The epidemiology of mental retardation: Challenges and opportunities in the new millennium

Mental Retardation and Developmental Disabilities Research Reviews

Volumn 8, Issue 3, 2002, Pages 117-134

  Leonard, Helen ^a,b   Wen, Xingyan ^b  

^a UNIVERSITY OF WESTERN AUSTRALIA   (Australia)

^b AUSTRALIAN INSTITUTE OF HEALTH AND WELFARE   (Australia)

Author keywords

Data linkage; Down syndrome; Etiology; Mental retardation intellectual disability impairment

Indexed keywords

ADOLESCENT; AGE; CHILD; DISEASE CLASSIFICATION; ECONOMIC ASPECT; ETHNOLOGY; FEMALE; GENDER; HUMAN; MALE; MENTAL DEFICIENCY; NEWBORN SCREENING; PRENATAL SCREENING; PREVALENCE; PRIORITY JOURNAL; REVIEW; RISK FACTOR; SOCIAL ASPECT; SOCIAL CLASS;

ADOLESCENT; ADULT; AGE DISTRIBUTION; CHILD; DATA COLLECTION; DOWN SYNDROME; HUMANS; MEDICAL RECORDS SYSTEMS, COMPUTERIZED; MENTAL RETARDATION; PREVALENCE; RISK FACTORS; SEX DISTRIBUTION; SOCIAL CLASS; WORLD HEALTH;

EID: 0036948248     PISSN: 10804013     EISSN: None     Source Type: Journal    
DOI: 10.1002/mrdd.10031     Document Type: Review

References (173)

1. Abadie V, Berthelot J, Feillet F, et al. 2001. Neonatal screening and long-term follow-up of phenylketonuria: the French database. Early Hum Dev 65:149-158.
2. Alberman E, Nicholson A, Wald K. 1992. Severe learning disability in young children. London: The Wolfson Institute of Preventive Medicine.
3. Alberman E, Mutton D, Ide R, et al. 1995. Down's syndrome births and pregnancy terminations in 1989 to 1993: preliminary findings. Br J Obstet Gynaecol 102:445-447.
4. Allen MC, Alexander GR, Tompkins ME, et al. 2000. Racial differences in temporal changes in newborn viability and survival by gestational age. Paediatr Perinat Epidemiol 14:152-158.
5. American Academy of Pediatrics. 2000. Committee on Substance Abuse and Committee on Children with Disabilities. Fetal alcohol syndrome and alcohol-related neurodevelopmental disorders. Pediatrics 106:358-361.
6. th ed. Washington DC.
7. Amir RE, Van den Veyver IB, Wan M, et al. 1999. Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2. Nat Genet 23:185-188.
8. Amir RE, Zoghbi HY. 2000. Rett Syndrome: Methyl-CpG-Binding Protein 2 Mutations and phenotype-genotype correlation. Am J Med Genet 97:147-152.
9. Australian Paediatric Surveillance Unit. 2001. Eighth Annual Report of the Australian Paediatric Surveillance Unit. Sydney: Division of Paediatrics, Royal Australasian College of Physicians.
10. Bagheri MM, Burd L, Martsolf JT, et al. 1998. Fetal alcohol syndrome: maternal and neonatal characteristics. J Perinat Med 26:263-269.
11. Baker E, Hinton L, Callen DF, et al. 2002. Study of 250 children with idiopathic metnal retardation reveals nine cryptic and diverse subtelomeric chromosome anomalies. Am J Med Genet 107:285-293.
12. Barnett WS. 1986. Definition and classification of mental retardation: a reply to Zigler, Balla, and Hodapp. Am J Ment Defic 91:111-119.
13. Bonduelle M, Joris H, Hofmans K, et al. 1998. Mental development of 201 ICSI children at 2 years of age. Lancet 351:1553.
14. Boussy CA, Scott KG. 1993. Use of database linkage methodology in epidemiological studies of mental retardation. International Review of Research in Mental Retardation 19: 135-161.
