Correlation between bone mineral density and plasma lipids in Taiwan

Many studies showed that depression is correlated with osteoporosis, while others showed that low cholesterol level is also related to depression. However, these relationships still remain controversial. Since the bone mineral density (BMD) is related to depression and depression is related to hypocholesterolemia, there might exist a correlation between BMD and plasma cholesterol levels. To prove this, we enrolled 5000 individuals, 2170 males, and 2830 females, who had health check-ups at a private clinic between 1998 and 1999. They were divided into three groups. Group 1 was composed of male subjects; Group 2, female subjects; and Group 3, females aged over 50 to exclude pre-menopausal females. Each subject had a routine physical examination, fasting blood drawing, BMD measured by dual energy x-ray absorptiometry (DEXA) over the wrist, and was given a questionnaire to answer. Between Groups 1 and 2, the females were significantly younger, had higher body mass index (BMI), total cholesterol (TC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), and platelet, but lower BMD, fasting plasma glucose (FPG), triglycerides (TG), hemoglobin (Hgb), and white blood cell (WBC) count. As for Groups 1 and 3, all the aforementioned findings still remained the same except that the systolic blood pressure (SBP) was higher and diastolic blood pressure (DBP) was lower in Group 3. Our results showed that BMD is negatively related to age in males. In females, it is negatively correlated with age, FPG, PPG, SBP, DBP, TC, LDLC, TG, and Hgb, but positively related to BMI and platelet. However, for females in Group 3, BMD is only negatively related to age, FPG, SBP, and TG but positively related to BMI. Stepwise multiple regression analysis showed that the BMD is negatively related to age but positively related to BMI in both males and females. In Group 3, BMD is negatively related to age and FPG but positively related BMI. In conclusion, no correlation exists between BMD and cholesterol. This implies that the depression is not significantly related to cholesterol and/or BMD. This might be due to various confounding factors, which could affect their relationships. The negative correlation between BMD and FPG is only observed in females older than 50 years. Further studies are needed to clarify these relationships.