It is incredibly difficult – if not impossible – to base the diagnosis of breast cancer on a specific cause. In reality, there are several different factors that can be combined to increase the risk such as a family history of cancer or a -specific genetic mutation as well as smoking and alcohol consumption. However, a new study suggests that delivery may increase the risk. This is understandably frightening, so we decided to dig deeper and put everything into context.
The study, published in the Annals of Internal Medicine on Monday, found an interesting link between a woman's breast cancer risk and whether she had given birth or not. But as usual this is much more complicated than it seems.
The results showed that women under the age of 55 had a slightly higher risk of developing breast cancer during the study.
The study Data from 889,944 women younger than 55 years contained data from 15 previous international studies conducted as part of the premenopausal breast cancer collaboration group. At the beginning, none of the women examined had breast cancer. Examining their long-term data, the researchers found that 18,826 of them (2 percent) contracted breast cancer during their studies.
They also found that women who gave birth were at greater risk of developing breast cancer compared to women who had never given birth. This increased risk peaked about five years after birth before it began to decline, and after 24 years, the risk of developing breast cancer was actually lower in births than in those who did not.
One thing to mention here is that the researchers used a measure called "hazard ratio" to calculate the risk of breast cancer in one group compared to the other, which is not a measure of the absolute risk. Overall, the risk of breast cancer in both groups is still low, as is the risk appetite among women who have children: women who gave birth had a 2.2 percent chance of being diagnosed with breast cancer at the age of 50, compared to 1.9 percent chance among those who did not give birth. So it's a difference of 0.3 percent.
In addition, the risks differed depending on the type of cancer that a participant had. The rate of ER-positive tumors that developed (ie, the tumor cells have estrogen receptors and can use the hormone to grow, Mayo Clinic ), which accounted for 76 percent of all cancers in the study, was similar to that Overall results of the study. On the other hand, although ER-negative cancers also peaked in the first few years after birth, before declining slightly, the rate of these cancers never went so far that children were associated with a kind of protective effect.
It's easy to see these results and assume that children somehow produce cancer, that's not really what the study suggests.
"This research is important because it shows that breast cancer risk factors for young women may differ from the risk factors for older women," says Hazel B. Nichols, co-author, lecturer in epidemiology The UNC Gillings School of Global Public Health, and the fact that the study contained data for such women A large group of participants is impressive.
But "should not raise an alarm," says Nichols. "Even with the increase we've seen, the overall risk of breast cancer for women in this age group is still low."
Plus, this was an observational study, meaning that it was able to show a connection between two things, but not what caused that connection. The study was not designed to analyze the specific factors responsible for this increased risk, but it is unlikely that it is actually the birth that is to blame. Janie Grumley, director of the Margie Petersen Breast Center at Providence Saint Johns Center and associate professor of surgery at the John Wayne Cancer Institute in Santa Monica, California, says SELF.
"For example, weight gain could be a factor," she says. "Patients within those first few years after birth tend to have more body weight, and increased adipose tissue and obesity increase a woman's risk of developing breast cancer." (That is, considering obesity as a risk factor for cancer, also complicated in its own way.)
An important limitation of this study is that only data for participants under the age of 55 were recorded. Considering the fact that breast cancer diagnoses become more common than we age (most are diagnosed over 50 years ) The study excludes many people who actually belong to the most ill diseases, and instead considers only a small piece of women who are already very unlikely to have breast cancer.
Also noteworthy: most research shows that the risk of breast cancer is higher overall in people who have never been pregnant and have never been breastfed.
Previous research has found that the risk of developing breast cancer is higher in women who did not give birth than in births. Breastfeeding (especially for at least one year ) as well as the first child you had in your life (in your twenties instead of your thirties) were previously associated with a reduction in breast cancer risk. In an older study frequently cited women who have their first child before the age of 20 have about half of the risk of breast cancer, as do those who have no children. More Recent research (published in 1996) suggests that a child over the age of 24 can reduce the risk of breast cancer throughout a person's life.
The mechanism of these relationships is believed to be at least partially related to exposure to reproductive hormones (estrogen and progesterone) produced by the ovaries, according to the National Cancer Institute . It is believed that factors that increase exposure to these hormones increase the risk of breast cancer. This includes staying longer between the first period and menopause, as you have more menstrual cycles throughout your life and therefore feel more exposed to those hormones. Conversely, pregnancy and breastfeeding stop the menstrual cycle for a while, reducing exposure to these hormones and are thought to lower the risk of breast cancer.
Why should this new study have such side effects? contradictory results? Again it could be the age of the women in the study. This study found a protective effect, but only after decades – and after a period of increased risk – occurred. In this study, the birth of a child was associated with a lower risk of breast cancer about 24 years after birth, and the risk of breast cancer was about 23 percent lower in women who had children 35 years after birth. "So if you have children in their thirties, for example, there are benefits in your 60s when breast cancer becomes a more general diagnosis," she says. However, due to the age group included in the study, this is an effect that only begins to show. (Earlier studies dealing with the Child Protection Association also included women in their 60s and 70s).
In addition, the protective effect on women with breast cancer was not as strong in the family. to point out that having children is probably not the most important factor in determining your cancer risk. Although the risk factors for early onset of breast cancer are not fully understood, those who were previously diagnosed tend to have a family history of the disease or a BRCA gene mutation (19459050) are strong risk factors for the disease in general, regardless of their occurrence).
Instead of worrying about the results of this one study, experts recommend keeping in mind the known risk factors for breast cancer.
Lifestyle factors, such as your diet and physical activity, as well as age, genetics, a family history of breast cancer, and an early onset of your period, says the American Cancer Society (1945S054) (ACS). "Breast cancer risk is not determined by a single cause, but by many different factors in a woman's life," says Nichols. "Our research confirms that these factors may have a different relationship to the risk of cancer sooner or later in life."
And of course, these results should not decide when you choose to have children. "I would never tell patients if they should decide whether to have a child based on this study." Grumley. If you are worried about your breast cancer risk, Dr. Grumley's ACS Recommendations to guide a healthy lifestyle. First of all, it is important to know your risk factors and to work with your doctor's doctor to find out a screening plan that makes sense for you.