Vitamin D deficiency intensifies deterioration of risk factors, such as male sex and absence of vision, leading to increased postural body sway

INTRODUCTION: Due to inconsistent findings, the influence of vitamin D on postural body sway (PBS) is currently under debate. This study evaluated the impact of vitamin D on PBS with regards to different foot positions and eye opening states in community-dwelling older individuals.

METHODS: In a cross-sectional study, we assessed PBS in 342 older individuals (264 females [average age (± SD): 68.3 ± 9.0 years], 78 males [65.7 ± 9.6 years]). A detailed medical history and vitamin D level were obtained for each individual. Fall risk was evaluated using the New York-Presbyterian Fall Risk Assessment Tool (NY PFRA). PBS parameters (area, distance, velocity, frequency) were evaluated on a pressure plate with feet in closed stance (CS) or hip-width stance (HWS), open eyes and closed eyes. Statistical analysis included logarithmic mixed models for repeated measures with the MIXED model procedure to test the influence of vitamin D (categorized in <10 μg/l, 10-20 μg/l, 21-30 μg/l, >30 μg/l), foot position, eye opening state, age, sex and frequency of physical activity on PBS.

RESULTS: Vitamin D was not an independent risk factor for falls experienced in the last 12 months. Nonetheless, PBS was higher in patients with vitamin D deficiency (<10 μg/l) in HWS (A/P p=0.028 and area p=0.037). Additionally, vitamin D deficiency intensified the deleterious effects of male sex (distance p=0.002) and absence of vision (area p<0.001) on PBS.

CONCLUSION: Independent risk factors for increased PBS like male sex and absence of vision are additionally compromised by vitamin D deficiency.