Vitamin D concentrations among older adults according to physical disability status: NHANES 2007-2014

Abstract

Background: older adults are at increased risk of vitamin D deficiency as a result of limited sun exposure and inadequate vitamin D intake. Despite this evidence, there are scarce data regarding the concentration of 25(OH)D and its metabolites among older adults with physical disability. Methods: the National Health and Nutrition Examination Survey 2007-2014 data were collected to compare 25(OH)D3, 25(H)D2, and total 25(OH) D concentrations among adults aged 60 years and older with and without physical disability. Moreover, general linear models adjusted for potential confounders were used to examine the independent effect of vitamin D intake, physical activity status and body mass index (BMI) categories on 25(OH)D concentrations by disability status. Results: of 6,250 older adults, 17.9% were defined as physically disabled. 25(OH)D concentrations were 71.3 and 78.2 nmol/l in subjects with and without disability, respectively. However, after adjustment for potential confounders, similar 25(OH)D concentrations were seen between disabled subjects and their non-disabled counterparts (75.6 vs 77.5 nmol/l; p = 1.17). In contrast, older adults with disability had significantly increased 25(OH)D2 concentrations (8.3 vs 6.1 nmol/l; p < 0.05). Notably, older adults with a daily vitamin D intake of ≥ 15 mcg achieved sufficient 25(OH) D concentrations, regardless of their disability status. Conclusion: 25(OH)D concentrations did not significantly differ among older adults by disability status. This finding was attributed to increased 25(OH)D2 concentrations among those with physical disability. Thus, adequate vitamin D intake is an effective strategy to maintain sufficient 25(OH)D concentrations, particularly among disabled older adults.