According to the clinical oncologist at Inca Ronaldo Corrêa, research coordinator, in general, cancer is a multifactorial disease. This means that there are several risk factors for the disease, including the consumption of tobacco, alcohol and red meat, physical inactivity and overweight or obesity.
The study concluded that the expenses with cancers linked to excess weight are high, considering the calculation of the attributable fraction. “We take the prevalence of the risk factor in the population, that is, how many people are overweight in the Brazilian population at different age groups and by sex and see what the prevalence of this risk factor is. The higher the prevalence, the greater the chance that the risk factor has been causing the cancer ”, said Corrêa today (5), in an interview with Agency Brazil.
The researchers consider yet another epidemiological factor, which is the relative risk. This measure of association indicates the chance that a person with obesity will have cancer compared to one who is not overweight. From the two measures – prevalence and relative risk – these values are applied to the Brazilian population and arrive at the assigned fraction.
The result shows how much excess weight contributes to the various types of cancers associated with obesity. The Inca study showed that, in endometrial cancer (body of the uterus), for example, the rate was around 24%. “So, 24% of endometrial cancers in Brazil, according to our study, are due to being overweight,” said the doctor. This means that, for every four cancers of the endometrium, one is due to being overweight.
According to Corrêa, in breast cancer, obesity contributes 5%; in colorectal cancer, with 1.8%; in gallbladder cancer, with 8%; in cancer of the end of the esophagus, cm, 16%; in advanced prostate cancer, with 2.5%. “In each cancer that is associated with being overweight, this factor has a relative contribution”.
The oncologist explained that if excess weight is eliminated among Brazilians, there may be 5% fewer cases of breast cancer, 25% less cases of endometrial cancer, and so on. The Inca study found that 80% of all cancer expenditure attributable to being overweight was for treatment of malignant breast, colorectal and endometrial tumors. Although the contribution of excess weight is relatively small for breast and colorectal cancers, when compared to endometrial cancers, the economic impact is high due to the high incidence of these cancers in the country.
Recent data from the National Health Survey, from the Ministry of Health, show the advance of overweight and obesity in the Brazilian population in recent years. The percentage of obese people in adulthood more than doubled in 17 years, going from 12.2%, between 2002 and 2003, to 26.8%, in 2019. During this period, the proportion of overweight adults went from 43.3% to 61.7%, which represents almost two thirds of Brazilians. Among the youngest, the data is also of concern: one in five adolescents aged 15 to 17 years was overweight, and about a third of people aged 18 to 24 are obese.
Ronaldo Corrêa warned that an overweight child or adolescent is at great risk of becoming an overweight adult. “Overweight in childhood and adolescence is likely to be a risk factor for people to remain overweight in adulthood.” Later, in adulthood, this teenager will be at risk of developing cancer.
The doctor argued that an analysis of Brazil in the past 20 years will indicate that there was an increase in excess weight in both the adult population and that of children and adolescents. For the experts, this signals that, in the future, there will be several health problems. “Not only cancer, but cardiovascular diseases, diabetes, among them.”
According to the coordinator of the Inca study, the treatment of excess weight could represent savings of R $ 60 million in the expenditure of R $ 1.4 billion registered by the federal government in SUS in 2018. The money saved with the elimination of this risk factor risk could be applied to more prevention and more effective treatments, which can reduce cancer mortality.
In Corrêa’s assessment, the social distance and confinement adopted to prevent the spread of covid-19 may increase the percentage of obese people in the country, due to a sedentary lifestyle and the increased consumption of processed and ultra-processed foods. “It is likely that, with these factors, there was an increase in excess weight in the population.” He clarified, however, that weight gain does not mean that the person will get cancer immediately. “There is what we call gap [lacuna] temporal. The person will spend a few years exposed to that risk factor to develop cancer. ”
Corrêa explained that the person begins adulthood at age 20. If she is overweight until she is 30, from 40, 50, 60 years old, she is much more at risk of cancer than adults who have kept their ideal weight. The doctor pointed out, however, that at the end of the pandemic, those who gained weight in this period can return to normal activities and lose weight. “It is not a condemnation,” said Corrêa, who defined the pandemic as a transitory event that will pass.
The director general of Inca, Ana Cristina Pinho, said that the results of the study can help policy makers, such as the institute itself, to give priority to cancer control actions, seeking a balance between what is spent on prevention, specifically overweight, and what is spent on cancer treatment.
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