On correlation between body mass index and lumbar spine average bone mineral density: a study in male patients with osteopenia and those with osteoporosis / 生物医学工程学杂志

From among the patients who visited the Dept. of Rehabilitation of West China Hospital for arthalgia in the period from Aug. 2003 to Dec. 2005, we recruited 566 male patients who were over 40 years of age and did not have hyperostosis in the lumbar spine, and whose T scores were each less than--1. Their ages ranged from 40 to 93 years, and the average age was 62.93 +/- 13.50. The dual-energy X-ray absorptiometry from DMS Company in France was used to measure the bone density of the L2-4 anterior-posterior. The basic data about the subjects, containing the age, height, weight, diabetes mellitus, exercise and smoking or not, were recorded. Then the body mass index were calculated. In accordance to the T score, the subjects were separated into two groups: osteopenia group and osteoporosis group. In comparison of the basic data between groups, BMI of osteoporosis group was significantly higher than that of the osteopenia group, but the number of the subjects who exercised was smaller (P < 0.05). Multiple linear regression analysis revealed that in the case BMI increased by 1 kg/m2, BMD significantly decreased by 0.003 g/cm2 (P = 0.002), and the age negatively correlated with BMD (B = -0.001, P = 0.035). "Exercise or not" was positively related to BMD (B = 0.028, P = 0.000). "Smoking or not" and BMD were not significantly correlated (P = 0.837). In conclusion, increase of BMI, or we may say, increase of fat, would decrease the lumbar spine average BMD in the patients of osteoporosis or osteopenia. Some reports have pointed out that only by increasing BMI with increased amount of muscles, but not with increased amount of fat, would be beneficial to the prevention of osteoporosis. So we concluded that the muscle amount in the subjects should be taken into account when we probe into the relation between BMI and BMD.

Study on the relationship between body mass index and osteoporosis in males / 生物医学工程学杂志

There were 482 male patients with non-hyperostosis diagnosed by X-ray among 1207 males who visited West China Hospital because of pain and/or numbness in bone or/and in joints from August 2003 to December 2005; the base-line information in records included age, stature, body weight(calculated BMD, symptoms, co-morbidities, exercise frequency, and smoking. The bone mineral density of lumbar spine was determined and used to judge osteoporosis or non-osteoporosis. Comparison was made on the basic information between osteoporosis group and non-osteoporosis group by t test or chi2 test statistical analysis; the relationship of multiple factors with osteoporosis was analyzed by Logistic Regression. The results of comparison between osteoporosis group and non-osteoporosis group indicated, there were significant differences among BMI, exercise and smoking, but no significant differences were seen among age, complications of hypertension and diabetes mellitus. According to the results of multiple regression analysis, BMI and smoking are the risk factors of osteoporosis, yet exercise is the protection factors of osteoporosis; the risk of osteoporosis increases by 0.654 times in men with BMI scaling up by 1 kg/m2 (P = 0.004). Therefore, we conclude that BMI is a risk factor of osteoporosis in male, and it may be related to body fat distribution.

Effect of body mass index on bone mass of lumbar spine of male patients with ostealgia and arthralgia but without osteoporosis / 生物医学工程学杂志

For the purpose of identifying the effect of body mass index on bone mineral density, an investigation was made in regard to the relationship between body mass index (BMI), bone mineral density (BMD) and bone mineral content (BMC) of lumbar vertebrals of men without osteoporosis. 838 male patients were diagnosed and treated in West China Hospital of Sichuan University because of ostealgia and arthralgia from Aug. 2003 to Dec. 2005. They were examined by dual-energy X-ray absorptiometry, their L2-L4 bone mineral density being < -2.5SD. Then they were graded by body mass index (Kg/m2) [1st group BMI > or =23, 454 cases (Group A BMI > or = 29, 46 cases; Group B 25 < or = BMI < 28.9, 201 cases; Group C 23 < or = BMI < 24, 9193 cases); 2nd group 18.5 < BMI < 22.9, 311 cases; 3rd group BMI < or = 18.5, 68 cases]. The relationships between BMI and BMD of lumbar spine were analyzed using SPSS 13.0. The results revealed their positions in series: (1) Among Groups 1-3, BMD, average BMD and aBMC of L2-L4 being 3rd group > 2nd group > 1st group, the differencs are statistically significant (P < 0.05 or P < 0.01); BMC, aBMC of L3 and L4 and aBMC of L2 being 3rd group > 2nd group > 2nd group, the differences are significant (P < 0.01); besides BMC of L2 and T-score,the differencs among three groups are not statistically significant (P > 0.05); (2) Among the 1st group, BMD and average BMD of L2-L4 being Group C > Group B > Group A,the differencs are significant (P < 0.05 or P < 0.01); BMC, aBMC of L and I being Group C > Group B > Group A,the differences among the three groups are significant (P < 0.05 or P < 0.01); BMC, aBMC of L3 and L4 and aBMC of L2 being Group C > Group B > Group A, the differences are significant, besides BMC of L2 and T-score,the differences among three groups are not significant (P > 0.05), (3) BMI correlated negatively (P < 0.01, r = -0.189) to the average BMD of lumbar spine. The average BMD of lumbar spine decreases when BMI increases in males without osteoporosis. When obesity is more obvious, the decrease in average BMD of lumbar spine bone is more evidently decreased. The decrease of BMD, BMC and total BMC in L3 and L may be greater than that in L2.