The relationship between body mass index (BMI) and mortality is controversial.
Dr Edward Yu and colleagues investigated the relationship between maximum BMI over 16 years and subsequent mortality.
The research team performed 3 prospective cohort studies, including the Nurses' Health Study I and II and Health Professionals Follow-Up Study.
The researchers observed 225,072 men and women with 32,571 deaths over a mean of 12 years of follow-up.
The team evaluated maximum BMI over 16 years of weight history and all-cause and cause-specific mortality.
|Maximum overweight was also associated with increased cause-specific mortality|
|Annals of Internal Medicine|
Maximum BMIs in the overweight, obese I, and obese II categories were associated with increases in risk for all-cause death.
The research team found that pattern of excess risk with a maximum BMI above normal weight was maintained across strata defined by smoking status, sex, and age, but the excess was greatest among those younger than 70 years and never-smokers.
In contrast, a significant inverse association between overweight and mortality was observed when BMI was defined using a single baseline measurement.
The team determined that maximum overweight was also associated with increased cause-specific mortality, including death from cardiovascular disease and coronary heart disease.
Dr Yu's team comments, "The paradoxical association between overweight and mortality is reversed in analyses incorporating weight history."
"Maximum BMI may be a useful metric to minimize reverse causation bias associated with a single baseline BMI assessment."