Background: A decline in masticatory function may indicate brain dysfunction related to dementia, but the relationship between masticatory function and dementia risk remains unclear. This study aimed to investigate whether masticatory function is associated with the risk of cognitive decline and dementia. Methods: Data were obtained from the nationwide prospective cohort study of randomly sampled community-dwelling Koreans aged ≥ 60 years. The 5,064 non-demented participants, whose number of chewing cycles per bite was assessed by clinical interview, were followed for 8 years with biennial assessments of cognitive performance and clinical diagnoses of all-cause dementia and Alzheimer’s disease (AD). Structural brain magnetic resonance imaging was collected from a subset of cohort participants and their spouses for imaging analyses. Results: Males who chewed ≥ 30 cycles/bite had faster decline in global cognition and memory function and were at higher risk for incident all-cause dementia (hazard ratio [HR], 2.91; 95% confidence interval [CI], 1.18–7.18) and AD (HR, 3.22; 95% CI, 1.14–9.11) compared to males with less than 10 cycles/bite. Additionally, increased chewing cycles in males were associated with reduced brain volume, particularly in regions involved in compensatory cognitive control of mastication. There was no significant association between chewing cycles and the risk of dementia or brain volume in females. Conclusion Older men who frequently chew their meals could be considered a notable population at risk for dementia who should be carefully assessed for their cognitive trajectories.

This study compared the solubility, water absorption, dimensional stability, release of various ions (hydroxyl, calcium, sulfur, strontium, and silicon), and cytotoxicity of lightcured resin-modified pulp-capping materials. Resin-modified calcium hydroxide (Ultrablend™ plus, UBP), light-cured resin-modified calcium silicate (TheraCal LC™, TLC), and dual-cure resin-modified calcium silicate (TheraCal PT™, TPT) were used. Each material was polymerized; solubility, 24-hour water absorption, and 30- day dimensional stability experiments were conducted to test its physical properties. Solubility was assessed according to the ISO 6876 standard, and 24 hours of water absorption, 30 days of dimensional stability were assessed by referring to the previous protocol respectively. Eluates at 3 and 24 hours and on 7, 14, and 28 days were analyzed according to the ISO 10993-12 standard. And the pH, Ion-releasing ability, cell proliferation rate, and cell viability were assessed using the eluates to evaluate biochemical characteristics. pH was measured with a pH meter and Ion-releasing ability was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Cell proliferation rate and cell viability were assessed using human dental pulp cells (hDPCs). The former was assessed by an absorbance assay using the CCK-8 solution, and the latter was assessed by Live and Dead staining. TPT exhibited lower solubility and water absorption than TLC. UBP and TPT demonstrated higher stability than TLC. The release of sulfur, strontium, calcium, and hydroxyl ions was higher for TLC and TPT than for UBP. The 28-day release of hydroxyl and silicon ions was similar for TLC and TPT. TLC alone exhibited a lower cell proliferation rate compared to the control group at a dilution ratio of 1 : 2 in cell proliferation and dead cells from Live and Dead assay evaluation. Thus, when using light-cure resin-modified pulp-capping materials, calcium silicate-based materials can be considered alternatives to calcium hydroxide-based materials. Moreover, when comparing physical and biochemical properties, TPT could be prioritized over TLC as the first choice.

Objective: To investigate the relationship between reduced glutathione (GSH), a key molecule of the antioxidant defense system in the blood, and glutathione reductase (GR), which reduces oxidized glutathione (glutathione disulfide [GSSG]) to GSH and maintains the redox balance, with the prevalence of Alzheimer’s dementia and cognitive decline. Methods: In all, 20 participants with Alzheimer’s dementia who completed the third follow-up clinical evaluation over 6 years were selected, and 20 participants with normal cognition were selected after age and sex matching. The GSH and GR concentrations were the independent variables. Clinical diagnosis and neurocognitive test scores were the dependent variables indicating cognitive status. Results: The higher the level of GR, the greater the possibility of having normal cognition than of developing Alzheimer’s dementia. Additionally, the higher the level of GR, the higher the neurocognitive test scores. However, this association was not significant for GSH. After 6 years, the conversion rate from normal cognition to cognitive impairment was significantly higher in the lower 50th percentile of the GR group than in the upper 50th percentile. Conclusion The higher the GR, the lower the prevalence of Alzheimer’s dementia and incidence of cognitive impairment and the higher the cognitive test scores. Therefore, GR is a potential protective biomarker against Alzheimer’s dementia and cognitive decline.