15. Bowen JR, Gibson FL, Leslie GI, et al. 1998. Medical and developmental outcomes at 1 year for children conceived by intracytoplasmic sperm injection. Lancet 315:1529-1534.
16. Bower C, Forbes R, Seward M, et al. 1989. Congenital malformations in Aborigines and nonAborigines in Western Australia, 1980-1987. Med J Aust 151:245-248.
17. Bower C, Payne J, Condon R, et al. 1994. Sequelae of Haemophilus influenzae type b meningitis in Aboriginal and non-Aboriginal children under 5 years of age. J Paediatr Child Health 30:393-397.
18. Bower C, Condon R, Payne J, et al. 1998. Measuring the impact of conjugate vaccines on invasive Haemophilus influenzae type b infection in Western Australia. Aust N Z J Public Health 22:67-72.
19. Bower C, Leonard H, Petterson B. 2000. Intellectual disability in Western Australia. J Paediatr Child Health 36:213-215.
20. Breslau N, Chilcoat HD, Susser ES, et al. 2001. Stability and change in children's intelligence quotient scores: a comparison of two socioeconomically disparate communities. Am J Epidemiol 154:711-717.
21. Brett KM, Schoendorf KC, Kiely JL. 1994. Differences between black and white women in the use of prenatal care technologies. Am J Obstet Gynecol 170:41-46.
22. Camp BW, Borman SH, Nichols PL, et al. 1998. Maternal and neonatal risk factors for mental retardation: defining the 'at risk' child. Early Human Development 50:159-173.
23. Cans C, Wilhelm L, Baille MF, et al. 1999. Aetiological findings and associated factors in children with severe mental retardation. Dev Med Child Neurol 41:233-239.
24. Chapman DA, Scott KG. 2001. The impact of maternal intergenerational risk factors on adverse developmental outcomes. Developmental Review 21:305-325.
25. Chelly J, Mandel JL. 2001. Monogenic causes of X-linked mental retardation. Nat Rev Genet 2:669-680.
26. Clayton-Smith J, Watson P, Ramsden S, et al. 2000. Somatic mutation in MECP2 as a non-fatal neurodevelopmental disorder in males. Lancet 356:830-832.
27. Cooper S, Bailey N. 2001. Psychiatric disorders amongst adults with learning disabilities-prevalence and relationship to ability level. Ir J Psych Med 18:45-53.
28. Couvert P, Bienvenu T, Aquaviva C, et al. 2001. MECP2 is highly mutated in X-linked mental retardation. Hum Mol Genet 10:941-946.
29. Crocker AC. 1989. The causes of mental retardation. Pediatr Ann 18:623-636.
30. Croen LA, Grether JK, Selvin S. 2001. The epidemiology of mental retardation of unknown cause. Pediatrics 107:E86.
31. Curran AL, Sharples PM, White C, et al. 2001. Time costs of caring for children with severe disabilities compared with caring for children without disabilities. Dev Med Child Neurol 43:529-533.
32. Decoufle P, Boyle CA. 1995. The relationship between maternal education and mental retardation in 10-year old children. Annals of Epidemiology 5:347-353.
33. Delange F, de Benoist B, Pretell E, et al. 2001. Iodine deficiency in the world: Where do we stand at the turn of the century? Thyroid 11:437-447.
34. de Vries BB, White SM, Knight SJ, et al. 2001. Clinical studies on submicroscopic subtelomeric rearrangements: a checklist. J Med Genet 38:145-150.
35. Dotti MT, Orrico A, De Stefano N, et al. 2002. A Rett syndrome MECP2 mutation that causes mental retardation in men. Neurology 58: 226-230.
36. Drews CD, Yeargin-Allsopp M, Decoufle P, et al. 1995. Variation in the influence of selected sociodemographic risk factors for mental retardation. American Journal of Public Health 85:329-334.
