Loss of weight in obese older adults: A biomarker of impending expansion of multimorbidity?

Objectives To determine whether weight loss in older adults may be a marker of impending burden of multimorbidity regardless of initial weight, testing the hypotheses that obesity but not overweight in elderly adults is associated with greater number of diseases than normal weight and that obese older adults who lose weight over time have the greatest burden of multimorbidity. Design Longitudinal cohort study (Invecchiare in Chianti Study). Setting Community. Participants Individuals aged 60 and older at baseline followed for an average of 4 years (N = 1,025). Measurements Multimorbidity was measured as number of diagnosed diseases. Baseline body mass index (BMI) was categorized as normal weight (<25.0 kg/m²), overweight (25.0-29.9 kg/m²), and obese (≥30.0 kg/m²). Loss of weight was defined as decrease over time in BMI of at least 0.15 kg/m² per year. Age, sex, and education were covariates. Results Baseline obesity was cross-sectionally associated with high multimorbidity and greater longitudinal increase of multimorbidity than normal weight (P =.005) and overweight (P <.001). Moreover, obese participants who lost weight over follow-up had a significantly greater increase in multimorbidity than other participants, including obese participants who maintained or gained weight over time (P =.005). In nonobese participants, changes in weight had no effect on changes in multimorbidity over time. Sensitivity analyses confirmed that one specific disease did not drive the association and that competing mortality did not bias the association. Conclusion Loss of weight in obese older persons is a strong biomarker of impending expansion of multimorbidity. Older obese individuals who lose weight should receive thoughtful medical attention.