Nutritional and other influences in childhood as predictors of adult obesity

Abstract

It has been proposed that there are critical periods during childhood that influence the development of obesity, including gestation and early infancy, the period of adiposity rebound that occurs between ages 5 and 7 years, and adolescence. Despite an extensive literature, there is to date only modest evidence for most of the factors such as nutrition, physical activity and other behavioural factors that are suspected as playing a role in the development of obesity. A recent review of this evidence (Parsons et al. 1999) showed, however, a consistent relationship between socio-economic status (SES) of origin and adult obesity, whereby those from lower SES backgrounds were fatter subsequently in adulthood. This association appeared to apply to both men and women, a finding that contrasts with the trends observed in cross-sectional studies, of an association with SES for women only. There are several potential explanations for the SES of origin-adult obesity relationship. SES of origin may be confounded by parental body size; studies to date provide insufficient evidence of an independent association with SES after allowing for parental body size. Alternatively, environment in early life (for which SES of origin is a proxy measure) may have a long-term impact on obesity later in adulthood, through one or more of several processes. Three major potential explanations can be identified: (1) nutrition in infancy and childhood, either over-or undernutrition, followed subsequently by overnutrition; (2) psychological factors, possibly involving emotional deprivation in childhood; (3) cultural or social norms regarding dietary restraint and attitudes to fatness that may be acquired during childhood.Obesity: Socio-economic status: Longitudinal studies: Behaviour SES, socio-economic status.Increasingly, we are appreciating that risk factors occurring in adult life provide insufficient explanation for adult health outcomes, and that factors occurring at different life stages need to be considered. To some extent this life-course approach is better established in obesity research than in other areas, but even here the role of childhood factors is not well understood. Potentially, there are several early life factors that might be involved in the development of obesity in adulthood (Parsons et al. 1999). To date, the best documented relationships are between parental size and adiposity in their offspring, and between childhood and adult fatness . Evidence is less complete for other factors, such as childhood diet and physical (in)activity, and it is not clear whether these factors influence adult obesity because of their effect on behaviours in adulthood.Unravelling the different life-course relationships involved in the development of obesity will be challenging, since the influence of different factors could be affected by their timing and duration, and also whether other cofactors are present. For example, in relation to timing of exposure, a factor occurring in early life may create biological and/or psychological vulnerabi...

Childhood poverty and abdominal obesity in adulthood: a systematic review

“…Brazilian studies found a direct association between childhood socioeconomic status and BMI in late adolescence and early adulthood in men 24,25 , and an inverse association in women 44 . Thus, although the results of cross-sectional studies are subject to reverse causality -whereby obesity can determine current socioeconomic status rather than vice-versa 4,6,8,28,30 -, the transition process described above is consistent with our finding of clearer associations in women than in men for the effects of early poverty. This long-term effect on abdominal obesity appears not to result only from persisting socioeconomic adversities in adulthood, since based on the results of the present review, current socioeconomic status was a partial mediator in the associations.…”

“…The arrows in the figure indicate the possible causal mechanisms. The most distal determinant is the inheritance of genetic characteristics, which supposedly affects the model's other components, including intra-gestational maternal adiposity, as well as the child's intrauterine and post-natal life 3,23,28 . Genetic load can also influence the parents' socioeconomic status, as in the case of discrimination against black 29 or obese individuals 30 .…”

“…In the second hierarchical level, parents' socioeconomic status can also affect lifetime adiposity 4,6,7,8,23 . This effect is supposedly mediated by the family's nutritional habits and physical activity, the child's disease history (particularly that of infectious diseases), and the individual's own socioeconomic status in adulthood 3,23,28 . This model suggests that controlling for genetic factors, if possible, would be justified by the possibility that such factors are influencing both socioeconomic level and nutritional status.…”

Increasing activity and improving nutrition through a schools-based programme: Project Energize. 1. Design, programme, randomisation and evaluation methodology

“…Social-ecological models have been developed allowing an understanding of potential contributing factors impacting on both activity (16) and nutrition (17) . There appear to be critical periods in childhood where adverse factors are associated with higher levels of adult morbidity and mortality, and these may present opportunities for positive intervention (18)(19)(20) .It has been argued that a comprehensive throughschool programme in partnership with health promotion services, with curricular, co-curricular and extracurricular elements, would be more likely to succeed. Interventions in both the school setting and the family setting have been proposed, and single-intervention trials in both settings have been evaluated with limited success (21) .…”

“…Social-ecological models have been developed allowing an understanding of potential contributing factors impacting on both activity (16) and nutrition (17) . There appear to be critical periods in childhood where adverse factors are associated with higher levels of adult morbidity and mortality, and these may present opportunities for positive intervention (18)(19)(20) .…”