Obesity and bigger waist size is linked to moderate levels of a widely used chemical.

Jun 08, 2008

Hatch, EE, JW Nelson, MM Qureshi, J Weinberg, LL Moore, M Singer and TF Webster. 2008. Association of urinary phthalate metabolite concentrations with body mass index and waist circumference: a cross-sectional study of NHANES data, 1999-2002. Environmental Health 7:27.

Synopsis by Michael D. Laiosa

In a new study, scientists have found that higher levels of phthalates in people are associated with larger weight and waist circumferences in both men and women.

A common chemical known to interfere with hormones is linked to higher body mass index (BMI) and bigger waist circumference in both men and women. Individuals with midlevels of the phthalates had the largest increase in BMI. BMI changes were more moderate in individuals with the lowest and highest urinary phthalate levels. Obesity is becoming a national epidemic, and is associated with a number of life-altering diseases, such as diabetes, stroke and heart problems. These findings build on an earlier study that focused exclusively on adult males. Phthalates are ubiquitous chemicals found in many consumer products including child toys, cosmetics, medical equipment, medications and food packaging. Humans are exposed to phthalates through food and water, and they are commonly absorbed through the skin. According to animal studies, phthalates may cause certain forms of cancer and harm reproductive organs. Phthalates also are known to interfere with hormone regulation including thyroid hormones and sex hormones, both of which affect fat metabolism and obesity. In this national health and nutritional study, five different phthalates were measured in the urine and compared to BMI in different age groups of both males and females. The highest levels of phthalates were found in children. However, phthalates were associated with increasing BMI and waist circumferences at most ages and both sexes. Interestingly, several of the phthalates were associated with an inverse effect on BMI in those 60-80 years old. Also of note, several of the phthalates yielded non-monotonic or “inverted U” responses on BMI. Non-monotonic responses are commonly observed with chemicals that modify hormonally controlled responses.