Prepregnancy body mass index and risk of childhood asthma

Barriers and facilitators to healthy gestational weight gain amongst pregnant women from ethnic minority groups: A systematic search and narrative synthesis

BACKGROUND

Excessive weight gain can be detrimental to the health and wellbeing of both mother and child. There is evidence that women from ethnic minority groups are more likely to gain excessive weight during pregnancy. For the purpose of this review, ethnic minority women are defined as those with different national or cultural traditions from the main population.

AIM

Our aim was to identify barriers and facilitators to healthy gestational weight gain in pregnant women in ethnic minority groups.

METHODS

Databases searched were MEDLINE, CINAHL, PsycInfo and PsycArticles between 2011 and 2022. Inclusion criteria were empirical studies of any method considering gestational weight gain in ethnic minority women published in English. Data were extracted according to aim, participants, methods, and findings in relation to barriers and facilitators. Included papers were assessed for quality according to relevant Joanna Briggs Institute checklists.

FINDINGS

Twenty-six studies were identified. Five themes were revealed: (1) knowledge and beliefs, (2) cultural and social influences, (3) confidence, (4) physical experiences, and (5) personal and environmental factors.

DISCUSSION

Some barriers and facilitators were relevant to all groups and others were more specific to ethnic minority groups. The latter included social and cultural influences, which were reported extensively. Our search was comprehensive, although it is possible we may not have captured all relevant papers.

CONCLUSION

We recommend that the barriers and facilitators identified here are considered in designing future, or adjusting current, health care practitioner mediated interventions to support healthy gestational weight gain in ethnic minority women.

Maternal obesity and childhood asthma risk: Exploring mediating pathways

BACKGROUND

Growing evidence for the effect of maternal obesity on childhood asthma motivates investigation of mediating pathways.

OBJECTIVE

To investigate if childhood body mass index (BMI), gestational weight gain (GWG) and preterm birth mediate the association of maternal obesity on childhood asthma risk.

METHODS

We used electronic medical records from mother-child pairs enrolled in Kaiser Permanente Northern California integrated healthcare system. Children were followed from their birth (2005-2014) until at least age 4 (n = 95,723), age 6 (n = 59,230) or age 8 (n = 25,261). Childhood asthma diagnosis at each age was determined using ICD-9/10 codes and medication dispensings. Prepregnancy BMI (underweight [<18.5], normal [18.5-24.9], overweight [25-29.9], obese [≥30] kg/m2) were defined using height and weight measurements close to the last menstrual period date. Child's BMI (Centers for Disease Control and Prevention BMI-for-age percentiles: underweight [<5th], normal [5th-85th], overweight [85th-95th], obese [>95th]) were obtained using anthropometric measurements taken the year preceding each follow-up age. GWG (delivery weight-prepregnancy weight) was categorised based on Institutes of Medicine recommendations (inadequate, adequate, excessive). Implementing first causal inference test (CIT) then causal mediator models (to decompose the natural direct and indirect effects), we examined the potential mediating effect of childhood BMI, GWG, and preterm birth on the association between prepregnancy BMI (continuous and categorical) and childhood asthma.

RESULTS

Overall, risk of childhood asthma increased as prepregnancy BMI increased (age 4 risk ratio: 1.07, 95% confidence interval: 1.04, 1.09, per 5 kg/m2 increase in BMI; similar for age 6 and 8). CIT identified childhood BMI and preterm birth, but not GWG as potential mediators. Causal mediation models confirmed childhood BMI, but not preterm birth, as having a partial mediating effect. Results were similar for age 6 and 8, and when continuous mediators (instead of binary) were assessed.

CONCLUSIONS

Childhood overweight/obesity has a modest mediating effect on the association between prepregnancy BMI and childhood asthma.

Relationship Between Birth Weight and Asthma Diagnosis: A Cross-Sectional Survey Study Based on the National Survey of Children's Health in the U.S

OBJECTIVE

To assess the association between birth weight and childhood asthma risk using data from the 2019-2020 National Survey of Children's Health database.

DESIGN

Cross-sectional study.

SETTING

The USA.

