It is my understanding that curing all forms of cancer will add 3 years to life expectancy. Curing all forms of vascular disease would add something like 7. Doing both would add about 8-9 due to some redundancy.
When people talk about the health risks of smoking, they mostly talk about lung cancer (a form of cancer) or heart disease.
However if totally eliminating all forms of cancer and vascular disease would only add 8-9 years to life expectancy, how can a lifestyle factor like smoking remove 10 years? How does the math work? Most smokers will never get lung cancer, and lung cancer is just one of many forms of cancer. Ergo, wouldn’t the life expectancy hit of lung cancer due to smoking be measured in months (a subset of a subset of 3 years)? Aren’t something like 1/4 of deaths attributed to smoking due to lung cancer, and another 50% due to a higher risk of cardiovascular disease? But a total elimination of both these conditions would have a smaller impact on life expectancy than smoking itself.
Recently I read that waist to height ratio is a better predictor of health than BMI (waist size should be 1/2 your height). The study claimed that having a waist 80% the size of your height (so about a 58" waist on a 6’ man) can take 20 years off life expectancy.
I don’t get it. How does the math work? I saw another blog where a guy did a calculation on eliminating the top 20 causes of death combined. All forms of vascular disease, cancer, accidents, suicides, homicides, lung failure, diabetes, alzheimer’s, etc. His calculation was if you eliminated all 20, then life expectancy goes up by about 20 years. How can a large waist have the same impact on life expectancy as all these things combined?