목적 : 한국인을 대상으로 혈청 25(OH) 비타민 D 농도와 근시와의 연관성을 알아보고자 하였다. 방법 : 국민건강영양조사 2010년도 자료를 이용하였으며, 나이는 10세 이상부터 69세까지 총 5,488명을 대상으로 하였다. 근시의 정도는 등가구면 굴절력을 기준으로 -3.00<SE≤-0.50 D를 경도 근시, -6.00<SE≤-3.00 D를 중등도 근시, SE≤-6.00 D를 고도 근시로 정의하였다. 혈청 25(OH) 비타민 D 농도는 20 ng/mL 이하일 경우 부족군으로 20 ng/mL 초과일 경우 정상군으로 정의하였다. 피어슨이 상관분석과 공변량을 보정한 복합표본 로지스틱회귀분석을 시행하여 혈청 25(OH) 비타민 D 농도와 근시와의 연관성을 평가하였다. 결과 : 혈청 25(OH) 비타민 D 농도와 등가구면 굴절력은 양의 상관성을 보이는 것으로 나타났다(r=0.132, p<0.001). 근시의 위험 인자는 나이, 가구 소득, 교육수준, 햇볕 노출, 비만, 당뇨, 고혈압, 백내장 그리고 안질환 가족력으로 나타났다. 혈청 25(OH) 비타민 D 농도가 20 ng/mL 이하일 경우 위험 인자를 보정한 후에도 고도 근 시의 위험이 2.55배(95% 신뢰구간: 1.27~5.16) 증가하였다. 결론 : 한국인에서 고도 근시는 혈청 25(OH) 비타민 D 농도와 연관성이 있었다.

Bone remodeling is a process controlled by the action of two major bone cells; the bone forming osteoblast and the bone resorbing osteoclast. In the process of osteoclastogenesis, stromal cells and osteoblast produce RANKL, OPG, and M-CSF, which in turn regulate the osteoclastogenesis. During the bone resorption by activated osteoclasts, extracellular Ca²+/PO₄²- concentration and degraded organic materials goes up, providing the hypertonic microenvironment. In this study, we tested the effects of hypertonicity due to the degraded organic materials on osteoclastogenesis in co-culture system. It was examined the cellular response of osteoblastic cell in terms of osteoclastogenesis by applying the sucrose, and mannitol, as a substitute of degraded organic materials to co-culture system. Apart from the sucrose, mannitol, and NaCl was tested to be compared to the effect of organic osmotic particles. The addition of sucrose and mannitol (25, 50, 100, 150, or 200 mM) to co-culture medium inhibited the number of tartrate-resistant acid phosphatase (TRAP) positive multinucleated cells induced by 10 nM (). However, NaCl did exert harmful effect upon the cells in this co-culture system, which is attributed to DNA damage in high concentration of NaCl. To further investigate the mechanism by which hypertonicity inhibits -induced osteoclastogenesis, the mRNA expressions of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) were monitored by RT-PCR. In the presence of sucrose (50 mM), RANKL mRNA expression was decreased in a dose-dependent manner, while the change in OPG and M-CSF mRNA were not occurred in significantly. The RANKL mRNA expression was inhibited for 48 hours in the presence of sucrose (50 mM), but such a decrement recovered after 72 hours. However, there were no considerable changes in the expression of OPG and M-CSF mRNA. Conclusively, these findings strongly suggest that hypertonic stress down-regulates -induced osteoclastogenesis via RANKL signal pathway in osteoblastic cell, and may playa pivotal role as a regulator that modulates osteoclastogenesis.