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Ashton, Deborah (2019) Early childhood obesity – exploring the impact of environmental and social factors and parental beliefs of caring for infants with known obesity risk factors. PhD thesis, University of Nottingham.

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Abstract

Background

Macrosomia (birthweight ≥4kg) and rapid weight gain in infancy are both strong independent risk factors for early child overweight. Whilst there are environmental and genetic factors that contribute to an infant’s high birthweight, the continued exposure to an obesogenic environment that predisposes macrosomia may also have an effect on early infant growth patterns. Rapid weight gain is potentially modifiable if identified during early life. There is some evidence from randomised controlled trials that interventions delivered in infancy may reduce the risk of early child overweight. However parental beliefs on infant size have identified a preference for bigger babies and as such these beliefs may be barriers to engaging with interventions that could mitigate rapid weight gain.

Aims

1. To determine the prevalence of macrosomia in a representative sample of infants in Nottinghamshire.

2. To explore the relationship between social disadvantage and macrosomia.

3. To determine the prevalence of rapid weight gain in the first year of life.



4. To explore the relationship between social disadvantage and rapid weight gain in the first year of life

5. To explore the interaction between macrosomia and rapid weight gain in socially deprived areas.

6. To investigate whether infants who undergo rapid weight gain in the first year of life in deprived areas remain heavy at year two.

7. To explore the relationship between social disadvantage and rapid weight gain in the first year of life in low birth weight infants.

For infants born big and/or growing rapidly the aim for the qualitative study was: To explore parental beliefs around caring for infants with risk factors for child obesity with a view to informing the development of a targeted behaviour change intervention.

Results

The research cohort contained 8904 term infants, born to mothers registered with a Nottinghamshire General Practitioner. In an area with a high rate of child obesity, the overall prevalence of macrosomia in the 2008 Nottingham birth research cohort was 12.2%, the proportion of rapid weight gain (as an increase of >0.67in weight-for-age z score) infants was 29.7%. Male infants were found to have a 1.9 times increased risk of macrosomia and a 1.4 times increased risk of rapid weight gain compared to females. Asian ethnicity appeared to be protective for both macrosomia (54%) and rapid weight gain (30%) compared to White infants. Black ethnicity was associated with a three-fold increased risk of being overweight at aged two. There was a 30% increased risk of macrosomia for infants born in the moderately deprived area compared with the most deprived. Infants in the most deprived areas had only 1.2 times increased risk of rapid weight gain compared to the least deprived areas. In a small subsample n=36, infants born macrosomic in the most deprived areas, the risk of rapid weight gain increased more than two-fold compared to infants in the least deprived areas. Being classified as macrosomic at birth increased the infant’s chances of being overweight at age two by 3.9 times. Infants who grew rapidly in their first year also had an increased chance of being overweight at aged two by 2.4 times. From this study there appears to be little evidence that deprivation is associated with either macrosomia or rapid infant weight gain. The strongest predictors of child overweight at aged two were being born macrosomic and growing rapidly in the first year.

Twenty four parents of infants who were born big and/or grew rapidly were recruited to the qualitative study. Four key themes emerged from the thematic data analysis. Parents were unconcerned about their child’s high weight and justified high weight status with a variety of explanations including familial traits and that weight gain was believed to be positive and indicative of health. Parents’ understanding of feeding baby demonstrated a propensity for overfeeding and parents’ weaning decisions were heavily influenced by infant size with parents believing that bigger infants required earlier weaning.

Implications for practice

There is emerging evidence that responsive feeding is effective in reducing early childhood overweight. However rather than targeting responsive feeding interventions in accordance to socioeconomic status for which this research found no justification, focusing on those infants who were born big or growing fast may be more effective. In order to recognise those infants with a growth pattern of concern it is recommended that all infants are weighed at 4 months. This would allow the Health Visiting teams the opportunity to assess early childhood overweight risk based on growth trajectory. The study also identifies that further research is needed to facilitate communication between Health Visitors and parents with regard to preventing rapid infant weight gain and a checklist grounded in the parental beliefs of caring for infants at risk of early childhood overweight needs to be developed.

Conclusions

Macrosomia and rapid weight gain prevalence rates are high in this representative birth cohort. For infants who are born big, and/or grow rapidly their parents report behaviours that will maintain this situation. Whilst responsive feeding interventions have shown promise in mitigating rapid infant growth, there is a need to facilitate communication between Health Visitors and parents on preventing rapid infant weight gain, for these interventions to become effective.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Glazebrook, Cris Standen, Penny
Keywords:	Macrosomia; Infants; Weight gain; Social disadvantage; Obesity; Risk factors
Subjects:	W Medicine and related subjects (NLM Classification) > WD Disorders of systemic, metabolic or environmental origin
Faculties/Schools:	UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID:	55807
Depositing User:	Ashton, Deborah
Date Deposited:	19 Jul 2019 04:40
Last Modified:	07 May 2020 11:47
URI:	https://eprints.nottingham.ac.uk/id/eprint/55807

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