Introduction
Methods
Search strategy and inclusion criteria
Study selection
First author, publication year, country | Number of participants, number of cases | Study period | Study quality | Smoking exposure | Comparison and quantity | Relative risk (95 % confidence interval) | Adjustment for confounders |
---|---|---|---|---|---|---|---|
Stampfer MJ et al. 1992, USA | 90302 women, age 34–59 years: 2122 symptomatic gallstone cases 488 unremoved gallbladder disease | 1980–1988, 6.7 years follow-up | 6 | Smoking status, cholecystectomy | Never | 1.00 | Age, body mass index, weight change, alcohol, postmenopausal hormone use, parity, energy intake, polyunsaturated fatty acid intake |
Former | 1.06 (0.94–1.18) | ||||||
Current, 1–14 cig/day | 1.13 (0.94–1.36) | ||||||
15–24 | 1.21 (1.04–1.42) | ||||||
25–34 | 1.36 (1.11–1.67) | ||||||
≥35 | 1.59 (1.24–2.05) | ||||||
Smoking status, unremoved symptomatic gallstones | Never | 1.00 | |||||
Former | 1.09 (0.89–1.33) | ||||||
Current, 1–14 cig/day | 1.06 (0.74–1.50) | ||||||
15–24 | 0.93 (0.68–1.29) | ||||||
25–34 | 1.21 (0.81–1.31) | ||||||
≥35 | 1.30 (0.78–2.16) | ||||||
Smoking status, both endpoints | Never | 1.00 | |||||
Former | 1.06 (0.96–1.17) | ||||||
Current, 1–14 cig/day | 1.10 (0.93–1.29) | ||||||
15–24 | 1.03 (0.90–1.19) | ||||||
25–34 | 1.31 (1.09–1.58) | ||||||
≥35 | 1.51 (1.20–1.89) | ||||||
Kato I, 1992, USA | 7831 Japanese men, age 45 to ≥65: 471 gallbladder disease | 1965–1968–1990, 19.5 years follow-up | 7 | Smoking status | Never | 1.0 | Age |
Former | 1.1 (0.9–1.5) | ||||||
Current | 1.3 (1.0–1.6) | ||||||
Pack-years of cigarettes | Non-smoker | 1.0 | |||||
<24.0 pack-years | 1.0 (0.8–1.3) | ||||||
24.0–40.0 | 1.3 (1.0–1.7) | ||||||
>40.0 | 1.4 (1.1–1.8) | ||||||
Murray FE et al. 1994, United Kingdom | 46,000 women, age NA: 1087 gallbladder disease cases | 1968–1969–1987, 19 years follow-up | 6 | Smoking status | Non-smokers | 1.00 | Age, parity, social class at recruitment |
Smokers | 1.19 (1.06–1.34) | ||||||
Grodstein F et al. 1994, USA | 96,211 women, age 25–42 years: 425 gallstone cases | 1989–1991, 2 years follow-up | 6 | Smoking status | Never | 1.0 | Age, oral contraceptive use, postmenopausal hormone use, parity, alcohol, body mass index, weight change |
Former | 1.1 (0.8–1.4) | ||||||
Current | 1.3 (1.0–1.7) | ||||||
Misciagna G et al. 1996, Italy | 1962 men and women, age 30–69 years: 104 gallstone cases | 1985–1986–1992–1993, ~ 7 years follow-up | 8 | Cigarette smoking | No | 1.00 | Age, sex, body mass index, weight change, years of schooling, use of laxatives, diabetes, wholemeal bread, fish, fried foods, olive oil, wine, coffee |
Yes | 2.15 (1.31–3.54) | ||||||
Sahi T et al. 1998, USA | 16,414 men, age 15–24 years: 268 cases of gallbladder disease | 1962–1966–1977, ~ 13 years follow-up | 6 | Smoking | Never | 1.00 | Age, calendar year, body mass index, body mass index change between college and 1962/66, physical activity index |
Former | 1.28 (0.89–1.85) | ||||||
Current, < 1 pack/day | 1.43 (1.00–2.06) | ||||||
≥1 pack/day | 1.52 (1.03–2.24) | ||||||
Yamada M et al. 2005, Japan | 11,982 men and women, age 13–98 years: 1136 gallstone cases | 1958–1998, ~23.6 years follow-up | 6 | Smoking | Never | 1.00 | Age, sex, city, period, age, radiation dose, drinking |
