Caries Risk Prediction Models in a Medical Health Care Setting

Despite development of new technologies for caries control, tooth decay in primary teeth remains a major global health problem. Caries risk assessment (CRA) models for toddlers and preschoolers are rare. Among them, almost all models use dental factors (e.g., past caries experience) to predict future caries risk, with limited clinical/community applicability owing to relatively uncommon dental visits compared to frequent medical visits during the first year of life. The objective of this study was to construct and evaluate risk prediction models using information easily accessible to medical practitioners to forecast caries at 2 and 3 y of age. Data were obtained from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) mother-offspring cohort. Caries was diagnosed using modified International Caries Detection and Assessment System criteria. Risk prediction models were constructed using multivariable logistic regression coupled with receiver operating characteristic analyses. Imputation was performed using multiple imputation by chained equations to assess effect of missing data. Caries rates at ages 2 y (n = 535) and 3 y (n = 721) were 17.8% and 42.9%, respectively. Risk prediction models predicting overall caries risk at 2 and 3 y demonstrated area under the curve (AUC) (95% confidence interval) of 0.81 (0.75-0.87) and 0.79 (0.74-0.84), respectively, while those predicting moderate to extensive lesions showed 0.91 (0.85-0.97) and 0.79 (0.73-0.85), respectively. Postimputation results showed reduced AUC of 0.75 (0.74-0.81) and 0.71 (0.67-0.75) at years 2 and 3, respectively, for overall caries risk, while AUC was 0.84 (0.76-0.92) and 0.75 (0.70-0.80), respectively, for moderate to extensive caries. Addition of anterior caries significantly increased AUC in all year 3 models with or without imputation (all P < 0.05). Significant predictors/protectors were identified, including ethnicity, prenatal tobacco smoke exposure, history of allergies before 12 mo, history of chronic maternal illness, maternal brushing frequency, childbearing age, and so on. Integrating oral-general health care using medical CRA models may be promising in screening caries-susceptible infants/toddlers, especially when medical professionals are trained to "lift the lip" to identify anterior caries lesions.

