Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies

Authors:Meta-Analysis, Lancet Body Mass Index Collaborative
This meta-analysis of 57 prospective studies is often quoted. Despite the conclusions made, the actual data indicate that smoking is a pretty good predictor of early death. Beyond that life expectancy appears to be reduced by 8-10 years at BMI 40+ There is also a definite excess mortality below BMI 22.5 that appears to be not fully explained with smoking-related disease. More questions than answers.