APOBEC3B promotes hepatocarcinogenesis and metastasis through novel deaminase-independent activity.

Cytidine deaminase APOBEC3B (A3B) is known to play important roles in creating de novo genomic C-to-T mutations in cancers and contribute to induction of genomic instability. Our study evaluated the roles of A3B in the progression and metastasis of human hepatocellular carcinoma (HCC). Using whole-transcriptome and whole-exome sequencing, and quantitative PCR, we found that A3B was overexpressed in human HCCs and A3B expression was significantly correlated with the proportion of genomic C-to-A and G-to-T mutations. Upon clinicopathological correlation, higher A3B expression was associated with more aggressive tumor behavior. Wild-type A3B (wt-A3B) overexpression in HCC cells promoted cell proliferation, and cell migratory and invasive abilities in vitro, and tumorigenicity and metastasis in vivo. On the other hand, knockdown of A3B suppressed cell proliferation, migratory, and invasive abilities of HCC cells with high endogenous A3B level. However, to our surprise, overexpression of A3B deaminase-dead double mutant (E68A/E255Q) led to similar results as wt-A3B in HCC. Furthermore, overexpression of wt-A3B and mutant A3B both enhanced cell cycle progression in HCC cells. Altogether, our data demonstrated a novel deaminase-independent role of A3B in contributing to HCC tumorigenesis and metastasis.

TSC1/2 mutations define a molecular subset of HCC with aggressive behaviour and treatment implication.

OBJECTIVE: We investigated the mutational landscape of mammalian target of rapamycin (mTOR) signalling cascade in hepatocellular carcinomas (HCCs) with chronic HBV background, aiming to evaluate and delineate mutation-dependent mechanism of mTOR hyperactivation in hepatocarcinogenesis. DESIGN: We performed next-generation sequencing on human HCC samples and cell line panel. Systematic mutational screening of mTOR pathway-related genes was undertaken and mutant genes were evaluated based on their recurrence. Protein expressions of tuberous sclerosis complex (TSC)1, TSC2 and pRPS6 were assessed by immunohistochemistry in human HCC samples. Rapamycin sensitivity was estimated by colony-formation assay in HCC cell lines and the treatment was further tested using our patient-derived tumour xenograft (PDTX) models. RESULTS: We identified and confirmed multiple mTOR components as recurrently mutated in HBV-associated HCCs. Of significance, we detected frequent (16.2%, n=18/111) mutations of TSC1 and TSC2 genes in the HCC samples. The spectrum of TSC1/2 mutations likely disrupts the endogenous gene functions in suppressing the downstream mTOR activity through different mechanisms and leads to more aggressive tumour behaviour. Mutational disruption of TSC1 and TSC2 was also observed in HCC cell lines and our PDTX models. TSC-mutant cells exhibited reduced colony-forming ability on rapamycin treatment. With the use of biologically relevant TSC2-mutant PDTXs, we demonstrated the therapeutic benefits of the hypersensitivity towards rapamycin treatment. CONCLUSIONS: Taken together, our findings suggest the significance of previously undocumented mutation-dependent mTOR hyperactivation and frequent TSC1/2 mutations in HBV-associated HCCs. They define a molecular subset of HCC having genetic aberrations in mTOR signalling, with potential significance of effective specific drug therapy.

Novel pre-mRNA splicing of intronically integrated HBV generates oncogenic chimera in hepatocellular carcinoma.

