Metabolomic profiles during early childhood and risk of food allergies and asthma in multiethnic children from a prospective birth cohort

BACKGROUND

There are increasing numbers of metabolomic studies in food allergy (FA) and asthma, which, however, are predominantly limited by cross-sectional designs, small sample size, and being conducted in European populations.

OBJECTIVE

We sought to identify metabolites unique to and shared by children with FA and/or asthma in a racially diverse prospective birth cohort, the Boston Birth Cohort.

METHODS

Mass spectrometry-based untargeted metabolomic profiling was performed using venous plasma collected in early childhood (n = 811). FA was diagnosed according to clinical symptoms consistent with an acute hypersensitivity reaction at food ingestion and food specific-IgE > 0.35 kU/L. Asthma was defined on the basis of physician diagnosis. Generalized estimating equations were applied to analyze metabolomic associations with FA and asthma, adjusting for potential confounders.

RESULTS

During a mean ± standard deviation follow-up of 11.8 ± 5.2 years from birth, 78 children developed FA and 171 developed asthma. Androgenic and pregnenolone steroids were significantly associated with a lower risk of FA, especially for egg allergy. N,N,N-trimethyl-5-aminovalerate (odds ratio [OR] = 0.65, 95% confidence interval [CI] = 0.48-0.87), and 1-oleoyl-2-arachidonoyl-sn-glycero-3-phosphoinositol (OR = 0.77; 95% CI = 0.66-0.90) were inversely associated with FA risk. Orotidine (OR = 4.73; 95% CI = 2.2-10.2) and 4-cholesten-3-one (OR = 0.52; 95% CI = 0.35-0.77) were the top 2 metabolites associated with risk of asthma, although they had no association with FA. In comparison, children with both FA and asthma exhibited an altered metabolomic profile that aligned with that of FA, including altered levels of lipids and steroids.

CONCLUSION

In this US multiethnic prospective birth cohort, unique and shared alterations in plasma metabolites during early childhood were associated with risk of developing FA and/or asthma. These findings await further validation.

Interaction of maternal asthma history and plasma folate levels on child asthma risk in the Boston Birth Cohort

BACKGROUND

Previous studies on maternal folate status during pregnancy and child asthma risk yielded mixed results, and few considered maternal asthma history, a known risk factor of childhood asthma. This study examined whether the role of maternal folate in childhood asthma differs by maternal asthma history and whether there is an interaction between the two factors.

METHODS

This study included 1948 mother-child dyads from the Boston Birth Cohort. Childhood asthma was defined based on physician diagnosis documented in electronic medical records, and maternal asthma was based on standard questionnaire interview. Maternal plasma folate level within a few days of delivery was measured by chemiluminescent immunoassay. Logistic regression models were applied to examine individual and joint associations of maternal asthma history and plasma folate level with childhood asthma, adjusting for other covariables.

RESULTS

When stratified by maternal asthma history, an L-shaped relationship between maternal folate level and child asthma was observed in children born to mothers with asthma history (p_interaction  = 0.03). The highest risk was found in children having maternal asthma history and low maternal folate level (odds ratio = 5.93; 95% confidence interval: 2.86-12.3) compared with children without maternal asthma history and with sufficient maternal folate levels. Sensitivity analyses using different definitions of asthma and stratified by major covariables yielded similar findings.

CONCLUSION

In this US prospective high-risk birth cohort, maternal asthma history and low folate level interactively increased the risk of child asthma. If further confirmed, optimizing maternal folate levels during pregnancy may mitigate child asthma risk in the setting of maternal asthma history.

Early Life Weight Gain and Development of Childhood Asthma in a Prospective Birth Cohort

RATIONALE

The prevalence of childhood asthma has been increasing worldwide in parallel with childhood obesity.

OBJECTIVES

We investigated whether there is a temporal relationship between early life weight gain (reflecting growth velocity) and early life body mass index (BMI) attained status (reflecting accumulative weight) with future risk of asthma in the Boston Birth Cohort.

METHODS

This report includes 1,928 children from the Boston Birth Cohort with a mean age of 7.8 years (standard deviation, 3.3 yr), enrolled at birth and followed prospectively. Asthma was defined using physician diagnosis code (International Classification of Diseases, Ninth Revision, Clinical Modification code 493.xx) in children 2 years and older. We categorized the children by their weight gain trajectory on the basis of changes in z-scores: slow (less than -0.67), on track (-0.67 to 0.67), rapid (0.67-1.28), and extremely rapid (>1.28); and by their BMI attained status (underweight, normal weight, and overweight) during the first 4, 12, and 24 months. Poisson regression models with robust variance estimation were applied to examine the relationship between early life weight gain/attained BMI and asthma.

RESULTS

During the first 4 months of life, 37% had on-track weight grain, 22% had slow weight gain, 15% had rapid weight gain, and 26% had extremely rapid weight gain. At 4 months, 61% were normal weight, 7% were underweight, and 32% were overweight. In adjusted analyses, extremely rapid early life weight gain during the first 4 and 24 months of life were each associated with increased risks of asthma (risk ratio, 1.34 for extremely rapid weight gain at 4 months; 95% confidence interval [CI], 1.06-1.70; risk ratio, 1.32 for extremely rapid weight gain at 24 months; 95% CI, 1.00-1.75) Similarly, overweight at 4, 12, and 24 months were each associated with an increased risk of asthma. Analyses that further adjusted for birthweight or preterm birth showed similar findings.

CONCLUSIONS

In this predominantly urban U.S. low-income minority birth cohort, excessive early life weight gain and overweight status were both associated with an increased risk of asthma in childhood.