37. Drews CD, Murphy CC, Yeargin-Allsopp M, et al. 1996. The relationship between idiopathic mental retardation and maternal smoking during pregnancy. Pediatrics 97: 547-553.
38. Durkin M, Khan N, Davidson L, et al. 2000. Prenatal and postnatal risk factors for mental retardation among children in Bangladesh. Am J Epidemiol 152:1024-1033.
39. Dykens EM, Hodapp RM. 2001. Research in mental retardation: toward an etiologic approach. Journal of Child Psychology & Psychiatry & Allied Disciplines 42:49-71.
40. English DR, Holman CDJ, Milne E, et al. 1995. Commonweath Department of Human Services and Health, Canberra.
41. Einfeld SL, Tonge BJ. 1996. Population prevalence of psychopathology in children and adolescents with intellectual disability. 1. Rationale and Methods. J Intellect Disabil Res 40:91-98.
42. Fernell E. 1996. Mild mental retardation in school children in a Swedish suburban municipality: prevalence and diagnostic aspects. Acta Paediatr 85:584-588.
43. Fernell E. 1998. Aetiological factors and prevalence of severe mental retardation in children in a Swedish municipality: the possible role of consanguinity. Dev Med Child Neurol 40: 608-611.
44. Fidler DJ, Hodapp RM. 1998. Importance of typologies for science and service in mental retardation. Ment Retard 36:489-495.
45. Fombonne E. 1999. The epidemiology of autism: a review. Psychological Medicine 29: 769-786.
46. Fryers T. 1987. Epidemiological issues in mental retardation. Journal of Mental Deficiency Research 31:365-384.
47. Fryers T. 1992. Epidemiology and taxonomy in mental retardation. Paediatr Perinat Epidemiol 6:181-192.
48. Fryers T, Mackay RI. 1979. The epidemiology of severe mental handicap. Early Hum Dev 3:277-294.
49. Gazarian M, Wiliams K, Elliot E, et al. 1999. Evaluation of a national surveillance unit. Archives of Diseases in Children 80:21-27.
50. Gibbons RJ, Higgs DR. 2000. Molecular-clinical spectrum of the ATR-X syndrome. Am J Med Genet 97:204-212.
51. Gilbert RE, Augood C, Gupta R, et al. 2001. Screening for Down's syndrome: effects, safety, and cost effectiveness of first and second trimester strategies. BMJ 323:423-425.
52. Gissler M, Hemminki E, Louhiala P, et al. 1998. Health registers as a feasible means of measuring health status in childhood-a 7-year follow-up of the 1987 Finnish birth cohort. Paediatr Perinat Epidemiol 12:437-455.
53. Gissler M, Jarvelin MR, Louhiala P, et al. 1999. Boys have more health problems in childhood than girls: follow-up of the 1987 Finnish birth cohort. Acta Paediatr 88:310-314.
54. Gleeson JG, Allen KM, Fox JW, et al. 1998. Doublecortin, a brain-specific gene mutated in human X-linked lissencephaly and double cortex syndrome, encodes a putative signaling protein. Cell 92:63-72.
55. Greenspan S. 1999. What is meant by mental retardation? International Review of Psychiatry 11:6-18.
56. Grossman F. 1973. Manual on terminology and classification in mental retardation. Washington DC: American Association on Mental Deficiency.
57. Grossman F. 1983. Classification in mental retardation. Washington DC, American Association on Mental Deficiency.
58. Gu XF, Chen RG. 1999. Current status of neonatal screening in China. J Med Screen 6: 186-187.
59. Haddow JE, Palomaki GE, Allan WC, et al. 1999. Maternal thyroid deficiency during pregnancy and subsequent neuropsychological development of the child. N Engl J Med 341: 549-555.
60. Hagberg B, Hagberg G. 1997. Rett-Syndrome Epidemiology and geographical variability. European Child & Adolescent Psychiatry 6:5-7.
61. Hagberg B, Hagberg G, Lewerth A, et al. 1981. Mild mental retardation in Swedish school children: I. Prevalence. Acta Paediatr Scand 70:441-444.
