Objectives Gamma-glutamyl transferase (GGT) is related to inflammation, osteoporosis, and vascular diseases. Recently, changes in metabolic parameters have been proposed as osteoporosis biomarkers. We aimed to assess longitudinally the association of GGT variability with osteoporotic fractures. Methods From the National Health Insurance Service-Health Screening Cohort database, participants who underwent three or more health examinations between 2003 and 2008 were included (n = 1,072,432). Variability indexes were as follows: (1) coefficient of variation (CV), (2) standard deviation (SD), and (3) variability independent of the mean (VIM). The primary outcome was occurrence of osteoporotic fracture, defined as identification of one of the following international classification of diseases-10 codes: vertebral fractures (S22.0, S22.1, S32.0, S32.7, T08, M48.4, M48.5, M49.5), hip fractures (S72.0, S72.1), distal radius fractures (S52.5, S52.6), or humerus fractures (S42.2, S42.3). Results During a median of 12.3 years (interquartile range 12.1–12.6), osteoporotic fractures occurred in 49,677 (4.6%) participants. In multivariable analysis, GGT variability based on CV positively correlated with the occurrence of osteoporotic fracture (adjusted hazard ratio [HR] of the highest quartile compared with the lowest quartile 1.15, 95% confidence interval [CI] 1.12–1.18, P < 0.001). These results were consistent even when GGT variability was defined by SD (adjusted HR 1.22, 95% CI 1.19–1.25, P < 0.001) and VIM (adjusted HR 1.12, 95% CI 1.09–1.15, P < 0.001). Conclusions Increased GGT variability is associated with an increased risk of osteoporotic fractures in the Korean population. Maintaining constant and stable GGT level may help reduce the risk of osteoporotic fractures.

To investigate the association of the oral health parameters with Meniere’s disease in a nationwide population-based longitudinal cohort database. The data of the participants who underwent an oral health screening by dentists in 2003 (n = 2,415,963) were retrieved from the National Health Insurance Database of the Korean National Health Insurance Service. The main outcome was the occurrence of Meniere’s disease, defined as two or more claims of the diagnostic code H810 with a previous audiometric examination. The occurrence of Meniere’s disease was analyzed using a Cox proportional hazard model according to the presence of periodontitis and the oral health examination findings, including missing teeth, the frequency of tooth brushing and dental scaling. Overall, the analysis included 2,240,282 participants. During a median follow-up of 16.7 years, Meniere’s disease developed in 112,106 (5.0%) participants. Poor oral health status was characterized by the presence of periodontitis (adjusted hazard ratio [aHR]: 1.18, 95% confidence interval [CI]: 1.14–1.22, p < 0.001) and an increased number of missing teeth (≥15; aHR: 1.25, 95% CI: 1.18–1.32, p < 0.001) was associated with an increased risk of Meniere’s disease. Better oral hygiene behaviors, such as frequent tooth brushing (≥3 per day; aHR: 0.75, 95% CI: 0.73–0.76, p < 0.001) and dental scaling within 1 year (aHR: 0.98, 95% CI: 0.97–0.99, p = 0.003) were negatively associated with the occurrence of Meniere’s disease. The presence of periodontitis and an increased number of missing teeth may augment the risk of the occurrence of Meniere’s disease. However, maintaining good oral hygiene through tooth brushing and dental scaling may be associated with a decreased risk of Meniere’s disease. Further studies should confirm the association between oral health and Meniere’s disease.

Objectives: Gamma-glutamyl transferase (GGT) is related to inflammation, osteoporosis, and vascular diseases. Recently, changes in metabolic parameters have been proposed as disease biomarkers. We aimed to assess longitudinally the association of GGT variability with osteoporotic fractures.  Methods: From the National Health Insurance Service-Health Screening Cohort database, participants who underwent three or more health examinations between 2003 and 2008 were included (n=1,072,432). Variability indexes were as follows: (1) coefficient of variation (CV), (2) standard deviation (SD), and (3) variability independent of the mean (VIM). The primary outcome was occurrence of osteoporotic fracture, defined as identification of one of the following international classification of diseases-10 codes: vertebral fracture (S22.0, S22.1, S32.0, S32.7, T08, M48.4, M48.5, M49.5), hip fracture (S72.0, S72.1), distal radius fracture (S52.5, S52.6), or humerus fracture (S42.2, S42.3). Results: During a median of 12.3 years (interquartile range 12.1 – 12.6), osteoporotic fractures occurred in 49,677 (4.6%) participants. In multivariable analysis, GGT variability based on CV positively correlated with the occurrence of osteoporotic fracture (adjusted hazard ratio [HR]of the highest quartile compared with the lowest quartile 1.15, 95% confidence interval [CI] 1.12-1.18, P < 0.001). These results were consistent even when GGT variability was defined by SD (adjusted HR 1.22, 95% CI 1.19-1.25, P < 0.001) and VIM (adjusted HR 1.12, 95% CI 1.09-1.15, P < 0.001). Conclusions: Increased GGT variability is associated with an increased risk of osteoporotic fractures in the Korean population. Maintaining constant and stable GGT level may help reduce the risk of osteoporotic fractures.