Diabetes is a common chronic metabolic disease with complex causes and pathogenesis. As an immunomodulator, vitamin D has recently become a research hotspot in the occurrence and development of diabetes and its complications. Many studies have shown that vitamin D can reduce the occurrence of diabetes and delay the progression of diabetes complications, and vitamin D can reduce oxidative stress, inhibit iron apoptosis, promote Ca²⁺ influx, promote insulin secretion, and reduce insulin resistance. Therefore, the prevention and correction of vitamin D deficiency is very necessary for diabetic patients, but further research is needed to confirm what serum levels of vitamin D₃ are maintained in the body. This article provides a brief review of the relationship between vitamin D and diabetes, including its acute and chronic complications.

Background: Vitamin D deficiency is considered to be a global health problem. The purpose of this study was to evaluate the prevalence of vitamin D deficiency and analyze its related factors among adult residents in Hainan, a tropical island province of southern China. Methods: A total of 1,700 healthy adults, aged 18–86 years (617 men and 1,073 women), were enrolled in our cross-sectional descriptive study. Binomial logistic regression analyses were performed to identify possible predictors of vitamin D status. Results: The average serum 25-hydroxyvitamin D [25(OH)D] concentration was 37.66±10.77 ng/mL (males 43.60±11.8 ng/mL, females 34.20±8.40 ng/mL; I<0.001). The proportions of vitamin D sufficiency [25(OH)D ≥30 ng/mL], insufficiency [20 ng/mL ≤25(OH)D <30 ng/mL], and deficiency [25(OH)D <20 ng/mL] were 76.6%, 20.5%, and 2.9%, respectively. Vitamin D deficiency in the young, middle-aged, and elderly groups were 4.2%, 2.7%, and 1.7%, respectively. Vitamin D sufficiency was found to be positively associated with male sex (P40 years (P=0.014), habitation in a rural area (P<0.0001), summer/autumn seasons (P<0.0001), and having <13 years of formal education (P<0.0001). Conclusions: Our study was the first to assess the vitamin D status and analyze related factors among adult residents in Hainan Province, China. We found that vitamin D deficiency has low prevalence in this population, suggesting that before developing a strategy for the clinical use of vitamin D supplements in a region, the levels of vitamin D in generally healthy populations of that region should be assessed, to avoid unnecessary supplementation.

Background. In recent years, the incidence of thyroid diseases has increased significantly, which has seriously affected people's work and life. The purpose of this study was to explore the epidemiological characteristics of thyroid diseases and autoantibodies. Method. According to the principle of overall sampling, resident residents 18 years and who will not move within 5 years are randomly selected. A total of 2136 eligible individuals were divided into case and control groups according to whether they have thyroid disease. Finally, the impact of potential risk factors on thyroid diseases was evaluated. Results. The overall prevalence of thyroid disease was 58.3, and there was a significant difference in the prevalence of thyroid disease between women and men (p=0.004). Except for the age group 70 years, with the increase in age, the prevalence gradually increased (p<0.05). Participants with positive thyroid autoantibodies (TPOAb or TgAb) had a higher prevalence than participants with negative autoantibodies. The positive rate of autoantibodies in women was higher than that in men (p<0.05). UIC (p=0.004) and free thyroid hormone (FT4) (p=0.001) levels of men were higher than those of women, and the TSH level of women was higher than that of men (p=0.002). The regression analysis showed that women, older age, and family history of thyroid disease were independent risk factors for thyroid disease. Conclusion. The prevalence of thyroid diseases in Hainan was high. Women are more susceptible to thyroid disease than men, and the prevalence increased with age.