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LONDON — Sudden and unintentional weight loss is associated with an increased risk of a cancer diagnosis in the coming year, according to a new study.
Researchers from Karolinska Institutet in Sweden found that the risk of sudden weight loss was particularly elevated for upper gastrointestinal cancer, haematological cancer, colorectal cancer and lung cancer.
However, it was not seen in breast cancer, urinary tract cancer, brain cancer or melanoma cancer patients.
The team urged healthcare professionals and the public to be vigilant about sudden and unintentional weight loss.
"If you lose weight without making changes to your diet and exercise routine, you should see a doctor to find out what the cause may be. There are several conditions that can result in unexpected weight loss. Doctors can evaluate whether it is something that needs further investigation," said Qiaoli Wang, a researcher at the Department of Clinical Science, Intervention and Technology, Karolinska Institutet.
The new study, published in JAMA, included 157, 474 people aged 40 and older in the US, who were followed for more than 30 years. Detailed information on weight and exercise was collected every two years and dietary data was reported every four years.
The researchers assessed weight loss-promoting behaviours by evaluating changes in participants' diet and exercise. Weight loss intentionality was classified as 'high' for those who had increased their physical activity and improved their diet, 'medium' if only one of the factors had changed, and 'low' if no changes had been made to the diet and exercise.
In the latter group, the incidence of cancer in the coming year was twice as high in people who lost more than 10 per cent of their body weight during the past two years compared to those who did not lose weight.
The study suggests that people who have recently lost weight, especially those with unintentional weight loss, should see their doctor for further examinations to rule out possible cancers.
Unintentional weight loss is important for healthcare providers to consider when assessing individual cancer risk.
"Intentional weight loss through more exercise or a healthier diet can be good for people's health. But unintentional weight loss that is not due to healthier behaviours may indicate an underlying disease, including cancer," said Wang.