Human genome meeting 2016 : Houston, TX, USA. 28 February - 2 March 2016

O1 The metabolomics approach to autism: identification of biomarkers for early detection of autism spectrum disorder A. K. Srivastava, Y. Wang, R. Huang, C. Skinner, T. Thompson, L. Pollard, T. Wood, F. Luo, R. Stevenson O2 Phenome-wide association study for smoking- and drinking-associated genes in 26,394 American women with African, Asian, European, and Hispanic descents R. Polimanti, J. Gelernter O3 Effects of prenatal environment, genotype and DNA methylation on birth weight and subsequent postnatal outcomes: findings from GUSTO, an Asian birth cohort X. Lin, I. Y. Lim, Y. Wu, A. L. Teh, L. Chen, I. M. Aris, S. E. Soh, M. T. Tint, J. L. MacIsaac, F. Yap, K. Kwek, S. M. Saw, M. S. Kobor, M. J. Meaney, K. M. Godfrey, Y. S. Chong, J. D. Holbrook, Y. S. Lee, P. D. Gluckman, N. Karnani, GUSTO study group O4 High-throughput identification of specific qt interval modulating enhancers at the SCN5A locus A. Kapoor, D. Lee, A. Chakravarti O5 Identification of extracellular matrix components inducing cancer cell migration in the supernatant of cultivated mesenchymal stem cells C. Maercker, F. Graf, M. Boutros O6 Single cell allele specific expression (ASE) IN T21 and common trisomies: a novel approach to understand DOWN syndrome and other aneuploidies G. Stamoulis, F. Santoni, P. Makrythanasis, A. Letourneau, M. Guipponi, N. Panousis, M. Garieri, P. Ribaux, E. Falconnet, C. Borel, S. E. Antonarakis O7 Role of microRNA in LCL to IPSC reprogramming S. Kumar, J. Curran, J. Blangero O8 Multiple enhancer variants disrupt gene regulatory network in Hirschsprung disease S. Chatterjee, A. Kapoor, J. Akiyama, D. Auer, C. Berrios, L. Pennacchio, A. Chakravarti O9 Metabolomic profiling for the diagnosis of neurometabolic disorders T. R. Donti, G. Cappuccio, M. Miller, P. Atwal, A. Kennedy, A. Cardon, C. Bacino, L. Emrick, J. Hertecant, F. Baumer, B. Porter, M. Bainbridge, P. Bonnen, B. Graham, R. Sutton, Q. Sun, S. Elsea O10 A novel causal methylation network approach to Alzheimer’s disease Z. Hu, P. Wang, Y. Zhu, J. Zhao, M. Xiong, David A Bennett O11 A microRNA signature identifies subtypes of triple-negative breast cancer and reveals MIR-342-3P as regulator of a lactate metabolic pathway A. Hidalgo-Miranda, S. Romero-Cordoba, S. Rodriguez-Cuevas, R. Rebollar-Vega, E. Tagliabue, M. Iorio, E. D’Ippolito, S. Baroni O12 Transcriptome analysis identifies genes, enhancer RNAs and repetitive elements that are recurrently deregulated across multiple cancer types B. Kaczkowski, Y. Tanaka, H. Kawaji, A. Sandelin, R. Andersson, M. Itoh, T. Lassmann, the FANTOM5 consortium, Y. Hayashizaki, P. Carninci, A. R. R. Forrest O13 Elevated mutation and widespread loss of constraint at regulatory and architectural binding sites across 11 tumour types C. A. Semple O14 Exome sequencing provides evidence of pathogenicity for genes implicated in colorectal cancer E. A. Rosenthal, B. Shirts, L. Amendola, C. Gallego, M. Horike-Pyne, A. Burt, P. Robertson, P. Beyers, C. Nefcy, D. Veenstra, F. Hisama, R. Bennett, M. Dorschner, D. Nickerson, J. Smith, K. Patterson, D. Crosslin, R. Nassir, N. Zubair, T. Harrison, U. Peters, G. Jarvik, NHLBI GO Exome Sequencing Project O15 The tandem duplicator phenotype as a distinct genomic configuration in cancer F. Menghi, K. Inaki, X. Woo, P. Kumar, K. Grzeda, A. Malhotra, H. Kim, D. Ucar, P. Shreckengast, K. Karuturi, J. Keck, J. Chuang, E. T. Liu O16 Modeling genetic interactions associated with molecular subtypes of breast cancer B. Ji, A. Tyler, G. Ananda, G. Carter O17 Recurrent somatic mutation in the MYC associated factor X in brain tumors H. Nikbakht, M. Montagne, M. Zeinieh, A. Harutyunyan, M. Mcconechy, N. Jabado, P. Lavigne, J. Majewski O18 Predictive biomarkers to metastatic pancreatic cancer treatment J. B. Goldstein, M. Overman, G. Varadhachary, R. Shroff, R. Wolff, M. Javle, A. Futreal, D. Fogelman O19 DDIT4 gene expression as a prognostic marker in several malignant tumors L. Bravo, W. Fajardo, H. Gomez, C. Castaneda, C. Rolfo, J. A. Pinto O20 Spatial organization of the genome and genomic alterations in human cancers K. C. Akdemir, L. Chin, A. Futreal, ICGC PCAWG Structural Alterations Group O21 Landscape of targeted therapies in solid tumors S. Patterson, C. Statz, S. Mockus O22 Genomic analysis reveals novel drivers and progression pathways in skin basal cell carcinoma S. N. Nikolaev, X. I. Bonilla, L. Parmentier, B. King, F. Bezrukov, G. Kaya, V. Zoete, V. Seplyarskiy, H. Sharpe, T. McKee, A. Letourneau, P. Ribaux, K. Popadin, N. Basset-Seguin, R. Ben Chaabene, F. Santoni, M. Andrianova, M. Guipponi, M. Garieri, C. Verdan, K. Grosdemange, O. Sumara, M. Eilers, I. Aifantis, O. Michielin, F. de Sauvage, S. Antonarakis O23 Identification of differential biomarkers of hepatocellular carcinoma and cholangiocarcinoma via transcriptome microarray meta-analysis S. Likhitrattanapisal O24 Clinical validity and actionability of multigene tests for hereditary cancers in a large multi-center study S. Lincoln, A. Kurian, A. Desmond, S. Yang, Y. Kobayashi, J. Ford, L. Ellisen O25 Correlation with tumor ploidy status is essential for correct determination of genome-wide copy number changes by SNP array T. L. Peters, K. R. Alvarez, E. F. Hollingsworth, D. H. Lopez-Terrada O26 Nanochannel based next-generation mapping for interrogation of clinically relevant structural variation A. Hastie, Z. Dzakula, A. W. Pang, E. T. Lam, T. Anantharaman, M. Saghbini, H. Cao, BioNano Genomics O27 Mutation spectrum in a pulmonary arterial hypertension (PAH) cohort and identification of associated truncating mutations in TBX4 C. Gonzaga-Jauregui, L. Ma, A. King, E. Berman Rosenzweig, U. Krishnan, J. G. Reid, J. D. Overton, F. Dewey, W. K. Chung O28 NORTH CAROLINA macular dystrophy (MCDR1): mutations found affecting PRDM13 K. Small, A. DeLuca, F. Cremers, R. A. Lewis, V. Puech, B. Bakall, R. Silva-Garcia, K. Rohrschneider, M. Leys, F. S. Shaya, E. Stone O29 PhenoDB and genematcher, solving unsolved whole exome sequencing data N. L. Sobreira, F. Schiettecatte, H. Ling, E. Pugh, D. Witmer, K. Hetrick, P. Zhang, K. Doheny, D. Valle, A. Hamosh O30 Baylor-Johns Hopkins Center for Mendelian genomics: a four year review S. N. Jhangiani, Z. Coban Akdemir, M. N. Bainbridge, W. Charng, W. Wiszniewski, T. Gambin, E. Karaca, Y. Bayram, M. K. Eldomery, J. Posey, H. Doddapaneni, J. Hu, V. R. Sutton, D. M. Muzny, E. A. Boerwinkle, D. Valle, J. R. Lupski, R. A. Gibbs O31 Using read overlap assembly to accurately identify structural genetic differences in an ashkenazi jewish trio S. Shekar, W. Salerno, A. English, A. Mangubat, J. Bruestle O32 Legal interoperability: a sine qua non for international data sharing A. Thorogood, B. M. Knoppers, Global Alliance for Genomics and Health - Regulatory and Ethics Working Group O33 High throughput screening platform of competent sineups: that can enhance translation activities of therapeutic target H. Takahashi, K. R. Nitta, A. Kozhuharova, A. M. Suzuki, H. Sharma, D. Cotella, C. Santoro, S. Zucchelli, S. Gustincich, P. Carninci O34 The undiagnosed diseases network international (UDNI): clinical and laboratory research to meet patient needs J. J. Mulvihill, G. Baynam, W. Gahl, S. C. Groft, K. Kosaki, P. Lasko, B. Melegh, D. Taruscio O36 Performance of computational algorithms in pathogenicity predictions for activating variants in oncogenes versus loss of function mutations in tumor suppressor genes R. Ghosh, S. Plon O37 Identification and electronic health record incorporation of clinically actionable pharmacogenomic variants using prospective targeted sequencing S. Scherer, X. Qin, R. Sanghvi, K. Walker, T. Chiang, D. Muzny, L. Wang, J. Black, E. Boerwinkle, R. 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Leimgruber O43 Cpipe: a convergent clinical exome pipeline specialised for targeted sequencing S. Sadedin, A. Oshlack, Melbourne Genomics Health Alliance O44 A Bayesian classification of biomedical images using feature extraction from deep neural networks implemented on lung cancer data V. A. A. Antonio, N. Ono, Clark Kendrick C. Go O45 MAV-SEQ: an interactive platform for the Management, Analysis, and Visualization of sequence data Z. Ahmed, M. Bolisetty, S. Zeeshan, E. Anguiano, D. Ucar O47 Allele specific enhancer in EPAS1 intronic regions may contribute to high altitude adaptation of Tibetans C. Zeng, J. Shao O48 Nanochannel based next-generation mapping for structural variation detection and comparison in trios and populations H. Cao, A. Hastie, A. W. Pang, E. T. Lam, T. Liang, K. Pham, M. Saghbini, Z. Dzakula O49 Archaic introgression in indigenous populations of Malaysia revealed by whole genome sequencing Y. Chee-Wei, L. Dongsheng, W. Lai-Ping, D. Lian, R. O. Twee Hee, Y. Yunus, F. Aghakhanian, S. S. Mokhtar, C. V. Lok-Yung, J. Bhak, M. Phipps, X. Shuhua, T. Yik-Ying, V. Kumar, H. Boon-Peng O50 Breast and ovarian cancer prevention: is it time for population-based mutation screening of high risk genes? I. Campbell, M.-A. Young, P. James, Lifepool O53 Comprehensive coverage from low DNA input using novel NGS library preparation methods for WGS and WGBS C. Schumacher, S. Sandhu, T. Harkins, V. Makarov O54 Methods for large scale construction of robust PCR-free libraries for sequencing on Illumina HiSeqX platform H. DoddapaneniR. Glenn, Z. Momin, B. Dilrukshi, H. Chao, Q. Meng, B. Gudenkauf, R. Kshitij, J. Jayaseelan, C. Nessner, S. Lee, K. Blankenberg, L. Lewis, J. Hu, Y. Han, H. Dinh, S. Jireh, K. Walker, E. Boerwinkle, D. Muzny, R. Gibbs O55 Rapid capture methods for clinical sequencing J. Hu, K. Walker, C. Buhay, X. Liu, Q. Wang, R. Sanghvi, H. Doddapaneni, Y. Ding, N. Veeraraghavan, Y. Yang, E. Boerwinkle, A. L. Beaudet, C. M. Eng, D. M. Muzny, R. A. Gibbs O56 A diploid personal human genome model for better genomes from diverse sequence data K. C. C. Worley, Y. Liu, D. S. T. Hughes, S. C. Murali, R. A. Harris, A. C. English, X. Qin, O. A. Hampton, P. Larsen, C. Beck, Y. Han, M. Wang, H. Doddapaneni, C. L. Kovar, W. J. Salerno, A. Yoder, S. Richards, J. Rogers, J. R. Lupski, D. M. Muzny, R. A. Gibbs O57 Development of PacBio long range capture for detection of pathogenic structural variants Q. Meng, M. Bainbridge, M. Wang, H. Doddapaneni, Y. Han, D. Muzny, R. Gibbs O58 Rhesus macaques exhibit more non-synonymous variation but greater impact of purifying selection than humans R. A. Harris, M. Raveenedran, C. Xue, M. Dahdouli, L. Cox, G. Fan, B. Ferguson, J. Hovarth, Z. Johnson, S. Kanthaswamy, M. Kubisch, M. Platt, D. Smith, E. Vallender, R. Wiseman, X. Liu, J. Below, D. Muzny, R. Gibbs, F. Yu, J. Rogers O59 Assessing RNA structure disruption induced by single-nucleotide variation J. Lin, Y. Zhang, Z. Ouyang P1 A meta-analysis of genome-wide association studies of mitochondrial dna copy number A. Moore, Z. Wang, J. Hofmann, M. Purdue, R. Stolzenberg-Solomon, S. Weinstein, D. Albanes, C.-S. Liu, W.-L. Cheng, T.-T. Lin, Q. Lan, N. Rothman, S. Berndt P2 Missense polymorphic genetic combinations underlying down syndrome susceptibility E. S. Chen P4 The evaluation of alteration of ELAM-1 expression in the endometriosis patients H. Bahrami, A. Khoshzaban, S. Heidari Keshal P5 Obesity and the incidence of apolipoprotein E polymorphisms in an assorted population from Saudi Arabia population K. K. R. Alharbi P6 Genome-associated personalized antithrombotical therapy for patients with high risk of thrombosis and bleeding M. Zhalbinova, A. Akilzhanova, S. Rakhimova, M. Bekbosynova, S. Myrzakhmetova P7 Frequency of Xmn1 polymorphism among sickle cell carrier cases in UAE population M. Matar P8 Differentiating inflammatory bowel diseases by using genomic data: dimension of the problem and network organization N. Mili, R. Molinari, Y. Ma, S. Guerrier P9 Vulnerability of genetic variants to the risk of autism among Saudi children N. Elhawary, M. Tayeb, N. Bogari, N. Qotb P10 Chromatin profiles from ex vivo purified dopaminergic neurons establish a promising model to support studies of neurological function and dysfunction S. A. McClymont, P. W. Hook, L. A. Goff, A. McCallion P11 Utilization of a sensitized chemical mutagenesis screen to identify genetic modifiers of retinal dysplasia in homozygous Nr2e3^rd7 mice Y. Kong, J. R. Charette, W. L. Hicks, J. K. Naggert, L. Zhao, P. M. Nishina P12 Ion torrent next generation sequencing of recessive polycystic kidney disease in Saudi patients B. M. Edrees, M. Athar, F. A. Al-Allaf, M. M. Taher, W. Khan, A. Bouazzaoui, N. A. Harbi, R. Safar, H. Al-Edressi, A. Anazi, N. Altayeb, M. A. Ahmed, K. Alansary, Z. Abduljaleel P13 Digital expression profiling of Purkinje neurons and dendrites in different subcellular compartments A. Kratz, P. Beguin, S. Poulain, M. Kaneko, C. Takahiko, A. Matsunaga, S. Kato, A. M. Suzuki, N. Bertin, T. Lassmann, R. Vigot, P. Carninci, C. Plessy, T. Launey P14 The evolution of imperfection and imperfection of evolution: the functional and functionless fractions of the human genome D. Graur P16 Species-independent identification of known and novel recurrent genomic entities in multiple cancer patients J. Friis-Nielsen, J. M. Izarzugaza, S. Brunak P18 Discovery of active gene modules which are densely conserved across multiple cancer types reveal their prognostic power and mutually exclusive mutation patterns B. S. Soibam P19 Whole exome sequencing of dysplastic leukoplakia tissue indicates sequential accumulation of somatic mutations from oral precancer to cancer D. Das, N. Biswas, S. Das, S. Sarkar, A. Maitra, C. Panda, P. Majumder P21 Epigenetic mechanisms of carcinogensis by hereditary breast cancer genes J. J. Gruber, N. Jaeger, M. Snyder P22 RNA direct: a novel RNA enrichment strategy applied to transcripts associated with solid tumors K. Patel, S. Bowman, T. Davis, D. Kraushaar, A. Emerman, S. Russello, N. Henig, C. Hendrickson P23 RNA sequencing identifies gene mutations for neuroblastoma K. Zhang P24 Participation of SFRP1 in the modulation of TMPRSS2-ERG fusion gene in prostate cancer cell lines M. Rodriguez-Dorantes, C. D. Cruz-Hernandez, C. D. P. Garcia-Tobilla, S. Solorzano-Rosales P25 Targeted Methylation Sequencing of Prostate Cancer N. Jäger, J. Chen, R. Haile, M. Hitchins, J. D. Brooks, M. Snyder P26 Mutant TPMT alleles in children with acute lymphoblastic leukemia from México City and Yucatán, Mexico S. Jiménez-Morales, M. Ramírez, J. Nuñez, V. Bekker, Y. Leal, E. Jiménez, A. Medina, A. Hidalgo, J. Mejía P28 Genetic modifiers of Alström syndrome J. Naggert, G. B. Collin, K. DeMauro, R. Hanusek, P. M. Nishina P31 Association of genomic variants with the occurrence of angiotensin-converting-enzyme inhibitor (ACEI)-induced coughing among Filipinos E. M. Cutiongco De La Paz, R. Sy, J. Nevado, P. Reganit, L. Santos, J. D. Magno, F. E. Punzalan , D. Ona , E. Llanes, R. L. Santos-Cortes , R. Tiongco, J. Aherrera, L. Abrahan, P. Pagauitan-Alan; Philippine Cardiogenomics Study Group P32 The use of “humanized” mouse models to validate disease association of a de novo GARS variant and to test a novel gene therapy strategy for Charcot-Marie-Tooth disease type 2D K. H. Morelli, J. S. Domire, N. Pyne, S. Harper, R. Burgess P34 Molecular regulation of chondrogenic human induced pluripotent stem cells M. A. Gari, A. Dallol, H. Alsehli, A. Gari, M. Gari, A. Abuzenadah P35 Molecular profiling of hematologic malignancies: implementation of a variant assessment algorithm for next generation sequencing data analysis and clinical reporting M. Thomas, M. Sukhai, S. Garg, M. Misyura, T. Zhang, A. Schuh, T. Stockley, S. Kamel-Reid P36 Accessing genomic evidence for clinical variants at NCBI S. Sherry, C. Xiao, D. Slotta, K. Rodarmer, M. Feolo, M. Kimelman, G. Godynskiy, C. O’Sullivan, E. Yaschenko P37 NGS-SWIFT: a cloud-based variant analysis framework using control-accessed sequencing data from DBGAP/SRA C. Xiao, E. Yaschenko, S. Sherry P38 Computational assessment of drug induced hepatotoxicity through gene expression profiling C. Rangel-Escareño, H. Rueda-Zarate P40 Flowr: robust and efficient pipelines using a simple language-agnostic approach;ultraseq; fast modular pipeline for somatic variation calling using flowr S. Seth, S. Amin, X. Song, X. Mao, H. Sun, R. G. Verhaak, A. Futreal, J. Zhang P41 Applying “Big data” technologies to the rapid analysis of heterogenous large cohort data S. J. Whiite, T. Chiang, A. English, J. Farek, Z. Kahn, W. Salerno, N. Veeraraghavan, E. Boerwinkle, R. Gibbs P42 FANTOM5 web resource for the large-scale genome-wide transcription start site activity profiles of wide-range of mammalian cells T. Kasukawa, M. Lizio, J. Harshbarger, S. Hisashi, J. Severin, A. Imad, S. Sahin, T. C. Freeman, K. Baillie, A. Sandelin, P. Carninci, A. R. R. Forrest, H. Kawaji, The FANTOM Consortium P43 Rapid and scalable typing of structural variants for disease cohorts W. Salerno, A. English, S. N. Shekar, A. Mangubat, J. Bruestle, E. Boerwinkle, R. A. Gibbs P44 Polymorphism of glutathione S-transferases and sulphotransferases genes in an Arab population A. H. Salem, M. Ali, A. Ibrahim, M. Ibrahim P46 Genetic divergence of CYP3A5*3 pharmacogenomic marker for native and admixed Mexican populations J. C. Fernandez-Lopez, V. Bonifaz-Peña, C. Rangel-Escareño, A. Hidalgo-Miranda, A. V. Contreras P47 Whole exome sequence meta-analysis of 13 white blood cell, red blood cell, and platelet traits L. Polfus, CHARGE and NHLBI Exome Sequence Project Working Groups P48 Association of adipoq gene with type 2 diabetes and related phenotypes in african american men and women: The jackson heart study S. Davis, R. Xu, S. Gebeab, P Riestra, A Gaye, R. Khan, J. Wilson, A. Bidulescu P49 Common variants in casr gene are associated with serum calcium levels in koreans S. H. Jung, N. Vinayagamoorthy, S. H. Yim, Y. J. Chung P50 Inference of multiple-wave population admixture by modeling decay of linkage disequilibrium with multiple exponential functions Y. Zhou, S. Xu P51 A Bayesian framework for generalized linear mixed models in genome-wide association studies X. Wang, V. Philip, G. Carter P52 Targeted sequencing approach for the identification of the genetic causes of hereditary hearing impairment A. A. Abuzenadah, M. Gari, R. Turki, A. Dallol P53 Identification of enhancer sequences by ATAC-seq open chromatin profiling A. Uyar, A. Kaygun, S. Zaman, E. Marquez, J. George, D. Ucar P54 Direct enrichment for the rapid preparation of targeted NGS libraries C. L. Hendrickson, A. Emerman, D. Kraushaar, S. Bowman, N. Henig, T. Davis, S. Russello, K. Patel P56 Performance of the Agilent D5000 and High Sensitivity D5000 ScreenTape assays for the Agilent 4200 Tapestation System R. Nitsche, L. Prieto-Lafuente P57 ClinVar: a multi-source archive for variant interpretation M. Landrum, J. Lee, W. Rubinstein, D. Maglott P59 Association of functional variants and protein physical interactions of human MUTY homolog linked with familial adenomatous polyposis and colorectal cancer syndrome Z. Abduljaleel, W. Khan, F. A. Al-Allaf, M. Athar , M. M. Taher, N. Shahzad P60 Modification of the microbiom constitution in the gut using chicken IgY antibodies resulted in a reduction of acute graft-versus-host disease after experimental bone marrow transplantation A. Bouazzaoui, E. Huber, A. Dan, F. A. Al-Allaf, W. Herr, G. Sprotte, J. Köstler, A. Hiergeist, A. Gessner, R. Andreesen, E. Holler P61 Compound heterozygous mutation in the LDLR gene in Saudi patients suffering severe hypercholesterolemia F. Al-Allaf, A. Alashwal, Z. Abduljaleel, M. Taher, A. Bouazzaoui, H. Abalkhail, A. Al-Allaf, R. Bamardadh, M. Athar

