It’s not entirely clear why colorectal cancer is increasing among adults under 50
Steve Gschmeisner/Science Photo Library
The incidence of colorectal cancer in young adults is increasing worldwide, but this trend appears to be most prevalent in high-income countries.
Previous studies have shown that the incidence of bowel or colorectal cancer is increasing. Over the past few decades, it has increased in this age group in Western countries, including the United States, Canada, Australia, and the United Kingdom. This has led to speculation that Western lifestyles, including a diet high in meat and processed foods, may be to blame.
To better understand the extent of the problem, Hyunah Sohn and colleagues at the American Cancer Society in Atlanta, Georgia, looked at the incidence of colorectal cancer in 50 countries and territories around the world. They typically used the World Health Organization’s database to collect data on incidence from 1975 to 2017, although some countries started reporting this information several years after 1975. Ta.
The research team found that the incidence of colorectal cancer among people aged 25 to 49 is rising in 27 countries and territories. These also include non-Western countries like Japan and less wealthy countries like Turkey, raising the possibility that Western lifestyles are not solely behind this trend.
The increase is also unlikely to be related to improved screening tests, the researchers said in the paper, as most countries do not routinely test people for colorectal cancer until age 50.
However, all 27 countries and territories have high or very high scores on the United Nations Human Development Index, which is based on life expectancy, education level, and per capita income.
Additionally, all but six are considered high-income earners, according to the World Bank. Unlike most of the high-income countries studied, in these six countries, cases of colorectal cancer among older people are increasing at the same or faster rate than among younger people.
“I think there’s still evidence of a trend that economic development and Westernization of lifestyles are actually playing a role,” said Andrew Chan of Harvard University, adding that many countries are seeing this shift as their economies grow. He pointed out that it incorporates lifestyle aspects. For example, Japan’s meat intake increased more than seven times between 1961 and 2021.
“Having said that, I think we need to take into account the fact that there are probably other factors at play, such as environmental contaminants,” Chan says.
The researchers note that their study has several limitations, the most obvious being that countries in Africa, Asia and small islands were underrepresented. For example, only one African country was included: Uganda. Some countries did not have complete datasets. For example, India’s figures represent only 4 percent of the population.
Still, these findings could improve our understanding of how colorectal cancer incidence varies in many countries and help devise new ways to prevent the disease, Zhang said. say.
topic:
