Social origins, early hardship and obesity: A strong association in women, but not in men?
Introduction
The role of early life exposures as determinants of adult health has been developed through two conceptual frameworks (Ben-Shlomo & Kuh, 2002). The latency or critical period model hypothesizes that certain experiences during childhood may have a permanent imprint in terms of individual biological or behavioral characteristics; alternatively, the pathway model hypothesizes that early childhood disadvantage initiates a chain of negative influences that lead to unfavorable socioeconomic conditions in adulthood, and thereafter elevate the risk of ill-health. In the lifecourse epidemiology literature, the finding that people having experienced poorer socioeconomic experiences during childhood are disadvantaged in terms of their health, and that this disadvantage remains after adjusting for adult socioeconomic position, is generally interpreted as an argument in favor of the first model, which emphasizes the intrinsic role of childhood conditions (Galobardes, Lynch, & Davey Smith, 2004).
Obesity is a health-related condition for which the critical period model of early life conditions is gaining ground in recent studies (Laitinen et al., 2001, Parsons et al., 1999, Power, 2002, Power et al., 2005, Power et al., 2003). There may be a behavioral explanation, if diet and exercise habits are set from childhood, or a biological explanation, if early deprivation entails permanent metabolic changes. Although both types of processes are likely to operate differently for men and women, there is limited consideration of gender in the epidemiological literature on obesity. Of the few studies which have documented gender differences in the contribution of early life conditions to adult obesity (Hamil-Luker and O'Rand, 2007, Heraclides et al., 2008, Langenberg et al., 2003), none has taken those differences as the main focus of empirical investigation. Evidence is needed to incorporate the gender perspective into the lifecourse epidemiology of obesity.
Most studies have assessed childhood socioeconomic conditions based on father's occupation (Laitinen et al., 2001, Parsons et al., 1999, Power, 2002, Power et al., 2003, Power et al., 2005), but some have added information on material deprivation during the period of upbringing as a predictor of adult health or mortality (Laaksonen et al., 2005, Laaksonen et al., 2007, van de Mheen et al., 1997). Both factors are of interest, but the specificity of the information on social origins as opposed to that on material hardship in terms of the biological versus behavioral processes involved needs to be clarified for a more thorough interpretation of the findings. Another indicator related to the household standard of living is mother's working status, whose impact on children's development is hard to predict: on one hand, mother's participation in the labor market provides additional material resources, while on the other hand, it may adversely affect children's cognitive maturation through reduced interaction with parents (Ermisch & Francesconi, 2001).
Further to childhood socioeconomic conditions, early family history is an aspect of early life which has been overlooked in lifecourse epidemiology. Parental splits may have consequences on children's well-being (Ermisch and Francesconi, 2001, Hill et al., 2001, Joshi et al., 1999), and childhood adversities were found to predict later eating disorders (Johnson et al., 2004, Thomas et al., 2008). Given the reciprocal relations between family break-ups and household resources (Jarvis & Jenkins, 1999), both dimensions must be considered simultaneously in order to elicit the intrinsic influence of early economic disadvantage.
The bulk of the evidence on the early life predictors of obesity originates from the United Kingdom, the Netherlands and the United States (Laitinen et al., 2001, Parsons et al., 1999, Power, 2002, Power et al., 2003, Power et al., 2005), but none from France, traditionally less concerned by obesity. And yet, the country is facing an “obesity crisis”, with rates rising at an alarming rate, from 5% in the age range 18–65 years in 1981 to 10% in 2003 (de Saint Pol, 2008). In addition, significant education-related inequalities in obesity have been found in France in comparison with other European countries, particularly for women (Mackenbach et al., 2008).
The purpose of this study was to investigate the childhood predictors of obesity in France with a gender perspective, based on the nationally representative 2003 Life History Survey. Special attention was given to assessing the specific roles of father's occupation, early material hardship, and family history during the period of upbringing, controlling for the influence of adult circumstances.
Section snippets
Survey design and study sample
The data of the Life History Survey were collected by the French National Institute for Statistics and Economic Studies (INSEE) in spring 2003 from a sample of 8403 individuals representative of the adult population aged 18 years and over living in private households in metropolitan France (Crenner, Donnat, Guérin-Pace, Houseaux, & Ville, 2006). The sample was drawn from the 1999 national census, with an over-representation of immigrants, people of immigrant descent and individuals aged under 60
Results
Men and women were similar in terms of obesity prevalence (about 10%) and most of the early life cycle variables (about 44% of the mothers were working, 9% had not always lived in an intact family, and 11% had experienced economic difficulties during childhood or adolescence), but there were significant differences with respect to father's occupation and to the adult life cycle factors (Table 1).
Among women, multivariate analyses (Table 2) restricted to early life cycle factors revealed a very
Discussion
This study is notable in many respects. First, to our knowledge, it is the first to explicitly analyse gender differences with respect to the role of early life conditions as predictors of obesity in a nationally representative sample. Second, it also incorporated different indicators of socioeconomic status during the period of upbringing and theorized the relevance of each in terms of the pathways under investigation. Third, it considered the role of early family history as a predictor of
Conclusion
We highlight in this study a distinct gender pattern with regard to the childhood predictors of obesity in a French national sample, and provide support for the critical period model of obesity for women, but not for men. Indeed, father's occupation and early economic hardship are found to independently influence the development of obesity in women, and we interpret this finding as reflecting the concurrent operation of behavioral and physiological pathways. The “habitus” hypothesis may be
Acknowledgements
We thank Arnaud Bringé, Annie Carré, Nicolas Razafindratsima and Daniel Ruffin for their valuable assistance in data management and analysis, Emmanuelle Cambois for her helpful comments on the first draft, and Catriona Dutreuilh for the English language editing. This research was funded by France's Ministry of Health (MIRE-DREES); “Exploitation de l'enquête Histore de Vie”.
References (68)
- et al.
The development of life course epidemiology
Revue d'Epidémiologie et de Santé Publique
(2007) - et al.
Early life programming of obesity and metabolic disease
Physiology & Behavior
(2008) Untying the Gordian knot of social inheritance
Research in Social Stratification and Mobility
(2004)- et al.
Systematic review of the influence of childhood socioeconomic circumstances on risk for cardiovascular disease in adulthood
Annals of Epidemiology
(2006) - et al.
The effects of childhood circumstances, adult socioeconomic status, and material circumstances on physical and mental functioning: a structural equation modelling approach
Annals of Epidemiology
(2007) - et al.
Family social class, maternal body mass index, childhood body mass index, and age at menarche as predictors of adult obesity
American Journal of Clinical Nutrition
(2001) - et al.
Socioeconomic position in childhood and in adulthood and functional limitations in midlife: data from a nationally-representative survey of French men and women
Social Science & Medicine
(2006) Nutrition and health outcomes associated with food insecurity and hunger
Journal of Nutrition
(1999)Childhood adversity still matters for adult health outcomes
The Lancet
(2002)- et al.
Childhood conditions that predict survival to advanced ages among Africans-Americans
Social Science & Medicine
(1998)