BMJ : British medical journal
-
Multicenter Study
The association between BMI and mortality using offspring BMI as an indicator of own BMI: large intergenerational mortality study.
To obtain valid estimates of the association between body mass index (BMI) and mortality by using offspring BMI as an instrumental variable for own BMI. ⋯ Use of offspring BMI as a predictor of own BMI, a technique that avoids problems of reverse causality, suggests that positive associations of BMI with all cause and cardiovascular mortality may be underestimated in conventional observational studies. Use of offspring BMI instead of own BMI in analyses of respiratory disease and lung cancer mortality, for which previous studies have reported consistent and strong inverse associations with own BMI, suggests that such studies have overstated the apparent adverse consequences of lower BMI with respect to these outcomes.