Past decades of division have led to substantial differences in medical environments between South and North Korea. However, little is known about North Korea's medical status and research field, especially regarding endocrinology. In this study, we report the characteristics of North Korea's articles regarding endocrine-related diseases.

Among the nine medical journals, articles published in Internal Medicine between 2006 and 2015 were reviewed. A total of 2,092 articles were included; among them, 96 articles were associated with endocrinology. We analyzed these articles according to the disease categories they focused on and evaluated their features.

Articles related to diabetes mellitus accounted for 55.2% (n=53) and those to thyroid disease accounted for 28.1% (n=27). Other disease categories, including adrenal gland (n=1), pituitary gland (n=1), and osteoporosis (n=3), comprised minor portions. Regarding diabetes mellitus, more than half the articles (n=33) focused on treatment and complications. Experimental studies were conducted with old hypoglycemic drugs or natural substances for the treatment of hyperglycemia. Regarding thyroid disease, articles related to hyperthyroidism were the most common (51.9%, n=14), followed by thyroid nodule/cancer (18.5%, n=5). Unique article features were short length, no figures, and less than five references.

North Korea's endocrinology articles mainly focused on diabetes mellitus and thyroid disease. Persistent studies have been carried out in North Korea with dedication despite the poor medical environment. We hope that this study will be the beginning of mutual medical exchange and collaboration between North and South Korea.

We examined whether white blood cell (WBC) count levels within normal range, could be associated with hemoglobin A1c (HbA1c) levels.

Among the 11,472 people (≥19 years of age) who participated in the 2011 to 2012 Korea National Health and Nutrition Examination, subjects with chronic disease or illness, including 807 patients with diabetes currently taking anti-diabetic medications and/or 1,149 subjects with WBC levels <4,000 or >10,000/µL were excluded.

Overall, adjusted HbA1c levels increased across the WBC quartiles (5.55%±0.01%, 5.58%±0.01%, 5.60%±0.01%, and 5.65%±0.01%, P<0.001) after adjusting for confounding factors, such as age, gender, fasting plasma glucose, college graduation, smoking history, waist circumference, presence of hypertension, serum total cholesterol, serum triglyceride, and presence of anemia. The adjusted proportions (%) of HbA1c levels of ≥5.7%, ≥6.1%, and ≥6.5% showed significant increases across WBC quartiles (P<0.001, P=0.002, and P=0.022, respectively). Logistic regression analyses of WBC quartiles for the risk of HbA1c levels of ≥5.7%, ≥6.1%, and ≥6.5%, using the variables above as covariates, showed that the odds ratios of the fourth quartile of WBCs were 1.59 (95% confidence interval [CI], 1.35 to 1.89; P<0.001), 1.78 (95% CI, 1.31 to 2.42; P<0.001), and 2.03 (95% CI, 1.13 to 3.64; P=0.018), using the first quartile of WBCs as the reference.

HbA1c levels were positively associated with WBC levels within normal range in a general adult population.