BACKGROUND & AIMS: Hepatitis B virus (HBV) integration is common in HBV-associated hepatocellular carcinoma (HCC) and may play an important pathogenic role through the production of chimeric HBV-human transcripts. We aimed to screen the transcriptome for HBV integrations in HCCs. METHODS: Transcriptome sequencing was performed on paired HBV-associated HCCs and corresponding non-tumorous liver tissues to identify viral-human chimeric sites. Validation was further performed in an expanded cohort of human HCCs. RESULTS: Here we report the discovery of a novel pre-mRNA splicing mechanism in generating HBV-human chimeric protein. This mechanism was exemplified by the formation of a recurrent HBV-cyclin A2 (CCNA2) chimeric transcript (A2S), as detected in 12.5% (6 of 48) of HCC patients, but in none of the 22 non-HCC HBV-associated cirrhotic liver samples examined. Upon the integration of HBV into the intron of the CCNA2 gene, the mammalian splicing machinery utilized the foreign splice sites at 282nt. and 458nt. of the HBV genome to generate a pseudo-exon, forming an in-frame chimeric fusion with CCNA2. The A2S chimeric protein gained a non-degradable property and promoted cell cycle progression, demonstrating its potential oncogenic functions. CONCLUSIONS: A pre-mRNA splicing mechanism is involved in the formation of HBV-human chimeric proteins. This represents a novel and possibly common mechanism underlying the formation of HBV-human chimeric transcripts from intronically integrated HBV genome with functional impact. LAY SUMMARY: HBV is involved in the mammalian pre-mRNA splicing machinery in the generation of potential tumorigenic HBV-human chimeras. This study also provided insight on the impact of intronic HBV integration with the gain of splice sites in the development of HBV-associated HCC.

Investigating the relationship between UMODL1 gene polymorphisms and high myopia: a case-control study in Chinese.

BACKGROUND: The UMODL1 gene was found to be associated with high myopia in Japanese. This study aimed to investigate this gene for association with high myopia in Chinese. METHODS: Two groups of unrelated Han Chinese from Hong Kong were recruited using the same criteria: Sample Set 1 comprising 356 controls (spherical equivalent, SE, within ±1 diopter or D) and 356 cases (SE ≤ -8D), and Sample Set 2 comprising 394 controls and 526 cases. Fifty-nine tag single nucleotide polymorphisms (SNPs) were selected and genotyped for Sample Set 1. Four SNPs were followed up with Sample Set 2. Both single-marker and haplotype analyses were performed with cases defined by different SE thresholds. Secondary phenotypes were also analyzed for association with genotypes. RESULTS: Data filtering left 57 SNPs for analysis. Single-marker analysis did not reveal any significant differences between cases and controls in the initial study. However, haplotype GCT for markers rs220168-rs220170-rs11911271 showed marginal significance (empirical P = 0.076; SE ≤ -12D for cases), but could not be replicated in the follow-up study. In contrast, non-synonymous SNP rs3819142 was associated with high myopia (SE ≤ -10D) in the follow-up study, but could not be confirmed using Sample Set 1. The SNP rs2839471, positive in the original Japanese study, gave negative results in all our analyses. Exploratory analysis of secondary phenotypes indicated that allele C of rs220120 was associated with anterior chamber depth (adjusted P = 0.0460). CONCLUSIONS: Common UMODL1 polymorphisms were unlikely to be important in the genetic susceptibility to high myopia in Han Chinese.

UPDG: utilities package for data analysis of pooled DNA GWAS.

BACKGROUND: Despite being a well-established strategy for cost reduction in disease gene mapping, pooled DNA association study is much less popular than the individual DNA approach. This situation is especially true for pooled DNA genomewide association study (GWAS), for which very few computer resources have been developed for its data analysis. This motivates the development of UPDG (Utilities package for data analysis of Pooled DNA GWAS). RESULTS: UPDG represents a generalized framework for data analysis of pooled DNA GWAS with the integration of Unix/Linux shell operations, Perl programs and R scripts. With the input of raw intensity data from GWAS, UPDG performs the following tasks in a stepwise manner: raw data manipulation, correction for allelic preferential amplification, normalization, nested analysis of variance for genetic association testing, and summarization of analysis results. Detailed instructions, procedures and commands are provided in the comprehensive user manual describing the whole process from preliminary preparation of software installation to final outcome acquisition. An example dataset (input files and sample output files) is also included in the package so that users can easily familiarize themselves with the data file formats, working procedures and expected output. Therefore, UPDG is especially useful for users with some computer knowledge, but without a sophisticated programming background. CONCLUSIONS: UPDG provides a free, simple and platform-independent one-stop service to scientists working on pooled DNA GWAS data analysis, but with less advanced programming knowledge. It is our vision and mission to reduce the hindrance for performing data analysis of pooled DNA GWAS through our contribution of UPDG. More importantly, we hope to promote the popularity of pooled DNA GWAS, which is a very useful research strategy.

