Osteoporosis is a bone disease with increasing prevalence with age . The bone mass of humans, which is related to age, increases in childhood and adolescents but begins to slowly decrease at a rate of approximately 0.5% per year after reaching its peak in adulthood . Bone mineral density (BMD) is an intrinsic factor associated with brittle fracture of the spine, and osteoporosis (low BMD) is the most serious risk factor . In the population over the age of 50, VCFs caused by osteoporosis, minor trauma or no obvious trauma are relatively common, causing serious public health problems due to disability, decreased quality of life and increased mortality .
In our study, nearly all the cases occurred in the 60 to 69 years group and the 70 to 79 years group. The number of cases were obviously higher than those in the 50 to 59 years group or the 80 to 89 years group. We believe that the loss of bone mass is not great enough to confer an extreme risk of VCF until the age of 60. However, the low rate of VCF in the 80 to 89 years group should be explained. The main reason for this phenomenon is that the population aged 80 to 89 years is smaller than the populations of the other age groups. According to the 2010 population census of China from the National Bureau of Statistics, the population of individuals aged 80 to 89 years was 19 million, whereas that of individuals aged 60 to 69 years was almost 100 million . Although the probability of VCF is higher in elderly individuals, the age group is the determining factor. Moreover, elderly individuals lose the ability and willingness to participate in social activities with increasing age, which means a relatively decreased risk of developing fracture . It has been estimated that more than 70% of VCFs are silent . Sometimes the symptoms are too minor to be noticed, and elderly individuals do not realize that they have a VCF until they undergo radiography for another condition or experience a secondary osteoporotic fracture. In addition, the lack of knowledge about osteoporotic fractures in elderly individuals and their families is an obstacle to being addressed.
In our study, we found that the proportion of VCF in female patients was higher than that in male patients aged 50–89 years. With increasing age, the proportion of VCF decreased in female patients and increased in male patients, with P values < 0.05, indicating a significant difference. The proportion of vertebral fractures in female patients aged 60–69 years was the highest (82.64%), and there was a significant decrease (66.36%) in the 80–89 years age group. The risk of fracture increases because the activity of osteoclasts increases, which can lead to osteoporosis because estrogen levels decline rapidly during late menopause . The peak bone mass in males is greater than that in females, and the occurrence of bone loss occurs later in life. In addition, the decline in androgens is gradual, so the amount and rate of bone loss in males is less than that in females. In this study, VCFs in females were found to predominate in the 60–69 years age group, while the proportion in the 80–89 years age group showed a significant decrease, which was statistically significant.
The results of this study showed that the P values between single-segment fractures and multisegment fractures in all age groups were > 0.05 and were not statistically significant. Moreover, the proportions of multisegment VCFs did not increase significantly. Therefore, this study shows that patients with single-segment fractures can be stabilized through prevention or treatment and may not develop multisegment fractures.
This study shows a trend that stress diffuses from T12, with stress gradually concentrating in L1, L2, L3, and L4 according to the comparison of the vertebral segment with fractures. However, only the P values of L4 vertebral fractures in each age group were significant, with values < 0.05 (0.047). When a patient falls backward, the energy of compression diffuses from his/her lower lumbar vertebrae up to thoracic vertebrae. The vertebra, which absorbs most of the energy, fractures. Therefore, the occurrence of VCF in L4 increases with age, indicating that the L4 vertebra is most affected by deterioration due to osteoporosis. We can regard VCF in L4 as a threshold of the degree of osteoporosis in a sense and as an indicator of the probability of suffering another osteoporotic fracture, including VCF.
In 2001, the United States National Institutes of Health (NIH) stated that osteoporosis is a bone disease causing a decrease in bone strength, resulting in an increase in fracture risk. Bone strength comprises two essential factors: bone mass and bone quality. The auxiliary method of quantitative CT (QCT) measurement of BMD combined with the finite element model to analyze bone strength may be more effective than a single method in preventing and treating osteoporotic VCF.
Twenty-one percent of women with osteoporosis experience one or more osteoporotic fractures, and they can suffer an additional fracture within one year after vertebroplasty . Physicians who perform vertebroplasty should inform patients with osteoporosis that they may experience fracture again within a year. Our study showed that the proportion of multisegment fractures was 20.68%, which is in accordance with the data above. The P values of the comparisons of the proportions of single-segment fractures and multisegment fracture in each age group were > 0.05, with no statistical significance. However, we found that the rate of multisegment fractures increased with age, as shown in Table 2. Lindsay et al.  found that once osteoporotic VCF occurs, there is a high risk of additional fracture in the future. The main risk factor is underlying osteoporosis. The rates of single and multiple VCFs increase with age, and the osteoporosis condition deteriorates. Considering the understanding of the progress trend of osteoporotic fractures, it is possible to prevent the occurrence of VCF.
Since this study was limited to inpatients in the Department of Spinal Surgery in the First Hospital of Jilin University, there may be bias in the structural composition of the study population; therefore, the sample size should be increased in a future in-depth study. In conclusion, there are certain rules to follow for VCFs in patients over the age of 50. Further research and knowledge can improve the ability to prevent and treat VCFs.