Body fat in Singaporean infants: development of body fat prediction equations in Asian newborns

BACKGROUND/OBJECTIVES

Prediction equations are commonly used to estimate body fat from anthropometric measurements, but are population specific. We aimed to establish and validate a body composition prediction formula for Asian newborns, and compared the performance of this formula with that of a published equation.

SUBJECTS/METHODS

Among 262 neonates (174 from day 0, 88 from days 1-3 post delivery) from a prospective cohort study, body composition was measured using air-displacement plethysmography (PEA POD), with standard anthropometric measurements, including triceps and subscapular skinfolds. Using fat mass measurement by PEA POD as a reference, stepwise linear regression was utilized to develop a prediction equation in a randomly selected subgroup of 62 infants measured on days 1-3, which was then validated in another subgroup of 200 infants measured on days 0-3.

RESULTS

Regression analyses revealed subscapular skinfolds, weight, gender and gestational age were significant predictors of neonatal fat mass, explaining 81.1% of the variance, but not triceps skinfold or ethnicity. By Bland-Altman analyses, our prediction equation revealed a non-significant bias with limits of agreement (LOA) similar to those of a published equation for infants measured on days 1-3 (95% LOA: (-0.25, 0.26) kg vs (-0.23, 0.21) kg) and on day 0 (95% LOA: (-0.19, 0.17) kg vs (-0.17, 0.18) kg). The published equation, however, exhibited a systematic bias in our sample.

