Cooking fumes behind some cancer cases?
MADAM Tay, in her 50s, has early stage lung cancer. But the online trader has never touched a cigarette in her life.
Neither have her family members, including her parents and an aunt, who live with her in a flat in Tampines.
"My neighbours don't smoke. I hardly go out. I don't even keep an altar at home," says Madam Tay in Mandarin. She says she has little exposure to second-hand smoke.
What she does a lot of, however, is cook. She declines to give her full name for privacy reasons.
Now, a recent study suggests that cooking food may have contributed to Madam Tay's condition.
More specifically, her use of the wok to stir-fry could have resulted in an increase of carcinogens (cancer-causing substances) in her body.
National University of Singapore's Koh Woon-Puay, with a team of researchers from the United States, spent two years gathering and putting together data from 328 Singaporean Chinese female non-smokers.
Each provided a urine sample and answered questions about her cooking habits and other factors.
The result: Frequent cooking with a wok leads to "significantly increased levels" of the toxicants acrolein and crotonaldehyde, substances which can attack a person's DNA.
This is due to the large amount of oil fumes created during stir-frying with a wok.
Says Professor Koh: "The problem for many of them is that the diagnosis is usually made at the late stage of disease, as this is not a diagnosis that they would expect."
Madam Tay's case is not unique.
Cigarette smoking is the main cause of lung cancer: the No. 2 killer of men and No. 3 killer of women here.
Between 2010 and last year, there was an average of 1,370 people in Singapore diagnosed with lung cancer yearly.
But three in 10 lung cancer patients here have never smoked, a study by the National Cancer Centre found.
Of these "never-smokers" with lung cancer, 70 per cent are women.
"We chose to conduct the study among Chinese female non-smokers because the incidence of lung cancer is disproportionately high relative to the very low rate of smoking in this population," says Prof Koh, a professor at the Saw Swee Hock School of Public Health and Duke-NUS Graduate Medical School.
Her team's decision to focus on this group was based on national health statistics.
Fortunately for Madam Tay, her cancer was detected early and had not spread beyond her lungs.
She had been coughing for nearly two weeks, deciding to visit a polyclinic only when the cough became distracting.
"The doctor told me the X-ray report was worrisome and referred me to a hospital. I was shocked when I found out it was lung cancer," says Madam Tay.
As there was no family history of lung cancer, she had little reason to suspect that it could happen to her.
She is undergoing treatment and was told by doctors that the survival rate in her case is around 80 per cent.
THE NEW PAPER