Metabolic Syndrome Independently Linked to Breast Cancer

(HealthDay News) — Metabolic syndrome (MetS) and obesity have independent and distinct associations with breast cancer subtypes and mortality, according to a study published online May 13 in Cancer.

Rowan T. Chlebowski, M.D., Ph.D., from The Lundquist Institute in Torrance, California, and colleagues examined the associations of MetS and obesity with postmenopausal breast cancer. The study population included 63,330 postmenopausal women without prior breast cancer and with normal mammogram, who had an entry MetS score (0, 1 to 2, 3 to 4), which included high waist circumference, high blood pressure, high-cholesterol history, and diabetes history.

The researchers found that after adjustment for body mass index, a higher MetS score was associated with more poor-prognosis, estrogen receptor (ER)-positive, progesterone receptor (PR)-negative cancers after more than 20 years of follow-up (hazard ratio, 1.47 for 3 to 4 versus 0), with increased breast cancer mortality and more deaths after breast cancer (hazard ratios, 1.44 and 1.53 for score of 3 to 4 versus 0). In analyses adjusted for MetS score, obesity status was associated with more good-prognosis ER-positive, PR-positive cancers and with a higher incidence of breast cancer. There was an increase in deaths seen after breast cancer among overweight and obese women, but breast cancer mortality was only significantly higher in women with grade 2 to 3 obesity.

“Postmenopausal women with higher MetS scores are a previously unrecognized population at higher breast cancer mortality risk,” Chlebowski said in a statement.

Several authors disclosed financial ties to the pharmaceutical industry.

What is metabolic syndrome?

Metabolic syndrome is a constellation of health conditions that significantly elevate your risk of developing chronic diseases like heart disease, stroke, and type 2 diabetes. It’s not a single disease, but rather a cluster of risk factors that often appear together. Having three or more of these factors qualifies as metabolic syndrome.

These factors include:

  • Large waist circumference: Excess fat around the abdomen, also known as abdominal obesity or “apple-shaped” body fat distribution, is a major indicator.
  • High blood pressure: Chronically elevated blood pressure puts undue stress on your heart and blood vessels.
  • High blood sugar: This can be a sign of prediabetes or undiagnosed type 2 diabetes, where your body struggles to regulate blood sugar levels.
  • Abnormal cholesterol levels: This typically involves high triglycerides, a type of fat in the blood, and low levels of HDL, the “good” cholesterol that helps remove LDL or “bad” cholesterol.

Metabolic syndrome is closely linked to factors like obesity, especially abdominal fat accumulation, physical inactivity, and insulin resistance. Insulin resistance is a condition where cells become less responsive to the hormone insulin, which regulates blood sugar levels. This can lead to high blood sugar and a cascade of other health problems.

Early diagnosis and intervention are crucial for managing metabolic syndrome. Lifestyle changes like a healthy diet, regular exercise, and maintaining a healthy weight can significantly improve your health and reduce your risk of chronic diseases.

How does weight affect breast cancer?

Weight is a significant risk factor for breast cancer, particularly in postmenopausal women. Excess body fat can elevate estrogen levels in the body, which can fuel the growth of some breast cancers. Estrogen is a hormone that can stimulate the growth of breast cells, both normal and cancerous.

Here’s how weight can influence breast cancer risk:

  • Estrogen Production: Adipose tissue, or fat tissue, in the body can produce estrogen. Obese women tend to have more adipose tissue, leading to higher estrogen levels and potentially increasing breast cancer risk.

  • Insulin Resistance: Obesity is often linked to insulin resistance, a condition where cells become less responsive to the hormone insulin. Chronically elevated insulin levels can further stimulate breast cancer cell growth.

  • Chronic Inflammation: Obesity can contribute to chronic, low-grade inflammation in the body, which may also play a role in breast cancer development.

The link between weight and breast cancer risk is complex, but research suggests that maintaining a healthy weight can significantly reduce your risk. Weight loss in overweight or obese women, particularly after menopause, has been shown to be protective.

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