CONCLUSIONS

Our equation requires only one skinfold site measurement, which can significantly reduce time and effort. It does not require the input of ethnicity and, thus, aid its application to other Asian neonatal populations.

Review of key findings from the Singapore Malay Eye Study (SiMES-1)

INTRODUCTION

This study highlights the key epidemiological findings from the Singapore Malay Eye Study (SiMES-1).

METHODS

SiMES-1 was a cross-sectional, population-based epidemiological study on eye diseases. It was performed on 3,280 randomly selected Malay adults living in the south-western part of Singapore. All study participants underwent various validated questionnaires and detailed eye examinations. A review of all papers published from SiMES-1 was performed.

RESULTS

A total of 24.6% of the study population had myopia, while 35.3% had hyperopia and 39.4% had astigmatism. 20.4% of the population had under-corrected refractive error. 1,338 (45.7%) participants were diagnosed to have cataracts in at least one eye. 8.6% of the study population had undergone cataract surgery in either eye, while 4.7% had bilateral cataract surgery. 150 (4.6%) participants were diagnosed to have glaucoma, of which primary open angle glaucoma was the most common type (3.2% of the study population), followed by secondary glaucoma (0.8%) and primary angle closure glaucoma (0.2%). Pterygium was diagnosed in 508 out of 3,266 study participants, giving a prevalence rate of 15.6%. The presence of diabetic retinopathy was observed in 421 (12.9%) out of 3,265 study participants. 183 (5.6%) study participants had some degree of age-related macular degeneration (AMD), of which 23 (0.7%) were classified as having late AMD.

CONCLUSION

This paper provides a summary of the prevalence of common eye diseases among the Singaporean adult Malay population and provides data useful for public health education and disease prevention.

Automatic detection of pathological myopia using variational level set

Pathological myopia, the seventh leading cause of legal blindness in United States, is a condition caused by pathological axial elongation and eyes that deviates from the normal distribution curve of axial length, resulting in impaired vision. Studies have shown that ocular risks associated with myopia should not be underestimated, and there is a public health need to prevent the onset or progression of myopia. Peripapillary atrophy (PPA) is one of the clinical indicators for pathological myopia. In this paper, we introduce a novel method, to detect pathological myopia via peripapaillary atrophy feature by means of variational level set. This method is a core algorithm of our system, PAMELA, an automated system for the detection of pathological myopia. The proposed method has been tested on 40 images from Singapore Cohort study Of the Risk factors for Myopia (SCORM), producing a 95% accuracy of correct assessment, and a sensitivity and specificity of 0.9 and 1 respectively. The results highlight the potential of PAMELA as a possible clinical tool for objective mass screening of pathological myopia.

Age-related macular degeneration in Singapore

INTRODUCTION

This study aimed to describe the morphology of age-related macular degeneration (AMD) as well as to obtain an estimate of the population-based incidence rate in Singapore.

METHODS

This is a retrospective hospital-based study of AMD cases seen in 1991 and 1992 at the Singapore National Eye Centre (SNEC), a tertiary eye centre. All case notes recorded with the International Classification of Diseases, ninth revision, clinical modification code '362.5', which is 'degenerations of the macula', were retrieved and analysed. Only case notes of patients who were aged 50 years and above and with documented AMD were included in the study.

RESULTS

There were 41 (21.8 percent) patients with drusen alone, 39 (20.7 percent) with dry AMD and 108 (57.5 percent) with exudative AMD. The morphology of the disease was similar among the Chinese and non-Chinese and there were no gender differences. A significant majority of patients with dry and exudative AMD had legal blindness at presentation (p-value is less than 0.0001). Notably, 27 (33.3 percent) patients with exudative AMD had improved vision with time. In comparison, the majority of patients with dry AMD or drusen alone tended to have the same or worsening visual acuity over time. The two-year SNEC hospital incidence rate of AMD in 1991-1992 was 0.38 percent or equivalent to 3.8 per 1,000 new cases seen at SNEC. The estimated population-based incidence rate of exudative AMD was 0.02 percent.

CONCLUSION

The population incidence of exudative AMD is lower but comparable to the Western population. Patients with exudative AMD tend to have poorer vision as compared to patients with geographical atrophy or drusen. The proportion of exudative AMD to geographical atrophy appears to be higher than in the West.

Education, socio-economic status and age-related macular degeneration in Asians: the Singapore Malay Eye Study

BACKGROUND/AIMS

Low socio-economic status is increasingly being identified as a risk marker for chronic diseases, but few studies have investigated the link between socio-economic factors and age-related macular degeneration (AMD). The present study aimed to assess the association between socio-economic status and the prevalence of AMD.

METHODS

A population-based cross-sectional study of 3280 (78.7% response rate) Malay adults aged 40-80 years residing in 15 south-western districts of Singapore. AMD was graded from retinal photographs at a central reading centre using the modified Wisconsin AMD scale. Early and late AMD signs were graded from retinal photographs following the Wisconsin grading system. Socio-economic status including education, housing type and income were determined from a detailed interview.

RESULTS

Of the participants, 3265 had photographs of sufficient quality for grading of AMD. Early AMD was present in 168 (5.1%) and late AMD in 21 (0.6%). After adjusting for age, gender, smoking, hypertension, diabetes and body mass index, participants with lower educational levels were significantly more likely to have early AMD (multivariate OR 2.2, 95% CI 1.2 to 4.0). This association was stronger in persons who had never smoked (multivariate OR 3.6, 95% confidence CI 1.4 to 9.4). However, no association with housing type or income was seen.

CONCLUSIONS

Low educational level is associated with a higher prevalence of early AMD signs in our Asian population, independent of age, cardiovascular risk factors and cigarette smoking.

Body mass index and its effects on retinal vessel diameter in 6-year-old children

PURPOSE

To examine the relationship between body mass index (BMI) and other anthropometric measures with retinal vessel diameter in children.

METHODS

A random cluster sample of 34 schools was selected in the Sydney metropolitan area during 2003-04, and 1740 children aged 6 years participated in The Sydney Childhood Eye Study. Retinal images were taken and vessel diameter was measured using a computer-imaging program. Anthropometric measures, including weight, height, waist circumference, BMI and body surface area (BSA), were obtained and defined using standardized protocols. Data on confounders, including ocular parameters, ethnicity, birth parameters and blood pressure, were similarly collected.

RESULTS

Mean BMI was 16.2 kg/m(2) (+/-2.1 s.d.) in 1608 (92.4%) children with complete data. After controlling for age, sex, ethnicity, axial length of the eyeball, birth weight and mean arterial blood pressure, children with BMI above the cardiovascular risk threshold (defined as BMI>16.1 kg/m(2) in boys and BMI>15.9 kg/m(2) in girls) had mean retinal venular diameter 2.1 microm larger than those with BMI below this threshold (P=0.026). Increasing weight and BSA were also positively associated with wider retinal venules. Children in the highest quartile of BMI had mean retinal arteriolar diameter 2.2 microm smaller than those in the lowest quartile. Increasing waist circumference and shorter height were also associated with narrower retinal arterioles.

CONCLUSIONS

In this sample of 6-year-old children, greater BMI, weight and BSA were associated with wider retinal venules, while greater BMI and larger waist circumference were associated with narrower retinal arterioles. These findings suggest a possible effect of increased body mass and adiposity on early microvascular structural alterations in childhood, long before the development of cardiovascular disease.

Eye growth changes in myopic children in Singapore

AIMS

To assess the longitudinal changes in biometric parameters and associated factors in young myopic children aged 7--9 years followed prospectively in Singapore.

METHODS

Children aged 7--9 years from three Singapore schools were invited to participate in the SCORM (Singapore Cohort study Of the Risk factors for Myopia) study. Yearly eye examinations involving biometry measures were performed in the schools. Only myopic children (n=543) with 3 year follow up data were included in this analysis.

RESULTS

The 3 year increases in axial length, anterior chamber depth, lens thickness, vitreous chamber depth, and corneal curvature were 0.89 mm, -0.02 mm, -0.01 mm, 0.92 mm, and 0.01 mm, respectively. Children who were younger, female, and who had a parental history of myopia were more likely to have greater increases in axial length. After adjustment for school, age, sex, race, parental myopia and reading in books per week, the age (p<0.001), sex (p=0.012), and parental myopia (p=0.027) remained significantly associated with the 3 year change in axial length. Reading in books per week, however, was not associated with axial length change. Children with faster rates of progression of myopia had greater increases in axial length (Pearson correlation coefficient (r)=-0.69) and vitreous chamber depth (r=-0.83).

