Organochlorine Compounds Linked to Obesity in Children

Summary
Over the past 30 years or so, the world has “seen dramatic increases in obesity prevalence in all age groups.” This recent study from Barcelona, Spain analyzed the association of organochlorine compound exposure before birth, with speedy weight gain and obesity in infants. In the study, levels of various organochlorine compounds were assessed in the first trimester of pregnancy, and the weight of the babies were measured at frequent intervals.  It was seen that exposure to organochlorine compounds within the womb is associated with rapid weight gain after birth.

Introduction
Studies in the past have identified chemicals which cause increased weight gain in children. Such chemicals, also termed obesogenic chemicals, include bisphenol A, organotins, tobacco, hexachlorobenzene, etc. This study was conducted to recognize the growth-promoting actions of organochlorine compounds such as dichlorodiphenyldichloro-ethylene (DDE), hexachlorobenzene (HCB), Beta hexachlorohexane (bHCH) etc. Growth hormone-mimicking properties of some of these organochlorine compounds were proven at the end of the study using various statistical methods, thus holding these chemicals responsible for undue weight gain in affected babies.

Methodology

  • A group of 657 women studied in this project, answered questionnaires at 3 months and 6 months of pregnancy, at delivery and at 6 and 14 months later. The questionnaires were designed to get information such as health status of mother, socioeconomic status, health of the father, country of origin etc.
  • Levels of organochlorine compounds were measured in the blood of the mother during the third month of pregnancy.
  • Weight and height of the baby was measured immediately after birth, throughout the next 6 months and again at 14 months.
  • The rate of weight gain was measured and correlated with levels of organochlorine compounds in the mother’s blood.
  • Results

  • In babies born to regular weight mothers, exposure to DDE during pregnancy was associated with a 2.4 times greater risk of rapid growth. This association was not seen in infants of women who were overweight at the time of pregnancy.
  • The speed of growth was much higher in boys than girls.
  • Rapid growth in the first 6 months of life was associated with a 5-times higher risk of obesity at 14 months of age.
  • Shortcomings
    In this study, maternal organochlorine compound assessment was performed only in the initial part of pregnancy. Levels of those compounds could have been estimated even at a later part of pregnancy, as there are many metabolic alterations during the later part of gestation. The sample size was modest; a larger group is necessary to confirm the findings of the present study. The infants’ growth was measured only up to 14 months; further follow-up of their growth is necessary.

    Conclusion
    This study proves that increased exposure of some organochlorine compounds during pregnancy is associated not only with faster growth of the child during the initial six months of life but also with increased chances of obesity later on. Organochlorine compounds, such as DDE, act at the genetic level to promote unusually high growth early in infancy and later. This study confirms the causal role of environmental pollutants like organochlorine compounds, especially DDE, in causing morbid diseases like obesity and other health hazards associated with them. The researchers state that, “More research exploring the potential role of chemical exposures in early onset obesity is needed.”

    For More Information:
    Association of Organochlorine Compound Exposure before Birth with Rapid Weight Gain and Overweight in Infancy
    Environmental Health Perspectives, October 2010
    By Michelle A. Mendez; Raquel Garcia-Esteban
    From the Centre for Research in Environmental Epidemiology, Barcelona, Spain
    The Municipal Institute of Medical Research, Barcelona, Spain
    CIBER Epidemiologia y Salud Pública (CIBERESP), Spain

    *FYI Living Lab Reports Are Summaries of the Original Research.
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