Ever | 1.19 (1.02–1.40) | ||||||
Gonzalez-Perez A et al. 2007, United Kingdom | Nested case–control study: 2353 gallbladder disease cases 10000 controls Men and women, age 20–79 years | 1996–1996, 0.9 years follow-up | 7 | Smoking status | Never | 1.00 | Age, sex, diabetes, alcohol, body mass index, heart failure, hyperlipidemia, hypertension, ischemic heart disease, stroke, osteoarthritis, rheumatoid arthritis |
Former | 1.18 (0.99–1.41) | ||||||
Current | 1.05 (0.94–1.19) | ||||||
Liu B et al. 2009, United Kingdom | 1,290,413 women, mean age 56 years: 23989 gallbladder disease cases | 1996–2001–2005, 6.1 years follow-up | 9 | Cigarette smoking | Never | 1.00 | Age, region of recruitment, socio-economic status, body mass index, alcohol |
Former | 1.10 (1.06–1.13) | ||||||
Current, 1–9 cig/d | 1.12 (1.05–1.19) | ||||||
10–19 | 1.23 (1.17–1.28) | ||||||
≥20 | 1.29 (1.22–1.37) | ||||||
Etminan M et al. 2011, USA | 2,721,014 women, mean age ~28.4 years: 27,087 cholecystectomies | 1997–2009, 0.9 years follow-up | 6 | Smoking | No | 1.00 | Age, obesity, diabetes, inflammatory bowel disease, pancreatitis, sickle-cell anemia, statin use, fibrate use, oral contraceptive use |
Yes | 2.06 (1.99–2.14) |
Data extraction
Statistical methods
Results
Smoking status
Dose–response analyses
Subgroup and sensitivity analyses and cumulative meta-analyses
Current smoking | Former smoking | Ever smoking | |||||||||||||
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n
| Relative risk (95 % CI) |
I
2 (%) |
P
h
a
|
P
h
2
|
n
| Relative risk (95 % CI) |
I
2 (%) |
P
h
a
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P
h
b
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n
| Relative risk (95 % CI) |
I
2 (%) |
P
h
a
|
P
h
b
| |
All studies | 6 | 1.19 (1.12–1.28) | 46.9 | 0.09 | 6 | 1.10 (1.07–1.13) | 0 | 0.88 | 7 | 1.15 (1.13–1.18) | 0 | 0.43 | |||
Follow-up | |||||||||||||||
<10 years | 4 | 1.17 (1.09–1.26) | 56.1 | 0.08 | 0.20 | 4 | 1.10 (1.07–1.13) | 0 | 0.77 | 0.66 | 4 | 1.15 (1.12–1.18) | 0 | 0.48 | 0.22 |
≥10 years | 2 | 1.37 (1.15–1.64) | 0 | 0.50 | 2 | 1.16 (0.94–1.43) | 0 | 0.51 | 3 | 1.24 (1.12–1.37) | 0 | 0.45 | |||
Gender | |||||||||||||||
Men | 2 | 1.37 (1.15–1.64) | 0 | 0.50 | 0.05/0.18d
| 2 | 1.16 (0.94–1.43) | 0 | 0.51 | 0.78/0.66d
| 2 | 1.28 (1.10–1.48) | 15.9 | 0.28 | 0.21/0.25d
|
Women | 3 | 1.21 (1.18–1.25) | 0 | 0.49 | 3 | 1.10 (1.06–1.13) | 0 | 0.78 | 3 | 1.15 (1.13–1.18) | 0 | 0.55 | |||
Men and women | 1 | 1.05 (0.94–1.19) | 1 | 1.18 (0.99–1.41) | 2 | 1.12 (1.03–1.21) | 0 | 0.35 | |||||||
Study design | |||||||||||||||
Cohort | 5 | 1.22 (1.18–1.25) | 0 | 0.45 | 0.08 | 5 | 1.10 (1.07–1.13) | 0 | 0.88 | 0.47 | 6 | 1.16 (1.13–1.19) | 0 | 0.48 | 0.28 |
Nested case–control study | 1 | 1.05 (0.94–1.19) | 1 | 1.18 (0.99–1.41) | 1 | 1.09 (0.99–1.20) | |||||||||
Outcometype | |||||||||||||||
Gallbladder disease | 5 | 1.19 (1.10–1.28) | 56.1 | 0.06 | 0.52 | 5 | 1.21 (1.18–1.25) | 0 | 0.43 | 0.05 | 5 | 1.15 (1.10–1.20) | 29.3 | 0.23 | 0.65 |
Gallstones | 2 | 1.16 (1.01–1.33) | 1.0 | 0.32 | 2 | 1.09 (0.93–1.29) | 0 | 0.96 | 3 | 1.15 (1.05–1.25) | 0 | 0.66 | |||