CONCLUSIONS

The 3 year change in axial length of Singapore children aged 7--9 years at baseline was high and greater in younger children, females, and children with a parental history of myopia. Myopia progression was driven largely by vitreous chamber depth increase.

Refractive errors in medical students in Singapore

INTRODUCTION

Refractive errors are becoming more of a problem in many societies, with prevalence rates of myopia in many Asian urban countries reaching epidemic proportions. This study aims to determine the prevalence rates of various refractive errors in Singapore medical students.

METHODS

157 second year medical students (aged 19-23 years) in Singapore were examined. Refractive error measurements were determined using a stand-alone autorefractor. Additional demographical data was obtained via questionnaires filled in by the students.

RESULTS

The prevalence rate of myopia in Singapore medical students was 89.8 percent (Spherical equivalence (SE) at least -0.50 D). Hyperopia was present in 1.3 percent (SE more than +0.50 D) of the participants and the overall astigmatism prevalence rate was 82.2 percent (Cylinder at least 0.50 D).

CONCLUSION

Prevalence rates of myopia and astigmatism in second year Singapore medical students are one of the highest in the world.

Prevalence of Parkinson disease in Singapore: Chinese vs Malays vs Indians

OBJECTIVE

To investigate the prevalence of Parkinson disease (PD) in Singapore and compare the rates between Singaporean Chinese, Malays, and Indians.

METHODS

A three-phase community-based survey among a disproportionate random sample of 15,000 individuals (9,000 Chinese, 3,000 Malays, 3,000 Indians) aged 50 years and above who live in central Singapore was conducted. In phase 1, trained interviewers conducted a door-to-door survey using a validated 10-question questionnaire. In phase 2, medical specialists examined participants who screened positive to any of the questions. Participants suspected to have PD had their diagnosis confirmed in phase 3 by a movement disorders specialist.

RESULTS

The participation rate was 67% among 22,279 eligible individuals. Forty-six participants with PD were identified of which 16 were newly diagnosed cases. The prevalence rate of PD for those aged 50 and above in Singapore was 0.30% (95% CI: 0.22 to 0.41), age-adjusted to US 1970 census. The prevalence rates increased significantly with age. The age-adjusted prevalence rates among Chinese (0.33%, 95% CI: 0.22 to 0.48), Malays (0.29%, 95% CI: 0.13 to 0.67), and Indians (0.28%, 95% CI: 0.12 to 0.67) were the same (p = 1.0).

CONCLUSIONS

The prevalence of PD in Singapore was comparable to that of Western countries. Race-specific rates were also similar to previously reported rates and similar among the three races. Environmental factors may be more important than racially determined genetic factors in the development of PD.

Myopia: attempts to arrest progression

Previous studies have evaluated the efficacy of several interventions to decrease the progression of myopia. These include devices that alter the perception of the visual environment and pharmacological treatments. There is no conclusive evidence thus far that alteration of the pattern of spectacle wear, bifocals, ocular hypotensives, or contact lenses retards the progression of myopia. Several randomised clinical trials have demonstrated that the rate of progression of myopia is lower in children given atropine eye drops than those given placebo. However, atropine is associated with short term side effects such as photophobia and possible long term adverse events including light induced retinal damage and cataract formation. Other more selective antimuscarinic agents such as pirenzipine are presently being evaluated. Further well conducted randomised clinical trials with large sample sizes and adequate follow up designed to evaluate treatments to retard the progression of myopia should be conducted, since the identification of an effective intervention may have a greater public health impact on the burden and morbidity from myopia than the few treatments currently available.

A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study)

STUDY OBJECTIVE

We evaluate a new technique of treating scalp lacerations, the hair apposition technique (HAT). After standard cleaning procedures, hair on both sides of a laceration is apposed with a single twist. This is then held with tissue adhesives. HAT was compared with standard suturing in a multicenter, randomized, prospective trial.

METHODS

All linear lacerations of the scalp less than 10 cm long were included. Severely contaminated wounds, actively bleeding wounds, patients with hair strand length less than 3 cm, and hemodynamically unstable patients were excluded. Patients were randomized to receive either HAT or standard suturing, and the time to complete the wound repair was measured. All wounds were evaluated 7 days later in a nonblinded manner for satisfactory wound healing, scarring, and complications.

RESULTS

There were 96 and 93 patients in the study and control groups, respectively. Wound healing trended toward being judged more satisfactory in the HAT group than standard suturing (100% versus 95.7%; P =.057; effect size 4.3%; 95% confidence interval 0.1% to 8.5%). Patients who underwent HAT had less scarring (6.3% versus 20.4%; P =.005), fewer overall complications (7.3% versus 21.5%; P =.005), significantly lower pain scores (median 2 versus 4; P <.001), and shorter procedure times (median 5 versus 15 minutes; P <.001). There was a trend toward less wound breakdown in the HAT group (0% versus 4.3%; P =.057). When patients were asked whether they were willing to have HAT performed in the future, 84% responded yes, 1% responded no, and 15% were unsure.

CONCLUSION

HAT is equally acceptable and perhaps superior to standard suturing for closing suitable scalp lacerations. Advantages include fewer complications, a shorter procedure time, less pain, no need for shaving or removal of stitches, similar or superior wound healing, and high patient acceptance. HAT has become our technique of choice for suitable scalp lacerations.[Ong Eng Hock M, Ooi SBS, Saw SM, Lim SH. A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study).

Effluents from a pulp and paper mill: a skin and health survey of children living in upstream and downstream villages

OBJECTIVES

A health survey of three villages (upstream village Rantau Baru and two downstream villages, Sering and Pelalawan) in the vicinity of a pulp and paper mill along the Kampar river in the province of Riau, Indonesia was conducted to find whether exposure to the effluents from the mill was related to skin conditions and ill health.

METHODS

A cross sectional survey was carried out of children living in the three villages.

RESULTS

Common skin conditions such as dermatitis, fungal infections, insect bites, and miliaria were found. No significantly increased risk of dermatitis or any illness in general was found with increasing levels of exposure to river water for downstream villages when compared with the upstream village. However, there was an increased risk of diarrhoea in Sering especially with drinking water directly from the river (prevalence rate ratio (PRR) 4.9, 95% confidence interval (95% CI) 0.4 to 63.9). An increased risk was also found within the upstream village Rantau Baru (PRR 2.3, 95% CI 0.9 to 5.8) and downstream village Sering (PRR 1.4, 95% CI 0.4 to 5.2) when children who drank water directly from the river were compared with those who never did. Analysis of the river water also showed physical and chemical variables within the acceptable range except for faecal coliforms (6 MPN/100 ml) found in the sample taken from Sering.

CONCLUSIONS

The effluent from the mill is unlikely to be causing skin conditions and ill health. Diarrhoea may be due to faecal coliform contamination of the water because all raw sewerage is deposited in the river. Community health outreach programmes are being implemented based on these findings.

Corneal and refractive error astigmatism in Singaporean schoolchildren: a vector-based Javal's rule

BACKGROUND

Traditional approaches to Javal's rule do not use data from subjects with oblique astigmatism and have not been used to make predictions about subjects with oblique astigmatism. Vector approaches to analyzing refractive error can circumvent these problems.

METHODS

Subjects were 993 Singaporean schoolchildren. We performed linear regression of refractive error astigmatism on corneal astigmatism, using J0 vectors to describe with-the-rule and against-the-rule astigmatism and J45 vectors to describe oblique astigmatism.

RESULTS

We obtained the following statistically significant regression relationships: RJ0 = 0.931 x CJ0 - 0.276 and RJ45 = 0.638 x CJ45 + 0.010, where R and C denote refractive error astigmatism and corneal astigmatism, respectively.

CONCLUSION

Our vector-based Javal's rule gives closer predictions of refractive astigmatism than the original Javal's rule and the simplified Javal's rule and can be applied in cases of corneal oblique astigmatism.

Familial clustering and myopia progression in Singapore school children

BACKGROUND

Familial factors may be related to the progression of myopia in children. A cohort study was conducted to determine the relationship between familial factors and myopia progression in children.

METHODS

From a larger clinical trial (n = 311), 153 Singapore children aged 6--12 years were recruited to participate in a cohort study of the risk factors for myopia progression. An in-person interview was conducted whereby information on the history of myopia in first-degree relatives was obtained. Other information collected included housing type, parental education and income. Cycloplegic refractive error as measured by subjective refraction and autorefraction were ascertained every six months. The average length of follow-up was 28 months.

RESULTS

The adjusted mean rate of progression of myopia was -0.60 (95% confidence interval -0.66, -0.55) diopters per year. The average rate of progression of myopia for children with a parental history of myopia was -0.63 (95% confidence interval -0.69, -0.56) diopters per year compared to -0.42 (95% confidence interval -0.57, -0.27) diopters per year for children whose parents were not myopic. The different measures of family history of myopia were related to rate of change in refractive error and refractive error in the final visit. There was no association between close work and myopia progression.

