Oon Hoe Teoh

Epidemiology, clinical characteristics and antimicrobial resistance patterns of community-acquired pneumonia in 1702 hospitalized children in Singapore

Objective and background:  Childhood community‐acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide. The features of childhood CAP vary between countries. The aim of this study was to delineate the clinical characteristics, complications, spectrum of pathogens and patterns of antimicrobial resistance associated with hospitalized cases of childhood CAP in Singapore.

The methodology of the GUSTO cohort study: a novel approach in studying pediatric allergy

Growing Up in Singapore Towards healthy Outcomes (GUSTO) is Singapores largest birth cohort study to date. The main aim of GUSTO is to evaluate the role of developmental factors in the early pathways to metabolic compromise. Detailed data is collected for a range of environmental exposures in the parents and offspring, and allergic disorders are among a number of outcomes assessed in infancy and childhood. Under the Allergy domain of GUSTO, this integrated study will describe the epidemiology of allergic manifestations and different phenotypes in the Asian context and help shed light on the association of metabolic disease to allergy. Epigenetic mechanisms and associations with other childhood disorders will also be explored. The aim of this report is to focus on methodology of GUSTO, and to suggest similar approaches (i.e., integrated cohort studies on pediatric allergy) worldwide. Recruitment commenced in 2009 with a cohort of 1,163 pregnant mothers in their first trimester. The mothers and children were followed throughout pregnancy and follow-up will continue until the child reaches 3 years of age. Preliminary results showed that 39.8% of the mothers had a personal history of having at least one allergic disease, which included asthma, eczema and allergic rhinitis. Further data collection and analyses are still ongoing. Allergy is a complex spectrum of disorders with numerous poorly-understood aspects. The ongoing GUSTO cohort study, with its longitudinal design and multi-disciplinary nature, may provide new insights into developmental influences on allergy. As a Singapore-based study, it will be the first integrated allergy cohort in Southeast Asia, of which recruitment started during pregnancy.

Allergic rhinitis and non-allergic rhinitis in children in the tropics: prevalence and risk associations.

The age‐related comparative prevalence of allergic rhinitis (AR) and non‐allergic rhinitis (NAR) in children is poorly defined. We aimed to characterize AR and NAR in children.

Sleep Quality and Nocturnal Sleep Duration in Pregnancy and Risk of Gestational Diabetes Mellitus

Study Objectives: To examine the influence of maternal sleep quality and nocturnal sleep duration on risk of gestational diabetes mellitus (GDM) in a multiethnic Asian population. Methods: A cohort of 686 women (376 Chinese, 186 Malay, and 124 Indian) with a singleton pregnancy attended a clinic visit at 26‐28 weeks of gestation as part of the Growing Up in Singapore Towards healthy Outcomes mother‐offspring cohort study. Self‐reported sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index (PSQI). GDM was diagnosed based on a 75‐g oral glucose tolerance test administered after an overnight fast (1999 WHO criteria). Multiple logistic regression was used to model separately the associations of poor sleep quality (PSQI score > 5) and short nocturnal sleep duration (<6 h) with GDM, adjusting for age, ethnicity, maternal education, body mass index, previous history of GDM, and anxiety (State‐Trait Anxiety Inventory score). Results: In the cohort 296 women (43.1%) had poor sleep quality and 77 women (11.2%) were categorized as short sleepers; 131 women (19.1%) were diagnosed with GDM. Poor sleep quality and short nocturnal sleep duration were independently associated with increased risk of GDM (poor sleep, adjusted odds ratio [OR] = 1.75, 95% confidence interval [CI] 1.11 to 2.76; short sleep, adjusted OR = 1.96, 95% CI 1.05 to 3.66). Conclusions: During pregnancy, Asian women with poor sleep quality or short nocturnal sleep duration exhibited abnormal glucose regulation. Treating sleep problems and improving sleep behavior in pregnancy could potentially reduce the risk and burden of GDM.

An independent association of prenatal depression with wheezing and anxiety with rhinitis in infancy

Different maternal psychological states during pregnancy have been associated with wheeze–rhinitis–eczema symptoms in children. However, previous studies were limited and it was unclear whether the type of prenatal psychological state was associated with a particular symptom. We examined the association of maternal depression and anxiety during pregnancy with wheeze–rhinitis–eczema symptoms in infancy.

Rhinitis in the first 18 months of life: Exploring the role of respiratory viruses

Rhinitis is common in early childhood, but allergic rhinitis is considered a later manifestation of the atopic march. This study aimed to evaluate rhinitis (allergic and non‐allergic) in the first 18 months of life, its link with other atopic manifestations and the role of respiratory viruses.

