Vitamin D Deficiency Is Associated With Impaired Muscle Strength And Physical Performance In Community-Dwelling Older Adults: Findings From The English Longitudinal Study Of Ageing

Aspell N, Laird E, Healy M, Lawlor B, O'Sullivan M

Purpose: Maintaining skeletal muscle function throughout life is a crucial component of successful ageing. Adequate vitamin D status may be important in preserving muscle function. We aimed to determine the association between impaired muscle function and serum vitamin D status in community-dwelling older adults. Falls were explored as a secondary aim.

Methods: Data were analyzed from adults aged ≥60 years, from Wave 6 of the English Longitudinal Study of Aging (ELSA). Handgrip strength (HGS) and the short physical performance battery (SPPB) were employed as measures of muscle strength and physical function, respectively. Serum 25-hydroxyvitamin D [25(OH)D] was assessed with concentration <30 nmol/L classed as vitamin D deficient.

Results: The study comprised 4157 community-dwelling adults with a mean age of 69.8 (SD 6.9). Overall, 30.6% had low HGS and 12.7% had low SPPB (≤6). Participants with the lowest serum 25(OH)D (<30 nmol/L) had the highest prevalence of impaired muscle strength and performance (40.4% and 25.2%) compared with participants with levels ≥50 nmol/L (21.6% and 7.9%). Consistent with this, vitamin D deficiency (<30 nmol/L) was a significant determinant of low HGS (OR 1.44 [1.22, 1.71], p<0.001) and poor physical performance (OR 1.65 [1.31, 2.09], p<0.001) in the logistic regression models. Older adults partaking in regular moderate physical activity had significantly lower odds of impaired muscle strength (OR 0.65 [0.58, 0.79]) and physical function (OR 0.30 [0.24, 0.38]), p <0.001, respectively. Single or multiple falls (15.8% and 10.5% in past year) were not associated with vitamin D status.

Conclusion: Vitamin D deficiency was associated with impaired muscle strength and performance in a large study of community-dwelling older people. It is generally accepted that vitamin D deficiency at the <30 nmol/L cut-off should be reversed to prevent bone disease, a strategy that may also protect skeletal muscle function in ageing.