Cholecystectomy | 1 | 1.27 (1.15–1.39) | 1 | 1.06 (0.94–1.18) | 1 | 1.18 (1.09–1.27) | |||||||||
Geographic location | |||||||||||||||
Europe | 2 | 1.14 (0.99–1.32) | 82.7 | 0.02 | 0.38 | 2 | 1.10 (1.07–1.14) | 0 | 0.44 | 0.67 | 2 | 1.14 (1.09–1.20) | 33.3 | 0.22 | 0.63 |
America | 4 | 1.23 (1.12–1.36) | 17.4 | 0.30 | 4 | 1.08 (0.99–1.17) | 0 | 0.80 | 4 | 1.18 (1.08–1.28) | 30.1 | 0.23 | |||
Asia | 0 | 0 | 1 | 1.19 (1.02–1.40) | |||||||||||
Number of cases | |||||||||||||||
Cases <1000 | 3 | 1.35 (1.17–1.56) | 0 | 0.75 | 0.17 | 3 | 1.14 (0.96–1.34) | 0 | 0.77 | 0.72 | 3 | 1.25 (1.12–1.40) | 0 | 0.49 | 0.21 |
Cases ≥1000 | 3 | 1.16 (1.07–1.25) | 69.2 | 0.04 | 3 | 1.10 (1.07–1.13) | 0 | 0.57 | 4 | 1.15 (1.12–1.18) | 0 | 0.48 | |||
Study quality | |||||||||||||||
0–3 stars | 0.55 | 0 | 0.65 | 0.83 | |||||||||||
4–6 stars | 3 | 1.24 (1.08–1.43) | 37.4 | 0.20 | 3 | 1.08 (0.98–1.18) | 0 | 0.61 | 4 | 1.18 (1.08–1.28) | 29.2 | 0.24 | |||
7–9 stars | 3 | 1.17 (1.05–1.31) | 67.5 | 0.05 | 3 | 1.10 (1.07–1.14) | 0 | 0.75 | 3 | 1.16 (1.13–1.18) | 0 | 0.43 | |||
Adjustment for confounding factors
c
| |||||||||||||||
Age | |||||||||||||||
Yes | 6 | 1.19 (1.12–1.28) | 46.9 | 0.09 | NC | 6 | 1.10 (1.07–1.13) | 0 | 0.88 | NC | 7 | 1.15 (1.13–1.18) | 0 | 0.43 | NC |
No | 0 | 0 | 0 | ||||||||||||
Alcohol | |||||||||||||||
Yes | 4 | 1.17 (1.09–1.26) | 56.1 | 0.08 | 0.20 | 3 | 1.10 (1.07–1.13) | 0 | 0.77 | 0.66 | 5 | 1.15 (1.13–1.18) | 0 | 0.62 | 0.20 |
No | 2 | 1.37 (1.15–1.64) | 0 | 0.50 | 2 | 1.16 (0.94–1.43) | 0 | 0.51 | 2 | 1.28 (1.10–1.48) | 15.9 | 0.28 | |||
BMI | |||||||||||||||
Yes | 5 | 1.19 (1.10–1.28) | 55.6 | 0.06 | 0.59 | 5 | 1.10 (1.07–1.13) | 0 | 0.77 | 0.99 | 5 | 1.15 (1.10–1.20) | 28.8 | 0.23 | 0.61 |
No | 1 | 1.30 (1.00–1.60) | 1 | 1.10 (0.90–1.50) | 2 | 1.19 (1.06–1.34) | 0 | 0.94 | |||||||
Weight change or BMI change | |||||||||||||||
Yes | 3 | 1.24 (1.08–1.43) | 37.4 | 0.20 | 0.55 | 3 | 1.08 (0.98–1.18) | 0 | 0.61 | 0.65 | 3 | 1.19 (1.06–1.35) | 50.4 | 0.13 | 0.83 |
No | 3 | 1.17 (1.05–1.31) | 67.5 | 0.05 | 3 | 1.10 (1.07–1.14) | 0 | 0.75 | 4 | 1.16 (1.13–1.19) | 0 | 0.61 | |||
Hormone replacement therapy | |||||||||||||||
Yes | 2 | 1.17 (1.08–1.27) | 0 | 0.42 | 0.74 | 2 | 1.06 (0.97–1.17) | 0 | 0.81 | 0.56 | 2 | 1.13 (1.06–1.20) | 0 | 0.51 | 0.50 |
No | 2 | 1.14 (0.99–1.32) | 82.7 | 0.02 | 2 | 1.10 (1.07–1.14) | 0 | 0.44 | 3 | 1.16 (1.13–1.18) | 0 | 0.44 | |||
Oral contraceptive use | |||||||||||||||
Yes | 1 | 1.30 (1.00–1.70) | 0.54 | 1 | 1.10 (0.80–1.40) | 0.99 | 1 | 1.20 (0.99–1.46) | 0.69 | ||||||
No | 3 | 1.16 (1.07–1.25) | 69.2 | 0.04 | 3 | 1.10 (1.07–1.13) | 0 | 0.57 | 4 | 1.15 (1.12–1.18) | 0 | 0.48 | |||
Parity | |||||||||||||||
Yes | 2 | 1.17 (1.08–1.27) | 0 | 0.42 | 0.74 | 2 | 1.06 (0.97–1.17) | 0 | 0.81 | 0.56 | 2 | 1.13 (1.06–1.20) | 0 | 0.51 | 0.50 |
No | 2 | 1.14 (0.99–1.32) | 82.7 | 0.02 | 2 | 1.10 (1.07–1.14) | 0 | 0.44 | 3 | 1.16 (1.13–1.18) | 0 | 0.44 | |||
Physical activity | |||||||||||||||
Yes | 1 | 1.47 (1.13–1.92) | 0.21 | 1 | 1.28 (0.89–1.85) | 0.46 | 1 | 1.40 (1.13–1.74) | 0.14 | ||||||
No | 5 | 1.18 (1.11–1.26) | 44.9 | 0.12 | 5 | 1.10 (1.07–1.13) | 0 | 0.89 | 6 | 1.15 (1.13–1.18) | 0 | 0.72 |