Association of Serum 25-Hydroxyvitamin D Deficiency with Risk of Incidence of Disability in Basic Activities of Daily Living in Adults >50 Years of Age.

BACKGROUND: Vitamin D deficiency compromises muscle function and is related to the etiology of several clinical conditions that can contribute to the development of disability. However, there are few epidemiological studies investigating the association between vitamin D deficiency and the incidence of disability. OBJECTIVES: We aimed to assess whether vitamin D deficiency is associated with the incidence of disability in basic activities of daily living (BADL) and to verify whether there are sex differences in this association. METHODS: A 4-y follow-up study was conducted involving individuals aged 50 y or older who participated in ELSA (English Longitudinal Study of Ageing). The sample consisted of 4814 participants free of disability at baseline according to the modified Katz Index. Vitamin D was assessed by serum 25-hydroxyvitamin D [25(OH)D] concentrations and the participants were classified as sufficient (>50 nmol/L), insufficient (>30 to ≤50 nmol/L), or deficient (≤30 nmol/L). Sociodemographic, behavioral, and clinical characteristics were also investigated. BADL were re-evaluated after 2 and 4 y of follow-up. The report of any difficulty to perform ≥1 BADL was considered as an incident case of disability. Poisson models stratified by sex and controlled for sociodemographic, behavioral, and clinical characteristics were carried out. RESULTS: After 4-y follow-up, deficient serum 25(OH)D was a risk factor for the incidence of BADL disability in both women (IRR: 1.53; 95% CI: 1.16, 2.03) and men (IRR: 1.44; 95% CI: 1.02, 2.02). However, insufficient serum 25(OH)D was not a risk factor for the incidence of BADL disability in either men or women. CONCLUSIONS: Independently of sex, deficient serum 25(OH)D concentrations were associated with increased risk of incidence of BADL disability in adults >50 y old and should be an additional target of clinical strategies to prevent disability in these populations

Accuracy of different handgrip values to identify mobility limitation in older adults

BACKGROUND/OBJECTIVE: Mobility limitation is commonly the first sign of impaired physical function and predisposes older adults to disability. Moreover, recent epidemiological studies have classified neuromuscular strength as the best explanator of mobility limitation. However, existing cutoffs have not been adequately analyzed regarding accuracy. Therefore, our aims were to define and compare the accuracy of different cutoff points of handgrip strength for the identification of mobility limitation. METHODS: Cross-sectional study with 5783 participants from the SABE (Saúde, Bem-Estar e Envelhecimento [Health, Wellbeing and Aging]) and ELSA (English Longitudinal Study of Ageing) cohorts aged 60 years or older. Handgrip strength was measured using a dynamometer. Walking speed <0.8 m/s was considered mobility limitation. Receiver operating characteristic curves and probabilities of presenting mobility limitation were calculated. RESULTS: Handgrip strength <32 kg for men and <21 kg for women demonstrated good diagnostic accuracy for mobility limitation, with 49.1% sensitivity and 79.8% specificity for men and 58.6% sensitivity and 72.9% specificity for women. The fully adjusted models had an area under the curve of 0.82 for men and 0.83 for women, with odds of presenting mobility limitation of 1.88 [95% CI: 1.50 - 2.37] for men and 1.89 [95% CI: 1.57 - 2.27] for women. CONCLUSIONS: The results of this study support the accuracy of handgrip strength as a clinical marker of mobility limitation. Furthermore, manual dynamometry is easily incorporated into clinical practice, has a good cost-benefit, besides being a simple, valid, reliable and effective method for use in both the scientific community and outpatient practice