Spanish investigation warns the real impact of obesity on breast cancer risk is underestimated

Being obese or overweight increases the risk of developing some types of cancer, but the reason is not clear. Some research suggests that the reason lies in the changes it causes (long-term inflammation and higher insulin levels), or perhaps in changes in the body caused by these physical conditions.

In any case, this is an alarming fact that may turn out to be worse than expected. Thus, according to a study conducted by Dr. Veronica Davila-Bautista from the Institute of Research in Biomedicine and Health Sciences of the University of Las Palmas de Gran Canaria, About 40% of hormone-positive postmenopausal breast cancers can be associated with excess body fat.

This share significantly exceeds 10% of cases currently attributed to excess weight based on body mass index (BMI)and indicates that the true impact of obesity on breast cancer risk has likely been underestimated, says this study published in the Journal of Epidemiology and Public Health.

The authors argue that BMI is not necessarily a very accurate measure of body fat, especially in older women, because it does not take into account age, gender or ethnicity.

The researchers compared BMI with the CUN-BAE equation, a useful tool for identifying women at higher risk of mortality among 1,033 postmenopausal women with breast cancer and 1,143 women without the disease but matched for age, sex and geographic location. region.

All women participated in the multiple case-control (MCC)-Spain study, which included 10,106 subjects and aims to evaluate environmental and genetic factors associated with colorectal, breast, gastric and prostate cancers, as well as chronic lymphocytic leukemia among people in their 20s. 85 years old.

All participants were asked about potentially influential risk factors: sociodemographics, lifestyle, and personal and family medical and reproductive history.

Dietary information was collected using a validated 140-item semi-structured food frequency questionnaire, and a self-administered questionnaire was used to collect information on habitual alcohol consumption in people aged 30 to 40 years.

CUN-BAE classifies body fat as: less than 35%; 35–39.9%; 40–44.9%; and 45% or more. On the other hand, BMI classifies weight as: less than 25 kg/m2; 25–29.9; 30–34.9; and 35 and older.

Well, the average BMI was just over 26 in the comparison group and just over 27 in the women with breast cancer. In contrast, the average CUN-BAE was just under 40% and almost 40.5%, respectively.

CUN-BAE of 45% or more was associated with more than double the risk of postmenopausal breast cancer compared with CUN-BAE of less than 35%.

In contrast, a similar trend was not observed for BMI, allowing the researchers to estimate that 23% of breast cancer cases were associated with excess body fat according to BMI, and 38% were associated with excess body fat according to CUN-BAE.

But these differences were found only in hormone-positive cancers. (680 cases) in which the estimated proportion of excess body fat was 20% (BMI) and 42% (CUN-BAE).

Causal factors cannot be established based on the results of this case-control study, say the researchers, who also acknowledge that the CUN-BAE formula was calculated based on sample of sedentary people and that the number of breast cancer cases that were not hormone positive was small.

However, “our study results indicate that excess body fat is a significant risk factor for hormone receptor-positive breast cancer in postmenopausal women” and that the true impact of obesity on women has likely been underestimated when using BMI. assessments, influence.

In this sense, the authors argue that “more accurate measures of body fat, such as CUN-BAE, should be considered when estimating the cancer burden associated with obesity in postmenopausal breast cancer.” This is critical for planning effective preventative measures. they add.