Birth Month and Prevalence of Atopic Dermatitis in Children Under 3 Years in Antananarivo, Madagascar

Background Several studies have been done to evaluate the relationship between month of birth and atopic diseases but the results are contradictory. Objective We aim to evaluate the correlation between the month of birth and the prevalence of AD in Malagasy children less than 3 years. Methods A case-control study was conducted based on patients' data of the department of Dermatology in the University Hospital Joseph Raseta Befelatanana (UH/JRB) Antananarivo. It included 438 children less than 3 years seen in this department between January 2010 and December 2019. For each atopic dermatitis (AD) patient, two age-and sex-matched controls without a history of AD were selected from the same period. Results This study included 146 AD cases and 292 non-AD controls. Our case-control study found that there is a statistically significant correlation between birth month and risk of AD in Malagasy children <3 years. Compared with people born in December, people born in April had the highest risk of AD (OR: 2.11, 95% CI 0.93-4.78), followed by people born in March (OR: 1.52, 95% CI 0.79-2,88). Asthma, allergic rhinitis and allergic conjunctivitis were significantly correlated with AD in our patients. Conclusion Our case-control study found that being born in April and March (dry season) may be associated with an increased risk of AD.