Teens who are overweight or grow up in economically depressed environments face a greater risk for esophageal and gastric cancers, according to a new study.

Researchers from the Rabin Medical Center in Israel collected body mass index (BMI) data on one million adolescent boys around age 17, from 1967 to 2005. They then crosschecked the data with the country’s cancer registry to see which boys eventually developed cancer, following up as soon as 2.5 years to as late as 40 years to track an individual’s progress.

The team was shocked to find how prevalent cancer became in males who grew up in low socioeconomic environments or were overweight throughout adolescence. Up to age 17, the risk factors showed significant influence on the boys’ lives. Adolescents who were overweight faced a 2.1-fold increased risk for esophageal cancer, while those who grew up disadvantaged faced a 2.2-fold increased risk for gastric cancer. Less education also saw rising risk for gastric cancer (1.9-fold) as did immigrant status from Asia or former USSR countries (3.0- and 2.28-fold, respectively).

Esophageal cancers are characterized by tumors in the tube connecting a person’s mouth to his stomach. Gastric cancers take place in the stomach, and mostly in the elderly. However, both types of cancers carry similar risks, according to data from the American Cancer Society. Esophageal cancer affects roughly one in 125 men and one in 435 women. Meanwhile, gastric cancer affects roughly one in 116 men, and slightly fewer women.

Study author Dr. Zohar Levi pointed to the persistent stress put on the esophagus in the overweight and obese as a possible cause for the team’s findings.

"Adolescents who are overweight and obese are prone to esophageal cancer, probably due to reflux that they have throughout their life,” Levi said in a statement. “Also, a lower socioeconomic position as a child has a lot of impact upon incidence of gastric cancer as an adult.”

Levi and his colleagues said further research should investigate the link between the two study groups and each variety of cancer, as the current examination offers no conclusions as to why impoverished teens don’t see greater rates of, say, pancreatic cancer.

What intrigues Levi, however, is the incidence of these cancers in the absence of age. Cardiovascular breakdowns typically occur in middle-age, but the current findings suggest behavior patterns in adolescence can have lasting impacts. Levi and his colleagues suggested further research into whether reversing a person’s diet or changing the individual’s socioeconomic status can impact his or her future cancer riss.

"We look at obesity as dangerous from cardiovascular aspects at ages 40 and over,” Levi said, “but here we can see that it has effects much earlier.”