The incidence of obesity in the Australian population has doubled over the past 20 years, so overweight and obesity may be directly associated with the development of 10,000 thyroid cancer patients over the next 10 years. Recently, a research report published in the international journal International Journal of Cancer entitled "Thyroid cancers potentially preventable by reducing overweight and obesity in Australia: a pooled cohort study", Scientists from institutions such as the University of New South Wales have assessed for the first time the burden of future thyroid cancer in Australian populations through research and found that avoiding excessive weight, especially obesity, may be a priority for preventing thyroid cancer.
Image source: Shutterstock
In the article, the researchers found that one in five thyroid cancer patients in Australia may be closely related to the current population levels of overweight and obesity. Researcher Dr Laaksonen points out that this may be very worrying because the incidence of obesity in the Australian population has doubled in the past 20 years, and 75% of Australian men and 60% of Australian women are overweight or obese. The findings in this paper mean that nearly 10,000 thyroid cancer patients will be diagnosed over the next 10 years, and obesity explains 75% of the burden Australia faces.
Now the International Cancer Research Structure has come to the clear conclusion that obesity is a causal risk factor for thyroid cancer; in this study, researchers for the first time assessed the burden of thyroid cancer in a population attributed to the current population's levels of excess weight and obesity, and the researchers also compared differences in this burden by sex. Thyroid cancer is one of the few types of cancer that is more common in women than in men, and the researchers found that the burden of future thyroid cancer may be more common in men who are overweight or obese than women.
Being overweight or obese can explain the occurrence of thyroid cancer in two-fifths of men and one in ten thyroid cancers in women; researchers still don't know exactly what causes the sex differences in thyroid cancer risk associated with overweight or obesity. However, the study in this paper provides some evidence for inhibiting and reversing the current trend of weight gain in the global population, especially the weight gain of men. Although this paper found that one in five thyroid cancers occur in the Australian population, the remaining four-fifths of thyroid cancers are not well understood.
Other lifestyle factors do not appear to be involved, but ionizing radiation exposure, iodine deficiency, and some genetic risk factors and family history are all factors known to increase the risk of thyroid cancer, which is a bit like prostate cancer, and researchers are not very clear about what the risk factors are. The results are based on seven Australian cohort studies involving 370,000 participants, which may help researchers conduct a comprehensive analytical assessment of less common cancers such as thyroid cancer.
Researcher Laaksonen said we linked data from these seven studies to data from the National Cancer and Death Database, which determined the BMI of participants' bodies at baseline, which allowed the researchers to assess the strength of the association between BMI-cancer and BMI-death during follow-up. The researchers analysed the latest prevalence of overweight and obesity in the Australian population from the latest National Health Survey 2017-2018, and then combined assessments of associated intensity and exposure prevalence to infer population attributable fractions (PAFs) ;P AFs describe that part of future cancer at population level is explained by current exposure. Researchers have done this by using the advanced PAF they have developed.
Image source: https://onlinelibrary.wiley.com/doi/10.1002/ijc.33889
This advanced PAF approach, which allows researchers to make unbiased disease burden projections and compare preventable disease burdens by population subpopulation at research centers, requires large cohort data; since the prevalence of overweight or obesity in male groups is higher than in women, this may increase the sex difference in thyroid cancer burden. Finally, researcher Laaksonen said, we multiply the estimate of PAF by the predicted number of thyroid cancer diseases in the next decade (2021-2030) to obtain the absolute number of thyroid cancer patients predicted due to obesity.
The study aims to assess for the first time the future preventable burden of cancer in the Australian population and its determinants; the next step will be for the researchers to conduct a study of the preventable burden of a variety of other cancers, including stomach and esophageal cancer, and they will also submit a summary document on the preventable burden of all cancers in Australia. In summary, the results of this paper suggest that avoiding overweight, especially obesity, may be effective in preventing the occurrence of thyroid cancer, and after further research, the stratification of tumor size may also reveal the potential role of overdiagnosis in the results of this study.
Original source:
Maarit A. Laaksonen,Robert J. MacInnis,Karen Canfell, et al. Thyroid cancers potentially preventable by reducing overweight and obesity in Australia: a pooled cohort study, International Journal of Cancer (2021). DOI:10.1002/ijc.33889