Study: Body Mass Index (BMI) may affect how well aspirin use protects against colorectal and ovarian cancer

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Contents

At a glance Clinical trials 
Study findings Guidelines
Strengths and Limitations Questions for your doctor
What does this mean for me? Resources and reference
In-depth  

 

STUDY AT A GLANCE

What is this study about?

This study is about whether daily aspirin use is protective against colorectal, prostate, ovarian, endometrial and breast cancers, and the effect of cancer risk factors such as being overweight, smoking, and having a family history of cancer on this protection.

 

Why is this study important?

Several studies have consistently shown a link between daily aspirin use and reduced cancer risk, especially for colorectal cancer. The United States Preventive Services Task Force recommends daily low-dose aspirin to help prevent the onset of colorectal cancer in adults age 50 and older who are at increased risk for colorectal cancer and aren’t at risk for bleeding.

Researchers have looked at whether daily aspirin use lowers the risk for prostate, ovarian, endometrial and breast cancers. Research has not consistently shown that aspirin protects against these cancer types. In addition, how different major risk factors for cancer, such as elevated body mass index (BMI), older age, smoking, physical inactivity and familial history of cancer affect the actions of aspirin on risk is unknown. BMI is a measure of body fat based on height and weight in adults (BMI calculators like this one, use height and weight to estimate BMI). Research shows that a BMI of 25 kg/m2 or greater can lead to serious medical conditions such as metabolic syndrome, high blood pressure, atherosclerosis, heart disease, diabetes, high blood cholesterol, sleep disorders and cancers.

In this study, researchers wanted to know if these major risk factors impact aspirin’s ability to protect against cancer.

 

Study findings

Researchers examined the medical information of more than 423,000 individuals ranging from ages 50 to 74 who were a part of two national clinical trials in the United States. Each study participant provided information about their aspirin use within a given year, cancer diagnosis, age, BMI, smoking status, physical activity and a family history of cancer.

The primary goal of the study was to compare the incidence of colorectal, ovarian, breast, endometrial or advanced prostate cancers among “daily aspirin users” (those who took a daily aspirin at least five days per week) and individuals who took fewer than five aspirins or no aspirin per week. Incidents of cancer were further evaluated by the patients’ risk factors for cancer, such as age, BMI, smoking status, physical activity and a family history of cancer.

Study findings showed that:

  • Daily aspirin use was associated with a 15% reduction in overall risk for colorectal cancer.
    • This protection was lost as participant BMI increased.
    • Other cancer risk factors, such as physical activity level and having a family history of cancer, did not impact the protective effect of aspirin against colorectal cancer.
  • Overall, daily aspirin use offered little protection against ovarian cancer.
    • However, daily aspirin use was associated with a 28% reduction in ovarian cancer risk among women who were considered to be obese (with a BMI of 30 kg/m2 or greater).
  • Daily aspirin use offered little or no protection against advanced prostate cancer, breast cancer or endometrial cancer.

 

Strengths and limitations

Strengths:

  • The study was large, including the medical information of more than 423,000 patients from multiple study sites.
  • The study took a broader look at whether aspirin use is associated with cancer prevention by examining its impact in the presence of major cancer risk factors, such as BMI, physical activity and a family history of cancer. The effectiveness of drugs, including aspirin, can have different outcomes based on these and other risk factors.
  • The study confirmed the diagnosis of cancer through review of medical records, not just based on patient reporting.

Limitations:

  • The study did not include data from people under the age of 50. This limits our ability to make conclusions about the benefits of aspirin in people of this age group.
  • The study was not particularly diverse regarding race and ethnicity. Ninety percent of the study participants identified as White, whereas White people comprise about 70% of the U.S. population.
  • Patient information concerning BMI, smoking and aspirin use was self-reported and not confirmed by medical records.

 

What does this mean for me?

In this study, daily aspirin use was linked with a reduction in the overall risk of colorectal cancer, however, this protection was lessened with increasing BMI.

For ovarian cancer, aspirin use was only protective in women with a BMI of 30 kg/m2 or greater. Because the study showed that aspirin protection can vary depending on individual cancer risk factors, it is important to talk to your doctor about measures that you can take to reduce your cancer risk.

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posted 3/19/21

This article is relevant for:

People concerned about their risk of colorectal or ovarian cancer.

This article is also relevant for:

Healthy people with average cancer risk

People with a family history of cancer

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Questions to Ask Your Doctor

  • How can I lower my risk for colorectal cancer, ovarian and other cancers?
  • I have a family history of colorectal cancer, ovarian and other cancers; will daily aspirin use benefit me?

