We found that this association between weight change and mortality rate depended on whether weight loss was intentional (P = 0.01 for interaction). To examine this interaction, we stratified data by both weight loss intention and actual weight loss (Table 2). When we controlled for age, sex, ethnicity, education, smoking, and initial BMI, persons with unintentional weight loss had a 77% higher mortality rate than persons who reported maintaining a stable weight and who were not trying to lose weight (HRR, 1.77 [CI, 1.38 to 2.26]). The excess mortality rate associated with unintentional weight loss was reduced to 31% (HRR, 1.31 [CI, 1.01 to 1.70]) in fully adjusted models and in models that excluded persons who smoked (HRR, 1.29 [CI, 0.95 to 1.77]) (Table 2). The increased mortality rate associated with unintentional weight loss was most evident (72% higher) in persons with a weight loss of at least 9.1 kg (HRR, 1.72 [CI, 1.24 to 2.38]) (Figure). Mortality rate was 38% lower in persons who gained weight and were not trying to lose weight (HRR, 0.62 [CI, 0.38 to 0.99]). This association tended to be stronger among men (HRR, 0.36 [CI, 0.16 to 0.80]) than women (HRR, 0.99 [CI, 0.56 to 1.73]) (data not shown) and diminished after those who smoked were excluded (HRR for men and women combined, 0.74 [CI, 0.44 to 1.24]) (Table 2).