Environmental pollutant linked with overweight
In recent decades, there has been a sharp increase in the number of overweight children and adults in both Norway and worldwide. It is suspected that diet and exercise alone cannot explain this large weight increase.
Researchers suggest that the increasing levels of endocrine disrupters in the environment may be a possible contributing factor. Therefore, this study was established and discovered the following:
- Daughters of mothers with the highest concentrations of PFOA in the blood during pregnancy were three times as likely to be overweight at the age of about 20 years as daughters of mothers with the lowest PFOA levels.
- The calculations took into account many variables, such as maternal weight and lifestyle factors.
- An association was also found between PFOA exposure before birth and elevated levels of insulin and leptin, two hormones that are linked to obesity.
- Levels of insulin and leptin were also elevated in the sons of mothers with high PFOA, but the relationship was weaker than for girls.
- There was no increased risk of development of obesity among the sons.
What does this mean for us?
“It is still too early to say what this might mean for us. The study indicates that factors such as environmental pollutants, in addition to diet and physical activity, play a role in the obesity epidemic we see today. But this remains to be confirmed by similar studies,” says Line Småstuen Haug at the Norwegian Institute of Public Health.
“In the late 1980s the levels of PFOAs and other PFCs in Norway were similar to the Danish study, which makes the findings also relevant for Norway. It is also important to note that the levels of several of these environmental pollutants in the blood of Norwegian women have decreased significantly since about 2000. However, this does not apply to all the substances and so we should try to limit our exposure to persistent pollutants to reduce the risk of adverse health effects,” says Småstuen Haug.
About the study
In 1988-1989, around 1,000 pregnant women in Aarhus, Denmark were recruited for a study where a sample of blood of women in week 30 of pregnancy was collected and frozen. In 2008-2009, the children from these pregnancies were contacted and asked to participate in a follow-up study in which, for instance, body mass index and waist circumference were recorded.
Approximately 650 of the children agreed to participate. Employees at the Norwegian Institute of Public Health analysed the levels of a variety of PFCs in the mothers' blood.
PFOA belongs to a group of environmental pollutants known as per-and polyfluorinated compounds (PFC). These compounds are used or have been used in a variety of consumer products and industrial processes such as impregnation, textiles, carpets and fire-fighting foam. Concerns about the use of these substances arose at the millennium as one of the substances, perfluorooctyl (PFOS), was found to be ubiquitous in wildlife and human populations worldwide.
Studies have shown that food is the major source for most of us, but that the indoor environment can be an important source for others. PFCs are transferred from mother to child through the placenta during pregnancy and in breast milk after birth. Many of the PFCs are persistent and can harm living organisms, which means they must be considered as environmental contaminants.
Halldorsson TI, Rider D, Haug LS, Bech BH, Danielsen I, Becher G, Henriksen TB, Olsen SF. Prenatal Exposure two Perfluorooctanoate and Risk of Over Weight at 20 Years of Age: A prospective cohort study. Environmental Health Perspectives. DOI: dx.doi.org/10.1289/ehp.1104034.