Open Clinical Trials

  • NCT03480776- Acetylsalicylic acid (aspirin) in Prevention of Ovarian Cancer (STICs and STONEs). While aspirin is not a cancer medication, research suggests that the anti-inflammatory action of aspirin reduces the probability of developing many types of cancer. Inflammation in the ovaries during ovulation is thought to contribute to the development of ovarian cancer; because aspirin is an anti-inflammatory medication, it may help to prevent it.

IN-DEPTH REVIEW OF RESEARCH


Study background

Since the 1980s, several studies have linked daily aspirin use and reduced colorectal cancer risk. Such evidence led the United States Preventive Services Task Force to recommend daily low-dose aspirin to help prevent the onset of colorectal cancer in adults who are at increased risk for the disorder.

Although other studies have investigated whether daily aspirin use offers similar protection against other cancers such as prostate, ovarian, endometrial and breast cancers, data do not consistently show that aspirin offers protection against these cancer types. Some researchers believe that data may be inconsistent because aspirin protection may be dependent on an individual’s risk factors for cancer, such as high body mass index (BMI), cigarette smoking and physical inactivity.

 

Researchers of this study wanted to know:

Whether age, BMI, cigarette smoking, physical inactivity and a family history of cancer can modify associations between daily aspirin use and the risk of cancers, including colorectal, ovarian, breast, endometrial and advanced prostate cancer.

 

Populations looked at in this study:

The study examined medical information from 423,495 individuals who were previously a part of two large-scale U.S. clinical studies—the NIH-AARP Diet and Health Study and the Prostate, Lunch, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Participants ranged from ages 50 to 74.

To be included in the current study, each participant was required to have information regarding their 12-month aspirin use, the status of any cancer, and information about their BMI, smoking status, physical activity and a family history of cancer. The status of cancer was confirmed by medical records and cancer registries.

 

Study design:

The study’s primary outcomes compared the incidence of colorectal, ovarian, breast, endometrial and advanced prostate cancers among “daily aspirin users” (those who took a daily aspirin at least five days per week) and individuals who took fewer than five aspirin or no aspirin per week. Incidents of cancer were further evaluated by the risks for cancer such as BMI, smoking status, physical activity and a family history of cancer.

 

Study findings:

Results from the analysis showed the following:

  • Daily aspirin use was associated with a 15% reduction in overall risk for colorectal cancer.
    • This protection against colorectal cancer was lost with increasing BMI.
    • Other cancer risk factors, such as physical activity level and having a family history of cancer, did not impact aspirin’s protective effect against colorectal cancer.
  • Overall, daily aspirin use offered little protection against ovarian cancer.
    • However, daily aspirin use was associated with a 28% reduction in ovarian cancer risk among women who were considered to be obese (with a BMI of 30 kg/m2 or greater).
  • Daily aspirin use offered little or no protection against advanced prostate cancer, breast cancer or endometrial cancer.

 

Strengths and Limitations

Strengths:

  • The study was large, including the medical information of more than 423,000 patients from multiple study sites.
  • The study took a broader look at whether aspirin use is associated with cancer prevention by examining its impact in the presence of major cancer risk factors, such as BMI, physical activity and a family history of cancer. The effectiveness of drugs, including aspirin, can have different outcomes based on these and other risk factors.
  • The study confirmed the diagnosis of cancer through review of medical records, not just based on patient reporting.

Limitations:

  • The study did not include data from people under the age of 50. This limits our ability to make conclusions about the benefits of aspirin in people of this age group.
  • The study was not particularly diverse regarding race and ethnicity. The study population was 90 percent White.
  • Patient information concerning BMI, smoking and aspirin use was self-reported and not confirmed by medical records.

 

Context

In this study, although daily aspirin use was linked with a reduction in the risk of colorectal cancer, overall, it offered minimal protection in those with an elevated BMI. However, daily aspirin use was linked to a reduced risk of ovarian cancer only in women with elevated BMIs. Because individuals have different risk factors that can lead to cancer, it is important to ask your doctor if aspirin is a viable option for you to prevent the onset of cancer.

 

Conclusions

Based on this study, the protective effects of daily aspirin use against colorectal cancer and ovarian cancer seem to be dependent upon an individual’s BMI. More studies are needed to further investigate the impact of BMI on aspirin’s protection against cancers. 

 

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posted 3/19/21

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