The duration of overweight and obesity in women's adult lives is correlated with cancer risk in a PLOS Medicine longitudinal study.

Yet its finding are not going to be taken seriously because they use body mass index (BMI) and link it epidemiologically to the risk of developing several types of cancer, the go-to methodology of the International Agency for Research on Cancer (IARC), which has come under fire for conflating hazard and risk, declaring sausage as hazardous as cigarette smoking. BMI has been disqualified for such use because it has been so easily abused, yet lead author Melina Arnold of IARC does it anyway.  The team used United States Women's Health Initiative (WHI) data to create dose-response relationships between long-term obesity and cancer rather than cross-sectional information.

Using multiple BMI measurements over time from approximately 74,000 women (over 6,000 cancers diagnosed during the 12.6-year mean follow-up), Arnold and colleagues examined the association between duration of overweight, obesity and cancer risk, taking into account other factors related to obesity, such as physical activity, diet, smoking, hormone use, and diabetes. They found every ten-year increase in adulthood overweight duration was associated with a 7% (95% confidence interval 6%-9%) increase in the risk of all obesity-related cancers, 5% (3%-7%) increase in risk of postmenopausal breast cancer, and 17% (12%-22%) increase in the risk of developing endometrial cancer. After adjusting for the intensity of overweight, these figures rose to 8% (5%-12%) for postmenopausal breast cancer and 37% (29%-46%) for endometrial cancer. 

They are aware of the flaws, though media will not be. BMI is not a good measure for body fat, and the WHI cohort is dominated by white women.

Is obesity a factor for cancer? It certainly is, second only to cigarette smoking. Almost 99 percent of cancer will be related to lifestyle factors that exaggerate rather than claims about toxins and chemicals promoted by environmentalists. And certainly cell phones, hot drinks and glyphosate, all promoted by IARC, are basically irrelevant.