Relationship Between Body Mass Index And Physical Function In Adults

Abstract

PURPOSE To determine the relationship between body mass index (BMI) and physical function in normal (BMI 18.5–24.9 kg*m−2), overweight (25.0–29.9 kg*m−2), and obese (>30.0 kg*m−2) adults. A secondary purpose was to determine the relationship between two methods of assessing physical function. METHODS Ninety-eight male and female subjects, ages (mean±SE) 40±14 y and BMI 27.2±4.9 kg*m−2, completed two tests of physical function: the timed get-up and go test (TGUG), in which the time required to rise from a chair, walk 3 m, and return to the chair was measured, and the physical functioning domain of the Short-Form 36 Health Status Survey (SF-36). The correlation between BMI and TGUG time and BMI and SF-36 score were used to evaluate the relationship between BMI and physical function. The TGUG time and SF-36 physical functioning domain score among the three BMI groups were also compared. RESULTS There was a significant relationship between BMI and TGUG time (r=0.40, p<0.001) and between BMI and SF-36 physical functioning score (r=−0.22, p<0.05). There was also a significant relationship between TGUG time and SF-36 score (r=0.37, p<0.001). Additionally, the mean TGUG time was significantly higher (p<0.01) in the obese group (9.07±1.46 s) compared to the normal (7.78±1.58 s) and overweight (7.90±1.09 s) groups. Likewise, the mean SF- 36 score was lower in the obese group (83±21) compared to the normal (91±15) or overweight (91±12) groups, although this difference was not statistically significant (p=0.07). CONCLUSIONS These findings indicate that there is a relationship between BMI and TGUG time and between BMI and SF-36 score and suggest that obese individuals have a lower level of physical function. The results also show that there is a significant relationship between TGUG time and SF-36 score.