Table 1 Characteristics of included studies
Author (year) Country | MS (n) | Control group (n) | F : M cases | Mean age at MS onset (years) | LAT | NOS Score | MS Dx criterion | Timing of surgery | Confounder variables | Exposure 1: Tonsil OR1 | Exposure 2: Append OR1 | Exposure 3: Adenoid OR1 | Exposure 4: Other OR1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
(95% CI) | (95% CI) | (95% CI) | (95% CI) | ||||||||||
Alonso (2011) Iran | 394 | 394 | 3.70 | 24.9 | 32 | 6 | M | Pre | Age, sex | 0.92 (0.51-1.64) | 1.07 (0.52-2.19) | -- | -- |
Alter (1968) USA | 36 | 72 | 45 | 4 | N | Pre | Age, sex, age at onset | -- | -- | -- | 0.78 (0.33-1.81) | ||
Anderson (1981) Denmark | 92 | 276 | 1.42 | 42.4 | 56 | 8 | A; after 1994, Mc | ≤ 20 y | Age, sex, month of birth, years in school | 0.73 (0.32-1.64) | 0.81 (0.22-2.98) | 1.08 (0.64-1.82) | -- |
Antonovsky (1965) Israel | 241 | 964 | 1.10 | 31 | 5 | N | ≤ 15 y, > 15 y | Age, sex, age of onset, region of birth | -- | -- | -- | NS2 | |
Bansil (1997) India | 56 | 147 | 1.67 | 28 | 24 | 3 | P | Pre | Birth place, religion, residence | -- | -- | -- | 0.97 (0.49-1.91) |
Berr (1989) France | 63 | 63 | 2.70 | 30.8 | 42 | 5 | P | Pre | Age, sex, residence | 1.0 (0.38-2.60) | -- | -- | -- |
Bobowick (1978) USA | 10 | 8 | 29.7 | 40 | 6 | N | ≤ 20 y | Age, sex | 2.50 (0.37-16.89) | 5.0 (0.21-120.4) | -- | -- | |
Broadley (2000) England | 595 | 372 | 3.16 | 28 | 52 | 1 | N | Pre | None stated | 1.02 (0.77-1.34) | -- | -- | -- |
Casetta (1994) Italy | 104 | 150 | 2.0 | 32.2 | 44 | 5 | Mc | ≤ 15 y, > 15 y | Age (> 3 y), sex, residence | 1.04 (0.62-1.76) | -- | -- | -- |
Cendrowski (1969) Poland | 300 | 300 | 31.9 | 52 | 3 | N | ≤ 15 y | None stated | 0.74 (0.43-1.27) | -- | -- | -- | |
Currier (1982) Canada & USA | 40 | 40 | 1.0 | 30 | 49 | 5 | A | Pre | Age, sex | -- | -- | -- | 2.22 (0.86-5.74) |
Currier (1974) Ireland | 60 | 60 | 1.4 | 26 | 53 | 3 | A | ≤ 20 y | Age, sex, social class, marital status | 1.18 (0.53-2.61) | 1.46 (0.54-3.93) | -- | 1.45 (0.62-3.41) |
de Gennaro (2009) Italy & Serbia | 104 | 150 | 2.06 | 28 | 44 | 3 | M | ≤ 15 y, > 15 y | Age, sex, residence | ≤ 15 y: 2.50 | < 15 y: 1.60 | -- | -- |
(1.42-4.41)* | (0.91-2.79) | ||||||||||||
> 15 y: | > 15 y: | ||||||||||||
2.20 (1.30-3.73)* | 1.92 (1.09-3.41)* | ||||||||||||
da Silva (2009) Brazil | 81 | 81 | 2.10 | 22 | 4 | N | Pre | Age, sex, place of birth | -- | -- | -- | 1.82 (0.95-3.51) | |
Dolan (2003) USA | 24 | 24 | 2.0 | 35.4 | 42 | 3 | P | ≤ 20 y | Age, sex | -- | -- | -- | 2.14 (0.63-7.33) |
Dokuchaeva (2006) Russia | 178 | 178 | 2.80 | 48 | No data | ≤ 15 y, > 15 y | Age, sex, ethnic origin | ≤ 15 y: 1.61 (1.01-2.56) | -- | -- | -- | ||
