Table 2 Individual study details and results

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