included in this article. Further enquiries can be directed to the corresponding author.

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