INTRODUCTION

The population of elderly has increased worldwide in recent decades, and it is estimated that this growth will continue in the coming years. According to the world health organization (who), in the year 2000, older adults accounted for 10% of the global population¹. In Peru in 2020, older adults represented 11% of the population, corresponding to approximately 3,613,000 individuals. The increase in this population is attributed to the demographic transition taking place in Peru². Elderly are highly susceptible to malnutrition and specific nutritional deficiencies. Vitamin B12 deficiency is caused by decreased absorption due to age-related factors such as hypochlorhydria or intrinsic factor deficiency³. Cobalamin or vitamin B12 plays an important role in the development and maturation of the central nervous system, neurotransmitter metabolism, and red blood cell formation. Cobalamin deficiency in older adults is associated with neurological manifestations, metabolic disorders, megaloblastic anemia, cardiovascular diseases, and mental disorders^3-6. In Peru, there is a lack of information regarding the association between vitamin B12 deficiency and cognitive impairment, despite the negative impact of this deficiency on the quality of life of older adults. The information obtained in this study aims to raise awareness about this issue and contribute to addressing this public health problem. Based on the above, the following research is proposed with the objective of determining the association between low vitamin B12 levels and cognitive impairment in elderly at the naval medical center of Peru, Lima, 2010-2015.

METHODOLOGY

RESULTS

The majority of patients seen were male, accounting for 57.6% of the sample, and the average age was 78 ± 8.4 years. Most patients were classified as elderly (75-90 years), representing 64.4% of the sample. Additionally, the majority had more than 11 years of education, accounting for 72.5%. Finally, the main pathologies observed in the study among the older adult patients are described. Diabetes mellitus was present in 18.3% of cases. Hypothyroidism was present in only 11% of all patients. Cerebrovascular disease was observed in 4.4% of the patients. Depression was present in 25.2% of the patients. As for the mini-mental state test, 41.2% showed cognitive impairment. Regarding vitamin B12 levels, 90.5% of the patients did not have a vitamin B12 deficiency (table 1).

Table 2describes the variables in relation to mmse ≤ 24, showing an association between hypothyroidism (p<0.001), cerebrovascular disease (p<0.001), depression (p<0.0001) and vitamin B12 (p=0.003) with cognitive impairment.

The factors independently associated with cognitive impairment were a history of cerebrovascular disease (pr = 1.375, 95% ci [1.239-1.527]), depression (pr = 1.881, 95% ci [1.796-1.971]), and vitamin B12 deficiency (pr = 1.102, 95% ci [1.012-1.200]) (table 3).

DISCUSSION

The present study found an association between low levels of vitamin B12 and cognitive impairment. Additionally, an association was found between a history of cerebrovascular disease (cvd) and depression with cognitive impairment. Vitamin B12 and folic acid are crucial in the methylation processes of the central nervous system, and their deficiency can lead to neuropsychiatric disorders and vascular cognitive impairment due to hyperhomocysteinemia and excitotoxic mechanisms¹¹. Previous studies have also described the association between cobalamin levels and cognitive function. Meertens et al. Conducted a study in a nursing home in Venezuela¹², Vogel et al. Conducted a longitudinal study in Spain¹³and Aguilar et al. Conducted a study in outpatient patients at a hospital in Mexico¹⁴all finding a significant relationship between low cobalamin levels and cognitive function.

Silva et al.¹⁵also found that vitamin B12 deficiency is common in older individuals and can lead to reversible dementia. In older adults aged 60 years and above with dementia, the prevalence of vitamin B12 deficiency has been determined to be 7.5%. Significant improvement in the median mmse score was observed at 6 weeks and 12 weeks after vitamin B12 supplementation¹⁶. This is explained by the fact that vitamin B12 deficiency leads to elevated homocysteine levels, which are a risk factor for vascular disease and cause DNA damage in the brain¹⁷.

Finally, this study found an association between cognitive impairment and a history of cerebrovascular disease (cvd). In Japan, the prevalence of cognitive impairment after a 3-year follow-up following a stroke increased with advanced age. Previous studies have also reported that the prevalence of cognitive impairment following a stroke ranges from 20% to 80% (¹⁸). Therefore, as a result of the high rates of mortality and disability associated with stroke occurrence, managing significant risk factors is of utmost importance in older adults¹⁹.

Similarly, vitamin B12 supplementation could be beneficial in reversing these symptoms in older adults. A case presented by Behres et al. At a hospital in Chile showed that treatment with parenteral cobalamin and vitamin b9 reversed the symptoms, leading to normal results in neuropsychological tests and consequently reintegrating the individual into their work²⁰. Additionally, vitamin b supplements have been found to delay or maintain cognitive decline in older adults²¹. However, it is indicated that higher dietary intake of folate, but not B12 or b6, is associated with a reduced risk of dementia in the elderly population without dementia, thus requiring further studies²².

Among the limitations of the present study, it was found that some variables could not be measured due to missing data in the original database or were unrelated to the patient. Additionally, this study was conducted at a Military Hospital In Peru, which may have some differences compared to findings in public hospitals under the Ministry Of Health Or The Social Health Insurance (ESSALUD). However, these older adults represent a significant percentage of patients living in middle-class areas of lima, where there is a considerable increase in the elderly population. Therefore, the results are important for obtaining an approximation of the influence of vitamin B12 on cognitive impairment in this population.

CONCLUSIONS

In this population, an association was found between low levels of vitamin B12 and cognitive impairment. These findings may indicate the influence of cobalamin on cognition in geriatric patients, as well as the potential usefulness of vitamin supplementation in slowing the progression of cognitive disorders in older adults.