How many times have children heard, "Look how tall you've grown over the summer!" While such comments may be annoying, it turns out rapid growth might also be a health hazard. A new study finds that growth spurts in women may put them at risk for breast cancer later in life.
Danish researchers followed almost 120,000 women born between 1930 and 1975, whose health was monitored closely by a school in Copenhagen. By the mid-1990s, 3300 of the women had been diagnosed with breast cancer.
The scientists found that women who grew rapidly in height between the ages of 8-14 were at increased risk of developing breast cancer later in life. They think growth factors responsible for the accelerated growth may also speed breast development, causing genetic mutations that cannot be repaired by the body.
The researchers concluded a woman's eventual height following puberty did not appear to increase her breast cancer risk.
Karin Michels, an epidemiologist at Harvard Medical School in Massachusetts, says this study is different from others.
"In our research, we have often looked later life risk factors; what women do when they are grown up, what do they eat, do they exercise? What these researchers do is they look earlier in life. And that is a trend that is now happening in breast cancer research. We are appreciating that breast cancer can originate earlier in life," she said.
Professor Michels commented on the study, which is published this week in the New England Journal of Medicine.
Experts speculate that diet is probably responsible for children's growth spurts, including the consumption of cow's milk. Researchers say it may one day be possible to prevent breast cancer by identifying and limiting foods that might cause girls to grow rapidly.