Three-year-old boys are more likely to have a shorter anogenital distance when their mothers have high levels of phthalates in their urine, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). In girls, the direct exposure to phthalates was associated with a shorter anogenital distance. The findings highlight how exposure to environmental pollutants can cause alterations in genital measurements during the first three years of life, which may affect sexual development and fertility later in life.
Phthalates are a large group of man-made chemicals widely used in everyday consumer products, such as household cleaners, food packaging, toys, cosmetics and personal care products. These endocrine-disrupting chemicals (EDCs) can interfere with our body's natural hormones and could have harmful health effects, including sexual development in children. For example, boys who are exposed to phthalates prenatally have been shown to develop genital defects, which could lead to infertility. Anogenital distance — the distance between the anus and genitals — is used as a marker of reproductive health related to hormone levels, lower semen quality, fertility and reproductive disorders.
In this study, researchers from the University of Modena and Reggio Emilia in Italy collected urine samples and anogenital distances from 188 children — at birth, 3 months, 6 months and 3 years — and from their 188 mothers, after giving birth and when their children turned 3 years old. They analysed these samples for 8 major phthalate metabolites and found that all of them were detectable in every sample in mothers and children, progressively increasing as time passed. In fact, most children and their mothers exceeded the newer and more conservative risk threshold for phthalate exposure.
In addition, the researchers found that maternal phthalate exposure impacted only boys, in which 3-year-old boys had a shorter anogenital distance. In contrast, anogenital distances of 3-year-old girls were affected by their own exposure to phthalates and the higher the exposure, the shorter the measurements were.
"We were surprised to find such high exposure for those phthalates which are currently less restricted. Bearing in mind that the cut-off levels for the anti-androgenic effect are dropping considerably, being exposed to these substances daily may indeed represent a major health risk for the younger generation in the long term," said Dr Laura Lucaccioni, lead author of the study. "Preventive public health measures to protect vulnerable groups are needed."
Dr Lucaccioni added: "The eight phthalate metabolites studied in our work can be found in a wide range of everyday products, including toys, make-up products and soaps, among others. The key priority is to check the origin of our daily-use products and implement straightforward protocols to minimise exposure."
"Our findings in boys suggest that both prenatal and family environmental exposure may significantly impact their sexual development. For girls, exposure to phthalates may play a role in other hormonal mechanisms. However, our study's sample size is small so we cannot firmly state that there are indeed differences between boys and girls, but we do establish that both may be affected by these endocrine disruptors," said Dr Lucaccioni.
The researchers plan to continue monitoring the population in their study and assess phthalate exposure and anogenital distances at pre-school age and around the time of puberty. "By continuing to monitor the population over time, we expect to identify the endocrine effects of prolonged exposure to phthalates, such as puberty disorders," said Dr Lucaccioni.
