INTRODUCTION Age-related cognitive disorders, including Alzheimer disease, are among the main causes of disability and dependence in older adults worldwide. High blood homocysteine levels (hyperhomocysteinemia) are a risk factor for diseases whose metabolism involves different B vitamins. Antioxidant vitamins provide a protective effect by mitigating oxidative stress generated by these diseases. Epidemiological studies have presented varying results on the relationships between blood levels of these vitamins and such cognitive disorders.

OBJECTIVE Evaluate the association of vitamin and homocysteine levels with mild cognitive impairment and Alzheimer disease in a group of Cuban older adults.

METHODS A cross-sectional study was conducted in Havana, Cuba, of 424 persons aged ≥65 years: 43 with Alzheimer disease, 131 with mild cognitive impairment, and 250 with no signs of cognitive impairment. Dementia was diagnosed using criteria of the International 10/66 Dementia Research Group and Diagnostic and Statistical Manual of Mental Disorders (DSM IV), and mild cognitive impairment was diagnosed using Petersen’s criteria. Blood levels of vitamins (thiamine, B-2, folate, B-12, C and A) and homocysteine were measured by standard procedures. Analysis of variance for continuous variables and percentage comparison tests for dichotomous variables were used to compare groups.

RESULTS Persons with Alzheimer disease presented significantly lower levels of vitamins B-2, C and A than healthy participants (p <0.05). Homocysteine levels were significantly higher in those with Alzheimer disease and mild cognitive impairment than in participants with no cognitive impairment (p <0.05). Statistically, levels of thiamine, folic acid, and vitamin B-12 were not significantly different across groups. Compared with those without cognitive impairment, prevalence rates (PR) in the Alzheimer group were significantly higher for hyperhomocysteinemia (PR = 3.26; 1.84–5.80) and deficiency of all B vitamins: thiamine (PR = 1.89; 1.04–3.43), B-2 (PR = 2.85; 1.54–5.26), folate (PR = 3.02; 1.53–5.95), B-12 (PR = 2.21; 1.17–4.19), vitamin C (PR = 3.88; 2.12–7.10) and A (PR = 5.47; 3.26–9.17). In mild cognitive impairment, prevalence rates were significantly higher for hyperhomocysteinemia (PR = 1.42; 1.08–1.87), vitamin B-2 deficiency (PR = 1.70; 1.24–2.32) and vitamin A deficiency (PR =1.88; 1.05–3.38).

CONCLUSIONS Hyperhomocysteinemia and various vitamin deficiencies are related to Alzheimer disease and mild cognitive impairment. Longitudinal studies are needed to further elucidate the relationship between different nutritional biomarkers and dementia. A better understanding of this relationship could provide a basis for therapeutic and preventive strategies.

KEYWORDS Vitamins, homocysteine, geriatrics, Alzheimer disease, cognitive impairment, Cuba

Introduction Approximately 24.2 million persons throughout the world suffer dementia with 4.6 million new cases reported annually. Only 10% of dementia and Alzheimer’s disease studies are conducted in developing countries where 66% of sufferers live. Cuba, a developing country, exhibits health indicators similar to those of developed nations. Its population of 11.2 million is aging rapidly: by the year 2020 it is estimated that personas aged ≥60 years will comprise 21.6 % of the population, making Cuban society the “oldest” in Latin America.

Objectives Ascertain and characterize behavior of dementia, its etiologies and risk factors in persons aged ≥65 years in the Havana City municipality of Playa.

Methods A two-phase, cross-sectional, door-to-door study was conducted in the municipality targeting all persons aged ≥65 years, achieving a 96.4% response rate (n=18,351). Folstein Mini Mental State Examination (MMSE), Hughes Clinical Dementia Rating (CDR) and a structured interview on risk factors were applied. DSM-IV, NINCDS-ADRDA and NINDS-AIREN criteria were used to determine dementia diagnosis, as well as other criteria for diagnosing Alzheimer’s and other specific forms of dementia.

Results Dementia prevalence was 8.2% of adults aged ≥65 years, with a slight predominance in males. The most frequent cause of dementia was Alzheimer’s disease, followed by mixed dementias. Dementia-associated risk factors were: history of stroke, hypertension, depression, skull-brain trauma, family history of dementia, low educational level and advanced age.

Conclusions This study corroborates that dementia and Alzheimer’s disease constitute an important and growing health problem for our country due to the accelerated aging of the Cuban population. It also underlines the importance of early diagnosis and proper treatment of hypertension and other vascular risk factors, as well as the need for a national public health program for the prevention and early diagnosis of dementia and Alzheimer’s disease, targeting elderly and at-risk populations.

Keywords Brain diseases, dementia, mental disorders, neurodegenerative diseases, Alzheimer’s disease, aging

The following errata have been corrected in all versions of this article.

Page 29, Abstract, Introduction, final sentence should read: “Its population of 11.2 million is aging rapidly: by the year 2020 it is estimated that personas aged ≥60 years will comprise 21.6 % of the population, making Cuban society the “oldest” in Latin America.”

Page 29, Introduction, paragraph 4 should read: “Cuba is a developing country with health indicators similar to those of developed countries and a rapidly aging population of 11.2 million. By the year 2020 Cuba will have the oldest population in Latin America, with adults aged ≥60 years accounting for 21.6% of total population.”