A study developed by researchers from the Departments of Physiotherapy (DFisio) and Gerontology (DGero) at UFSCar identified that there is a relationship between low blood levels of vitamin D and the risk of developing functional disability in instrumental activities of daily living (IADL) in men.
The research was developed by Mariane Marques Luiz, currently a doctoral student in Physiotherapy at UFSCar, under the guidance of Tiago da Silva Alexandre, professor at DGero at UFSCar and coordinator of the International Collaboration of Longitudinal Studies of Aging (InterCoLAging), a consortium of longitudinal studies, which covers the English Longitudinal Study of Aging (ELSA Study), a large longitudinal study of the health of older people in England. The study also involved researchers from University College London (UCL) in the United Kingdom.
IADLs are everyday activities that require a higher level of complexity and attention during their execution, such as household activities, managing finances, and the ability to use means of transport and communication. These activities are essential for the maintenance of the functional capacity of the elderly, which reflects the ability to independently meet the physical demands of everyday life.
According to the researchers, previous studies have already identified that low blood levels of vitamin D impair functional capacity, because they compromise performance in basic activities of daily living (BADL), which are those related to self-care such as eating, bathing and dressing. if. However, it had not yet been verified whether vitamin D deficiency would also be associated with a higher risk of developing disability specifically in IADL. According to Mariane Luiz, “the research aimed to investigate whether vitamin D deficiency was a risk factor for developing disability in IADL and to verify whether this risk occurred differently between men and women”.
For this purpose, 4,768 English individuals participating in the ELSA Study, aged 50 years or older, who had no difficulty in any of the following IADL: managing finances, using means of transport, shopping, preparing meals, using the telephone/means of communication were evaluated. , manage medications and perform household chores. Subjects had their blood vitamin D levels classified as sufficient, insufficient or deficient and had other information collected such as socioeconomic data, lifestyle habits and health conditions. After four years of follow-up, these individuals were reassessed to see if there was any development of difficulty in performing one or more of the IADL. According to the author of the study, at the end of the four years of follow-up, no association was found between vitamin D deficiency and incidence of disability in IADL for women. However, vitamin D deficiency increased the risk of developing disability in men by 43%.
Tiago Alexandre explains “that vitamin D has an important action for the functioning of the muscles and, when its levels are low, it leads to muscle weakness and atrophy, which compromises the performance in daily activities, resulting in difficulty in IADL”. It also points out that “vitamin D plays a protective action on the central nervous system and there is evidence that its deficiency favors cognitive decline, which may explain the worse performance in IADL, since they are activities that need cognitive capacity preserved”.
The authors suggest that the results found only for men are possibly due to the association between vitamin D and testosterone. “Men experience greater atrophy of muscle fibers than women due to reduced testosterone levels with aging. Since vitamin D contributes to the production of testosterone, its deficiency can intensify muscle atrophy in these individuals”, they report. The researchers add that testosterone has a protective effect on cognitive ability and the reduction in its levels, which is intensified by vitamin D deficiency, may favor earlier cognitive decline in men. “Thus, the worst muscular and cognitive performance in these individuals may be associated with disability in IADL”, point out Mariane Luiz and Tiago Alexandre.
The research concluded that vitamin D deficiency represents an early indicator of functional impairment in the elderly and the authors reinforce that this deficiency is a modifiable condition. In addition, they emphasize that monitoring vitamin D levels can be a strategy to prevent difficulty in IADL and prevent the development of disability in the elderly.
The authors warn that the results found may be similar in the Brazilian scenario and that the assessment of vitamin D levels should be performed by measuring the concentrations of 25-Hydroxyvitamin D (25OHD) in the blood. Although the main source of vitamin D is sun exposure, when its levels are deficient, vitamin D supplementation should be a treatment strategy, needing to be prescribed only by nutritionists and doctors.
The study was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp), the Coordination for the Improvement of Higher Education Personnel (Capes) and the National Council for Scientific and Technological Development (CNPq). Recently, the research was published in Nutrients, a renowned journal in the field of Nutrition. The full article can be accessed at this link (https://bit.ly/3zu3Z0e).