62. Hall SM, Roberts C. 1993. Occasional Papers: The British Paediatric Surveillance Unit. The Bulletin of the Royal College of Pathologists 82:12-16.
63. Hansen H, Belmont L, Stein Z. 1980. Epidemiology. Mental Retardation and Devlop Disabilities 11:21-54.
64. Hansen M, Kurinczuk J, Bower C, et al. 2002. The risk of major birth defects after intracytoplasmic sperm injection and in vitro fertilisation. N Engl J Med 346:725-730.
65. Haveman MJ. 1996. Epidemiological issues in mental retardation. Current Opinion in Psychiatry 9:305-311.
66. Heber R. 1961. Modifications in the manual on terminology and classification in mental retardation. Am J Ment Defic 64:499-500.
67. Holman CD. 2001. The impracticable nature of consent for research use of linked administrative health records. Aust N Z J Public Health 25:421-422.
68. Hou JW, Wang TR, Chuang SM. 1998. An epidemiological and aetiological study of children with intellectual disability in Taiwan. J Intellect Disabil Res 42:137-143.
69. Hurtado EK, Claussen AH, Scott KG. 1999. Early childhood anemia and mild or moderate mental retardation. American Journal of Clinical Nutrition 69:115-119.
70. Hutchesson AC, Bundey S, Preece MA, et al. 1998. A comparison of disease and gene frequencies of inborn errors of metabolism among different ethnic groups in the West Midlands, UK. J Med Genet 35:366-370.
71. Imessaoudene B, Bonnefont JP, Royer G, et al. 2001. MECP2 mutation in non-fatal, non-progressive encephalopathy in a male. J Med Genet 38:171-174.
72. Islam S, Durkin MS, Zaman SS. 1993. Socioeconomic status and the prevalence of mental retardation in Bangladesh. Ment Retard 31: 412-417.
73. Kawachi I, Kennedy B. 1997. Socioeconomic determinants of health: Health and cohesion: why care about income inequality? BMJ 314: 1037.
74. Kearins J. 2000. Children and Cultural Differences In: Dudgeon P, Garvey D, Pickett H, eds. Working with indigenous Australians: a handbook for psychologists. Perth, Western Australia: Gunada Press.
75. Kelleher KJ, McInerny TK, Gardner WP, et al. 2000. Increasing identification of psychosocial problems: 1979-1996. Pediatrics 105:1313-1321.
76. Kiely M. 1987. The prevalence of mental retardation. Epidemiol Rev 9:194-218.
77. Kok JH, den Ouden AL, Verloove-Vanhorick SP, et al. 1998. Outcome of very preterm small for gestational age infants: the first nine years of life. Br J Obstet Gynaecol 105: 162-168.
78. Kozinetz CA, Skender ML, MacNaughton N, et al. 1993. Epidemiology of Rett syndrome: a population-based registry. Pediatrics 91:445-450.
79. Kruse RL, Ewigman BG, Tremblay GC. 2001. The zipper: a method for using personal identifiers to link data while preserving confidentiality. Child Abuse Negl 25:1241-1248.
80. Kurinczuk JJ, Bower C, Lewis B, et al. 2002. Congenital hypothyroidism in Western Australia 1981-1998. J Paediatr Child Health 38: 187-191.
81. Larson SA, Lakin KC, Anderson L, et al. 2001. Prevalence of mental retardation and developmental disabilities: estimates from the 1994/1995 National Health Interview Survey Disability Supplements. Am J Ment Retard 106:231-252.
82. Last JM. 1995. A Dictionary of Epidemiology. New York: Oxford University Press.
83. Leonard H, Fletcher JM. 1999. Inherited metabolic diseases: beyond newborn screening. Med J Aust 170:573-574.
84. Leonard H, Bower C, English D. 1997. The prevalence and incidence of Rett syndrome In Australia. European Child & Adolescent Psychiatry 6:8-10.
