Weight gain in the first two years of life, asthma and atopy: the SCAALA cohort study

Growth pattern during early infancy, body mass index during childhood and childhood asthma

BACKGROUND

There is a lack of longitudinal studies of associations between growth from infancy to childhood and asthma development.

OBJECTIVE

The objective of the study was to investigate the effects of weight change during infancy, body mass index (BMI) and the interaction of these factors on the risk of childhood asthma.

METHODS

We enrolled children born in 2008 and 2009 at full-term and with normal birth weight. The weight change in infancy was grouped into slow, on-track and rapid. BMI status in childhood was stratified into low, normal and high groups and used as a time-varying variable. The outcome was asthma, defined as two or more diagnoses of asthma separated by at least 1 year after 2 years of age. The risk of asthma was assessed using Cox proportional hazard regression, with adjustment for sex, residence area at birth, economic status and feeding types in infancy.

RESULTS

Of 917,707 children born in Korea in 2008 and 2009, 271,871 were eligible for analysis. The risk of asthma was greater in groups with low birth weight (aHR 1.06, 95% CI 1.04 to 1.08), rapid body weight change during early infancy (aHR 1.08, 95% CI 1.07 to 1.10) and high BMI during childhood (aHR 1.06, 95% CI 1.04-1.08). The interaction of weight change during early infancy with BMI during childhood was significant for asthma (p < .01). Rapid weight gain in infancy was associated with lower risk of asthma in those with low BMI during childhood; had no association with asthma in those with normal BMI during childhood; and was associated increased asthma risk in those with high BMI during childhood-aHR 1.26 (95% CI 1.19 to 1.33) and aHR 1.33 (95% CI 1.12 to 1.56) compared with on-track and slow infant weight gain, respectively.

CONCLUSION

Low birth weight, high BMI during childhood and, in those with high childhood BMI, rapid weight gain during early infancy are associated with increased risk of childhood asthma.

Longitudinal changes in body mass index Z-scores during infancy and risk of childhood allergies

BACKGROUND

Few studies address the dynamic changes of body mass index (BMI) Z-scores during infancy with breastfeeding and their impact on childhood atopic diseases.

METHODS

A total of 183 children from a birth cohort regularly followed-up for 4 years were enrolled in this study. Time series data of BMI Z-scores from 1 month to 2 years of age was clustered using K-means method in R software. Breastfeeding status during the first 6 months of life was recorded and classified. The total serum and specific immunoglobulin E (IgE) levels to food and inhalant allergens were measured at age 0.5, 1, 1.5, and 2 years.

RESULTS

Using K-means clustering, the dynamic changes in BMI Z-scores were classified into three clusters (cluster A, increasing, n = 62; cluster B; decreasing, n = 62; cluster C, constant low, n = 59). Despite having no statistical association with atopic diseases, a decreasing trend in infantile BMI Z-scores was significantly associated with a higher prevalence of IgE sensitization at age 1 which increased the risk of rhinitis development at age 4 (P = 0.007). No difference in BMI Z-scores was determined between different breastfeeding patterns. However, exclusive formula feeding ≥6 months was found to be significantly associated with mite sensitization at age 1.5 years which risks asthma development at age 4 (P = 0.001).

CONCLUSIONS

A decreasing trend of BMI Z-scores during infancy is determined to be inversely associated with IgE and allergen sensitization, which may potentially increase the risk of allergies in early childhood.

Pediatric obesity-related asthma: A prototype of pediatric severe non-T2 asthma

Childhood obesity contributes to many diseases, including asthma. There is literature to suggest that asthma developing as a consequence of obesity has a nonallergic or non-T2 phenotype. In this review, obesity-related asthma is utilized as a prototype of non-T2 asthma in children to discuss several nonallergic mechanisms that underlie childhood asthma. Obesity-related asthma is associated with systemic T helper (Th)1 polarization occurring with monocyte activation. These immune responses are mediated by insulin resistance and dyslipidemia, metabolic abnormalities associated with obesity, that are themselves associated with pulmonary function deficits in obese asthmatics. As in other multifactorial diseases, there is both a genetic and an environmental contribution to pediatric obesity-related asthma. In addition to genetic susceptibility, differential DNA methylation is associated with non-T2 immune responses in pediatric obesity-related asthma. Initial investigations into the biology of non-T2 immune responses have identified the upregulation of genes in the CDC42 pathway. CDC42 is a RhoGTPase that plays a key role in Th cell physiology, including preferential naïve Th cell differentiation to Th1 cells, and cytokine production and exocytosis. Although these novel pathways are promising findings to direct targeted therapy development for obesity-related asthma to address the disease burden, there is evidence to suggest that dietary interventions, including diet modification, rather than caloric restriction alone, decrease disease burden. Adoption of a diet rich in micronutrients, including carotenoids and 25-OH cholecalciferol, a vitamin D metabolite, may be beneficial since these are positively correlated with pulmonary function indices, while being protective against metabolic abnormalities associated with the obese asthma phenotype.

