Association between insulin resistance and compartment-specific bone mineral density and strength of femur neck in general Korean population

Abstract

배경 및 목적 인슐린 저항성은 골밀도, 그리고 골강도와 연관성이 있는 것으로 보고되어 왔다. 그러나 대부분의 연구들이 골밀도를 뼈의 구획 별로 나누지 않고, 전체 골밀도만을 평가했으며, 이를 골강도와 함께 조사한 연구도 부족하다. 인슐린 저항성이 뼈 건강에 미치는 전반적인 영향을 평가하기 위해서는 골밀도와 골강도를 함께 조사할 필요가 있다. 본 연구의 목적은 한국의 지역사회 거주 일반 성인 인구를 대상으로 인슐린 저항성과 골밀도, 골강도와의 독립적인 관련성을 평가하는 것이다. 연구 방법 본 연구는 지역사회기반 코호트인 Cardiovascular and Metabolic Disease Etiology Research Center (CMERC) 에 연구참여 동의 및 기반조사를 마친 2,533명의 성인 (856명의 남자와 1,497명의 여자) 을 대상으로 진행하였다 (평균나이 49.3세). 인슐린 저항성은 HOMA-IR 지표를 이용하여 측정하였다. 골밀도는 Quantitative computed tomography (QCT)로 측정하였고, 골강도는 Compression strength index (CSI), Bending strength index (BSI), Impact strength index (ISI) 의 세 가지 평가방법을 이용하여 측정하였다. 혼란변수로는 연령, 체중, 흡연상태, 음주상태, 신체활동, 혈중 비타민 D 등을 보정하였다. 연구 결과 모든 혼란변수를 보정하였을 때, 남자에서는 인슐린 저항성이 total BMD (β=-0.029, p=0.001), trabecular BMD (β=-0.015, p=0.000), CSI (β=-0.286, p<0.001), ISI (β=-0.018, p=0.004) 와 통계적으로 유의한 음의 관련성을 보였지만, cortical BMD (β=-0.015, p=0.095), BSI (β=-0.058, p=0.946) 와는 통계적으로 유의한 관련성을 보이지 않았다. 여자에서는 모든 혼란변수를 보정하였을 때, 인슐린 저항성과 total BMD (β=-0.017, p=0.015), CSI (β=-0.182, p<0.001), ISI (β=-0.017, p<0.001) 와 독립적인 관련성이 있었으나, cortical BMD (β=-0.012, p=0.082), trabecular BMD (β=-0.04, p=0.174), 그리고 BSI (β=-0.074, p=0.879) 와는 연관성을 보이지 않았다. 연구 결론 본 연구에서, 한국 지역사회 일반 성인 인구에서는 높은 인슐린 저항성을 가진 사람들이 그렇지 않은 사람에 비해 더 낮은 골밀도와 골강도를 보이는 것이 관찰되었다.

Introduction Insulin resistance has been reported to be associated with bone mineral density (BMD) and bone strength of femoral neck. Low BMD and bone strength are risk factors for falls or fracture and may even lead to cardiovascular disease (CVD). However, it has not been fully investigated whether compartment-specific BMD and bone strength of femur neck are associated with insulin resistance. The aim of this study was to investigate the association between insulin resistance and compartment-specific BMD and bone strength of femur neck. Methods This cross-sectional study used baseline data from the Cardiovascular and Metabolic Disease Etiology Research Center (CMERC) cohort study. A total of 2,533 study participants completed both questionnaire survey and health examinations between 2013 and 2015. After excluding participants who were taking drugs for diabetes (n=122) and osteoporosis (n=53) and who had missing data on key variables (n=5), 856 men and 1,497 women aged 30-64 years were included in this study. Cortical and trabecular BMD of femur neck were measured with quantitative computed tomography. Fasting insulin level was assayed using a RIA procedure on an immunoradiometric assay. Fasting glucose was determined by the colorimetry method. The association between insulin resistance and BMD (total bone compartment, cortical bone compartment and trabecular bone compartment) femur neck and bone strength index (compressive strength index, CSI; bending strength index, BSI; impact strength index, ISI;) was investigated by multiple linear regression model. Age, body mass index (BMI), smoking, alcohol intake, physical activity and 25-hydroxy vitamin D were considered as a covariates. Results In men, there was inversely associated with total BMD (ß=-0.029, p=0.001), trabecular BMD (ß=-0.015, p=0.000), CSI (ß=-0.286, p<0.001) and ISI (ß=-0.018, p=0.004) when adjusted for all covariates. However, the association with cortical BMD (ß=-0.015, p=0.095) and BSI was not significant (ß=0.058, p=0.946). In women, there was a negative association between HOMA-IR and total BMD (ß=-0.017, p=0.015), CSI (ß=-0.182, p<0.001) and ISI (ß=-0.017, p<0.001), not significant with compartment-specific BMD (Cortical: ß=-0.012, p=0.082, Trabecular: ß=-0.004, p=0.174) and BSI (ß=0.074, p=0.879). Conclusions High insulin resistance was negatively associated with total and trabecular BMD, CSI and ISI in men, however, there was significant association with CSI and ISI only in women.