Percentage height of center of mass is associated with the risk of falls among elderly women: A case-control study.

Falls are a serious health problem for aged people, causing social and economic burden. Despite being an important determinant of balance, the positioning of the center of mass (COM) has not been evaluated as a risk factor for falls. This study examined the association between the percentage height of COM (%COM) and the risk of falls in the elderly. Healthy women aged 60 years and older were consecutively selected in a case-control study. Forty-eight individuals classified as "fallers" (having suffered two or more falls in the previous year) were the cases while 48 age and weight-matched women with one fall or no falls in the previous year were the controls ("non-fallers"). Body composition and bone mineral density (BMD) by DXA, 30-second chair stand test, abdominal circumference, Berg's balance scale and %COM using the reaction board method were evaluated in all participants. Body composition parameters were not significantly different between groups. Spine and hip BMD tended to be lower in the fallers, but the difference was significant only at the femoral neck (0.80±0.10g/cm(2) versus 0.87±0.76g/cm(2); p<0.01). Berg's balance scale scores were lower among fallers than non-fallers (p<0.05). Percentage height of COM was significantly higher among fallers (p<0.001) and this was associated with a higher number of fractures (p<0.05). Percentage height of COM is significantly higher in the elderly with frequent falls. Further work is needed in order to determine the value of board reaction measurements in a clinical setting to identify patients at high risk.