Long-term effects of change in body weight on all-cause mortality. A review.

OBJECTIVE: To summarize published studies analyzing the effects of long-term change in body weight on all-cause mortality and have not been reported elsewhere in these proceedings. DATA SOURCES: Thirteen reports from 11 diverse population studies, 7 from the United States and 4 from Europe. STUDY SELECTION: All studies included a weight change period of 4 or more years, followed by a mortality assessment period of 8 or more years. All weight changes occurred in persons 17 years or older. DATA EXTRACTION: Data from individual studies are presented as number of participants, number of deaths, ages at initial and final weight measurements, duration of the mortality follow-up period, consideration of cigarette smoking and other potential confounders, exclusion criteria, temporal separation between the weight change and mortality follow-up periods, and the association between weight change and all-cause mortality. DATA SYNTHESIS: Results are summarized by weight change associated with the lowest mortality rate and by the effects of long-term weight loss on mortality rate.
CONCLUSIONS: Despite the diversity of the populations studied, the degree of "clinical clean-up" at entry, the techniques used to assess weight change, and the differences in analytic techniques (including consideration of potentially confounding variables), certain conclusions may be drawn. Evidence suggests that the highest mortality rates occur in adults who either have lost weight or have gained excessive weight. The lowest mortality rates are generally associated with modest weight gains.