Adhering to a healthy diet could reduce the risk for premature aging among adult survivors of childhood cancer, according to a recent report from the St. Jude Lifetime Cohort Study.

Each 10-point increase in the Healthy Eating Index-2015 score was associated with a 20% decrease in the odds of falling into the high-risk category for premature aging. Similarly, every 1-point increase in the Alternate Mediterranean diet score correlated with a 9% reduction in the same odds.

Personalized dietary interventions are needed to improve long-term health outcomes in this at-risk population, which has historically shown low adherence to established dietary guidelines, lead author Tuo Lan, PhD, of the Washington University School of Medicine, St. Louis, and colleagues, reported.

This focus on lifestyle factors comes amid growing recognition of the hidden toll of accelerated aging in long-term cancer survival, prompting research into possible interventional strategies.

“Studies have shown that dietary habits, such as the Mediterranean diet, the Dietary Approaches to Stop Hypertension, and the prudent diet, were associated with a lower risk of aging-related chronic diseases in both the general population and adult cancer survivors,” the investigators wrote in Cancer. “However, little is known about the effect of a healthy diet on aging in childhood cancer survivors, who are particularly vulnerable to premature aging.”

Lan and colleagues previously reported reduced risk for premature aging among adult survivors of childhood cancer who consumed certain individual foods like vegetables, nuts, and seeds. It remained unclear, however, if similar benefits would come from adherence to established dietary guidelines like the Mediterranean diet and the Dietary Guidelines for Americans.

To learn more, the investigators conducted a cross-sectional analysis of data from 3322 adult survivors of childhood cancer in the St. Jude Lifetime Cohort Study. Participants were at least 18 years old and had survived for a minimum of 5 years following their initial cancer diagnosis.

Participants’ diets over the previous year were evaluated using a validated 110-item self-administered food frequency questionnaire. The Healthy Eating Index-2015 was used to measure adherence to the Dietary Guidelines for Americans on a 100-point scale, while the Alternate Mediterranean diet score measured adherence to a modified Mediterranean diet on a 9-point scale.

Premature aging was quantified according to the deficit accumulation index (DAI), a proxy measure that incorporates up to 44 aging-related factors, including physical and psychosocial function, activities of daily living, and various chronic health conditions. Scores ranged from 0 to 1, enabling categorization of participants into low (< 0.2), medium (0.2 to < 0.35), or high-risk (at least 0.35) groups.

Multinomial logistic regressions were used to estimate associations between the dietary pattern scores and the DAI categories. Adjustments were made for an array of potential confounding factors, including age, sex, race and ethnicity, education, neighborhood socioeconomic status, smoking, supplement use, total energy intake, and specific cancer treatment histories, such as radiation and chemotherapy.

The Challenges of Eating a Healthy Diet

According to the investigators, the findings of the new study are particularly concerning because more than 80% of the participants had unhealthy dietary patterns compared with 63% of community control individuals.

Senior author Yikyung Park, ScD, of the Washington University School of Medicine, St. Louis, told Medscape Medical News that children undergoing cancer treatment are encouraged to eat “anything at all.” This often leads to consumption of a high-calorie, nutrient-poor diet, she said, which may become a lifelong habit after treatment is complete.

“Additionally, the late effects of treatment — such as fatigue, sensory changes, and emotional stress — often lead survivors to reach for convenient foods rather than cooking healthy meals,” Park added.

Evaluating the Evidence and Next Steps

When asked about clinical relevance, Jason Oke, DPhil, MSc, departmental lecturer in medical statistics and cancer research at the University of Oxford, Oxford, England, first noted the scale of the change.

“A change of 10 [points in the Healthy Eating Index-2015] equates to roughly a reduction of...0.03 units of the DAI scale,” Oke told Medscape Medical News.

Because the total gap between the low-risk and high-risk thresholds was only 0.15 points, a 0.03-point drop in DAI bridges 20% of the distance between the low- and high-risk categories.

This is “not a small change,” Oke said, although it is “difficult to say” how clinically impactful the reduction might be.

He also cautioned against a causal interpretation.

“That’s the billion-dollar question in epi research: When, if at all, can we infer cause from observational data?” Oke said. “In this case, I think it’s low confidence because it is cross-sectional.”

In an accompanying editorial, Rusha Bhandari, MS, MD, and Lee W. Jones, PhD, of City of Hope Comprehensive Cancer Center, Duarte, California, along with Yue Liao MPH, PhD, of the University of Texas at Arlington, noted that adjusting for sociodemographic and treatment-related factors attenuated the association between diet and premature aging, particularly in men.

“This underscores the urgent need to better determine how factors such as education, lifestyle, environment, and treatment exposures differentially impact health outcomes in this patient population,” they wrote.

The editorialists also noted that physical activity, which is a key lifestyle factor related to both diet and aging, was not included in the multivariable models.

When asked about this perceived limitation, Park explained that physical health is actually part of the DAI assessment itself, which is why it was not adjusted for as a separate variable.

“In general, survivors with a healthy diet tended to be more active than those with a poor diet. However, the difference was minimal,” Park said. “Even after controlling for physical activity…the results didn’t change meaningfully.”

Ultimately, both the editorialists and the investigators agreed upon the need for personalized interventions, such as one-on-one nutrition education, to help this vulnerable population overcome barriers to healthier lifestyles.

“As [survivors of childhood cancer] get older, some may try to change their diet, but struggle to find the information or intervention that is right for their specific needs,” Park said. “We need to provide a tailored intervention to each survivor, addressing their specific need, at each stage of their survivorship journey.”

This study was supported by the National Institutes of Health, the St. Jude Children’s Research Hospital-Washington University St. Louis Implementation Sciences Collaborative, and the American Lebanese-Syrian Associated Charities. The investigators, editorialists, and Oke reported having no conflicts of interest.