Can weight loss lower risks of cancers linked to obesity? Study says an intensive program may help
Following an intensive weight-loss program is likely to yield benefits for those looking to cut their risks of developing obesity-related cancers, including breast, ovarian and colorectal cancers. A new study found that the regimen may have lowered the rates of cancers in adults with excess body fat and type 2 diabetes. The study examined if an intensive lifestyle intervention (ILI) -- a weight loss regimen that involves exercise and a lower calory intake -- could reduce cancer rates in participants whose body mass index (BMI) was higher than 25.
"Obesity is a global, major public health issue," Dr Hsin-Chieh "Jessica" Yeh, from Johns Hopkins University in Baltimore, told MEA WorldWide (MEAWW). Previous observational studies have detected a connection between obesity and liver, kidney, pancreas, breast, ovarian, and colorectal cancers, multiple myeloma, brain tumor, to name a few.
"But, there have been no clinical trials that have evaluated whether weight loss can reduce cancer risks," Dr Yeh, who is the corresponding author of the study, explained. So the team turned to data from the Look AHEAD trial, a clinical trial designed to study the long-term impacts of ILI on weight loss. The study is randomized -- making it a gold-standard experiment for assessing the effects of ILI on cancer rates.
They looked at 4,859 participants. Of them, some were randomly placed in the ILI group, while others were in the Diabetes Support and Education (DSE). Those in the former group had a goal: a weight-loss of at least 7%. To achieve that, they were put on a diet plan diet that allowed only 1,200-1,800 calories per day. They also had to engage in moderate-intensity physical activity every week for at least 175 minutes, Dr Yeh said. The latter group, on the other hand, merely received diabetes support and education on diet, exercise, and social support.
The team followed up on the participants, comparing cancer outcomes between the two groups. "Our study found in patients with overweight or obesity and with type 2 diabetes, ILI reduced obesity-related cancers by 16% as compared to the DSE group," she added.
So how is ILI lower the rates of obesity-related cancers? Theories have suggested the obesity increases the risk of cancer by raising the levels of estrogen and other sex hormones, inflammations, and insulin and other growth factors, in the body. Dr Yeh and her colleagues speculate that ILI could be altering these mechanisms.
Commenting on the study, Dr Tiffany L Carson, from the University of Alabama at Birmingham, said the research was underpowered to detect significant differences. However, she said, the analysis is a noteworthy contribution because it provides empirical data, suggesting that a weight loss-focused lifestyle intervention can help to lower the risk of obesity-related cancers.
Carson, who was not involved in the research, added: "in addition to having adequate sample sizes to test for effects which will likely require pooled data, future studies should also explore the magnitude of weight loss that is needed to lower risk for obesity-associated cancers."
The study is published in Obesity.