85. Leonard H, Fyfe S, Danielle D, et al. 2000a. Using genetic epidemiology to study Rett syndrome: the design of a case control study. Paediatr Perinat Epidemiol 14:85-93.:
86. Leonard H, Fyfe S, Leonard S, et al. 2001. Functional status, medical impairments, and rehabilitation resources in 84 females with Rett syndrome: a snapshot across the world from the parental perspective. Disabil Rehabil 23: 107-117.
87. Leonard H, Petterson B, Bower C, et al. 2002a. Prevalence of intellectual disability in Western Australia. Paediatr Perinat Epidemiol (in press).
88. Leonard S, Bower C, Petterson B, et al. 2000b. Survival of infants born with Down's syndrome: 1980-96. Paediatr Perinat Epidemiol 14:163-171.
89. Leonard S, Bower C, Petterson B, et al. 1999. Medical aspects of school-aged children with Down syndrome. Dev Med Child Neurol 41:683-388.
90. Leonard S, Msall M, Bower C, et al. 2002b. The functional status of school-aged children with Down syndrome. J Paediatr Child Health (38: 160-165).
91. Luckasson R, Coulter DL, Polloway EA, et al. 1992. Mental retardation: Definition, classification, and systems of supports. Washington DC: American Association on Mental Retardation.
92. Louhiala P. 1995. Risk indicators of mental retardation: changes between 1967 and 1981. Dev Med Child Neurol 37:631-636.
93. Luckasson R, Reeve A. 2001. Naming, defining, and classifying in mental retardation. Ment Retard 39:47-52.
94. Matte TD, Bresnahan M, Begg MD, et al. 2001. Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study. BMJ 323: 310-314.
95. McDermott S, Cokert AL, McKeown RE. 1993. Low birthweight and risk of mild mental retardation by ages 5 and 9 to 11. Paediatr Perinat Epidemiol 7:195-204.
96. McDermott S, Daguise V, Mann H, et al. 2001. Perinatal risk for mortality and mental retardation associated with maternal urinary-tract infections. J Fam Pract 50:433-437.
97. MacMillan DL, Gresham FM, Siperstein GN. 1993. Conceptual and psychometric concerns about the 1992 AAMR definition of mental retardation. Am J Ment Retard 98: 325-335.
98. MacMillan DL, Gresham FM, Siperstein GN. 1995. Heightened concerns over the 1992 AAMR definition: advocacy versus precision. Am J Ment Retard 100:87-95.
99. McLaren J, Bryson SE. 1987. Review of recent epidemiological studies of mental retardation: prevalence, associated disorders, and etiology. Am J Ment Retard 92:243-254.
100. McLennan W, Madden R. 1999. The health and welfare of Australia's Aboriginal and Torres Strait Islander peoples. Canberra: Australian Bureau of Statistics, Australian Institute of Health and Welfare.
101. Meloni I, Bruttini M, Longo I, et al. 2000. A mutation in the Rett syndrome gene, MECP2, causes X-linked mental retardation and progressive spasticity in males. Am J Hum Genet 67:982-985.
102. Menezo YJR, Veiga A, Pouly JL. 2000. Assisted Reproductive Technology (ART) in humans: facts and uncertainties. Theriogenology 53:599-610.
103. Mercer J. 1973. The myth of 3% prevalence In: Eyman R, Myers C, Tarjan G, eds. Sociobehavioural studies in mental retardation. Monographs of the American Association on Mental Deficiency.
104. Mervis CA, Decoufle P, Murphy CC, et al. 1995. Low birthweight and the risk for mental retardation later in childhood. Paediatr Perinat Epidemiol 9:455-468.
105. Moldavsky M, Lev D, Lerman-Sagie T. 2001. Behavioural phenotypes of genetic syndromes: a reference guide for psychiatrists. J Am Acad Child Adolesc Psychiatry 40:749-761.
