Fresh evidence links adiposity with multiple cancers

The International Agency for Research on Cancer (IARC) working group recently reviewed epidemiological data, studies in experimental animals, and mechanistic data and concluded that excess body fatness causes cancer of the colon and rectum, liver, gallbladder, pancreas, kidney, thyroid, breast (postmenopausal), endometrium, ovary, oesophagus (adenocarcinoma), and gastric cardia, as well as meningioma and multiple myeloma.1 This potentially makes excess body fat the second most important modifiable cancer risk factor after tobacco use.

The study by Kyrgiou and colleagues2 took up the challenge of evaluating the robustness of multiple, sometimes overlapping, meta-analyses that reported an association between body adiposity measures (such as body mass index, weight gain, and waist circumference) and cancer. The authors conducted an umbrella review, also known as a “review of reviews” or “meta-review,”34 and initially identified a total of 204 individual meta-analyses from 49 papers. They further examined the 95 meta-analyses that reported the association between body fatness measured on a continuous scale (mostly body …