Association of the asporin D14 allele with lumbar-disc degeneration in Asians.

Lumbar-disc degeneration (LDD) is a polygenic disease. Susceptibility genes reported so far are mainly extracellular matrix proteins. D14 allele of asporin (ASPN) is associated with osteoarthritis (OA). Candidate-gene association studies showed that the D14 allele is also significantly associated with LDD in Chinese and Japanese individuals. Meta-analysis showed that individuals harboring a D14 allele had higher risk with a summary odds ratio of 1.70 (p = 0.000013). ASPN expression in vertebral discs increased with age and degeneration. Our results indicate ASPN is a LDD gene in Asians, and common risk factors may be considered for OA and LDD.

Intervertebral disc degeneration: new insights based on "skipped" level disc pathology.

OBJECTIVE: Typically, age and abnormal physical loading ("wear and tear") have been associated with the development of intervertebral disc degeneration. In the past decade, various additional etiologic factors for disc degeneration have been sporadically reported in the literature; however, many investigators continue to place tremendous emphasis on the effects of age and biomechanics associated with disc degeneration. The aim of this study was to provide additional insight into the notion that age and biomechanics are key factors in the development of disc degeneration. To this end, we addressed the prevalence of and risk factors associated with a unique pattern of disc degeneration of the lumbar spine, "skipped" level (nonconsecutive) disc degeneration (SLDD). METHODS: As part of a large genetics-based study in southern Chinese individuals (n = 1,989), a cross-sectional analysis was performed in subjects exhibiting disc degeneration in > or = 2 levels (n = 838) who were then categorized as having SLDD (n = 174) or non-SLDD (contiguous, multilevel; n = 664). Various radiographic parameters were assessed based on T2-weighted magnetic resonance imaging (MRI). Subject demographics were assessed, and univariate and multivariate logistic regression analyses were performed. RESULTS: Overall, 8.7% of the whole population (n = 1,989) had SLDD, while it was present in 20.8% of subjects with multilevel disc degeneration (n = 838). SLDD was more prevalent in male subjects (adjusted odds ratio [OR] 1.48, 95% confidence interval [95% CI] 1.04-2.10, P = 0.028). SLDD was significantly associated with the presence of Schmorl's nodes (adjusted OR 2.72, 95% CI 1.78-4.15, P < 0.001), which also presented in levels with no disc degeneration. A history of disc bulge/extrusion (P = 0.004) and/or a history of back injury (P = 0.010) was significantly associated with non-SLDD, and a greater degree of overall severity of disc degeneration was also associated with non-SLDD. Other demographic and MRI findings did not significantly differ between groups. CONCLUSION: To our knowledge, this report is the first to describe the prevalence and risk factors associated with SLDD. Our study challenges the paradigm that age and biomechanics are the key factors associated with the development of disc degeneration. Although age and biomechanical factors may play a role in the manifestation of disc degeneration, our novel findings of SLDD patterns provide further awareness of and support for the notion that additional etiologic factors may play a role in the development of disc degeneration. Such factors warrant further investigation to shed light on the cause of disc degeneration.

Association between promoter -1607 polymorphism of MMP1 and lumbar disc disease in Southern Chinese.

