Relationship of body surface area with bone density and its risk of osteoporosis at various skeletal regions in women of mainland China

Effect of Body Surface Area on Severe Osteoporotic Fractures: A Study of Osteoporosis in Changsha China

Clinical vertebral fractures and femoral neck fractures are severe osteoporotic fractures that increase morbidity and mortality. Anthropometric variables are associated with an increased risk of osteoporotic fractures, but it is not clear whether body surface area (BSA) has an effect on clinically severe osteoporotic fractures. The study included total of 3,694 cases of clinical vertebral fractures and femoral neck fractures (2,670 females and 1,024 males) and 3,694 controls without fractures who were matched with the cases by sex and age. There was a significant positive correlation between BSA and bone mineral density (BMD) in female and male fracture patients (females: r = 0.430-0.471, P < 0.001; males: r = 0.338-0.414, P < 0.001). There was a significant systematic increase in BMD in both genders at various skeletal sites, grouped by BSA quartile. The osteoporosis rates of the lumbar spine (97.9%), femoral neck (92.4%) and total hip (87.1%) in the female Q1 group were significantly higher than those in the Q4 group (P < 0.001), which were 80.0%, 57.9% and 36.9%, respectively, in the Q4 group; the osteoporosis rates of the lumbar spine, femoral neck, and total hip were 53.9%, 59.4%, and 36.3% in the male Q1 group, and 15.2%, 21.9%, and 7.03% in the Q4 group, which were significantly lower than those in the Q1 group (P < 0.001). In age-adjusted Cox regression models, the risk of fracture in the remaining three groups (Q2, Q3, and Q4) for weight, BMI, and BSA for both genders, compared with the highest quartile (Q1 by descending quartile stratification) were significantly higher. In models adjusted for age and BMD, only men in the BSA Q3 (HR = 1.55, 95% CI = 1.09-2.19) and BSA Q4 groups (HR = 1.41, 95% CI = 1.05-1.87) had significantly higher fracture risks. In models adjusted for age, height, weight, BMI, and BSA, low BMD was the greatest fracture risks for both sexes. Our results showed that BSA was closely related to BMD, prevalence of osteoporosis, and fracture risk, and that a decline in BSA may be a new potential risk factor for osteoporotic fractures in Chinese men.

Bone mass of overweight affluent Indian youth and its sex-specific association with body composition

SUMMARY: The study assessed whether overweight is associated with better bone densities in healthy youth. It was observed that overweight individuals had better BMDs at the hip but not at other sites after controlling for the bone area. Lean body mass was an important determinant of BMDs in men, but both lean and fat mass were important for BMDs in women. INTRODUCTION: The study assessed the relationship of overweight and obesity to the bone mass in young men and women consuming adequate calcium. METHODS: Bone and body composition parameters were measured using dual energy X-ray absorptiometry in overweight men (n = 74) and women (n = 77) in the age group of 20-35 years and compared with controls having normal body mass index (BMI). Biochemical parameters of bone metabolism were also assessed. RESULTS: After adjustment for whole body bone area, bone mineral densities (BMDs) at femoral neck and hip were significantly higher in overweight individuals when compared with controls. However, BMD at lumbar spine, forearm, and whole body were not significantly different in the two BMI groups. Overweight women had lower vitamin D and higher parathormone levels than controls. Regression analyses indicated that height was an important determinant of BMD at most of the skeletal sites in both men and women. Lean body mass was an important determinant of BMDs in men, but both lean and fat mass were important for BMDs in women. CONCLUSION: Overweight may be associated with better BMDs at the hip but not at other sites after controlling for the bone area. Body composition parameters may have sex-specific associations with BMD.

Vertebral dimensions as risk factor of vertebral fracture in osteoporotic patients: a systematic literature review

This systematic literature review studied the potential association between vertebral fracture risk and vertebral dimensions. Analysis showed that patients with vertebral fractures have smaller non-fractured vertebrae than patients without fractures. Vertebral size is an independent risk factor of vertebral fractures.

INTRODUCTION

Biomechanical factors such as vertebral dimensions may be a risk factor for vertebral fractures beside bone mineral density (BMD). The objective of this study was to evaluate potential association of vertebral size and shape with osteoporotic fracture risk through a systematic literature review.

METHODS

Systematic analysis of published reports comparing vertebral dimensions of patients with and without osteoporotic fractures was performed. Data sources were electronic databases. Data extraction included methods, site, reproducibility and results of vertebral measurement, study population characteristics. It was noted if populations were matched or data were adjusted for age, height, weight and BMD.

RESULTS

Of 634 reports identified by the literature search, the final review included 13 reports studying 4,428 women and 508 men; median age 64.2 years [range 51.7%-73.0%]. Measurements were performed with computed tomography scan, X-ray, or dual energy X-ray absorptiometry. Vertebral body height, width, depth, area, cross-sectional area (CSA), and volume were 5.5% to 9.5% smaller in fractured group than control group. After adjustment for confounding factors, area, CSA and volume were, respectively, 10.2% [range 7.1%-13.3%], 7.7% [range 1.2%-14.2%] and 9.5% [8.5%-10.5%] smaller in fractured group.

CONCLUSIONS

Vertebral size should be considered as a potential independent vertebral fracture risk factor.

Hyperbilirubinemia is not a major contributing factor to altered bone mineral density in patients with chronic liver disease

Reduced bone density is commonly encountered in patients with chronic liver disease. Prior studies have shown that unconjugated bilirubin inhibits osteoblast activity and function in vitro and in animal models of bone mineralization. To determine whether hyperbilirubinemia promotes the development of hepatic osteodystrophy, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry in a cohort of 86 consecutive patients with chronic liver disease referred for liver transplant evaluation. The mean age of the study population was 52 years (range, 22-73), in which 52% were female and 90% were white. Average bone density values were significantly lower than expected for age, race, and sex, with Z-scores for the femoral neck and spine of -0.50 (95% confidence interval [CI] -0.63 to -0.37; p=0.0003) and -0.69 (95% CI -0.85 to -0.52; p=0.0001), respectively. Sixty-one subjects (71%) exhibited reduced BMD (T-score of femoral neck or spine<or=-1 standard deviation [SD] below the young-adult mean), and 18 subjects (21%) met criteria for osteoporosis (T-score<-2.5 SD). Stepwise logistic regression analyses identified significant associations between BMD and serum creatinine, alkaline phosphatase, age, and gender. On the other hand, neither unconjugated, nor conjugated, nor total serum bilirubin levels were found to predict diminished BMD. The lack of association between serum unconjugated bilirubin levels and bone mineralization was validated in hyperbilirubinemic Gunn rats, in which BMD and serum osteocalcin levels were no different than in wild-type rodents. In conclusion, the finding that serum bilirubin levels do not correlate with reduced BMD in patients with end-stage liver disease, and that chronic unconjugated hyperbilirubinemia does not lead to alterations in bone mineralization in Gunn rats, suggests that bilirubin is not a major contributing factor to hepatic osteodystrophy.