CONCLUSIONS

A positive family history is related to the progression of myopia and final refractive error in Singapore children, thus supporting evidence that hereditary factors may play an important role in myopia progression.

Academic achievement, close up work parameters, and myopia in Singapore military conscripts

AIM

To determine the relation of refractive error to environmental factors, including close up work, in Singapore military conscripts.

METHODS

A cross sectional study was conducted on 429 Singapore military conscripts. Non-cycloplegic refraction and A-scan biometry were performed in both eyes. A detailed questionnaire was administered by in-person interview to obtain information about current and past near work activity, extra tuition lessons, educational experiences, and family demographics.

RESULTS

Myopia associated with the conscript having been educated in the (gifted, special, or express) educational streams (adjusted odds ratio (OR) = 3.8, 95% confidence interval CI 2.0-7.3), and having completed pre-university education (OR=4.1, 95% CI 1.9-8.8). The reported close up work activity at age 7 years did correlate with age of onset of myopia (p<0.001). In parallel, supplemental tuition lessons in primary school has (OR=2.6, 95% CI 1.4-4.9) associated with conscript myopia. Parental myopia was positively associated with myopia (p<0.001), but this relation disappeared when adjusted for environmental factors. Current (p=0.83) and past close up work activity at age 7 years (p=0.13) did not correlate with myopia.

CONCLUSION

Educational level and educational stream positively related to myopia. A relation was observed with reported close up work activity in early childhood and with tuition classes during elementary school, but not with current close up work activity. These results underscore the strong influence of environment in myopia pathogenesis but a role for close up work activity remains indeterminate.

A population-based prevalence survey of skin diseases in adolescents and adults in rural Sumatra, Indonesia, 1999

Skin disorders are one of the most common presenting health problems and pose a considerable public health problem in developing and developed countries. A population-based survey (n = 917) was conducted in October and November 1999 to determine the prevalence of skin diseases in 3 rural villages in Indonesia (Riau province, Sumatra). The overall individual response rate was 96%. Household interviews were conducted to obtain information on skin conditions, basic socio-demographic factors and lifestyle habits. Trained doctors performed a thorough clinical skin examination of each subject in the household. The overall prevalence of skin disease in the 3 villages was 28.2% (95% confidence intervals 24.6-31.8). The prevalence of fungal infections (12.0%) was twice as high as dermatitis (5.1%). As skin conditions are common in rural Indonesia, it is advisable to improve the training of nurses and doctors in the prevention and treatment of skin disorders.

Does education explain ethnic differences in myopia prevalence? A population-based study of young adult males in Singapore

PURPOSE

To study interethnic variation in myopia prevalence and severity in young adult males in Singapore and to determine whether these variations are related to differences in education level.

METHODS

A population-based survey of refractive errors in a cohort of 15,095 military conscripts between July 1996 and June 1997 using noncycloplegic autorefraction and a standard questionnaire. Prevalence rates of myopia (<-0.5 D) and severe myopia (<-6.0 D) were determined for Chinese, Malay, and Indian men; prevalence rate ratios were compared after adjusting for education level.

RESULTS

Singapore has one of the highest prevalences of myopia (79.3%) and severe myopia (13.1%), with Chinese having higher rates (82.2%, 95% confidence interval 81.5, 82.9) compared with Indians (68.7%, 95% confidence interval 65.1, 67.1) and Malays (65.0%, 95% confidence interval 62.9, 67.1). Education was strongly associated with prevalence and severity of myopia. However, significant interethnic variation persisted after adjusting for education.

CONCLUSIONS

There is a high prevalence of myopia in Singapore. Although prevalence and severity of myopia were strongly associated with education, interethnic variation observed was not fully explained by differences in education level.

Myopia and night lighting in children in Singapore

AIM

To examine the role of night time lighting and myopia in children in Singapore

METHODS

A cross sectional study was conducted on 1001 children in two Singapore schools. Cycloplegic refraction and A-scan biometry measurements were made in both eyes. A detailed questionnaire was completed by the parents to obtain information on night time lighting, near work activity, educational and demographic factors.

RESULTS

There was no difference in myopia prevalence rates in children exposed to night time light (33.1%) compared with children who slept in the dark (31.4%) before age 2. In addition, vitreous chamber depth was not related to night light (p = 0.58) before age 2. These results remained even after controlling for near work.

CONCLUSION

Myopia is not associated with night light in Asian populations.

Myopia in Singapore kindergarten children

PURPOSE

The purpose of this study was to examine whether close-up work was related to myopia in Singapore kindergarten children.

METHODS

One hundred twenty-eight children, ages 3 to 7 years, from a kindergarten in Singapore were examined by cycloplegic autorefraction. The parents also completed a questionnaire on the different types of close-up work activities each child was engaged in, socioeconomic status, and parental history of myopia.

RESULTS

Myopic children spent 3.0 hours per day (median) on close-up work activity, while nonmyopic children spent 2.0 hours per day (median) on close-up work activity. The prevalence of myopia in the sample was 8.6%.

CONCLUSION

Close-up work activity was not related to myopia in pre-school children.

Near-work activity and myopia in rural and urban schoolchildren in China

PURPOSE

To examine the prevalence of myopia in rural and urban schoolchildren in Xiamen, China, and to assess the impact of environmental factors on rates of myopia.

METHODS

Second-grade children attending either a city (n=119) or rural (n=91) school in Xiamen, China, were examined using cycloplegic autorefraction and biometry. Detailed questions on socioeconomic status, near-work activity, reading and writing habits, and family histories of myopia were asked in a face-to-face interview using a standard questionnaire.

RESULTS

The prevalence of myopia was 19.3% (95% confidence interval [CI], 12.3, 29) in the city and 6.6% (95% CI, 2.4, 14.3) in the countryside. The average hours per day children spent reading and writing outside of school was 2.2 hours in the city compared with 1.6 hours in the countryside (P<.0001). In both schools, the odds ratio for total reading and writing, adjusted for parental history of myopia, was 2.2 (95% CI, 1.1, 4).

CONCLUSION

These data suggest the prevalence of myopia is higher in the city than in the countryside. One possible explanation for these different rates could be that schoolchildren in the city spend more time reading and writing outside of school compared with children in the countryside. Myopic children in both the city and the countryside spent more time reading and writing compared with nonmyopic children. This increased near-work activity may contribute to the prevalence of myopia.

The design and assessment of questionnaires in clinical research

Questionnaires are one of the most commonly used tools for data collection in clinical research. Despite its simplicity and convenience of use, the design of questionnaire instruments that accurately measure health status and their determinants is nevertheless a difficult and challenging task.We review the two most important issues which are reliability and validity. Reliability can be defined as the degree to which a measure gives 'consistent' or 'reproducible' values when applied in different situations. Validity refers to the extent in which the true value of a variable is correctly measured by the instrument. For different types of questionnaire measurement instruments, specific issues of content, construct and criterion validity should be appropriately addressed. Accuracy in questionnaire-based measurement in clinical studies is achieved by paying attention to the relevant specific issues of reliability and validity during development and testing of such questionnaires.

Risk factors for hip fracture in Asian men and women: the Asian osteoporosis study

The objectives of the Asian Osteoporosis Study (AOS) were to determine risk factors for hip fracture in men and women in four Asian countries, that is, Singapore, Malaysia, Thailand, and the Philippines. A total of 451 men and 725 women (aged 50 years and over) with hip fractures were compared with an equal number of community controls. A standardized questionnaire was administered by interview. The following relative risks (RRs) were found in women and men by multiple logistic regression: dietary calcium intake < 498 mg/day, 2.0 for women (95% CI, 1.5-2.8) and 1.5 for men (95% CI, 1.0-2.2); no load bearing activity in the immediate past, 2.0 for women (95% CI, 1.4-2.7) and 3.4 for men (95% CI, 2.3-5.1); no vigorous sport activities in young adulthood, 7.2 for women (95% CI, 4.0-13.0) and 2.4 for men (95% CI, 1.6-3.6); cigarette smoking, 1.5 for men (95% CI, 1.0-2.1); alcohol consumption 7 days a week, 2.9 for women (95% CI, 1.0-8.6) and 1.9 for men (95% CI, 1.1-3.2); fell twice or more in the last 12 months, 3.0 for women (95% CI, 1.8-4.8) and 3.4 for men (95% CI, 1.8-6.6); a history of fractures after 50 years of age, 1.8 for women (95% CI, 1.1-2.9) and 3.0 for men (95% CI, 1.6-5.6); a history of stroke, 3.8 for women (95% CI, 2.0-7.1) and 3.6 for men (95% CI, 1.8-7.1); use of sedatives, 2.5 for women (95% CI, 1.0-6.3) and 3.0 for men (95% CI, 1.0-9.7); and use of thyroid drugs, 7.1 for women (95% CI, 2.0-25.9) and 11.8 for men (95% CI, 1.3-106.0). Women who were 1.56 m or taller had an RR of 2.0 (95% CI, 1.3-3.0) for hip fracture and men who were 1.69 m or taller had an RR of 1.9 (95% CI, 1.2-3.1) for hip fracture. Based on these findings, primary preventive programs for hip fracture could be planned in Asia.

