You are what you earn: chemical body burden reflects socioeconomic status

Using data from the US National Health and Nutrition Examination Survey, a research team analysed possible links between a person’s socioeconomic status and the prevalence of chemicals in their body.

The team, led by Dr Jessica Tyrrell from the University of Exeter Medical School’s European Centre for Environment & Human Health, in Cornwall, found that people across the poverty spectrum were accumulating chemicals in their bodies but, importantly, that it was the type of toxicant that was dependent on economic status.

Dr Tyrrell and the team were not expecting their findings to contradict the conventional thinking that lower socioeconomic status will lead to a greater prevalence of harmful elements in the body: “We’ve found that as people become better off, changes in their lifestyle alter the types of chemicals in their bodies, rather than reducing the overall amount. This realisation has a profound impact on the way we treat chemical build-ups, suggesting we should move to dealing with groups based on lifestyle, rather than earnings.”

By comparing the results from six separate populations, the researchers have been able to show strong associations between 18 different chemicals and poverty ratings.

Individuals with higher incomes had larger amounts of several toxicants, including urinary mercury, arsenic, caesium and thallium, with diet likely to play a key role in their accumulation.

“The age-old adage of ‘you are what you eat’ seems to be true when explaining some of the trends we’re seeing in the data. It’s certainly very likely that fish and shellfish consumption is partially responsible for build-ups in mercury, arsenic and thallium,” says Dr Tyrrell.

The use of sunscreen was also found to be an important factor in the accumulation of benzophenone-3, with people from higher socioeconomic groups more likely to use products containing the chemical.

Those with lower incomes were more likely to have build-ups of urinary lead, cadmium, antimony and bisphenol A. Cigarette smoking and a poor diet were among the factors likely to lead to the build-up of both lead and cadmium in these groups.

“Long-term exposure to chemicals, even in very small quantities, can lead to a number of adverse health effects such as diabetes and cardiovascular disease. This study has produced a robust analysis of how the accumulation of these chemicals relates to socioeconomic status, giving us an important understanding that will help to inform strategies aimed at improving health,” Dr Tyrrell concludes.

The study Associations between socioeconomic status and environmental toxicant concentrations in adults in the USA: NHANES 2001-2010 has been published in the journal Environment International.

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