Effect of co-morbidity on the association of high body mass index with walking limitation among men and women aged 55 years and older

BACKGROUND AND AIMS: Obesity among older persons is rapidly increasing, thus affecting their mobility negatively. The aim of this study was to examine the association of high body mass index (BMI) with walking limitation, and the effect of obesity-related diseases on this association. METHODS: In a representative sample of the Finnish population of 55 years and older (2055 women and 1337 men), maximal walking speed, chronic diseases, and BMI were ascertained in a health examination. Walking limitation was defined as maximal walking speed of less than 1.2 m/s or difficulty in walking 500 meters. To analyze the effects of chronic conditions, smoking, marital status, and education on BMI class differences in walking limitation, covariates were sequentially adjusted in logistic regression analyses. RESULTS: In women, an increasing gradient in the age-adjusted risk of walking limitation was observed with higher BMI: overweight (OR 1.47, 95% CI 1.10-1.96), obese (OR 2.77, 95% CI 2.01-3.82), and severely obese (OR 5.80, 95% CI 3.52-9.54). In men, the risk was significantly increased among the obese (OR 1.63, 95% CI 1.04-2.55) and severely obese (OR 4.33, 95% CI 2.20- 8.53). After adjustment of multiple covariates, the association remained significant among the obese (OR 1.99, 95% CI 1.38-2.86) and severely obese women (OR 3.64, 95% CI 2.12-6.26), as well as severely obese men (OR 2.78, 95% CI 1.30-5.95). Knee osteoarthritis in women and diabetes in men contributed most to the excess risk of walking limitation among obese persons, 18 and 32% respectively. CONCLUSIONS: Obesity increases the risk of walking limitation, independent of obesity-related diseases, smoking, marital status, and education, especially in older women. The results of this study emphasize the importance of maintaining normal body weight, in order to prevent obesity-related health risks and loss of functioning in older age.