New Chinese University study finds possible link between rise in obesity and number of Hongkongers getting colorectal cancer at younger age
Researchers find increase in cases among city’s residents under the age of 55, while latest figures show more than 5,000 were diagnosed with the disease
More people in Hong Kong are getting colorectal cancer at a younger age, and rising obesity could be a major cause, Chinese University researchers said on Tuesday.
The team studied data from more than 100 million people in six cities and countries – Hong Kong, Shanghai, Japan, Britain, the United States and Sweden – collected between 1988 and 2007. They found an annual increase of 1.7 per cent in colon cancer cases, and a rise of 3.5 per cent in rectal cancer cases among Hongkongers under the age of 55.
In contrast, the number of people in the city aged 55 or older suffering from colon cancer fell annually by 1.3 per cent.
“Obesity might be an important factor [leading to the younger trend of colorectal cancer],” said Professor Joseph Sung Jao-yiu, who was involved in the study.
Colorectal cancer is the most common cancer in Hong Kong, with the latest statistics from the city’s cancer registry showing more than 5,000 people diagnosed with the disease in 2015. The disease can start in either the rectum or colon.
The university used cancer and population data from the World Health Organisation’s International Agency for Research on Cancer to conduct its analysis, and found close to 66,000 people from the 100 million profiles were diagnosed with colorectal cancer.
Like Hong Kong, the United States saw a decrease in the number of colon cancer patients aged 55 and above, but an increase in younger patients. When it came to rectal cancer, five of the six cities and countries, with Japan the exception, had an increase in younger rectal cancer sufferers.
Findings of the study were presented at the Digestive Disease Week, a medical conference held in the US earlier this month.
Sung explained that obesity was a possible causation in various types of cancer.
“When a person is obese … diversity of bacteria in gut would be lower and some types of bacteria, which might lead to cancer, would grow faster,” said Sung, adding the increasing trend of obesity around the world could have contributed to a general rise in some types of cancer.
While the government announced in the latest budget it would extend a colorectal cancer screening programme to cover people aged 50 to 75, Sung said there was no need at the moment to screen those below 50.
“We don’t see an urgent need … younger people’s risk is still relatively low, compared to the older population,” he said.
Resources should be directed at screening those with a higher risk of getting cancer, while everyone else, he said, should endeavour to be healthier and reduce their risk of the disease by eating more vegetables and less meat.
Cancer accounts for about one-third of deaths in Hong Kong each year, according to the Department of Health. A government population health survey released in December last year revealed half of the city’s population aged 15 to 84 was overweight or obese.
Of the 12,000 respondents surveyed, nearly 95 per cent of people were found to not be eating enough fruit and vegetables.