Don't chew betel nut

High value
Evidence A
Buys life
Free
Takes minutes
Some willpower

In plain words

People who chew betel nut have about a 20% higher chance of dying over the same period than people who don't. Their risk of diabetes and metabolic syndrome is higher by nearly 50%. The risk of mouth cancer and esophageal cancer comes on top of that.

Cost: Free, and it takes no time; you also save the money you would spend on betel nut. The hard part is breaking the chewing habit.
What you get: Pooling 17 Asian studies with 388,000 (38.8万) people, people who chewed betel nut had about 21% higher risk of death than people who didn't (relative risk 1.21, P=0.02). The death figure is based on 179,600 (17.96万) of those people. The risk of diabetes was about 47% higher (1.47). The risk of metabolic syndrome was about 51% higher (1.51). Betel nut itself is also a known risk factor for mouth cancer and esophageal cancer
Notes: The more years you have chewed and the more you chew each day, the higher the risk of mouth cancer. After quitting, the risk goes down over time. Betel nut that contains tobacco is more dangerous
Evidence grade: A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.
Sources: Yamada T, Hara K, Kadowaki T (2013). Chewing betel quid and the risk of metabolic disease, cardiovascular disease, and all-cause mortality: a meta-analysis. PLoS One, 8(8), e70679. https://doi.org/10.1371/journal.pone.0070679

Translated from the Chinese original. Original book, section 2, tip 8. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer