What BMI's have been found to have the lowest mortality risk in smokers and non-smokers?
return BMI 's ;return mortality risk in  smokers of #1 ;return mortality risk in  non-smokers of #1 ;return #1 where #2 is the  lowest ;return #1 where #3 is the  lowest ;return #1 in  both #4 and  #5
['select', 'project', 'project', 'comparative', 'comparative', 'intersection']