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Table 2 Individual study details and results

From: Association of Down's syndrome and water fluoride level: a systematic review of the evidence

Study Details Outcome and exposure Inclusion/Exclusion Group Water Number of Results
  details Criteria   fluoride level live births* (crude risk)
     (parts per   per 100 000*
     million)   
Author (year) Method of outcome Inclusion criteria Group 1: 0.7–1.1 20760 159.0
Berry (1958) assessment: Children born in study Group 2: 1.9–2.0 14710 122.4
Region of study Institutions, death areas during study Group 3: 0.9 9492 137.0
Essex, England certificates, records of period, mothers living Group 4: <0.2 12620 190.2
Year study started medical officers of in study area at time of Group 5: <0.2 11587 164.0
1945 health authorities, birth Group 6: 0.2 22452 164.8
Study Length personal knowledge of   Group 7: 0.2 14873 107.6
9 years health visitors   Control: 0.2 6870 131.0
Author (year) Method of outcome Inclusion criteria    Metropolitan  
Erickson(1976) assessment: Birth of white children    area  
Region of study Cases identified through only, areas in which Group 1: High 95254 99
Georgia, USA surveillance mothers' usual place Group 2: Low 25373 85
Year study started programmes, data was of residence at birth of    NIS p>0.05
1960–1973 supplemented by a child permitted    surveillance  
Study Length retrospective determination of    areas  
13 years ascertainment (using exposure to fluoridated Group 1:   234300 49
  multiple sources) of water Group 2:   1032100 51
  children born between      p>0.05
  1960 and 1967.      
Author (year) Method of outcome Inclusion criteria     
Erickson(1980) assessment: Cities with 1970     
Region of study Data from birth populations >= 250     
USA certificates obtained 000, Cities fluoridated Group 1: >= 0.7 432580 41.1
Year study started from US Nation Center for >= 5 years by 1973 Group 2: 0.7 204185 44.1
1973 for Health Statistics, Exclusion criteria     
Study Length denominator number of Cities with mixed     Indirect age
2 years live births in study areas fluoridation status     standardised
   States which do not     rates:
   report birth defects on     41.0
   birth certificates     44.0
   Cities fluoridated for     
   <5 years by 1973     
Author (year) Method of outcome Inclusion criteria Group 1: 1 81017 153.1
Needleman(1974) assessment: Children born with Group 2: 0.3 1752435 133.8
Region of study Cases identified through Down's's syndrome     
Massachusetts, USA maternity and paediatric      
Year study started hospitals, Departments      
1950 of Public and Mental      
Study Length Health, private nurseries      
17 years and school for mentally      
  retarded children,      
  karyotyping laboratories      
  and several      
  miscellaneous sources      
Author (year) Method of outcome Inclusion criteria Group 1: 1.0–2.6 67053 71.6
Rapaport (1963) assessment: All cases children with Group 2: 0.3–0.7 70111 47.1
Region of study Cases identified from Down's's syndrome Group 3: 0.1–0.2 132665 39.2
Illinois, USA birth and death born during study Group 4 0.0 63521 23.6
Year study started certificates, registers of period     
1950 specialist medical Town (of mother's     
Study Length educational state residence) size 10 000     
6 years institutions -100 000     
Author (year) Method of outcome Inclusion criteria Dakota    
Rapaport (1957) assessment: Not stated Group 1: >3 31575 34.8
Region of study Alive subjects with Exclusion criteria Group 2: <3 467685 15.2
USA Down's's syndrome Not stated Illinois    
Year study started identified through   Group 1: 1.6–2.6 41618 14.4
Not stated institutions (cases living   Group 2: 1.0–1.2 210628 11.4
Study Length in the community not   Group 3: 0.4–0.7 196258 12.2
Not stated identified)   Group 4 0.3 151167 6.6
    Group 5: 0.1–0.2 670120 6.0
    Group 6: 0.0 7049 3.9
    Wisconsin    
    Group 1: 2.8 52735 30.3
    Group 2: 1.4 21538 32.5
    Group 3: 0.5 51189 25.4
    Group 4 0.1 1076876 13.5
  1. * Rapaport (1957) did not report the total number of births, for this study the population figures are provided and the crude risk is the risk per 100 000 population