Service-National Health Screening Cohort Research Articles

Association between hemoglobin trajectories and the incidence of dementia in a cohort of females aged 55-79 years.

To assess the association between pattern changes in hemoglobin levels over time and the incidence of dementia using trajectories in females aged 55-79 years. We conducted a retrospective cohort study using females of aged 55-79 years from the National Health Insurance Service National Health Screening Cohort in Korea. To identify hemoglobin trajectories over eight years (2002-2009), we performed a three-step approach comprising measures of change, factor analysis, and cluster analysis. Univariate and multivariate Cox proportional hazard models were used to assess the associations between hemoglobin trajectories and the incidence of dementia. We included 20,195 of 235,742 female participants. New dementia (N = 2664) was developed during follow-up period (2010-2015). Five hemoglobin trajectories were identified: high, mid, low, increasing, and decreasing. With high as a reference, the hazard ratios (HRs) for low and decreasing trajectories were significant, 1.28 (95% confidence interval [CI], 1.13-1.45) and 1.21 (95% CI, 1.10-1.34) in univariate models, respectively. However, only the HR for the decreasing trajectory was significant, 1.12 (95% CI, 1.01-1.24) after adjustment for confounders. The decreasing trajectory of hemoglobin levels within the normal range was associated with dementia. Even females aged 55-79 years without anemia might be vulnerable to dementia development risk.

Physical Activity, Sunshine Duration, and Osteoporotic Fractures: A Nested Case-Control Study.

This study examined the associations between the occurrence of osteoporotic fractures in detailed sites and combined physical activity (PA) and sunshine duration (SD). Data from the Korean National Health Insurance Service—National Health Screening Cohort for 7-year periods and from the Korea Meteorological Administration were used. Osteoporotic fractures (n = 12,103), including vertebral fractures, hip fractures, and distal radius fractures, and matched controls (n = 24,206) were selected in 1:2 ratios by age, sex, income, and region of residence. PA was classified as moderate- to high-intensity PA (High PA) and low-intensity PA (Low PA). SD was classified as Short SD (<6.1 h) and Long SD (≥6.1 h). Conditional logistic regression was used to calculate the odds ratios (ORs) with 95%-confidence intervals (CIs) of the combined PA and SD groups for the occurrence of each osteoporotic fracture. Compared to ‘Low PA + Short SD’, the adjusted ORs (95% CIs) for vertebral fracture in ‘High PA + Short SD’ and ‘High PA + Long SD’ were 0.83 (0.76–0.91) and 0.84 (0.77–0.92), respectively. Hip/distal radius fractures were not associated with the combined PA and SD group. We suggest that a higher intensity of PA is inversely associated with the risk of vertebral fracture.

Increased risk of open-angle glaucoma among patients with diabetes mellitus: a 10-year follow-up nationwide cohort study.

To evaluate the risk of open-angle glaucoma among patients with diabetes. This retrospective propensity score-matched cohort study included patients with diabetes and a matched comparison group from the Korean National Health Insurance Service National Health Screening Cohort, which includes approximately 500000 adults aged ≥40years. Nondiabetes group was matched to diabetes group in a 1:1 ratio using a propensity score based on age, sex, comorbidities, antihypertensive medication use and medical care visits. Each group was followed from January 1, 2004 to either the date of developing open-angle glaucoma or the date of last follow-up in 2013. Incidence of open-angle glaucoma was 20.0/10000 person-years in diabetes group (n=58358) and 17.0/10000 person-years in nondiabetes group (n=58358). Age- and sex- adjusted hazard ratio (HR) was 1.19 (95% confidence interval [CI], 1.09-1.30). In the subgroup analyses, diabetes was associated with an increased risk of open-angle glaucoma in both younger and older age groups (HR=1.20 for those aged 40-59years and HR=1.18 for those aged 60-79years) and in both sexes (men, HR=1.13; women, HR=1.27). Patients diagnosed with diabetes were more likely to develop open-angle glaucoma compared with patients without diabetes.