Maternal PUFA status and offspring allergic diseases up to the age of 18 months

Studies have suggested that maternal PUFA status during pregnancy may influence early childhood allergic diseases, although findings are inconsistent. We examined the relationship between maternal PUFA status and risk of allergic diseases in early childhood in an Asian cohort. Maternal plasma samples from the Growing Up in Singapore Towards Healthy Outcomes mother-offspring cohort were assayed at 26-28 weeks of gestation for relative abundance of PUFA. Offspring (n 960) were followed up from 3 weeks to 18 months of age, and clinical outcomes of potential allergic diseases (rhinitis, eczema and wheezing) were assessed by repeated questionnaires. Skin prick testing (SPT) was also performed at the age of 18 months. Any allergic disease with positive SPT was defined as having any one of the clinical outcomes plus a positive SPT. The prevalence of a positive SPT, rhinitis, eczema, wheezing and any allergic disease with positive SPT was 14·1 % (103/728), 26·5 % (214/808), 17·6 % (147/833), 10·9 % (94/859) and 9·4 % (62/657), respectively. After adjustment for confounders, maternal total n-3, n-6 PUFA status and the n-6:n-3 PUFA ratio were not significantly associated with offspring rhinitis, eczema, wheezing, a positive SPT and having any allergic disease with positive SPT in the offspring (P>0·01 for all). A weak trend of higher maternal n-3 PUFA being associated with higher risk of allergic diseases with positive SPT in offspring was observed. These findings do not support the hypothesis that the risk of early childhood allergic diseases is modified by variation in maternal n-3 and n-6 PUFA status during pregnancy in an Asian population.

Low Food Allergy Prevalence Despite Delayed Introduction of Allergenic Foods—Data from the GUSTO Cohort

BACKGROUND There is mounting evidence that early introduction of allergenic food decreases the risk of food allergy development, especially in high-risk infants with eczema. However, there is a lack of data to suggest whether this association holds true in Asian populations. OBJECTIVE To investigate the relationship between the timing of introduction of allergenic foods and food allergy outcomes in infants in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study. METHODS The GUSTO cohort recruited 1152 mothers of Chinese, Malay, and Indian ethnicity who had singleton, naturally conceived pregnancies and followed their offspring prospectively. Information on demographic characteristics, child health, infant feeding practices, and a convincing history of IgE-mediated food allergy was obtained from interviewer-administered questionnaires at multiple time points. Corroborative skin prick tests to food allergens were performed at 18 and 36 months. RESULTS Most of the infants were introduced to egg (49.6%), peanut (88.7%), and shellfish (90.2%) after age 10 months. Food allergy prevalence was, however, very low between age 12 and 48 months: egg, 0.35% to 1.8%; peanut allergy, 0.1% to 0.3%; and shellfish, 0.2% to 0.9%. There were no significant associations between the timing of introduction of allergenic foods and the development of food allergy, adjusted for confounders including breast-feeding and eczema. CONCLUSIONS Food allergy rates in Singapore are low despite delayed introduction of allergenic foods. Early introduction of allergenic foods may thus not be necessary in populations in which overall food allergy prevalence is low, and thus infant feeding recommendations should be carefully tailored to individual populations.

Associations between poor subjective prenatal sleep quality and postnatal depression and anxiety symptoms

BACKGROUND Symptoms of depression and anxiety are common during pregnancy and the postnatal period. A risk factor for mood disorders is poor sleep quality. In this study we investigate the effects of poor subjective prenatal sleep quality on postnatal depressive and anxiety symptoms, independent of prenatal depression or anxiety, amongst pregnant women in the general population. METHODS We analysed data from a subset of women taking part in a prospective cohort study, Growing Up in Singapore towards Healthy Outcomes. The participants completed the Edinburgh Postnatal Depression Scale and State-Trait Anxiety Inventory between 26 and 28 weeks of pregnancy (Time 1) and at 3 months postpartum (Time 2), and the Pittsburgh Sleep Quality Index at Time 1. Logistic regression analyses were used to investigate the associations between subjective prenatal sleep quality and postnatal depressive and anxiety symptoms, while adjusting for prenatal depressive/anxiety symptoms and education. RESULTS Although borderline-high depressive/anxiety symptoms were the strongest predictors of postnatal depressive/anxiety, independent of this, poor subjective sleep quality during pregnancy was also associated with borderline-high postnatal depressive symptoms, but not with postnatal anxiety. LIMITATIONS Sleep quality and prenatal/postnatal mood were derived from self-reported questionnaires, which may be more susceptible to bias. CONCLUSION Although treatment of symptoms of prenatal depression and anxiety will be the most important for reducing postnatal depression and anxiety, in addition to that, future studies may explore treatments improving prenatal sleep quality, particularly for women with antenatal depressive symptoms.

Effect of maternal dietary patterns during pregnancy on self-reported allergic diseases in the first 3 years of life: Results from the GUSTO study

Background: Maternal diet during pregnancy has been suggested to be an important early-life exposure that influences immune tolerance and the development of allergic diseases in offspring. Methods: We examined the relationship between maternal dietary patterns assessed using 24-h recalls and food diaries at 26-28 weeks of pregnancy and the subsequent development of allergic outcomes in the offspring in the Growing Up in Singapore towards Healthy Outcomes (GUSTO) birth cohort. Exploratory factor analysis was used to characterize maternal dietary patterns during pregnancy. During repeated visits in the first 36 months of life, questionnaires were administered to ascertain allergic symptoms, namely, eczema, rhinitis, and wheeze. At ages 18 and 36 months, we administered skin-prick testing to inhalant and food allergens. Results: Of the 3 maternal dietary patterns that emerged, the seafood and noodles pattern was associated with a reduced risk of developing allergen sensitization at both 18 months (odds ratio [95% confidence interval]: 0.7 [0.5-0.9]) and 36 months (0.7 [0.6-0.9]) after adjustment for a family history of allergy, and ethnicity, sex, and maternal education levels. No associations between the patterns vegetables, fruit, and white rice or pasta, cheese, and processed meat were observed with any of the allergic outcomes in the first 18 and 36 months of life. Conclusion: Maternal diet during pregnancy can influence the subsequent development of allergic outcomes in offspring.