106. Murphy CC, Boyle C, Schendel D, et al. 1998. Epidemiology of mental retardation in children. Ment Retard Dev Disabil Res Rev 4:6-13.
107. Murphy CC, Yeargin-Allsopp M, Decoufle P, et al. 1995. The administrative prevalence of mental retardation in 10-year-old children in metropolitan Atlanta, 1985 through 1987. Am J Public Health 85:319-323.
108. Mutton DE, Alberman E, Ide R, et al. 1991. Results of first year (1989) of a national register of Down's syndrome in England and Wales. BMJ 303:1295-1297.
109. Nelson KB, Grether JK, Croen LA, et al. 2001a. Neuropeptides and neurotrophins in neonatal blood of children with autism or mental retardation. Ann Neurol 49:597-606.
110. Nelson RM, Botkjin JR, Kodish ED, et al. 2001b. Ethical issues with genetic testing in pediatrics. Pediatrics 107:1451-1455.
111. O'Brien G. 2001a. Adult outcome of childhood learning disability. Dev Med Child Neurol 43:634-638.
112. O'Brien G. 2001b. Defining learning disability: what place does intelligence testing have now? Dev Med Child Neurol 43:570-573.
113. O'Leary P, Bower C, Murch A, et al. 1996. The impact of antenatal screening for Down syndrome in Western Australia: 1980-1994. Australian and New Zealand Journal of Obstetrics & Gynaecology 36:385-388.
114. OMIM. 2001. Vol. 2001. Center for Medical Genetics, Johns Hopkins University (Baltimore, MD) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, MD) World Wide Web URL: http://www.ncbi.nlm.nih.gov/omim/.
115. Orrico A, Lam C, Galli L, et al. 2000. MECP2 mutation in male patients with non-specific X-linked mental retardation. FEBS Lett 481: 285-288.
116. Partington M, Mowat D, Einfeld S, et al. 2000. Genes on the X chromosome are important in undiagnosed mental retardation. Am J Med Genet 92:57-61.
117. Paz I, Laor A, Gale R. et al. 2001. Term infants with fetal growth restriction are not at increased risk for low intelligence scores at age 17 years. J Pediatr 138:87-91.
118. Peckham CS, Dezateux C. 1998. Issues underlying the evaluation of screening programmes. Br Med Bull 54:767-778.
119. Phenylalanine Hydroxylase Locus Knowledgebase. http://ww2.mcgill.ca/pahdb
120. Pollitt E. 1999. Early iron deficiency anemia and later mental retardation. American Journal of Clinical Nutrition 69:4-5.
121. Pollitt RJ. 1999. Tandem mass spectrometry screening: proving effectiveness. Acta Paediatr Suppl 88:40-44.
122. Quaderi NA, Schweiger S, Gaudenz K, et al. 1997. Opitz G/BBB syndrome, a defect of midline development, is due to mutations in a new RING finger gene on Xp22. Nat Genet 17: 285-291.
123. Rantakallio P, von Wendt L. 1985. Risk factors for mental retardation. Archives of Disease in Childhood 60:946-952.
124. Reschly D. 1992. Mental retardation: conceptual foundations, definitional criteria, and diagnostic operations. In: Hooper S, Hynd G, Mattison R, eds. Developmental disorders: diagnostic criteria and clinical assessment. Hillsdale: Lawrence Erlbaum Associates.
125. Reschly DJ, Jipson FJ. 1976. Ethnicity, geographic locale, age, sex, and urban-rural residence as variables in the prevalence of mild retardation. Am J Ment Defic 81:154-161.
126. Richardson SA, Katz M, Koller H. 1986. Sex differences in number of children administratively classified as mildly mentally retarded: an epidemiological review. Am J Ment Defic 91:250-256.
127. Roberts K, Lawton D. 2001. Acknowledging the extra care parents give their disabled children. Child Care Health Dev 27:307-319.
128. Robinson EG, Rathbone GN. 1999. Impact of race, poverty, and ethnicity on services for persons with mental disabilities: call for cultural competence. Ment Retard 37:333-338.
