Adult survivors of childhood cancer are more likely to be underweight than the general population, study findings suggest.

“The majority of underweight survivors have an underlying problem that may be contributing to their leanness that should be identified and treated,” Dr. Lillian R. Meacham, at Emory University in Atlanta, and members of the Childhood Cancer Survivor Study group, report in the medical journal Cancer.

The authors surveyed 7,195 adults who were children when they were diagnosed with cancer between 1970 and 1986; had survived for at least 5 years; and were 20 years old or older at the time of the survey.

Meacham’s group found that 8.6 percent of the women and 4.1 percent of the men were underweight, defined as having a body mass index (BMI) of less than 18.5. The corresponding proportions in the general population were 4.7 percent of women and 0.9 percent of men, according to the 1995 National Health Interview Survey.

Obesity, defined as a body mass index (BMI) of 30 or higher, was documented in 13.4 percent of female survivors and 12.3 percent of male survivors, compared with 16.5 percent and 16.7 percent of men and women in the general population. Only survivors of acute lymphoblastic leukemia were more likely to be obese.

Among women, those treated for Wilm’s tumor, Hodgkin’s disease, and bone malignancies without amputation were at higher risk of being underweight.

Among men, those who had acute lymphoblastic leukemia, brain tumors, Hodgkin’s disease, Wilm’s tumor, Neuroblastoma and Soft tissue sarcoma were the most likely to be underweight.

Treatment risk factors associated with low BMI included having total or abdominal radiation, and chemotherapy with alkylating and anthracycline drugs.

Men’s risk was increased by 60 percent among smokers compared with nonsmokers, by 80 percent among those with a major medical condition, and by 150 percent among those with general poor health. Among women, a major medical condition increased the risk by 80 percent.

The authors note that their findings may not be applicable to children treated after the early 1980s with what was often more aggressive treatment.

“Emphasis on balanced nutrition, proactive instruction for exercise and avoidance of sedentary lifestyles, the prevention of (bone loss), and optimization of health should begin soon after the diagnosis of childhood cancer, continue through long-term follow up, and extend into adulthood,” the study group recommends.

SOURCE: Cancer, April 15, 2005.