Tobacco chewing has been linked to an increased risk of stroke and cancer
A meta-analysis of more than a hundred scientific papers on the health risks associated with tobacco chewing has found that people who practice it are more likely to experience strokes and certain types of cancer.
The authors of the paper, a team of scientists from the University of Washington in the US, noted that while chewing tobacco is not as common as smoking, an estimated 274 million people around the world use it in this way. Most live in Southeast Asia, predominantly India and Bangladesh. Often chewing tobacco is an important part of local customs and culture.
Statistics show that while global smoking rates have declined since the 1990s, the popularity of chewing tobacco seems to be increasing, including among adolescents and women. The harms of tobacco products are well known, yet some believe that smokeless chewable forms are not as dangerous. With their review, American scientists decided to draw attention to the topic and summarize the information available so far on the health risks of chewing tobacco.
After searching three scientific databases, the authors selected 111 papers on the topic, published from 1970 to January 2023. The researchers used meta-regression and Bayesian statistical methods to estimate the risks.
It turned out that chewing tobacco increased the risk of stroke by at least 16%, and the likelihood of esophageal cancer more than doubled. In the case of lip and mouth cancer, the relative risk ratio was 3.64. However, the scientists characterized the correlation as weak, noting that the risk of developing these cancers increased when the sample was limited to studies in Asian countries.
In addition, the meta-analysis found tobacco chewers had an increased risk of nasopharyngeal, pharyngeal and laryngeal cancers. The degree of correlation in these cases ranged from weak to moderate. However, the researchers found little evidence of an association between chewing tobacco and the development of coronary heart disease.
In conclusion, the authors emphasized the need to pay more attention to the negative effects of tobacco chewing and to strengthen the control of tobacco products.
Earlier, medics from South Korea found that quitting smoking reduces the risk of cancer at any age. Having analyzed data from almost three million residents of the country from 30 years, scientists found that those who quit smoking were 17% less likely to develop all types of cancer than current smokers. For such cancers as lung, liver and colon cancer, the reductions were 42%, 27% and 20%, respectively.