Lithium-induced blepharospasm in a middle-aged woman with recurrent depressive disorder: a case report.

Alzheimer's disease (AD), the most common cause of dementia, is a progressive neurodegenerative disorder characterized by gradual and irreversible cognitive decline. More than 55 million people worldwide are currently living with dementia, and this number is projected to nearly triple by 2050, making dementia a major public health challenge in aging societies. Current diagnostic strategies often rely on invasive and resource‐intensive procedures, including cerebrospinal fluid biomarker testing and positron emission tomography (PET), to detect amyloid‐β and tau pathology. Although these approaches provide high diagnostic accuracy, their broader implementation is limited by cost, availability, and the need for specialized infrastructure and expertise. In many clinical and community settings, these resources remain inaccessible. Cognitive screening tools, such as the Mini‐Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), are more widely used; however, they require trained personnel, are time‐consuming to administer, and depend on patient cooperation, which may be compromised in older adults and individuals with more advanced cognitive impairment. Consequently, there is a need for noninvasive, accessible, and scalable approaches that can complement existing methods for AD detection and monitoring. AD arises from a complex interplay between genetic susceptibility and environmental exposures. Among environmental factors, disturbances in elemental homeostasis have been increasingly implicated in AD pathogenesis. Several toxic metals, including lead (Pb), cadmium (Cd), and mercury (Hg), are well‐established neurotoxins, and chronic exposure to these metals has been associated with an increased risk of cognitive decline and dementia., In addition, imbalances in essential trace elements, such as iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn), may impair neural function through mechanisms involving oxidative stress, mitochondrial dysfunction, and altered neurotransmission. Essential nonmetallic elements, including selenium (Se) and iodine (I), have also been associated with AD and cognitive dysfunction., Collectively, these findings suggest that multidimensional serum elemental profiles may contain diagnostically relevant information for AD. However, previous studies have generally been limited by restricted elemental coverage, small sample sizes, or both. In the present study, we conducted a retrospective cross‐sectional analysis of 874 clinically characterized adults from the Brain Aging National Cohort–Peking Union Medical College (BANC‐PUMC). Participants were classified as cognitively normal controls (NCs) or as having AD according to established diagnostic criteria. Most participants underwent standardized cognitive assessments, including the MMSE and MoCA. Serum samples were analyzed using inductively coupled plasma mass spectrometry (ICP‐MS) to quantify 20 elements, including 18 metallic or metalloid elements—magnesium (Mg), calcium (Ca), chromium (Cr), Mn, Fe, cobalt (Co), nickel (Ni), Cu, Zn, arsenic (As), strontium (Sr), molybdenum (Mo), Cd, tin (Sn), antimony (Sb), Hg, Pb, and bismuth (Bi)—and two essential nonmetallic elements, Se and I.