First would be our genetics. 50% of the odds of your dying in a given year is determined by your genetics, how long people in your family lineage have lived.
Second is disease. 50% of the chance that you will get a debilitating or terminal disease, especially cancer, is a throw of the dice, good or bad luck on whether particular genes randomly mutate to a bad place when cells divide, we get to influence only 30% of the risk of our getting cancer by changing lifestyle, diet, supplements, whatever.
Third would be our early life situation. 50% of what determines your cognitive vitality and intelligence in later life depends on how you started out - your intelligence when you were 11 years old. Your general cognitive ability with respect to your peers remains constant over your life course.
The bottom line is that ~2/3 of the odds of whether we are going go bonkers or croak at a given age is random chance, genetics, or early life experience over which we had no control.The balance of the talk deals with the 30% or so of the odds we can influence: what we eat and drink, how we move, how we think, how we socialize.