129. Roeleveld N, Zielhuis GA, Gabreels F. 1997. The prevalence of mental retardation: a critical review of recent literature. Dev Med Child Neurol 39:125-132.
130. Rose G. 2001. Sick individuals and sick populations. Int J Epidemiol 30:427-432.
131. Sampson PD, Streissguth AP, Bookstein FL, et al. 1997. Incidence of fetal alcohol syndrome and prevalence of alcohol-related neurodevelopmental disorder. Teratology 56:317-326.
132. Schalock RL, Stark JA, Snell ME, et al. 1994. The changing conception of mental retardation: implications for the field. Ment Retard 32: 181-193.
133. Shann F, Steinhoff MC. 1999. Vaccines for children in rich and poor countries. Lancet 354: SII7-SII11.
134. Slone M, Durrheim K, Lachman P, et al. 1998. Association between the diagnosis of mental retardation and socioeconomic factors. Am J Ment Retard 102:535-546.
135. Society for Assisted Reproductive Technology and American Society for Reproductive Medicine. 2000. Assisted reproductive technology in the Unites States: 1997 results generated from the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry. Fertility and Sterility 74:641-653.
136. Sonnander K, Claesson M. 1997. Classification, prevalence, prevention and rehabilitation of intellectual disability: an overview of research in the People's Republic of China. J Intellect Disabil Res 41:180-192.
137. Stanley FJ, Sim M, Wilson G, et al. 1986. The decline in congenital rubella syndrome in Western Australia: an impact of the school girl vaccination program? Am J Public Health 76: 35-37.
138. Stanley FJ, Read AW, Kurinczuk JJ, et al. 1997. A population maternal and child health research database for research and policy evaluation in Western Australia. Seminars in Neonatology 2:195-201.
139. Starza-Smith A. 1989. Recent trends in prevalence studies of children with severe mental retardation. Disability, Handicap & Society 4:177-195.
140. Stevenson DK, Verter J, Fanaroff AA, et al. 2000. Sex differences in outcomes of very low birthweight infants: the newborn male disadvantage. Arch Dis Child Fetal Neonatal Ed 83:F182-185.
141. Strömberg B, Dahlquist G, Ericson A, et al. 2002. Neurological sequelae in children born after in-vitro fertilisation: a population-based study Lancet 359:461-465.
142. Stromme P, Diseth T. 2000. Prevalence of psychiatric diagnoses in children with mental retardation: data from a population-based study. Dev Med Child Neurol 42:266-270.
143. Stromme P, Hagberg G. 2000. Aetiology in severe and mild mental retardation: a populationbased study of Norwegian children. Dev Med Child Neurol 42:76-86.
144. Stromme P, Magnus P. 2000. Correlations between socioeconomic status, IQ and aetiology in mental retardation: a population-based study of Norwegian children. Soc Psychiatry Psychiatr Epidemiol 35:12-18.
145. Stromme P, Valvatne K. 1998. Mental retardation in Norway: prevalence and sub-classification in a cohort of 30037 children born between 1980 and 1985. Acta Paediatr 87:291-296.
146. Sutcliffe AG, Taylor B, Saunders K, et al. 2001. Outcome in the second year of life after invitro fertilisation by intracytoplasmic sperm injection: a UK case-control study. Lancet 357:2080-2084.
147. Tariverdian G, Vogel F. 2000. Some problems in the genetics of X-linked mental retardation. Cytogenet Cell Genet 91:278-284.
148. Toledano-Alhadef H, Basel-Vanagaite L, Magal N, et al. 2001. Fragile-X carrier screening and the prevalence of premutation and full-mutation carriers in Israel. Am J Hum Genet 69:351-360.