> 15 y: | |||||||||||||
1.0 (0.64-1.56) | |||||||||||||
Gronning (1993) Norway | 155 | 200 | 1.50 | -- | 60 | 4 | B | ≤20 y | Age, sex, residence | 1.90 (1.15-3.16)* | 1.10 (0.53-2.28) | -- | -- |
Gusev (1996) Russia | 155 | 155 | 1.63 | 25.8 | 56 | 3 | Mc | ≤ 15 y, > 15 y | Age, sex, residence, and ethnicity | 0.85 (0.38-1.89) | -- | -- | -- |
Hopkins (1991) USA | 14 | 56 | 4.30 | 35.2 | 41 | 7 | P | Pre | Age, sex, race | -- | -- | -- | NS2 |
Koch (1974) USA | 7 | 7 | 2.50 | 29.3 | 46 | 4 | N | Pre | None stated | -- | -- | -- | 1.0 (0.12-8.31) |
Koch-Henriksen (1989) Denmark | 297 | 297 | 1.42 | 32 | 56 | 8 | A | ≤ 15 y, > 15 y | Age, sex | ≤ 15 y: | ≤ 15 y: | ≤ 15 y: | -- |
0.89 (0.52-1.53) | 2.19 (0.93-5.16) | 0.85 (0.54-1.34) | |||||||||||
> 15 y: | > 15 y: | ||||||||||||
1.49 (0.72-3.08) | 1.24 (0.70-2.21) | ||||||||||||
Kurtzke (1997) Norway | 23 | 127 | 1.55 | 30 | 62 | 5 | Schumacher committee | Pre | Age, sex | -- | -- | -- | 1.19 (0.48-2.95) |
Lamoureux (1976) Canada | 23 | 23 | 1.09 | 5 | N | Pre | Age, sex, place of origin | 3.56 (1.05-12.05) | 3.05 (0.78-11.96) | -- | -- | ||
Lauer (1994) Germany | 150 | 150 | 2.04 | 30.3 | 51 | 4 | B | ≤ 14 y | Age, sex, type of residence | -- | NS2 | -- | 0.53 (0.32-0.86)* |
Martinez-Sobrepera (2001) Cuba | 50 | 50 | 4.50 | -- | 21 | 5 | P | Pre | Age, gender, skin color | -- | -- | -- | 1.50 (0.68-3.29) |
Poskanzer (1980) USA | 77 | 77 | 2.04 | 31 | 42 | 4 | N | Pre | None stated | NS2 | -- | -- | NS2 |
Poskanzer (1965) Scotland | 210 | 210 | 1.31 | 33.6 | 60 | 8 | A | ≤ 20 y | Age, sex, residence | 1.69 (1.15-2.50)* | 1.42 (0.86-2.35) | -- | -- |
Roshanisefat (2011) Sweden | 20,542 | 204,157 | 1.87 | 46.3 | -- | 6 | MS register | ≤ 20 y, > 20 y | Age, sex, age at onset, region | -- | ≤ 20 y: | -- | -- |
1.11 (0.94-1.31) | |||||||||||||
> 20 y: | |||||||||||||
1.02 (0.93-1.11) | |||||||||||||
Westlund (1953) Canada | 112 | 123 | 1.43 | 30.3 | 49 | 5 | N | Pre | Age, sex, age at onset | -- | -- | -- | 2.26 (1.24-4.15)* |
YosefiPour (2002) Iran | 149 | 100 | 1.19 | -- | 32 | 4 | N | Pre | Age, sex | -- | -- | -- | 3.93 (1.97-7.84)* |
Zaadstra (2008) Netherlands | 2,821 | 2,550 | 2.30 | -- | 52 | 7 | N | < 25 y | Age, sex, education, residence | 1.25 (1.11-1.40)* | -- | -- | -- |
Zilber (1996) Israel | 70 | 64 | 1.73 | 25.2 | 31 | 6 | M | ≤ 20 y, Pre | Age, sex | ≤ 20 y: | -- | < 10 y: 3.0 (0.77-11.62) | 0.58 (0.29-1.17) |
1.06 (0.47-2.39) | |||||||||||||
Pre: 0.96 (0.44-2.11) | |||||||||||||
Zorzon (2003) Italy | 140 | 131 | 1.72 | 31.2 | 45 | 5 | M | Pre | None stated | -- | -- | -- | 0.46 (0.28-0.76)* |