BACKGROUND: Matrix metalloproteinases (MMPs) are involved in the degradation of the extracellular matrix of the intervertebral disc. A SNP for guanine insertion/deletion (G/D), the -1607 promoter polymorphism, of the MMP1 gene was found significantly affecting promoter activity and corresponding transcription level. Hence it is a good candidate for genetic studies in DDD. METHODS: Southern Chinese volunteers between 18 and 55 years were recruited from the population. DDD in the lumbar spine was defined by MRI using Schneiderman's classification. Genomic DNA was isolated from the leukocytes and genotyping was performed using the Sequenom platform. Association and Hardy-Weinberg equilibrium checking were assessed by Chi-square test and Mann-Whitney U test. RESULTS: Our results showed substantial evidence of association between -1607 promoter polymorphism of MMP1 and DDD in the Southern Chinese subjects. D allelic was significantly associated with DDD (p value = 0.027, odds ratio = 1.41 with 95% CI = 1.04-1.90) while Genotypic association on the presence of D allele was also significantly associated with DDD (p value = 0.046, odds ratio = 1.50 with 95% CI = 1.01-2.24). Further age stratification showed significant genotypic as well as allelic association in the group of over 40 years (genotypic: p value = 0.035, odds ratio = 1.617 with 95% CI = 1.033-2.529; allelic: p value = 0.033, odds ratio = 1.445 with 95% CI = 1.029-2.029). Disc bulge, annular tears and the Schmorl's nodes were not associated with the D allele. CONCLUSION: We demonstrated that individuals with the presence of D allele for the -1607 promoter polymorphism of MMP1 are about 1.5 times more susceptible to develop DDD when compared with those having G allele only. Further association was identified in individuals over 40 years of age. Disc bulge, annular tear as well as Schmorl's nodes were not associated with this polymorphism.

uGPA: unified Gene Pathway Analyzer package for high-throughput genome-wide screening data provides mechanistic overview on human diseases.

BACKGROUND: Gene set or pathway analysis (GPA) can provide a comprehensive mechanistic overview in delineating molecular pathoetiology of human diseases. Existing tools that can handle for GPA on both mutational and gene expressional aspects are limited. This leads to the development of uGPA (unified Gene Pathway Analyzer). METHODS: uGPA package provides a unified solution to knowledge base-driven competitive GPA that can analyze genome-wide screening data derived from multiple platforms (next generation sequencing or microarray) and sample sources (genomic or transcriptomic) on both mutational and gene expressional perspectives. It allows for a quick assessment of perspective outline of gene sets on the studied disease through enrichment test modeled by cumulative hypergeometric distribution and reports the gene components detected with events (mutation or differential gene expression) in the gene sets. RESULTS: uGPA package has been successfully verified to be applicable on input data generated from NGS-based platforms (transcriptome sequencing and whole-exome sequencing). Genome-wide screening data from other platforms should also apply. CONCLUSIONS: uGPA package delivers a simple, flexible and platform-independent functionality to multiple aspects of GPA. It equips clinicians and scientists with a useful tool in studying molecular mechanism of human diseases using modern high-throughput genome-wide screening strategy, which assists personalized therapy.

Virus-Clip: a fast and memory-efficient viral integration site detection tool at single-base resolution with annotation capability.

Viral integration into the human genome upon infection is an important risk factor for various human malignancies. We developed viral integration site detection tool called Virus-Clip, which makes use of information extracted from soft-clipped sequencing reads to identify exact positions of human and virus breakpoints of integration events. With initial read alignment to virus reference genome and streamlined procedures, Virus-Clip delivers a simple, fast and memory-efficient solution to viral integration site detection. Moreover, it can also automatically annotate the integration events with the corresponding affected human genes. Virus-Clip has been verified using whole-transcriptome sequencing data and its detection was validated to have satisfactory sensitivity and specificity. Marked advancement in performance was detected, compared to existing tools. It is applicable to versatile types of data including whole-genome sequencing, whole-transcriptome sequencing, and targeted sequencing. Virus-Clip is available at http://web.hku.hk/~dwhho/Virus-Clip.zip.

