Study: Do sugared beverages increase the risk of early-onset colorectal cancer?

IN-DEPTH REVIEW OF RESEARCH

Study background

Sugar-sweetened beverages (sugary drinks) contribute to metabolic conditions (such as type 2 diabetes) and gastrointestinal diseases (such as Crohn’s disease). These diseases increase the risk of colorectal cancer.

The number of new cases of early-onset colorectal cancer (colorectal cancer that is identified in people younger than age 50) has been on the rise for the past two decades. The consumption of sugar-sweetened beverages has more than doubled during the same time.

Researchers of this study wanted to know

The researchers wanted to know if consuming sugary drinks increases the risk of early-onset colorectal cancer.

Populations looked at in this study

This study looked at a group of 95,464 female nurses in the United States. The participants were between the ages of 24 and 42 when they enrolled.  Women who had a history of colorectal cancer or inflammatory bowel disease prior to the study were excluded.

Study design

The women were followed for up to 24 years or until a diagnosis of colorectal cancer, their 50th birthday, death, or they dropped out of the study. Participants were asked to complete questionnaires about lifestyle choices, demographics, medical history and family history of cancer, including colorectal cancer. Additionally, they completed a survey every four years about the frequency of their food and beverage consumption in the previous 12 months.

Some participants were asked to provide information regarding their eating habits as teenagers. This subset of participants completed a food survey that asked them how frequently they consumed different food items when they were between ages 13 and 18.

Study findings

By the end of the study, 109 participants had been diagnosed with early-onset colorectal cancer (or 0.1%). This is not a large number of participants which makes detecting small difference among groups of participants difficult. 

Compared to participants who rarely or never consumed sugar-sweetened beverages, participants who drank two or more servings per day had more than double the risk of early-onset colorectal cancer.

Each serving per day of sugary beverages was associated with a 16 percent increase in risk for the disease. However the absolute risk was small and the groups were not different statistically.

Among participants who completed adolescent food surveys, each daily serving of sugary drinks during adolescence was associated with a 32 percent increase in the risk of colorectal cancer. Participants who reported a higher intake of sugar-sweetened beverages during adolescence and adulthood tended to be less physically active and overall more likely to have a poorer diet quality (e.g., consumed higher amounts of red meat and were less likely to take multivitamins). However, the results were not statistically significant.

Researchers found no link between consumption of fruit juice or artificially sweetened beverages and early-onset colorectal cancer.  

Strengths and Limitations

Strengths

• The study looked at a large number of participants which allows the researchers to observe early-onset colorectal cancer cases in the time frame of this study.
• The study followed the participants for a long time, allowing researchers to look at how consumption impacts risk over time.
• The surveys provided enough information so that researchers could test statistically for confounding factors, such as hereditary risk.
• Researchers were able to account for reporting bias and trends in consumption throughout the 24-year study period.

Limitations

• None of the trends observed were statistically significant.
• The study only included women in the United States who worked as nurses, many of whom were white. The results of the study may not be generalizable to the broader population, such as men or women from different racial or ethnic backgrounds.
• Whether sugary beverages are truly a risk factor is not clear. There are many factors that may differ in the people studied and there may be other risk factors for early-onset of colorectal cancer that are still unknown.
• Researchers were unable to determine whether diabetes was a possible contributor to early-onset of colorectal cancer due to the low numbers of participants with diabetes.
• The small number of early-onset colorectal cancer cases limited the researchers’ to reach a strong conclusion about the impact of sugary beverages on cancer risk and limits the researcher's ability to identify the time in one’s life when sugary beverage consumption had the greatest impact on cancer risk.

Context

Prior studies found no association between consumption of sugar-sweetened beverages and colorectal cancer. However, most previous studies had few total cases of cancer or few individuals who consumed more than one serving per day of sugar-sweetened beverages. This likely limited their ability to identify a connection. Furthermore, previous studies looked at the lifetime risk for colorectal cancer, while this study focused specifically on early-onset colorectal cancer. These researchers propose that the contribution of sugar-sweetened beverage consumption to early-onset colorectal cancer may differ significantly from late-onset colorectal cancer which may account for the difference in findings.

Conclusions

Excessive consumption of sugar-sweetened beverages may increase the risk of early-onset colorectal cancer. This relationship may contribute to the rising incidence of early-onset colorectal cancer from 1950 to 2000 when Americans’ consumption of sugary drinks nearly doubled. However, the results of this study may not apply to the general population. More research is needed to validate the link between sugar-sweetened beverages and early-onset colorectal cancer. A balanced diet, and/or dietary intake with moderation promotes a healthy lifestyle, and may in turn have beneficial impact on cancer risk.

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posted 9/21/21