Researchers at the University of Hawai'i John A. Burns School of Medicine are studying why Native Hawaiians who smoke have a higher risk for lung cancer than white and Japanese people with the same smoking history.

Over the past 25 years, the school has collaborated with the Cancer Research Center of Hawaii and the University of Southern California to study 215,000 smokers to analyze how lung cancer risk differed among ethnicities.

The Cancer Research Center of Hawaii, established by UH, changed its name to the UH Cancer Center in 2011.

The study found that even though individuals had the same smoking history, the risk to Native Hawaiian smokers for lung cancer was 60% greater than for white smokers. The study also found that the Japanese smokers’ lung cancer risk was 50% lower than white smokers.

Loic Le Marchand, an associate director at the UH cancer center who helped author the study, said he is conducting research to identify the reasons why Native Hawaiian smokers have a higher risk of lung cancer.

“We are trying to explain the reasons for those differences, and one finding that we have is, depending on how fast you metabolize nicotine, you smoke differently,” Marchand said.

He explained that people who metabolize nicotine, an addictive chemical in cigarettes, inhale more while smoking. “You try to replenish your store of nicotine,” he said. “In addition to smoking more intensely, you also get more carcinogens.”

Marchand said a person’s nicotine metabolism is determined by genetics.

“Depending on your DNA sequence of the genes for the enzymes that metabolize nicotine, some of the forms of the enzymes are more active than others,” he said.

Marchand has already established that Japanese smokers metabolize nicotine slower than white smokers.

“Now we are trying to follow up and understand why Native Hawaiians have a higher risk,” he said. He suspects that Native Hawaiian smokers will have a higher metabolism for nicotine.

Marchand expects to finish the study by the end of the year. He plans on publishing the study about a year later.

Researchers are seeking Japanese smokers who are over 21-years-old and smoked at least five cigarettes per day for at least the last three months to participate in the study.

Marchand encouraged people who want to be part of the study to contact him at smokersstudy@cc.hawaii.edu.