Genetic, dietary, and other lifestyle determinants of plasma homocysteine concentrations in middle-aged and older Chinese men and women in Singapore

BACKGROUND

Epidemiologic studies have identified the plasma homocysteine concentration as a risk factor for atherothrombotic vascular disease. There is little information on the distributions and determinants of homocysteine concentrations in Asian populations.

OBJECTIVE

The present study was designed to examine the relations between genetic and lifestyle factors and plasma homocysteine concentrations among Chinese in Singapore.

DESIGN

Plasma total homocysteine, folate, vitamin B-12, and vitamin B-6 concentrations and genetic variation at the methylenetetrahydrofolate reductase (MTHFR) locus were measured in 486 Chinese men and women aged 45-74 y in Singapore. Data on dietary and other lifestyle factors were collected in face-to-face interviews.

RESULTS

Men had higher plasma concentrations of total homocysteine than women (P = 0.0001). Age was positively associated with plasma homocysteine in both sexes (P for trend = 0.0001). Plasma concentrations of folate, vitamin B-12, and vitamin B-6 were inversely associated with homocysteine concentrations. Among individuals with low plasma folate, those possessing 2 copies of MTHFR mutant alleles had significantly higher homocysteine concentrations than did those with > or = 1 copy of the wild-type allele. Cigarette smoking, daily coffee consumption, and physical inactivity were positively related to plasma homocysteine concentrations in both sexes (P < 0.05). However, these associations disappeared after adjustment for plasma folate concentrations.

CONCLUSIONS

Age, sex, plasma folate, vitamin B-12 and B-6 concentrations, and MTHFR genotype are independent determinants of plasma homocysteine in middle-aged and older Chinese in Singapore. These factors combined could account for up to 40% of the total variation in homocysteine concentrations in this Asian population.

Hip fracture incidence rates in Singapore 1991-1998

In this population-based study, we determined the incidence rates of hip fracture among Singapore residents aged 50 years and above. Information was obtained from a centralized database system which captured admissions with the primary diagnosis of a closed hip fracture (ICD-9 codes 820, 820.0, 820.2 and 820.8, n = 12,927) from all health care establishments in the country from 1991 to 1998 inclusive. After removing duplicates, hospital transfers, readmissions and non-acute care admissions, the total number of hip fractures was 9406. Based on the national population census 1990 (n = 464,100) and yearly population estimates, the age-adjusted hip fracture rates for 1991-1998 (per 100,000) were 152 in men and 402 in women. This was 1.5 and over 5 times higher than corresponding rates in the 1960s. From 1991 to 1998, these hip fracture rates tended to increase by 0.7% annually in men and by 1.2% annually in women. Among the three major racial groups, in men, the Chinese had significantly higher age-adjusted hip fracture rates (per 100,000): 168 (95% confidence interval (CI) 158-178) compared with 128 (95% CI 105-152) for Indians and 71 (95% CI 54-88) for Malays. A similar pattern occurred in women: 410 (95% CI 395-425), for Chinese compared with 361 (95% CI 290-432) for Indians and 264 (95% CI 225-303) for Malays. Since the 1960s, the main increases in hip fracture rates have been seen in the Chinese and Malays, with the rates in Indians appearing to decrease. Hip fracture incidence rates in Singapore have risen rapidly over the past 30-40 years, particularly in women, and are now among the highest in Asia. Significant racial differences in hip fracture rates occur within the same community. Time trends in hip fracture rates differed between races.

The incidence of hip fracture in four Asian countries: the Asian Osteoporosis Study (AOS)

The Asian Osteoporosis Study (AOS) is the first multicenter study to document and compare the incidence of hip fracture in four Asian countries. Hosital discharge data for the year 1997 were obtained for the Hong Kong SAR, Singapore, Malaysia and Thailand (Chiang Mai). The number of patients who were 50 years of age and older and who were discharged with a diagnosis of hip fracture (ICD9 820) was enumerated. The age-specific incidence rates were deduced and were directly adjusted to the US white population in 1989. The age-adjusted rates for men and women (per 100,000) are as follows: Hong Kong, 180 and 459; Singapore, 164 and 442; Malaysia, 88 and 218; Thailand, 114 and 289; compared with US White rates of 187 in men and 535 in women, published in 1989. We conclude that there is moderate variation in the incidence of hip fracture among Asian countries. The rates were highest in urbanized countries. With rapid economic development in Asia, hip fracture will prove to be a major public health challenge.

Cross-sectional study of near-work and myopia in kindergarten children in Singapore

INTRODUCTION

In view of the high and increasing myopia rates amongst young Singaporean children, we aimed to assess the relationship between near-work and myopia in 414 pre-school children aged 4 to 6 years.

MATERIALS AND METHODS

We measured near-work indices such as tuition classes outside school and other possible risk factors via a questionnaire. We then measured myopia with a hand-held autorefractor.

RESULTS

Children who had 3 or more hours per week of near-work classes outside school had a higher rate [odds ratio 1.39 (95% confidence interval 1.02, 2.53)] of myopia.

CONCLUSIONS

This suggests that there may be an association between near-work and myopia, even at such a young age. Given the increasing emphasis on near-work in Singapore, it may be important to call for increased visual health awareness, although further studies will be needed to establish if near-work causes myopia.

Factors related to the progression of myopia in Singaporean children

PURPOSE

To examine the possible factors related to the progression of myopia in Singapore children.

METHODS

One hundred fifty-three Singapore children aged 6 to 12 years were recruited to participate in a concurrent cohort study of the risk factors for the progression of myopia. Socioeconomic status, outdoor activity, and near-work activity were documented in a face-to-face clinic interview. The changes in cycloplegic subjective refraction and autorefraction were ascertained with the use of a Nidek ARK 900 over a 2-year period.

RESULTS

The average rate of progression of myopia as measured by subjective refraction was -0.59 D per year (95% confidence interval -0.52, -0.66). Younger children and children who were more myopic at the beginning (refractive error worse than -2.0 D) of the study had higher myopia progression rates.

CONCLUSIONS

Myopia progression was faster for younger children and for children who had more severe myopia at baseline. Socioeconomic status and near-work activity were not related to myopia progression.

Clinical drug trials: practical problems of phase III

INTRODUCTION

Phase III randomised clinical trials provide the highest level of evidence to support the superior effectiveness of a new drug or therapy. The main practical problems encountered in the initiation, design, conduct and completion of both investigator-initiated and sponsor-initiated phase III clinical drug trials will be reviewed.

METHODS

A Medline search of clinical drug trials conducted in Singapore as well as journal articles highlighting important methodological considerations and practical problems encountered in phase III clinical trials was performed.

RESULTS

Several phase III randomised clinical trials have been conducted in Singapore which include the investigation of interventions that include tramadol, estradiol patch and colloidal bismuth subcitrate. The main problems encountered in phase III clinical drug trials include difficulties with recruitment of subjects for the study, proper filing of case report forms, special problems in children and the elderly, adequate compensation for adverse events and the adequate archival of documents of the completion of trials. In investigator-initiated trials, careful attention should be given to identifying a suitable study question, choice of study design, sample size calculations and data analysis. In sponsor-initiated trials, a good working relationship with the sponsor is essential and publication terms should be spelt from the onset of the trial.

CONCLUSIONS

Well-planned clinical trials led by a team of competent investigators are essential for the conduct of rigorous sponsor-initiated and investigator-initiated clinical trials.

Temporal variations in myopia progression in Singaporean children within an academic year

PURPOSE

Excessive nearwork is believed to be associated with myopia development and progression. To investigate this further, we studied refractive error changes and their correlation with nearwork in a cohort of grade school children in Singapore.

METHODS

Cycloplegic autorefraction was performed 5 times over 10 months on 168 children aged 7, 9, and 12 years who were further divided into myopic and nonmyopic subgroups based in their initial refractive errors. Information about nearwork was obtained through diaries filled out over 24 h at the commencement of the study.

RESULTS

Myopia progression was high (overall mean: -0.87 D per year) and largely linear throughout the year, but significantly higher rates were seen after the final school examinations in 7-year-old myopes and nonmyopes. Overall, myopic groups exhibited higher progression rates than nonmyopic groups, although 33.6% of subjects from the latter groups had become myopic by the end of the study. Nearwork scores derived from the diaries were generally not well correlated with overall myopia progression.

CONCLUSIONS

The tendency for myopia progression rates to increase after the final school examinations in 7-year-olds is interpreted as a delayed effect of the intense nearwork associated with preparing for them. The timing of nearwork-diary data collection at the beginning of the study could be responsible for the poor correlation between these data and overall myopia progression rates.

