Association between Trace elements and cognitive function among Elderly Subjects with Osteoporosis: A retrospective study

Abstract

Background: Cognitive dysfunction and osteoporosis (OP) are common among elderly subjects. Different mechanisms are reported. However the potential role of trace elements is not well studied.  The current work aimed to estimate the toenail levels of trace elements in older patients with cognitive function with or without osteoporosis.

Methods:  In a retrospective manner, we collected data of people older than 60 years of age. We collected data of 165 subjects, with 1:1:1 distribution for studied groups (i.e., 55 subjects in each group). The first group for normal cognition with no OP; the second for cognitive dysfunction with no OP and the third for cognitive dysfunction with OP.  The cognitive function was determined by the mini-mental state examination (MMSE), while osteoporosis was diagnosed by the measurement of bone mineral density (BMD) with calculation of T-scores.  Toenail samples were collected and prepared to estimate the levels of trace elements. 

Results: Calcium and zinc were significantly reduced in groups (2 and 3) than the normal group (15.44±1.17 and 13.47±1.81 versus 18.93±1.90 µg/g, respectively; and 88.16±6.10 and 84.07±6.56 versus 104.27±4.79 µg/g, respectively). However, there were significant increase of toenail lead, aluminum and copper in the second and third groups than the first group. But, chromium and selenium were reduced in the second and third groups than the first group. The MMSE and T-scores were proportionately correlated with T-score, body mass index, calcium, zinc, chromium and selenium. But, inversely correlated with lead, aluminum and copper. Finally, calcium, zinc lead, age and BMI were the significant predictors of cognitive impairment and OP.

Conclusion: Trace elements are associated with cognitive impairment with or without osteoporosis. Some are protective and others had harmful effects with different mechanism. Thus, monitoring of these trace elements should be considered to avoid further cognitive decline with or without osteoporosis in future.