149. Trevathan E, Moser HW. 1988. Diagnostic Criteria for Rett Syndrome. Annals of Neurology 23: 425-428.
150. Turner G, Webb T, Wake S, et al. 1996. Prevalence of fragile X syndrome. Am J Med Genet 64:196-197.
151. Van den Veyver IB. 2001. Skewed X inactivation in X-linked disorders. Semin Reprod Med 19:183-191.
152. Villard L, Cardoso AK, Chelly PJ, et al. 2000. Two affected boys in a Rett syndrome family: clinical and molecular findings. Neurology 55: 1188-1193.
153. Viscardi RM, Sun CC. 2001. Placental lesion multiplicity: risk factor for IUGR and neonatal cranial ultrasound abnormalities. Early Hum Dev 62:1-10.
154. Wald NJ, Huttly WJ, Hennessy CF. 1999. Down's syndrome screening in the UK in 1998. Lancet 354:1264.
155. Wan M, Lee SS, Zhang X, et al. 1999. Rett syndrome and beyond: recurrent spontaneous and familial MECP2 mutations at CpG hotspots. Am J Hum Genet 65:1520-1529.
156. Wang HY, Zhang FC, Gao JJ, et al. 2000. Apolipoprotein E is a genetic risk factor for fetal iodine deficiency disorder in China. Molecular Psychiatry 5:363-368.
157. Wellesley D, Hockey A, Stanley F. 1991. The aetiology of intellectual disability in Western Australia: a community-based study. Dev Med Child Neurol 33:963-973.
158. Wellesley DG, Hockey KA, Montgomery PD, et al. 1992. Prevalence of intellectual handicap in Western Australia: a community study. Med J Aust 156:94-102.
159. Wen X. 1997. The definition and prevalence of intellectual disability in Australia. Canberra: Australian Institute of Health and Welfare.
160. Williams CA. 1995. Angelmans Syndrome: Consensus for Diagnostic Criteria. Am J Med Genet 56:237-238.
161. Willms JD. 1997. Literacy Skills of Canadian Youth, Ottawa: Statistics Canada and Human Resources Development Canada.
162. Wilska M, Kaski M. 1999. Aetiology of intellectual disability - the Finnish classification: development of a method to incorporate WHO ICD-10 coding. J Intellect Disabil Res 43: 242-250.
163. World Health Organisation (WHO). 1980. International classification of functioning, disability and health. Geneva: WHO.
164. World Health Organization (WHO). 1992. International statistical classification of diseases and related health problems: 10th revision, vol 1. Geneva: WHO.
165. World Health Organization (WHO). 1993. International statistical classification of diseases andrelated health problems: 10th revision, vol 2. Geneva: WHO.
166. World Health Organisation (WHO). 2001. International classification of functioning, disability and health. Geneva: WHO.
167. Yeargin-Allsopp M, Murphy CC, Oakley GP, et al. 1992. A multiple-source method for studying the prevalence of developmental disabilities in children: the Metropolitan Atlanta Developmental Disabilties Study. Pediatrics 89:624-629.
168. Yeargin-Allsopp M, Drews CD, Decoufle P, et al. 1995. Mild mental retardation in black and white children in metropolitan Atlanta: a case-control study. Am J Public Health 85: 324-328.
169. Yeargin-Allsopp M, Murphy CC, Cordero JF, et al. 1997. Reported biomedical causes and associated medical conditions for mental retardation among 10-year-old children, metropolitan Atlanta, 1985 to 1987. Dev Med Child Neurol 39:142-149.
170. Zaren B, Lindmark G, Bakketeig L. 2000. Maternal smoking affects fetal growth more in the male fetus. Paediatr Perinat Epidemiol 14:118-126.
171. Zigler E. 1987. The definition and classification of mental retardation. Ups J Med Sci Suppl 44: 9-18.
172. Zigler E, Balla D, Hodapp R. 1984. On the definition and classification of mental retardation. Am J Ment Defic 89:215-230.
173. Zubrick SR, Kurinczuk J, McDermott BMC, et al. 2000. Fetal growth and subsequent mental health problems in children aged 4 to 13 years. Dev Med Child Neurol 42:14-20.