In an article published on May 5, 2014 by the news provider Environmental Health News (EHS), journalist Lindsey Konkel reports on new research linking phthalates and bisphenol A (BPA) to slight weight gains in women (Song et al 2014). Epidemiologists from Harvard and Brown University, both U.S., compared urinary phthalate and BPA levels of 977 women from the Nurses’ Health Study (NHS) to self-reported weight gains over a 10-year period. Spot urine samples were provided between 1996 and 2002. The researchers report that women in the highest quartile of BPA exposure gained around 0.23 kg more weight per year than women in the lowest exposure group. Also phthalic acid, monobenzyl phthalate, and monobutyl phthalate levels were associated with prospective weight gain. Body weight at the beginning of the study was not correlated with chemical burden of BPA and phthalates. In the EHN article, the researchers contend that self-reporting of weight may have introduced bias and that the single spot urine measurement may not accurately characterize long-term chemical burden. However, single spot urine levels can reflect a pattern of exposures as people often have stable behaviors. Qi Sun, Assistant Professor at the Harvard School of Public Health and senior author of the study, considers the strong pattern highly suggestive irrespective of only one spot measurement. Further, prospective cohort studies are considered the ‘gold standard’ in epidemiology, Konkel asserts. The study is the first to monitor weight changes in relation to BPA exposure over time. Previous studies observed that people with higher body weight also have a higher BPA burden.
Lindsey Konkel (May 5, 2014). “Household chemicals linked to slight weight gain.”
Song, Y. (2014). “Urinary concentrations of bisphenol a and phthalate metabolites and weight change: a prospective investigation in US women.” International Journal of Obesity (published online April 11, 2014).