Objective: : Spinal cord stimulation (SCS) is an effective treatment for chronic neuropathic pain. However, its clinical efficacy in regard to specific types of pain has not been well studied. The primary objective of this study was to retrospectively analyze the clinical outcomes of paddle-type SCS according to the type of neuropathic pain. Methods: : Seventeen patients who underwent paddle-lead SCS at our hospital were examined. Clinical outcomes were evaluated pre- and postoperatively (3 months, 1 year, and last follow-up) using the Neuropathic Pain Symptom Inventory (NPSI). The NPSI categorizes pain as superficial, deep, paroxysmal, evoked, or dysesthesia and assess the duration of the pain (pain time score). Changes in NPSI scores were compared with change in Visual analogue scale (VAS) scores. Results: : After SCS, the pain time score improved by 45% (independent t-test, p=0.0002) and the deep pain score improved by 58% (independent t-test, p=0.001). Improvements in the pain time score significantly correlated with improvements in the VAS score (r=0.667, p=0.003, Spearman correlation). Additionally, the morphine milligram equivalent value was markedly lower after vs. before surgery (~49 mg, pared t-test, p=0.002). No preoperative value was associated with clinical outcome. Conclusion : The NPSI is a useful tool for evaluating the therapeutic effects of SCS. Chronic use of a paddle-type spinal cord stimulation improved the deep pain and the pain time scores.

This study estimated the direct and indirect socioeconomic costs of 238 diseases and 22 injuries from a social perspective in Korea from 2007 to 2015. The socioeconomic cost of each disease group was calculated based on the Korean Standard Disease Classification System. Direct costs were estimated using health insurance claims data provided by the National Health Insurance Service. The numbers of outpatients and inpatients with the main diagnostic codes for each disease were selected as a proxy indicator for estimating patients’ medical use behavior by disease. The economic burden of disease from 2007 to 2015 showed an approximately 20% increase in total costs. From 2007 to 2015, communicable diseases (including infectious, maternal, pediatric, and nutritional diseases) accounted for 8.9-12.2% of the socioeconomic burden, while non-infectious diseases accounted for 65.7-70.7% and injuries accounted for 19.1-22.8%. The top 5 diseases in terms of the socioeconomic burden were self-harm (which took the top spot for 8 years), followed by cirrhosis of the liver, liver cancer, ischemic heart disease, and upper respiratory infections in 2007. Since 2010, the economic burden of conditions such as low back pain, falls, and acute bronchitis has been included in this ranking. This study expanded the scope of calculating the burden of disease at the national level by calculating the burden of disease in Koreans by gender and disease. These findings can be used as indicators of health equality and as useful data for establishing community-centered (or customized) health promotion policies, projects, and national health policy goals.

Objective: This study estimated the incidence of driving-related adverse events and examined the association of cognitive function with the risk of future driving-related adverse events in the elderly Korean male population. Methods: We analyzed 1,172 male drivers aged 60 years or older in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). Using the data from Korean National Police Agency, we classified the participants into three groups: safe driving (drove for 2 years after baseline without a traffic accident or repeated violations), driving cessation (stopped driving), and risky driving (one or more traffic accidents or repeated violations). We estimated the incidences of driving cessation and risky driving, and examined the effect of cognitive function on their risks. Results: The incidence of driving cessation and risky driving in the Korean male drivers aged 60 years or older was 19.3 and 69.9 per 1,000 person-years respectively and increased in the late 80s. Drivers with better baseline Word List Memory Test scores showed less risky driving (OR=0.94, p=0.039). Conclusion Driving-related adverse events increased in late 80s, and better memory function was protective against these events.

Objective: Cardiovascular diseases are representative risk factors for the onset of cognitive decline. The purpose of this study was to confirm the relationship between diastolic blood pressure and cognitive function in elderly people in Korea. Methods: Data from subjects who were enrolled in the prospective Korean Longitudinal Study on Cognitive Aging and Dementia were used in this study. Data from 701 subjects whose diastolic blood pressure range did not change (≤79 mm Hg or ≥80 mm Hg) over 2 years were analyzed. To analyze the differences in cognitive function between the groups at the 2-year follow-up, an analysis of covariance was performed with covariates, which were significantly different between the two groups, and the baseline cognitive function. Results: Significant differences were observed between the two groups, and the mean scores on the constructional praxis (η2=0.010) and word list recall tests (η2=0.018) in the diastolic blood pressure ≥80 mm Hg group were higher than those in the diastolic blood pressure ≤79 mm Hg group at the 2-year follow-up. Conclusion These results indicate that maintaining a DBP below 79 mm Hg presents a greater risk of cognitive decline in Korean elderly people.

Objective: We investigated the frequency of depressive disorders in the elderly with normal cognition (NC), mild cognitive impairment (MCI) and dementia patients living in the community to find out the association between cognitive disorders and depressive disorders in the community dwelling elderly. Methods: 6,262 baseline study subjects from November 2010 through October 2012 were enrolled based on the Korean longitudinal study on cognitive aging and dementia which is the first nationwide multi-center population based prospective cohort study in Korea. Diagnosis of MCI, dementia, major depressive disorder (MDD), minor depressive disorder (mDD) and subsyndromal depression (SSD) was made by psychiatrists with expertise in dementia based on the appropriate diagnostic criteria. Results: 4,303 NC, 1,737 MCI, 222 dementia were enrolled. The frequency of MDD, mDD, SSD were highest in dementia and lowest in NC and showed significant difference among three groups. The odds ratio also increased significantly in MCI and dementia compared with NC showing highest odds ratio in dementia. Conclusion Our findings propose that MCI and dementia in the community dwelling elderly were significantly associated with various types of depressive disorders showing highest association tendency in dementia.