Effectiveness of a life story work program on older adults with intellectual disabilities.

OBJECTIVE: This study examines the effectiveness of a life story work program (LSWp) in older adults with mild-to-moderate levels of intellectual disability (ID). METHODS: Using a quasiexperimental design, this study assigned 60 older adults who were between 50-90 years old with mild-to-moderate levels of ID to receive either the LSWp (intervention group, N=32) or usual activities (control group, N=28) during a period of 6 months. Evaluation was made based on the outcomes assessed by the Mood Interest and Pleasure Questionnaire, the Vineland Adaptive Behavior Scales, and the Personal Wellbeing Index - ID. RESULTS AND CONCLUSION: LSWp shows potential for improving the quality of life and preventing the loss of interest and pleasure in older adults with ID. It also shows promise in enhancing their socialization skills. Patients with better communication abilities seemed to benefit more from the LSWp.

Effectiveness of cognitive training for Chinese elderly in Hong Kong.

In Hong Kong, the evidence for cognitive-training programs in fighting against memory complaints is lacking. This study aimed to evaluate the effectiveness of the Active Mind cognitive-training program in improving the cognitive function and quality of life (QoL) for local community-dwelling Chinese older adults. A total of 200 subjects were recruited from 20 different district elderly community centers (DECCs). Centers were randomly assigned into either the intervention group or control group. The intervention group underwent eight 1-hour sessions of cognitive training, while the control group were included in the usual group activities provided by the DECCs. Standardized neuropsychological tests (the Chinese version of Mattis Dementia Rating Scale [CDRS] and the Cantonese version of the Mini-Mental State Examination) and the QoL questionnaire SF12 were used to assess participants' cognitive function and QoL before and after the trial. A total of 176 subjects completed the study. The intervention group showed greater improvement in the cognitive function measured by total CDRS score (treatment: 12.24 ± 11.57 vs control: 4.37 ± 7.99; P < 0.001) and QoL measured by total SF12 score (treatment: 7.82 ± 13.19 vs control: 3.18 ± 11.61; P = 0.014). Subjects with lower education level were associated with better cognitive response to the cognitive-training program. The current findings indicated that the Active Mind cognitive-training program was effective in improving the cognitive function and QoL for community-dwelling Chinese older adults in Hong Kong.

Lumbar disc degeneration is linked to a carbohydrate sulfotransferase 3 variant.

Lumbar disc degeneration (LDD) is associated with both genetic and environmental factors and affects many people worldwide. A hallmark of LDD is loss of proteoglycan and water content in the nucleus pulposus of intervertebral discs. While some genetic determinants have been reported, the etiology of LDD is largely unknown. Here we report the findings from linkage and association studies on a total of 32,642 subjects consisting of 4,043 LDD cases and 28,599 control subjects. We identified carbohydrate sulfotransferase 3 (CHST3), an enzyme that catalyzes proteoglycan sulfation, as a susceptibility gene for LDD. The strongest genome-wide linkage peak encompassed CHST3 from a Southern Chinese family­based data set, while a genome-wide association was observed at rs4148941 in the gene in a meta-analysis using multiethnic population cohorts. rs4148941 lies within a potential microRNA-513a-5p (miR-513a-5p) binding site. Interaction between miR-513a-5p and mRNA transcribed from the susceptibility allele (A allele) of rs4148941 was enhanced in vitro compared with transcripts from other alleles. Additionally, expression of CHST3 mRNA was significantly reduced in the intervertebral disc cells of human subjects carrying the A allele of rs4148941. Together, our data provide new insights into the etiology of LDD, implicating an interplay between genetic risk factors and miRNA.

Genome-wide meta-analyses of multiancestry cohorts identify multiple new susceptibility loci for refractive error and myopia.

