Coffee and tea

Coffee

Drinking coffee is probably associated with a decreased risk of endometrial cancer. This association is seen with caffeinated and decaffeinated coffee.

For every cup of coffee a woman drinks per day, the risk of endometrial cancer decreases by about 5%. The decreased risk is likely to be seen only in women who are overweight or obese or in women who have never used menopausal hormone therapy (also known as hormone replacement therapy).

There are various ways in which coffee may affect the risk of endometrial cancer. This includes effects of caffeine on hormone levels, as well as effects of other chemicals in coffee on proteins in the blood that may contribute to development of endometrial cancer.

Green tea

Drinking green tea may be associated with a decreased risk of endometrial cancer.

Green tea contains antioxidants, which may play a role in stopping the growth of cancer-causing cells.

Black tea

There is no conclusive evidence that drinking black tea is associated with a decreased risk of endometrial cancer. Only a small number of studies have been conducted and these are of poor quality.

The difference in effect seen between green tea and black tea may be because some of the antioxidants found in green tea are removed when black tea is produced.

Fat in the diet

There is no conclusive evidence that eating foods containing high levels of fat* or cholesterol is associated with increased risk of endometrial cancer. Results from studies are not consistent, and these studies are of poor quality.

A high-fat diet has been shown to increase levels of the female hormone oestrogen and other hormones that are known to increase the risk of endometrial cancer. This has led researchers to look at whether a high-fat diet affects the risk of endometrial cancer.

*Studies have looked at diets containing high levels of total fat, animal fat, cholesterol and saturated fats.

Glycaemic load in the diet

High intake of foods that raise blood glucose levels is probably associated with an increased risk of endometrial cancer. This is called a high glycaemic load*.

A number of studies have shown that the risk of endometrial cancer increases in women who have a high intake of foods that raise blood glucose levels. In these studies, the risk of endometrial cancer increased by about 15% for every 50-unit increase in daily glycaemic load. This means that if a woman’s daily diet includes the equivalent of 50 grams of glucose, her risk of endometrial cancer increases by 15% and the more glucose the higher the risk.

Not all studies have shown an association between glycaemic load and risk of endometrial cancer.

There are several ways in which glycaemic load may increase the risk of endometrial cancer. It is possible that the increased risk is due to a combination of hormonal factors and effects on the way cells produce energy.

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer

* Glycaemic load is a way of measuring the effect of different types of food on a person's blood glucose levels. Each ‘unit’ of glycaemic load is the same as eating one gram of glucose.

Overweight and obesity

Being overweight or obese is associated with an increased risk of endometrial cancer.

Body fatness is often measured as body mass index (BMI*). For each 5-unit increase in BMI, the risk of endometrial cancer increases by 50%. This means that a woman who is overweight is around 1.5 times more likely to develop endometrial cancer than a woman of healthy weight. A woman whose BMI is in the ‘obese’ range is between 2 and 10 times more likely to develop endometrial cancer than a woman of healthy weight.

Over one-quarter of cases of endometrial cancer in Australia are estimated to be due to overweight and obesity.  

Other ways of measuring body fatness include waist circumference, weight gain in adulthood and waist-to-hip ratio (the circumference of the waist compared to the circumference of the hips). Increases in all these measures have been associated with an increased risk of endometrial cancer. For example:

• for every 10 cm increase in waist circumference, the risk of endometrial cancer increases by 27%.
• for every 5 kg of weight gained in adulthood, the risk of endometrial cancer increases by 16%.

There are various ways in which body fatness may increase the risk of endometrial cancer. Weight gain is associated with higher levels of the hormone oestrogen, which can promote the development of endometrial cancer. People who are obese or overweight also have higher levels of certain proteins and other factors in their blood caused by inflammation. In women, these factors may also increase the risk of endometrial cancer.

*Body mass index (BMI) is a measure of body fatness based on a person’s weight in relation to their height. It applies to most adult men and women aged 20 years and over.

Commonly accepted BMI ranges are: underweight, under 18.5 kg/m²; normal weight, 18.5 to 25 kg/m²; overweight, 25 to 30 kg/m²; obese, over 30 kg/m².

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer
• Healthy Weight Guide – Australian Government Department of Health
• Australia’s Physical Activity and Sedentary Behaviour Guidelines – Australian Government Department of Health

Passive smoking

There is no conclusive evidence that passive smoking (also known as second-hand smoking) is associated with risk of endometrial cancer. Only a small number of low-quality studies have been conducted.

