Obesity and breast cancer: how are they linked

In recent years, interest has grown in the relationship between obesity and cancer. Increasingly, obesity has been identified as a significant risk factor for many cancers and, after tobacco use, may be the single greatest modifiable cancer risk factor.

For breast cancer, a clear association between obesity and disease risk seems to have been established (mostly in post-menopausal women).

Studies of body mass index (BMI) and breast cancer risk have found that postmenopausal women whose BMI falls in the obese category have about twice the breast cancer risk of women with a BMI in the normal weight category.

The relationship of obesity to breast cancer is complex and may be modified by other risk factors including menopausal status, use of postmenopausal hormones, drinking alcohol, age, genetics, and physical activity.

Obesity before menopause has been related to a weak decrease in premenopausal breast cancer risk while obesity after menopause has been related to a moderate increase in postmenopausal breast cancer.

A study on 15,000 black women found that being overweight or obese increased a woman’s risk of cancer by 31 percent. That risk doubled among women who had a healthy body weight in their early 20s and gained most of their weight during adulthood.

Losing weight after menopause may help lower risk of breast cancer.

One large study found women who lost 4 to 11 pounds after menopause had more than a 20 percent lower risk of breast cancer compared to women whose weight did not change.

Body shape may also affect breast cancer risk. Some findings show women who put on extra weight around their middles (“apple-shaped”), as opposed to their hips and thighs (“pear-shaped”), have a small to moderate increased risk of breast cancer.

Precautions

1. Know your risk  by learning about your family health history and consulting your health care provider about your personal risk of breast cancer.

2. Get screened

By your health care provider about the right screening tests.
Have a mammogram every year starting at age 40 if you are at average risk
Have a clinical breast exam at least every three years starting at age 20, and every year starting at age 40

3. Know what is normal for you and see your health care provider if you notice any breast changes: Lumps, hard knot / thickening inside the breast or underarm area /Swelling, warmth, redness or darkening of the breast…

4. Make healthy lifestyle choices

- Maintain a healthy weight
- Add exercise into your routine
- Limit alcohol intake
- Limit menopausal hormone therapy (postmenopausal hormone use)
- Breastfeed, if you can

Researchers estimate that overweight and obesity are behind around 17,000 cases of cancer each year in the UK. This number may well increase in the future since the number of people who are overweight is increasing.

Studies have found that:

• Putting on 2-10 kg after the age of 50 increases the risk of breast cancer by 30% .
• Putting on 25 kg after the age of 18 increases the risk of breast cancer by 45%.

Menopausal status modifies the association of obesity and the risk of breast cancer:

	Risk Of Premenopausal Breast Cancer	Risk Of Postmenopausal Breast Cancer
Women Who Are Obese Before Menopause	Moderate Decrease	Moderate Increase (if weight is retained)
Women Who Are Obese After Menopause	(Does not apply)	Moderate Increase
Women Who Gain Weight During Adulthood	Moderate Decrease	Moderate Increase

Prevention of weight gain is a critical first step toward dealing with obesity and breast cancer risk reduction.

Current and future research should focus on the clarification of mechanisms and the determination of whether prospective interventions might alter risk.

There is also a myriad of non-clinical factors that must be considered when attempting to relate obesity to outcomes after cancer, including race/ethnicity, socioeconomic status, health behaviors, and energy balance/nutrition, among others.

We cannot change genetics or family history, but we alter obesity by eating smaller potions, choosing healthier foods and being more active to lower breast cancer risk and other illnesses.

 Source: watchfit.com

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