Although the prevalence of cigarette smoking has declined in Western countries over the past few decades, a comparable decline among males has not been observed in Asian countries, especially in South Korea, where approximately 40%–50% of men and 4%–8% of women have been identified as smokers, and there is a pressing need to understand the background of cigarette smoking in these populations. The present study is a narrative review of the research literature on cigarette smoking in South Korea. First, we describe the social, economic, and cultural factors that impact cigarette smoking in South Korea. The paper also reviews the available peer-reviewed literature comprising observational studies and interventional studies, including randomized controlled trials. The extant literature on smoking in Korean Americans is also reviewed. Cigarette smoking in South Korea has been relatively understudied, and this review identifies priority areas for future research, including the use of mobile interventions.

Osteoclasts are multinucleated bone-resorbing cells and a key player in bone remodeling for health and disease. Since the discovery of osteoclasts in 1873, the structure and function of osteoclasts and the molecular and cellular mechanisms of osteoclastogenesis have been extensively studied. Moreover, it has been well established that osteoclasts are differentiated in vitro from myeloid cells such as bone marrow macrophages or monocytes. The concept showing that osteoclasts are derived from a specific population (named osteoclast precursor cells [OCPs]) among myeloid cells has been long hypothesized. However, the specific precursor population of osteoclasts is not clearly defined yet. A growing body of work provides evidence of the developmental origin and lifespan of murine osteoclasts, particularly in vivo. Here, we review the emerging evidence that supports the existence of OCPs and discuss current insights into their identity.