Table 1 Characteristics of studies included in the meta-analysis.

From: MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk

First Author

Publication Year

Number of Cases (male/female)

Number of Controls (male/female)

Type of controls

Mean age, year Cases/Controls

Racial decent

Types

Country

Ref No.

Weinstein

2002

519 (NA/NA)

629 (NA/NA)

Healthy controls (Age-, gender- matched; population-based)

63.2/61.0

Caucasian

Oral cavity

USA

43

Kureshi

2004

50 (33/17)

54 (30/24)

Healthy controls (Age-, gender- matched; population-based)

51.3/50.2

Mixed

Combined

Pakistan

28

Capaccio

2005

65 (57/8)

100 (88/12)

Healthy controls (Age-, gender-, drinking-, smoking status- matched; population-based)

61.3/58.8

Caucasian

Combined

Italy

23

Neumann

2005

537 (411/126)

545 (401/144)

Non-cancerous controls (Age-,sex-, smoking status-matched; hospital-based)

NA/NA

Caucasian

Combined

USA

29

Vairaktaris

2006

110 (94/16)

120 (102/18)

Healthy controls (Age-, sex, ethnicity-matched; population-based)

52.1/51.5

Caucasian

Oral cavity

GreekGerman

41

Hsiung

2007

278 (193/85)

526 (377/149)

Healthy controls (Age-, gender, town of residence-matched; population-based)

60.1/61.0

Mixed

Combined

USA

26

Reljic

2007

81 (NA/NA)

102 (37/65)

Healthy controls (Age-matched; population-based)

NA/NA

Caucasian

Combined

Croatia

33

Suzuki

2007

237 (188/49)

711 (564/147)

Non-cancerous controls (Age-,sex-matched; hospital-based)

57.9/58.4

Asian

Combined

Japan

39

Ni

2008

207 (189/18)

400 (362/38)

Healthy controls (Age-,sex-matched; population-based)

NA/NA

Asian

Larynx

China

30

Siraj

2008

223 (NA/NA)

513 (NANA)

Healthy controls (Age-matched; population-based)

NA/NA

Mixed

Thyroid

Saudi Arabia

36

Solomon

2008

126 (NA/NA)

100 (NA/NA)

Healthy individuals(population-based)

54.7/55.4

Asian

Oral cavity

India

37

Cao

2010

529 (339/190)

577 (367/210)

Healthy controls (Age-,sex-, ethnicity-matched; population-based)

46.1/45.4

Asian

Nasopharynx

China

22

Kruszyna

2010

131 (131/0)

250 (250/0)

Healthy controls (population-based)

59.4/56.8

Caucasian

Larynx

Poland

27

Rodrigues

2010

100 (84/16)

100 (76/24)

Non-cancerous controls (hospital-based)

59.5/43.6

Mixed

Combined

Brazil

34

Fard-Esfahani

2011

154 (34/120)

198 (50/148)

Non-cancerous controls (hospital-based)

NA/NA

Mixed

Thyroid

Iran

24

Prasad

2011

97 (27/70)

241 (116/125)

Healthy controls (population-based)

NA/NA

Asian

Thyroid

India

32

Sailasree

2011

130 (88/42)

139 (92/47)

Non-cancerous controls (Age-,gender-matched; hospital-based)

58.0/57.0

Asian

Oral cavity

India

35

Supic

2011

96 (72/24)

162 (130/32)

Non-cancerous controls(Age-, gender-, ethnicity-matched; population-based)

58.0/58.0

Caucasian

Oral cavity

Serbia

38

Tsai

2011

620 (583/37)

620 (572/48)

Healthy controls (Age-, gender-, habits-matched; population-based)

65.5/63.5

Asian

Oral cavity

China

40

Galbiatti

2012

322 (280/42)

531 (384/147)

Healthy controls (population-based)

NA/NA

Mixed

Combined

Brazil

25

Ozdemir

2012

60 (11/49)

50 (21/29)

Healthy controls (population-based)

55.3/68.6

Mixed

Thyroid

Turkey

31

Vylliotis

2013

160 (NA/NA)

168 (NA/NA)

Healthy controls (Age-, gender-, ethnicity-, working environment-matched; population-based)

58.5/54.7

Caucasian

Oral cavity

Greece

42

Kweon

2014

2194 (404/1790)

1669 (812/857)

Healthy controls (Age-, gender-, matched; population-based)

50.6/52.2

Asian

Thyroid

Korea

44

  1. NA: not available