The Association Between Zinc and Cognitive Impairment in Elderly People of Iran

Background: The association between serum zinc levels and cognitive impairment is a controversial issue. Objectives: The association between serum zinc levels and cognitive impairment was investigated in the elderly population of Amirkola city, northern Iran. Methods: The data of this cross-sectional study came from a large cohort study, known as the Amirkola health and ageing project (AHAP). The sample included 1004 eligible participants aged 60 years or older (486 females and 518 males). The staff of healthcare centers interviewed the participants and completed the Persian version of the Mini Mental State Examination (MMSE). Their serum zinc levels were measured using the ZishChem diagnostic kit. Results: Of all of the participants, 347 (33.3%) had cognitive impairment. Furthermore, 254 participants (25.2%) were classified as having mild cognitive impairment, 82 (8.2%) moderate, and 11 (1.1%) severe. A total of 160 females (32.9%) and 180 males (34.7%) were within the normal range of serum zinc (80 to 120 μg/dL), 133 females (27.4%) and 121 males (23,4%) were within the high range of serum zinc (> 120 μg/dL), and 193 males (39.7%) and 217 males (41.9%) were at low range of serum zinc (< 80 μg/dL). There was no difference between the 2 groups of the elderly population (normal MMSE and abnormal MMSE) with respect to the level of serum zinc. Conclusions: The results do not support the belief that serum zinc levels may be associated with cognitive function in the elderly population.