Reacción a "Grandparents' exposure to environmental chemicals could influence their granddaughters' first menstruation"

A study links the age of menarche with the exposure of grandparents and parents to environmental pollutants that disrupt the endocrine system, demonstrating the intergenerational transmission of these environmental risks to reproductive health.

In recent decades, there has been a global advance in the age of puberty in girls (between one and two years since the beginning of the 20th century), as well as in the age of the milestones that define it, namely the onset of thelarche (breast budding) and menarche (first menstruation). This advance may have important implications in later stages of life, increasing the likelihood of mental health problems, cardiometabolic diseases and even cancer.

Although there is no single reason behind this advance, the research group led by Dr Barbara Cohn of the Berkeley Public Health Institute in California suggests that exposure to environmental chemicals capable of disrupting the endocrine system (Endocrine Disrupting Chemicals, EDCs) may be behind earlier puberty.

The researchers used data from the ‘Study of Child Health and Development,’ a prospective birth cohort of pregnant women that began in the 1960s, who were followed along with their daughters (247 girls, born around 1963) and granddaughters (139 girls, born around 1990).

They measured exposure to different environmental pollutants in blood samples collected from the three generations. Specifically, they looked at 250 pairs (parents) from the first generation, 247 daughters from the second generation, and 139 granddaughters from the third generation. The results showed that, although the age of menarche remained stable between the first and second generations, it was brought forward by a full year in the third generation, and that this advance was associated with certain endocrine-disrupting chemicals present in the blood of both mothers and fathers.

This research highlights the importance of reducing exposure to endocrine-disrupting chemicals during conception and pregnancy, but above all the lasting impact of these environmental exposures on reproductive health across generations.

The study adds another point of interest that has not been sufficiently addressed until now: the relevance of paternal exposure and not just that of the mother who conceives. The researchers observed, for example, that exposure to phenoxyethanol, a common preservative in personal hygiene products and also in food, was associated with earlier puberty when both parents had been exposed, but the influence of the father was even greater.

This is therefore one of the first population studies to highlight the role of paternal and grandpaternal exposures in the reproductive development of their daughters and granddaughters, supporting the role of epigenetic inheritance.