Association of pediatric obesity and asthma, pulmonary physiology, metabolic dysregulation, and atopy; and the role of weight management

Introduction: Obesity affects about 40% of US adults and 18% of children. Its impact on the pulmonary system is best described for asthma. Areas covered: We reviewed the literature on PubMed and Google Scholar databases and summarize the effect of obesity, its associated metabolic dysregulation and altered systemic immune responses, and that of weight gain and loss on pulmonary mechanics, asthma inception, and disease burden. We include a distinct approach for diagnosing and managing the disease, including pulmonary function deficits inherent to obesity-related asthma, in light of its poor response to current asthma medications. Expert opinion: Given the projected increase in obesity, obesity-related asthma needs to be addressed now. Research on the contribution of metabolic abnormalities and systemic immune responses, intricately linked with truncal adiposity, and that of lack of atopy, to asthma disease burden, and pulmonary function deficits among obese children is fairly consistent. Since current asthma medications are more effective for atopic asthma, investigation for atopy will guide management by distinguishing asthma responsive to current medications from the non-responsive disease. Future research is needed to elucidate mechanisms by which obesity-mediated metabolic abnormalities and immune responses cause medication non-responsive asthma, which will inform repurposing of medications and drug discovery.

Infant Feeding, Vitamin D and IgE Sensitization to Food Allergens at 6 Years in a Longitudinal Icelandic Cohort

Nordic Nutrition Recommendations (NNR) recommend exclusive breastfeeding until 6 months, partial breastfeeding until 1 year or longer and irrespective of breastfeeding, avoiding solid foods before 4 months. Strong evidence was found for benefits of breastfeeding regarding growth and infections but limited/inconclusive evidence regarding atopic disease and asthma. Vitamin D is of special interest in the Nordic diet. The aim of this prospective study was to compare infant feeding and vitamin D between immunoglobulin E (IgE) sensitized (n = 14) and non-sensitized (n = 130) children at 6 years. Information on diet and vitamin D supplement use were collected with dietary recall (<5 months), 1-d food records (5 and 6 months) and 3-d weighed food records (12 months and 6 years). Serum-specific IgE-antibodies against milk, egg, cod, wheat, soy and peanut (cut-off specific IgE ≥ 0.35 kUA/L) were measured at 6 years and serum 25-hydroxyvitamin D at 12 months and 6 years. At 4 months, 57% of IgE sensitized vs. 23% of non-sensitized children (p < 0.01) had received solid food. At 12 months, IgE sensitized children had a lower intake of vitamin D (median (25th, 75th percentiles): 3.9 μg/d (3.2, 7.2) vs. 8.1 μg/d (4.4, 12.3), p = 0.03) and at 6 years, fewer used vitamin D supplements regularly (23% vs. 56%, p = 0.03). Introduction of solid foods prior to 4 months increased the odds of IgE-sensitization, OR = 4.9 (95%, CI = 1.4–16.6) and vitamin D supplement at 6 years decreased the odds of IgE-sensitization, OR = 0.2 (95%, CI = 0.1–0.98), adjusting for maternal smoking. These observations support the NNR in their recommendation against introducing complementary solid foods before the age of 4 months. Furthermore, they support encouraging vitamin D intake for young children at northern latitudes.

Effects of infant weight gain on subsequent allergic outcomes in the first 3 years of life

Background

The association between early weight gain and later allergic outcomes has not been well studied. We examined the relation between weight gain and the subsequent development of allergic outcomes in the first 36 months of life in a Singapore birth cohort.

Methods

In repeated visits in the first 15 months, we measured infant weight and administered questionnaires ascertaining allergic outcomes. At ages 18 and 36 months, we administered skin prick tests (SPTs) to inhalant and food allergens.

Results

At 18 months, 13.5% had a positive SPT, 3.5% had wheeze and a positive SPT, 3.9% had rhinitis and a positive SPT, and 6.1% had eczema and a positive SPT. Higher weight gain from 6 to 9 months, 9 to 12 months and 12 to 15 months were independently associated with a reduced risk of developing a positive SPT at 18 months (p-trend ≤0.03). At 36 months, 23.5% had a positive SPT, 11.9% had wheeze and a positive SPT, 12.2% rhinitis and a positive SPT, and 11.5% eczema and a positive SPT. Higher weight gain from 12 to 15 months was associated with a reduced risk of developing a positive SPT at 36 months (p-trend <0.01). No significant associations were observed between weight gain in any period and wheeze, rhinitis or eczema combined with a positive SPT at 18 or 36 months.

Conclusion

Higher weight gain in the first 15 months of life was associated with a reduced risk of allergen sensitization, but not with combinations of allergic symptoms.

Trial registration

NCT01174875 Registered 1 July 2010, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-017-0890-0) contains supplementary material, which is available to authorized users.