Although the association between bone mineral density (BMD) and osteoarthritis (OA) has been reported, the relationship of BMD and OA has long been still controversial. The aim of this study was to evaluate the association between knee OA and BMD of body parts in relation to sex.
This study was designed as a cross sectional analysis using data on BMDs of body parts measured using dual energy X-ray absorptiometry in 7764 people in the Fourth and Fifth Korea National Health and Nutrition Examination Survey. Knee OA was assessed from a weight-bearing anteroposterior radiography and graded on a scale of Kellgren-Lawrence (KL) grade. The radiographic OA was defined as the participants who had a KL grade≥2. The associations between knee OA and BMD of body parts (Total, pelvis and lower leg) were assessed. The BMDs of the body part was divided into quartiles and the relationship between OA and BMD was examined according to sex.
The Total, pelvis and lower leg BMDs were negatively related with the increase of KL grade in women (all p<0.001). However, none of body parts BMDs showed significant association from KL grade 0 to 4 in men (all p>0.05). There was a significant correlation with decreasing linear trend between the odds ratios of each quarter percentile group of total, pelvis and lower leg BMDs, and knee OA in women (all p <0.05). After adjusting for age, waist circumference, the presence of hypertension and diabetes, smoking, alcohol, the significant association has been maintained (all p<0.05). However, there were no relationships between all BMD of each body parts and knee OA before and after adjusting for aforementioned variables in men (all p>0.05).
Low BMDs of body parts including total, pelvis and lower leg were associated with the presence and degree of knee OA in women, but not in men.