DDT exposure linked to an increased risk of breast cancer in all women up to the age of 54

A six-decade study revealed a 40-year induction period between time of exposure and diagnosis

All women exposed to high levels of DDT are at increased risk of bad cancer up to the age of 54, but the timing of the cancer risk depends on when they were exposed for the first time times, according to a new study published today in the Journal of the National Cancer Institute. Women exposed before age 14, especially in early childhood and early life, were the most likely to develop bad cancer before menopause, while those exposed after early childhood were at increased risk of developing cancer. later, between 50 and 54 years old.

"What we've learned is that timing really matters, we know that if harmful exposures occur at times when the bad tissue is changing rapidly, such as during puberty, they have an impact. on bad development so as to eventually cause cancer, "said lead author Barbara A. Cohn, Ph.D., studies on health and child development at the Institute of Health public. "The research published today suggests that DDT influences bad cancer as an endocrine disruptor, that the time between first exposure and the risk of cancer appears to be about 40 years – and that d & # 39; Other chemicals that disrupt the endocrine system could potentially simulate this type of risk. "

In the United States, many women and girls were exposed to DDT in the mid-20th century, while the pesticide was widely used – the youngest of them reaching the age of increased risk of bad cancer. DDT was banned by many countries in the 1970s, but it remains widespread in the environment and continues to be used to control malaria in Africa and Asia.

The researchers found that:

• The first exposure of a woman to p, p -DDT was badociated with the time of bad cancer diagnosis, occurring about 40 years later.
• A doubling of DDT was badociated with an almost three-fold higher risk of postmenopausal bad cancer (50 to 54 years) for women exposed for the first time after childhood.
• Women with an increased risk of bad cancer before menopause (before age 50) were exposed to DDT for the first time during the in utero period and during infancy during puberty, but not after 14 years; the highest risk was badociated with the first exposure before the age of 3 years.
• DDT exposure during childhood and puberty (aged 3 to 13 years) was a risk factor for early (before age 50) and later (elderly) bad cancer from 50 to 54 years old).
• Women who were exposed for the first time after the age of 14 had only an increased risk of bad cancer after menopause (between 50 and 54 years old). These women had no increased risk of bad cancer until they were 50 years old.

"Although there have been numerous studies on the environment and bad cancer, only a very small fraction actually measured environmental exposures during periods of susceptibility, in this case at an early age and before menarche, "said Mary Beth Terry, PhD, author of the study. , Professor of Epidemiology and Environmental Health Sciences at the Columbia University Mailman School of Public Health and the Herbert Irving Comprehensive Cancer Center. "Studies that measured environmental exposures during periods of susceptibility, like our study, are much more consistent in supporting a positive badociation with the risk of bad cancer," said Terry.

A 2007 study on maternal bad cancer as part of PHI's Health and Child Development (CHDS) studies looked at exposure windows, but only diagnoses of cancer before the age of 50. 50-54, when most women have recently completed menopause.

This study followed 15,528 women attending CHDS for nearly six decades, following the age of first exposure to DDT, DDT levels during pregnancy, and the age of bad cancer diagnosis. To determine levels of exposure to DDT, the researchers badyzed stored blood samples that had been collected from 1959 to 1967 during pregnancy, each quarter, and early postpartum. Researchers used official records to identify 153 cases of bad cancer diagnosed from 1970 to 2010 in women aged 50 to 54 years. They then compared each of these cases with highly comparable control women who did not develop cancer. The previous 2007 study used the same methods, comparing 129 bad cancer cases diagnosed from 1962 to 1994 among women aged 50 and over to comparable controls who did not develop cancer.

"As you travel through life, your risk periods are changing," said Cohn. "Given the trends we have observed, working backwards to determine when a woman came into contact with the chemical could help inform early detection and treatment of DDT-badociated bad cancer."