Relationship Between Body Mass Index, Depression, and Ambulation in a Multiple Sclerosis Population
Obesity has become a national epidemic within the U.S.1. However, less attention has focused on the relationship between obesity and disability due to multiple sclerosis (MS)2. Evidence suggests obesity, a pro-inflammatory state, may exacerbate neurological diseases,3 and may have implications for depression, quality of life (QoL), and ambulation. Data suggest depression and QoL are significantly worse in overweight/obese MS patients4. Evidence is mixed with regard to weight and ambulation but higher BMI has been associated with accelerated disability in MS5. Less is known about the relationship between ambulation and depression but a recent study found depression to be predictive of walking impairment over time6.
To expand current knowledge regarding the relationship between BMI, mood, QoL, and ambulation in an MS population.
Data collected retrospectively from a large clinical database at the Cleveland Clinic. Inclusion criteria: new/follow-up neurology visit at the Mellen Center during six-month period, >18 years of age, MS diagnosis, BMI data for visit, and ambulatory. Height/weight data collected exclusively by medical staff. Ambulation was measured by the Timed-25-foot-walk (T25FW), QoL by the EuroQOL (EQ-5D), and depression by the Patient Health Questionnaire (PHQ9).
Nearly 67% of the study sample (N=2256) was classified as overweight/obese. Separate multivariate linear regression models were run for T25FW, BMI, and PHQ9. For the T25FW model, BMI and depression were significant predictors of walking speed. Patients experienced a slower walking speed with a higher BMI as well as with higher levels of depressive symptoms. For the depression model, increased BMI was significantly associated with an increased PHQ total score. For the QoL model, increased BMI was significantly associated with a decreased EQ-5D index score.
Overall, higher body mass was associated with decreased walking speed, increased symptoms of depression, and lower QoL. Findings suggest obesity is associated with significant adverse outcomes for emotional/physical functioning in an MS cohort. Clinically, results suggest need for weight loss programs to target patients with higher BMI to possibly preserve or improve ambulation. The relationship between depression and decreased ambulation highlight the importance of ongoing depression screening at neurology visits, and appropriate referrals to behavioral medicine. Walking impairments have been identified as particularly damaging to QoL7; thus, a comprehensive approach to managing depression may have far reaching benefits for overall health of MS patients.
Future studies should utilize longitudinal designs, as well as examine the role of co-morbidities as they relate to obesity in MS; such understanding may provide clinical utility for providers and possibly improve long-term emotional/physical functioning of individuals with MS.