Washington, Oct 9 : Researchers from Oregon Health & Science University have discovered that the size and shape of a woman’s hips is strongly associated with her daughter’s risk of developing breast cancer.

In a study of 6,370 women, Dr. David J.P. Barker and Dr. Kent Thornburg have shown that wide round hips represent markers of high sex hormone concentrations in the mother, which increase her daughter’s vulnerability to breast cancer.

A woman’s hips are shaped at puberty when the growth of the hipbones is controlled by sex hormones but is also influenced by the level of nutrition. Every woman has a unique sex hormone profile, which is established at puberty and persists through her reproductive life.

The researchers claim that their study is the first to show that the pubertal growth spurt of girls is strongly associated with the risk of breast cancer in their daughters.

During the study, they followed up on 6,370 women born in Helsinki from 1934 to 1944, whose mothers’ pelvic bones were measured during routine prenatal care.

It was found that breast cancer rates were more than three times higher among the women in the cohort, born at or after term, whose mothers had wide hips. The risk was more than seven times higher if the mothers had already given birth to one or more children.

The study found that a woman’s vulnerability to breast cancer was greater if her mother’s “intercristal diameter” – the widest distance between the wing-like structures at the top of the hip bone – was more than 30 centimeters, or 11.8 inches. The risk also was higher if the wing-like structures were round.

The breast cancer risk was 2.5 times higher for the daughters of women in whom the widest distance was more than 3 centimetres greater than the distance at the front.

The study proposes that breast cancer is initiated in the first trimester of a pregnancy by exposure of the embryo’s developing breast tissue to the mother’s circulating sex hormones. The primary mammary cord, which gives rise to milk producing breast lobules, develops in the foetus at 10 weeks. The foetal breast is known to be stimulated by circulating hormones; the intensity of the stimulation is such that half of all newborn babies have breast secretions.

“Our findings support the hypothesis that wide round hips reflect high levels of sex hormone production at puberty, which persist after puberty and adversely affect breast development of the daughters in early gestation,” the authors said.

They further said that they could only speculate on the exact nature of this adverse effect but pointed out: “Catechol estrogen, a metabolite or estradiol, is thought to cause chromosomal instability by breaking DNA strands. High catechol estrogen concentrations in the maternal circulation could produce genetic instability in differentiating breast epithelial cells, which would make the breast vulnerable to cancer in later life”.

The findings also shed new light on the link between breast cancer and nutrition.

“Mothers whose daughters developed breast cancer were of similar height to the other mothers,” Barker and Thornburg said.

“This suggests that they had similar nutrition through childhood. Our findings do not therefore indicate that good nutrition through childhood is linked to breast cancer in the next generation. But they do show that the pubertal growth spurt of girls, which reflects the level of nutrition, is strongly associated with the risk of breast cancer in their daughters,” they added.

The study carried out by researchers with colleagues in Finland and the United Kingdom, is published online by the peer-reviewed American Journal of Human Biology. (ANI)