Weight gain changes the body shape and leads to mechanical constraints that can compromise daily living activities. Thus, it has been suggested that body weight is a strong predictor for postural
balance (PB). However, it seems controversial since studies reported no difference between obese and control group regarding the position of the center of pressure (COP) in static PB. Therefore, the
aim of this study was to evaluate the association of obesity with poor static PB in asymptomatic adults as well as with occurrence of falls in a subsample of middle-aged and older adults.
We conducted a cross-sectional study with 624 participants from the EPIMOV Study (Epidemiological Study of Human Movement and Hypokinetic Diseases). They were questioned about previous health problems
and history of falls. Then, we measured height, body mass, and circumferences of hip and waist. Cardiorespiratory fitness was obtained from the cardiopulmonary exercise testing. We assessed the level
of physical activity in daily life using triaxial accelerometers. Body composition was obtained through bioelectrical impedance. Muscle function was measured by using an isokinetic dynamometer. We
evaluated postural balance using the kinetic displacement of the COP on a force platform. Initially, the whole sample was stratified according to the quartiles of body mass index (BMI), waist-to-hip
ratio, waist-to-height ratio and percentage of fat body mass (FBM). We performed the MANOVA to compare which variables of the PB were different between quartiles. As for the associations with the
occurrence of falls, we carried out a logistic regression analysis adjusted for main confounders. The history of falls was considered as the outcome and the categorized aforementioned variables as the
The fourth quartile of BMI has the greater values for all variables, except for peak torque of the knee extension and peak V’O2, which indicates lower physical fitness in the most severe obesity. Our
results demonstrate differences between first and fourth quartiles, especially for body sway on the lateral-lateral direction in more challenging tasks (e.g., eyes closed and semi-tandem stance). When
established PB and body weight association, the most clinically relevant variable was the percentage of FBM. Thus, the use of body composition variables, measured by bioelectrical impedance, might be
more suitable for identifying obesity-related PB changes. Despite the association of greater severity of obesity and higher central obesity with worse PB, obesity was not related to the occurrence of
falls as shown by logistic regression analysis.
Obesity influences PB only in more severe cases and in situations with greater instability. Besides these aforementioned findings, body weight alone has little association with PB and the occurrence
of falls, after adjustment for the main confounders. We conclude that obesity per se presents little influence on the maintenance of static PB as well as to the occurrence of falls among subjects aged
40 years and above.