J Gerontol A Biol Sci Med Sci. 2011 Feb 16.
Change in 25-Hydroxyvitamin D and Physical Performance in Older Adults.
Houston DK, Tooze JA, Hausman DB, Johnson MA, Nicklas BJ, Miller ME, Neiberg RH, Marsh AP, Newman AB, Blair SN, Kritchevsky SB.
BACKGROUND: Vitamin D deficiency is common among older adults and is associated with poor physical performance; however, studies examining longitudinal changes in 25-hydroxyvitamin D (25OHD) and physical performance are lacking. We examined the association between 25(OH)D and physical performance over 12 months in older adults participating in the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P), a multicenter physical activity intervention trial.
METHODS: Plasma 25(OH)D and physical performance, assessed by the short physical performance battery (SPPB) and 400-m walk test, were measured at baseline, 6-month, and 12-month follow-up in community-dwelling adults aged 70-89 years at risk for disability (n = 368). Mixed models were used to examine the association between 25(OH)D and physical performance adjusting for demographics, intervention group, season, body mass index, and physical activity.
RESULTS: One half of the participants were vitamin D deficient (25OHD < 20 ng/mL) at baseline. In cross-sectional analyses, vitamin D deficiency was associated with lower SPPB scores and slower 400-m walk speeds (mean difference SE: 0.35 0.16, p = .03 and 0.04 0.02 m/s, p = .01, respectively). Although baseline 25(OH)D status was not significantly associated with change in physical performance over 12 months, individuals who were vitamin D deficient at baseline but no longer deficient at follow-up had significant improvements in SPPB scores (mean difference SE: 0.55 0.22, p = .01) compared with those whose 25(OH)D status remained the same.
CONCLUSION: Increases in 25(OH)D to greater than or equal to 20 ng/mL were associated with clinically significant improvements in physical performance among older adults.
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“All analyses were adjusted for randomization arm and a randomization arm by study visit interaction term. Furthermore, there was not a significant interaction between 25(OH)D status and randomization arm, and the associations between 25(OH)D status and physical performance were similar when the analyses were restricted to the successful aging arm. Among those participants whose 25(OH)D improved, we do not have information on why 25(OH)D improved, such as changes in dietary or supplemental intake of vitamin D or sun exposure.”
The researchers controlled for physical activity, and alluding to the idea that “getting physical activity got the elderly outdoors,” where they then got Vitamin D, would not be an accurate take-away from this study.
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Known: Seniors whose vitamin D levels went up during the study exercised more at the end of the study
- Overview Seniors lack Vitamin D
- Overweight and elderly both sunbathe less - 2009
- Elderly often trapped in vitamin D vicious circles getting outdoor breaks those downward circles