Refractive error is the most common eye disorder worldwide and is a prominent cause of blindness. Myopia affects over 30% of Western populations and up to 80% of Asians. The CREAM consortium conducted genome-wide meta-analyses, including 37,382 individuals from 27 studies of European ancestry and 8,376 from 5 Asian cohorts. We identified 16 new loci for refractive error in individuals of European ancestry, of which 8 were shared with Asians. Combined analysis identified 8 additional associated loci. The new loci include candidate genes with functions in neurotransmission (GRIA4), ion transport (KCNQ5), retinoic acid metabolism (RDH5), extracellular matrix remodeling (LAMA2 and BMP2) and eye development (SIX6 and PRSS56). We also confirmed previously reported associations with GJD2 and RASGRF1. Risk score analysis using associated SNPs showed a tenfold increased risk of myopia for individuals carrying the highest genetic load. Our results, based on a large meta-analysis across independent multiancestry studies, considerably advance understanding of the mechanisms involved in refractive error and myopia.

Effect of physical restraint reduction on older patients' hospital length of stay.

OBJECTIVES: Physical restraints are often used to prevent falls and to secure medical devices in older people in hospitals. Restraint reduction has been advocated on the grounds that physical restraints have negative psychological effects and are not effective in preventing falls. The potential effect of restraint reduction on length of hospital stay (LOS) has not been investigated. This study was undertaken to compare the average length of stay of older patients in a convalescent medical ward setting before and after a restraint reduction program. DESIGN: This is a retrospective study. SETTING: A convalescent hospital in Hong Kong. PARTICIPANTS: This study included 2000 patient episodes. MEASUREMENTS: The use of physical restraint, LOS, and clinical outcomes of randomly selected patient episodes in the year before and after the implementation of a restraint reduction program were compared. The clinical outcomes included Modified Functional Ambulatory Categories and modified Barthel index. Subgroup analysis was performed on those with confusion as defined by dementia diagnosis, low abbreviated mental test score, or abnormal mental domain of Norton Score. RESULTS: A total of 958 and 988 patient episodes admitted to 10 medical wards in a convalescent hospital in 2007 and 2009 were examined. There were no significant differences in the baseline characteristics of patients in the 2 years. With the implementation of the restraint reduction scheme, the rate of physical restraint use declined significantly from 13.3% in 2007 to 4.1% in 2009 for all patients. The average LOS of patients was significantly lower in the year after the implementation of restraint reduction (19.5 ± 20.7 versus 16.8 ± 13.4 days in 2007 and 2009 respectively, P < .001). On subgroup analysis, the reduction in LOS was significant in the cognitively impaired patients (23.0 ± 26.5 to 17.8 ± 15.0 days in 2007 and 2009 respectively, P < .001), but not in the cognitively normal patients. There were no significant differences between the 2 years in the incidence of fall, mobility, and activities of daily living on discharge. CONCLUSION: Physical restraint reduction was associated with significant reduction in average length of stay in convalescent medical wards, especially in the cognitively impaired patients.

Association of high myopia with crystallin beta A4 (CRYBA4) gene polymorphisms in the linkage-identified MYP6 locus.

BACKGROUND: Myopia is the most common ocular disorder worldwide and imposes tremendous burden on the society. It is a complex disease. The MYP6 locus at 22 q12 is of particular interest because many studies have detected linkage signals at this interval. The MYP6 locus is likely to contain susceptibility gene(s) for myopia, but none has yet been identified. METHODOLOGY/PRINCIPAL FINDINGS: Two independent subject groups of southern Chinese in Hong Kong participated in the study an initial study using a discovery sample set of 342 cases and 342 controls, and a follow-up study using a replication sample set of 316 cases and 313 controls. Cases with high myopia were defined by spherical equivalent ≤ -8 dioptres and emmetropic controls by spherical equivalent within ±1.00 dioptre for both eyes. Manual candidate gene selection from the MYP6 locus was supported by objective in silico prioritization. DNA samples of discovery sample set were genotyped for 178 tagging single nucleotide polymorphisms (SNPs) from 26 genes. For replication, 25 SNPs (tagging or located at predicted transcription factor or microRNA binding sites) from 4 genes were subsequently examined using the replication sample set. Fisher P value was calculated for all SNPs and overall association results were summarized by meta-analysis. Based on initial and replication studies, rs2009066 located in the crystallin beta A4 (CRYBA4) gene was identified to be the most significantly associated with high myopia (initial study: P = 0.02; replication study: P = 1.88e-4; meta-analysis: P = 1.54e-5) among all the SNPs tested. The association result survived correction for multiple comparisons. Under the allelic genetic model for the combined sample set, the odds ratio of the minor allele G was 1.41 (95% confidence intervals, 1.21-1.64). CONCLUSIONS/SIGNIFICANCE: A novel susceptibility gene (CRYBA4) was discovered for high myopia. Our study also signified the potential importance of appropriate gene prioritization in candidate selection.

