TORONTO -- Obesity-related cancers in young Canadians are on the rise, according to , prompting concerns about age recommendations for cancer screening programs.

The study, which looked at more than five million cancer cases diagnosed in Canada between 1971 and 2015, found that there has been an overall increase in cancers not normally found in young adults, including breast and colon cancer.

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The highest increase in cancer cases was found in women aged 30 to 39.

鈥淭he most striking results from these analyses relate to increasing incidence trends among younger adults for breast, colorectal, pancreatic, endometrial and kidney cancers,鈥� wrote co-author Dr. Darren Brenner, from the Cumming School of Medicine at the University of Calgary, in the study released Monday.

鈥淥besity is a risk factor for these cancer sites, and the rising incidence runs parallel to the growing prevalence of obesity in recent decades.鈥�

This increasing trend is especially worrisome because most young adults are ineligible for cancer screening programs, the study author鈥檚 noted.

However, the study showed that there has been a decrease in the overall rate of new cancer cases in people over the age of 50, a trend study author鈥檚 say is likely thanks to prevention campaigns.

For example, the study author鈥檚 suggest there may be a link between smoking cessation programs and a decrease in lung cancer cases. Similarly, better sun safety behaviours could be linked to lower cases of melanoma in women younger than 40 and men younger than 50.

The rate of cancer diagnoses in Canada is well documented. However, the study notes that less is known about trends by age groups.

According to the study, age-specific cancer rates help identify the impact of changes of cancer-prevention tactics, including screening programs.

The study, published in the Canadian Medical Association Journal, was conducted by researchers from the University of Calgary and CancerControl Alberta, along with researchers from Carleton University, McMaster University, and the Canadian Cancer Society.