PATIENTS

A representative cohort of American children.

EXPOSURE

The exposure of this study was birth weight regardless of gestational age. Birth weight was divided into three groups: <1500 g, 1500-2500 g and >2500 g.

MAIN OUTCOME MEASURES

Primary outcomes were parent-reported diagnosis of asthma.

METHOD

The Rao-Scott χ2 test was used to compare the groups. The main analyses examined the association between birth weight and parent-report asthma in children using univariable and multivariable logistic models adjusting for preterm birth, age, sex, race, family poverty, health insurance, smoking, maternal age. Subgroup analysis was performed based on interaction test.

RESULTS

A total of 60 172 children aged 3-17 years were enrolled in this study; of these, 5202 (~8.6%) had asthma. Children with asthma were more likely to be born preterm, with low birth weight (LBW) or very LBW (VLBW). The incidence of asthma was the highest in VLBW children at 20.9% and showed a downward trend with an increase in birth weight class, with rates of 10.7% and 8.1% in the LBW and normal birthweight groups, respectively. Children with VLBW (OR 1.97; 95% CI 1.29 to 3.01) had higher odds of developing asthma in the adjusted analysis model. However, VLBW was only shown to be a risk factor for asthma among Hispanics, black/African-Americans and children between the ages of 6 and 12 years, demonstrating racial and age disparities.

CONCLUSIONS

VLBW increases the risk of childhood asthma; however, racial and age disparities are evident.

Complex interplay of gut microbiota between obesity and asthma in children

Obesity is an important risk factor and common comorbidity of childhood asthma. Simultaneously, obesity-related asthma, a distinct asthma phenotype, has attracted significant attention owing to its association with more severe clinical manifestations, poorer disease control, and reduced quality of life. The establishment of the gut microbiota during early life is essential for maintaining metabolic balance and fostering the development of the immune system in children. Microbial dysbiosis influences host lipid metabolism, triggers chronic low-grade inflammation, and affects immune responses. It is intimately linked to the susceptibility to childhood obesity and asthma and plays a potentially crucial transitional role in the progression of obesity-related asthma. This review article summarizes the latest research on the interplay between asthma and obesity, with a particular focus on the mediating role of gut microbiota in the pathogenesis of obesity-related asthma. This study aims to provide valuable insight to enhance our understanding of this condition and offer preliminary evidence to support the development of therapeutic interventions.

The Role of Confounders in Statistical Analysis

Researchers can limit the effects of study design limitations on research findings through statistical analysis that includes crucial covariates and accounts for confounding.

Maternal high-fat diet increases airway sensory innervation and reflex bronchoconstriction in adult offspring

Children born to obese mothers are prone to develop asthma and airway hyperresponsiveness, but the mechanisms behind this are unclear. Here we developed a mouse model of maternal diet-induced obesity that recapitulates metabolic abnormalities seen in humans born to obese mothers. Offspring of dams fed a high-fat diet (HFD) showed increased adiposity, hyperinsulinemia, and insulin resistance at 16 wk of age despite being fed only a regular diet (RD). Bronchoconstriction induced by inhaled 5-hydroxytriptamine was also significantly increased in offspring of HFD-fed versus RD-fed dams. Increased bronchoconstriction was blocked by vagotomy, indicating this reflex was mediated by airway nerves. Three-dimensional (3-D) confocal imaging of tracheas collected from 16-wk-old offspring showed that both epithelial sensory innervation and substance P expression were increased in the offspring of HFD-fed dams compared with offspring of RD-fed dams. For the first time, we show that maternal high-fat diet increases airway sensory innervation in offspring, leading to reflex airway hyperresponsiveness.NEW & NOTEWORTHY Our study reveals a novel potential mechanism, by which maternal high-fat diet increases the risk and severity of asthma in offspring. We found that exposure to maternal high-fat diet in mice leads to hyperinnervation of airway sensory nerves and increased reflex bronchoconstriction in offspring fed a regular diet only. These findings have important clinical implications and provide new insights into the pathophysiology of asthma, highlighting the need for preventive strategies in this patient population.