Eye cancer incidence in Singapore

AIM

To describe the epidemiological characteristics of patients with primary intraocular, conjunctival, and orbital cancers seen in Singapore from 1968 to 1995.

METHODS

Epidemiological data of all cancers diagnosed in Singapore are collected by the Singapore Cancer Registry. The data of all cases of Singapore residents with eye cancers (ICD-9, site 190) were retrieved for analysis. This includes intraocular, conjunctival, and orbital cancers but excludes cancer of the eyelids.

RESULTS

There were 125 patients of which 67 (53.6%) were male and 58 (46.4%) were female. The average annual age standardised incidences for male and female Singapore residents were 1.89 and 1.81 per million respectively. The most common cancer was retinoblastoma (53.6%), followed by malignant melanoma (19.2%) and squamous cell carcinoma (11.2%). The most common cancer among patients younger than 15 years was retinoblastoma (95.7%) and that for those 15 years and older was malignant melanoma (42.6%). The most common subsite was the retina (53.6%), followed by conjunctiva (12.8%), orbit (8.8%), and lacrimal gland (6.4%).

CONCLUSION

The annual age standardised incidence have been stable for the 28 years studied. Retinoblastoma is much more common than melanoma in Singapore. These expanded epidemiological characteristics serve to provide ophthalmologists and epidemiologists with a foundation to monitor future disease patterns in Singapore and provide a basis for comparison with other selected populations elsewhere.

Outdoor work and the risk of pterygia: a case-control study

AIM

To investigate the relationship between outdoor work and pterygium formation in a hospital-based case-control study in Singapore.

METHOD

Sixty-one patients with pterygium (49 males, mean age 54.2 years) and 125 controls (41 males, mean age 50.2 years), excluding patients with cataract and age-related macular degeneration presenting at outpatient clinics of the Singapore National Eye Centre were interviewed face-to-face with a standard questionnaire. Demographic data and information on outdoor work and eye protection, were collected.

RESULTS

Thirty-eight subjects (20.4%) were outdoor workers and 148 (79.6%) were indoor workers. Outdoor workers were more likely to be male smokers and alcohol drinkers with lower family income and higher sunlight exposure than indoor workers. The crude odds ratio for pterygium in outdoor workers was 7.0 (95% confidence interval 3.2, 15.3). The adjusted odds ratio was 4.2 (95% confidence interval 1.7, 10.1).

CONCLUSION

There is a statistically significant association between outdoor work and pterygium formation, which may be related to the higher exposure to sunlight and dust in outdoor workers. Efforts may be made to educate outdoor workers to wear proper equipment to protect their eyes against excessive sunlight.

Refractive errors in Singapore and Xiamen, China--a comparative study in school children aged 6 to 7 years

PURPOSE

To compare and contrast the prevalence of myopia and other refractive errors in Xiamen city, Xiamen countryside (Southern China), and Singapore.

METHODS

One hundred thirty-two schoolchildren aged 6 to 7 years from Xiamen city, 104 from Xiamen countryside, and 146 from Singapore city were recruited to join the study. Cycloplegic autorefraction, keratometry, and biometry measurements were performed on all children.

RESULTS

The prevalence of myopia was 12.3% in Singapore city, 9.1% in Xiamen city, and 3.9% in Xiamen countryside. The prevalence of astigmatism was higher in Singapore compared with Xiamen. The rates of hyperopia and anisometropia were similar in all three locations.

CONCLUSIONS

The myopia rate in Singapore city was higher than in Xiamen city; the lowest rates were found in Xiamen countryside. As the Chinese population from all three sites is of similar genetic stock (predominantly from Southern China), it is postulated that the differences in myopia rates in these three localities may be related to environmental factors.

Ophthalmic involvement in cranio-facial trauma

OBJECTIVES

This is a retrospective descriptive case study which will look into the spectrum of ophthalmic involvement in cases with orbital and eye injuries after cranio-facial trauma and to analyse the visual and motility outcome.

MATERIAL

One hundred and four cases with ophthalmic involvement after cranio-facial trauma that were referred to and seen in the eye department of a tertiary teaching hospital in Singapore between 1991-97 were included in the study.

METHODS

The case records of 104 such patients were traced. The demographic data, the mode of injury, the type of fracture sustained and presence of serious eye injury were noted. The details about visual acuity, significant diplopia and enophthalmos at the first and last visits were charted. Presence of traumatic optic neuropathy including the type of treatment given was recorded.

RESULTS

There was a male preponderance (82%). The industrial accidents were 21%, only next to road traffic accidents, which constituted approximately 36.5%. The predominant types of fractures seen were blow-out orbital fractures, complex fractures comprising of Le-Fort II, III, panfacial and fronto-basilar skull fractures. Diplopia was the most common presenting feature (40%) with visual acuity disturbance (23% having <6/60) as the next most common finding. Traumatic optic neuropathy was seen in 20% of patients and serious eye injury was present in 9% of patients. The incidence of traumatic optic neuropathy was significantly higher (p<0.001) in patients with complex fractures and fronto-basilar fractures, as compared to the blow-out and zygomatico-maxillary fractures. Analysis of final results indicated 15% as having significant diplopia in one or more gazes and 12.5% as having a vision of <6/60.

CONCLUSION

Diplopia and visual acuity disturbances seem to be the most common ophthalmic presentations in cranio-facial trauma. A significant number of patients suffer from poor vision and significant diplopia despite treatment.

Myopia: gene-environment interaction

INTRODUCTION

Myopia has reached epidemic proportions in Japan, Hong Kong, Taiwan and Singapore. This review summarises the evidence for environmental and genetic factors as well as gene-environment interaction for myopia for both epidemiologic studies as well as animal models.

METHODS

A literature review was conducted after a Medline search on articles on the genetic or environmental aetiology of myopia in animal or epidemiologic studies. Articles on the methodology of gene-environment studies were also reviewed. All articles reviewed were articles published in peer-reviewed journals.

RESULTS

Cross-sectional studies have found a positive association between myopia and near work activity such as reading and writing. Likewise, laboratory research has shown that environmental factors such as visual deprivation may lead to the development of myopia in animals. While linkage studies in humans are currently being conducted to identify possible markers for myopia in the human genome, several neurotransmitters, modulators and growth factors that influence refractive development have already been identified in animal models that may help identify candidate genes. Epidemiologic studies have also evaluated the combined effects of hereditary factors, environmental factors and gene-environment interaction on myopia development.

CONCLUSIONS

Both genes and environmental factors may be related to myopia. There are no conclusive studies at present, however, that identify the nature and extent of possible gene-environment interaction. Further linkage analysis, affected sib-pair studies, and family-based association studies may better identify the nature of gene-environment interaction.

Risk factors for the development of pterygium in Singapore: a hospital-based case-control study

PURPOSE

A hospital-based case-control study, designed to evaluate the risk factors for the development of pterygium in Singapore.

METHODS

Sixty-one cases and 125 controls were interviewed at the Singapore National Eye Centre. Information on present and past (5 and 10 years ago) exposure to sunlight on weekdays and weekends, sociodemographic data, behavior lifestyle and family history of eye disease was collected.

RESULTS

Patients with pterygia were mostly males, smoked and drank alcohol more often, had lower combined family incomes and were more likely to have a family history of eye disease. The adjusted odds ratios for the development of pterygia were 1.27 (95 percent confidence interval 1.06 to 1.54) and 1.31 (95 percent confidence interval 1.09 to 1.57) for participants who had spent more time in the sun five and ten years ago respectively.

CONCLUSIONS

Pterygium is an important public health problem in Singapore and its development is related to the amount of sunlight exposure.

Incidence and survival characteristics of retinoblastoma in Singapore from 1968-1995

PURPOSE

To describe the incidence and survival of 69 Singapore residents with retinoblastoma in all Singapore hospitals from 1968-1995.

METHODS

Data of all Singapore residents diagnosed with retinoblastoma from 1968-1995 were collected by the Singapore Cancer Registry based on notifications from physicians, pathology records, hospital discharge records, and death certificates. The medical records of 46 patients were traced, and information on laterality of tumor, spread of tumor, mode of treatment, and family history of retinoblastoma was obtained. Time trends and survival characteristics of the cohort were described.

RESULTS

The incidence rate of retinoblastoma was 2.4 per 1 million for children <9 years and 11.1 per 1 million for children <5 years. The incidence of retinoblastoma has been almost uniform over time from 1968-1995, except for an apparent increase in 1988-1992. The 3-year survival rate for retinoblastoma was 83%. Survival rates were higher in children <2 years because children who present at a younger age may have tumors diagnosed at earlier stages of the disease. There was no difference in survival rates for sex, race, laterality, family history of retinoblastoma, treatment, or year of diagnosis.

CONCLUSION

Retinoblastoma is the most common eye cancer in children that may cause blindness or death. The incidence rates of retinoblastoma in Singapore have remained fairly stable over 28 years, and the survival rate is higher in younger children. This study will be helpful in monitoring future disease patterns in Asian populations.