Genotyping performance assessment of whole genome amplified DNA with respect to multiplexing level of assay and its period of storage.

Whole genome amplification can faithfully amplify genomic DNA (gDNA) with minimal bias and substantial genome coverage. Whole genome amplified DNA (wgaDNA) has been tested to be workable for high-throughput genotyping arrays. However, issues about whether wgaDNA would decrease genotyping performance at increasing multiplexing levels and whether the storage period of wgaDNA would reduce genotyping performance have not been examined. Using the Sequenom MassARRAY iPLEX Gold assays, we investigated 174 single nucleotide polymorphisms for 3 groups of matched samples: group 1 of 20 gDNA samples, group 2 of 20 freshly prepared wgaDNA samples, and group 3 of 20 stored wgaDNA samples that had been kept frozen at -70°C for 18 months. MassARRAY is a medium-throughput genotyping platform with reaction chemistry different from those of high-throughput genotyping arrays. The results showed that genotyping performance (efficiency and accuracy) of freshly prepared wgaDNA was similar to that of gDNA at various multiplexing levels (17-plex, 21-plex, 28-plex and 36-plex) of the MassARRAY assays. However, compared with gDNA or freshly prepared wgaDNA, stored wgaDNA was found to give diminished genotyping performance (efficiency and accuracy) due to potentially inferior quality. Consequently, no matter whether gDNA or wgaDNA was used, better genotyping efficiency would tend to have better genotyping accuracy.

Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individuals.

STUDY DESIGN: A cross-sectional population study of magnetic resonance imaging (MRI) changes. OBJECTIVE.: To examine the pattern and prevalence of lumbar spine MRI changes within a southern Chinese population and their relationship with back pain. SUMMARY OF BACKGROUND DATA: Previous studies on MRI changes and back pain have used populations of asymptomatic individuals or patients presenting with back pain and sciatica. Thus, the prevalence and pattern of intervertebral disc degeneration within the population is not known. METHODS: Lumbar spine MRIs were obtained in 1043 volunteers between 18 to 55 years of age. MRI changes including disc degeneration, herniation, anular tears (HIZ), and Schmorl's nodes were noted by 2 independent observers. Differences were settled by consensus. Disc degeneration was graded using Schneiderman's classification, and a total score (DDD score) was calculated by the summation of the Schneiderman's score for each lumbar level. A K-mean clustering program was used to group individuals into different patterns of degeneration. RESULTS: Forty percent of individuals under 30 years of age had lumbar intervertebral disc degeneration (LDD), the prevalence of LDD increasing progressively to over 90% by 50 to 55 years of age. There was a positive correlation between the DDD score and low back pain. L5-S1 and L4-L5 were the most commonly affected levels. Apart from the usual patterns of degeneration, some uncommon patterns of degeneration were identified, comprising of subjects with skip level lesions (intervening normal levels) and isolated upper or mid lumbar degeneration. CONCLUSION: LDD is common, and its incidence increases with age. In a population setting, there is a significant association of LDD on MRI with back pain.