It is time to bring our focus back to lowering the risk or reducing the onset of new cases of breast cancer at all ages. Worldwide incidence of the disease is rising as societies across the globe modernize, which brings with it higher rates of breast cancer risk factors, such as overweight, lack of physical activity, and key reproductive factors like beginning families later in life and have fewer children.
While modernization has many important benefits, it is also directly driving up the risk of breast cancer. Globally, one in every four new cancers diagnosed in women is breast cancer, and over 1.7 million new cases are diagnosed each year.
We need a global breast cancer prevention strategy – now.
We currently understand how the longer interval from first menstrual period (menarche) to first baby increases lifetime risk for beast cancer. This interval has expanded over centuries in Western Europe following the Industrial Revolution, and – in dramatic fashion – over just a few decades in Asian countries. Data from China and Korea show a rapid decline in age at first menstrual period since World War II, as well as a decline in number of children, which has accelerated. The age women have their first babies is now above the Organization for Economic Cooperation and Development (OECD) average of 28 years old. This means that a typical woman has 16 or more years between her first period and her first baby (first birth at 28 minus first period at 12 years of age). In 1950 in China, this interval was just three years (first birth at 19 minus first period at 16).
Given these social movements, are there approaches early in life that can help mitigate the impact of these changes in reproductive factors? It appears so.
We, and others, have studied diet and physical activity as two key aspects of lifestyle, and then alcohol intake in later adolescence and early adult life.
- Eating a diet high in fiber and vegetable protein is related to significantly lower risk of both premalignant breast lesions and breast cancer.
- Being more physicaly active from ages 12 to 22 is powerfully protective against breast cancer.
- Avoiding alcohol before first pregnancy is strongly protective against both benign breast lesions and invasive breast cancer.
Together, we need to work to improve diet in children, adolescents, and young adults – fostering access to, and consumption of, fruits, vegetables, and whole grains – as well as reducing alcohol intake among women under age. Especially for high school- and college-aged women, we must create an environment that encourages less alcohol intake. Also important is sustaining physically active lifestyles through the adolescent and early adult years, which has both immediate and long-term benefits.
Multifaceted approaches are needed to achieve such behaviors across a broad set of the population, but doing so will have lasting benefits, not only for breast cancer but also colon cancer, heart disease, stroke, as well as mental health. Momentum in this direction can take time to gather, but is achievable and important, and can have a positive impact for generations to come.
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Colditz GA & Bohlke K. Priorities for the Primary Prevention of Breast Cancer. CA. DOI: 10.3322/caac.21225