Incidence and Mortality of Vertebral Compression Fracture Among All Age Groups: A Nationwide, Population-based Study in the Republic of Korea

BACKGROUND

Although several studies have examined the epidemiological features of vertebral compression fractures (VCF) among elderly patients, few studies have reported the epidemiology of VCF among younger individuals.

OBJECTIVE

To examine trends in the incidence and mortality of VCF in both the old (>= 65 years) and young (< 65 years) age groups. This study aimed to investigate the incidence and mortality of VCF among all age groups in Korea.

STUDY DESIGN

Population-based cohort study.

SETTING

A nationwide, population-based setting.

METHODS

Using the Korean National Health Insurance database, which has complete population coverage, we identified patients diagnosed with VCF between 2005 to 2018. Differences in incidence, survival and mortality were compared across groups using Kaplan-Meier analysis and Cox regression for all age groups and both genders.

RESULTS

We identified a total of 742,993 VCF patients and the annual incidence was 140.09/100,000 individuals. Although the incidence of VCF was significantly higher in the older age compared to younger age group (556.38/100,000 vs. 44.09/100,000 individuals), the mortality rate ratio for VCF patients was higher among younger compared to older individuals (old: 1.59 vs. young: 2.87). In our multivariable-adjusted analysis, the hazard ratio for multiple fractures, traumatic injury and osteoporosis were higher in patients aged < 65 years compared to patients aged >= 65 years, suggesting that the impact of these clinical variables on mortality is more significant in the younger age group.

LIMITATION

A limitation of this study was its lack of information on clinical features, such as disease severity and laboratory data. The precise cause of death of VCF patients could not be confirmed from the study database.

CONCLUSIONS

The mortality rate ratio and hazard ratio were significantly higher among younger patients with VCF, indicating the need for further research on VCF in younger age groups.

Risk factors for hemorrhagic stroke in Wonju, Korea

Although stroke is a great public health challenge in Korea, there have have been few epidemiologic studies of the risk factors stroke. A case-control study was performed to evaluate the risk factors for hemorrhagic stroke in Wonju, Korea. Ninety-five subarachnoid hemorrhage (SAH) and 102 intracerebral hemorrhage (ICH) patients aged 21-86 years, and 267 controls were recruited among the inpatients of Wonju Christian Hospital during 1994-1995. Information was gathered through interview and examinations. After adjustment for age and sex, family and past history of hypertension, drinking habits, age of menarche, height, weight, body mass index, waist and hip circumference, earlobe crease, prothrombin time, white blood cell count, hemoglobin, and total cholesterol were all found to be significantly associated with both SAH and ICH. The risk factor significantly associated only with ICH was smoking habits. In multiple logistics analyses, the independent risk factors for SAH and ICH were the same. Those included family and past history of hypertension, age of menarche, earlobe crease, prothrombin time, white blood cell count, hemoglobin and total cholesterol. In general, the risk factors for SAH and ICH were similar with each other, except smoking habits. Risk factors found in this study congruent with previous studies were family and past history of hypertension, drinking habits, body mass index, prothrombin time, white blood cell count, and hemoglobin. Those incongruent or rather newly found were age of menarche, a big physique, earlobe crease, and total cholesterol.

Friend virus replication as a function of age

We have investigated the effect of age on the replication of Friend spleen focus-forming virus (SFFV). Recovery of SFFV from the spleens of four strains of mice was determined following intravenous infection with NB-tropic Friend virus (FV) complex at ages ranging from 6 to 134 weeks. In C57BL/6 mice, the virus did not replicate in adults up to 40 weeks of age, but beyond that there was a steep exponential increase with age in the amounts of SFFV recoverable. In C3H/He mice, which replicate the virus as young adults, the amount of SFFV recovered was 6-fold greater in old than in young mice. Recovery of virus was biphasic with age in SJL mice; in A strain mice no consistent change with age was noted. In C57BL/6 mice, reconstitution of lethally irradiated recipients with syngeneic marrow cells, followed by i.v. infection with FV, showed that the amounts of SFFV recovered depended on the age of the recipient. The present work shows that Friend SFFV replication is a sensitive indicator and can be used as a tool for the investigation of aging processes. The mechanisms responsible for the age-dependent change in regulation of virus replication and for the polymorphism remain to be determined.

Strain-dependence and cellular aspects of the acceleration of age-dependent shift in class-specific helper and suppressor activity in the thymus of MRL/Mp mice by the LPR gene

Previous studies of the immunoregulatory activity of thymocytes from SJL/J mice have shown loss of suppressor activity for the antibody response by 24 weeks of age with appearance of helper activity. At the same time, suppressor cells developed which inhibit the generation of cytotoxic T lymphocytes (CTL). We now show a similar pattern of helper and suppressor activity in MRL/Mp mice. Presence of the lpr/lpr genotype significantly accelerated the onset of these changes in thymocyte activity. A similar pattern of thymocyte activity was not detected in C57B1/6 mice. In aged MRL-lpr mice, evidence of increased suppressor cell activity for the CTL response could be demonstrated in spleen, and the suppressor was sensitive to treatment with anti-thy 1.2 + complement. The magnitude of the deficiency in the CTL response in MRL-lpr mice was greater than could be accounted for by suppressor cell activity alone. Measurement of the frequency of CTL precursors (CTLP), the yield of CTL per CTLP, and the ability to produce and to respond to interleukin 2 (IL-2) indicated that a drop in CTLP frequency, subnormal generation of IL-2, and probably an intrinsic defect in the responsiveness of MRL-lpr CTLP to IL-2 was contributing to the defective CTL response. We were not able to link suppressor T cells with reduced responsiveness to IL-2. Ageing involves different patterns of change in immunoregulatory T-cell subsets in different strains of mice, depending on their genetic constitution. The general implications of this conclusion for prediction of immune dysfunction with age in genetically distinct members of an outbred population are discussed.