October 24, 2011 (Boston, Massachusetts) — Obesity in young adulthood is associated with an increased risk for non-Hodgkin's lymphoma (NHL) later in life. In addition, NHL risk might be associated with trans fat intake in women and a low intake of vegetables in men and women.

These findings come from a study presented here at the Tenth Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research.

Women with a body mass index (BMI) of 30 kg/m2 or higher at 18 years of age (compared with a BMI below 21 kg/m2) had a 19% higher risk for NHL (hazard ratio [HR], 1.19). The risk for men was substantially higher; those with a BMI of 30 kg/m2 or higher at 21 years of age (compared with a BMI below 23 kg/m2) had a risk that was 63% higher (HR, 1.63).

The data sources are 2 large well-known epidemiology studies.

"We looked at data from the Nurses Health Study [NHS], which is a large cohort of women, and we also looked at data from the Health Professionals' Follow-Up Study [HPFS], which is a large cohort of men," explained study author Kimberly Bertrand, ScD, a research fellow in the Department of Epidemiology at the Harvard School of Public Health, Boston, Massachusetts, who presented the results of the study during a poster session.

We found that "being obese as a young adult (ages 18 to 21) was associated with an increased risk of non-Hodgkin's lymphoma later in life," she said. Dr. Bertrand noted that the length of time that a person was obese has not yet been evaluated.

"This was basically a snapshot — what people reported their weight to be at age 18 through age 21," she told Medscape Medical News. "Body mass index in early adulthood is highly correlated with body mass index in adulthood. We saw that current body mass index was associated with NHL in men, but we didn't see that in women."

These are preliminary results and need to be confirmed in other trials, Dr. Bertrand cautioned. "We don't understand the risk factors for this disease very well, especially modifiable risk factors," she explained. "That's why research that looks at diet and lifestyle is really important; it might inform future prevention messages aimed at people who are at a higher risk."

In the future, she pointed out, her team is going to look at body weight in childhood and weight change over time. "We have a lot of data. Again, these are just preliminary results," she noted. However, "there may be great opportunities for preventive measures to be taken earlier."

Trans Fats and Veggies

In previous analyses of the NHS, the researchers reported positive associations between NHL and trans fat intake and inverse associations between NHL and vegetable intake after14 years of follow-up. The current study was undertaken to expand on these earlier findings. Dr. Bertrand and colleagues evaluated the association between risk for NHL and obesity, specific types of dietary fats, and fruits and vegetables.

The cohort consisted of 91,227 women who completed the 1980 NHS food frequency questionnaire (FFQ) and 47,542 men who completed the 1986 HPFS FFQ and had no history of cancer. There were 966 confirmed incident diagnoses of NHL among women through 2008 and 566 cases among men through 2006.

In addition to obesity in early adulthood, current BMI was associated with NHL in men with a BMI of 30 kg/m2 or higher (HR, 1.48). However, this association was not observed in women a BMI of 30 kg/m2 or higher (HR, 0.88).

The authors also found that total and specific dietary fats were not associated with NHL risk, but data suggested that women who consumed the highest amounts of trans fat in their diets had a nonstatistically significant increased risk for NHL overall (HR, 1.19).

In addition, both men and women who consumed 4 or more servings of vegetables per day, compared with those who consumed less than 2 servings per day, had a slightly lower risk for NHL (HR for men, 0.87; HR for women, 0.84). Total fruit intake was not associated with NHL.

"It is plausible that there is etiologic heterogeneity across the more than 30 NHL histologic subtypes," conclude the authors. "Ongoing analyses to examine the relationship of obesity and diet with major NHL histologic subtypes in the NHS and HPFS may yield further insights into their roles in NHL etiology and prevention."

Tenth Annual American Association for Cancer Research (AACR) International Conference on Frontiers in Cancer Prevention Research: Abstract A73. Presented October 23, 2011.


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