Abstract
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Dramatic
increases in the prevalence of overweight and obesity have prompted a focus
on prevention. Weight is known to have a strong genetic basis, but the speed
of change in rates of overweight and obesity against a relatively stable gene
pool suggests that exposure to an 'obesogenic' environment is important. The
home environment is thought to play a key role in early weight trajectories,
providing an avenue for long-term obesity prevention. There is evidence for
associations between various aspects of the home environment and
energy-balance behaviours; however, evidence for associations with weight is
limited, particularly in early childhood. Few studies have used
comprehensive, psychometrically-tested measures of the home environment, and
no studies have tested for gene-environment interaction in the home context.
This thesis uses data from the Gemini twin cohort to further examine the role
of the home environment. Study one describes the development of a
comprehensive measure of the home environment in early childhood, including
the quantification of the extent that the home is likely to be obesogenic.
Study two explores the utility of a novel tool called SenseCam to examine and
validate aspects of the home environment measure. Study three identifies a number
of maternal characteristics associated with the obesogenic quality of the
home environment. Study four shows associations between the obesogenic
quality of the home environment and energy-balance behaviours; while study
five finds no association with weight. Findings from study six highlight the
role of gene-environment interaction, showing that the heritability of weight
is higher among children living in home environments with greater obesogenic
potential. Overall, the findings of this thesis further understanding on how
the home environment contributes to the development of overweight and
obesity. Implications, limitations, and avenues for future research are
discussed.
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