Passive smoking means breathing in the smoke from other people’s cigarettes, cigars and pipes. This smoke is made up of the smoke that the smoker breathes out and the smoke that comes from the burning cigarette.

Second-hand tobacco smoke contains the same cancer-causing chemicals that are inhaled by smokers and is known to cause cancer of the lung.

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer

Physical activity

Physical activity is probably associated with a decreased risk of endometrial cancer.

The risk of endometrial cancer in women who do high levels of vigorous physical activity is about 20% lower than in women who are not physically active. Studies have shown similar results, regardless of the type of physical activity the woman does (recreational or work activity, household tasks, walking or biking). The decrease in risk associated with physical activity is mainly seen among overweight and obese women.

It is estimated that about 6% of cases of endometrial cancer in Australia are due to women doing less than the recommended weekly amount of 300 minutes of moderate-intensity physical activity.

There are several ways in which physical activity could lower the risk of endometrial cancer. This includes lowering the level of the female hormone oestrogen and other hormones such as insulin in the body. The association between physical activity and endometrial cancer may in part be due to the fact that higher levels of physical activity can lower the body mass index (BMI).

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer
• Building more movement into your daily life – Australian Government Department of Health

Recommended levels of physical activity in Australia are at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous physical activity per week to help improve blood pressure, cholesterol, heart health and muscle and bone strength. This should be increased to 300 minutes of moderate intensity physical activity or 150 minutes of vigorous intensity physical activity per week for greater health benefits and to help prevent cancer and unhealthy weight gain.

Sedentary behaviour

Sedentary behaviour* such as spending a lot of time sitting or lying down may be associated with an increased risk of endometrial cancer.

The association between sedentary behaviour and risk of endometrial cancer may be due to the low level of energy used by women who spend a lot of time sitting or lying down. It may also be caused by other associated factors that are known to affect the risk of endometrial cancer, such as having a higher body mass index (BMI).

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer
• Australia’s Physical Activity and Sedentary Behaviour Guidelines – Australian Government Department of Health

*Sedentary behaviour means spending a lot of time sitting or lying down and not using much energy.

Smoking

Studies have shown that the risk of endometrial cancer is lower in postmenopausal women who currently smoke or who have smoked in the past compared with women who have never smoked.

However, the major health risks associated with smoking far outweigh this effect. Tobacco smoking causes lung cancer and cancers of many other organs including the nasal cavity, throat, stomach, liver, kidney, bowel and bladder. Smoking is the major known and preventable cause of cancer worldwide. Tobacco smoke contains more than 5,300 chemicals, including more than 70 chemicals that are known to cause cancer.

The association between smoking and decreased risk of endometrial cancer is likely to be due to hormones. Studies suggest that the female hormone oestrogen is associated with risk of endometrial cancer. Smoking tobacco can lower levels of oestrogen and this may lower a woman’s risk. Smoking may also lead to earlier menopause and can lower body fat, both of which can affect a woman’s hormone levels.

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer
• My QuitBuddy – Australian Government Department of Health

Weight loss

Losing weight as a result of dieting or surgery by women who are obese may be associated with a decreased risk of endometrial cancer.

It is estimated that at least one-quarter of cases of endometrial cancer in Australia could be prevented if all women had a healthy weight.*

Increasing body fatness in adult women increases the risk of endometrial cancer. People who are obese have higher levels of the female hormone oestrogen, which can increase the risk of endometrial cancer. They may also have higher levels of certain proteins and other factors in their blood caused by inflammation, which may increase the risk of endometrial cancer. Weight loss is likely to reduce levels of these hormones and proteins, decreasing the risk of endometrial cancer.

Further information can be found at:

• Cancer Australia Position Statement – Lifestyle risk factors and the primary prevention of cancer
• Healthy Weight Guide – Australian Government Department of Health
• Australia’s Physical Activity and Sedentary Behaviour Guidelines – Australian Government Department of Health

*Body mass index (BMI) is a measure of body fatness based on a person’s weight in relation to their height. It applies to most adult men and women aged 20 years and over. Commonly accepted BMI ranges are: underweight, under 18.5 kg/m^2; normal weight, 18.5 to 25 kg/m²; overweight, 25 to 30 kg/m²; obese, over 30 kg/m².