Background
Menthol
Mentholated cigarettes
Carcinogenicity, genotoxicity and pharmacological effects
Effects on smoking characteristics
Differences between Black and White people in the US
Relative use of mentholated cigarettes
% of current smokers using mentholated cigarettesb
| |||
---|---|---|---|
Gender | Age | White people | Black people |
Male | 12-17 | 45.1 | 79.1 |
18-25 | 29.5 | 86.5 | |
26-34 | 22.7 | 89.6 | |
35-49 | 14.9 | 87.9 | |
50+ | 20.2 | 70.4 | |
All ages | 21.8 | 83.5 | |
Female | 12-17 | 46.9 | 51.8 |
18-25 | 36.0 | 88.7 | |
26-34 | 24.1 | 94.0 | |
35-49 | 28.0 | 95.1 | |
50+ | 28.6 | 89.4 | |
All ages | 29.6 | 90.9 |
Relative lung cancer rates in Black and White people in the US
White people | Black people | Black/White | |||||
---|---|---|---|---|---|---|---|
Gender | Year | Age | Deaths | Rate | Deaths | Rate | Rate |
Male | 2000 | 35-44 | 1133 | 6.1 | 361 | 13.3 | 2.19 |
45-54 | 5588 | 35.7 | 1383 | 70.7 | 1.98 | ||
55-64 | 15173 | 150.7 | 2436 | 223.4 | 1.48 | ||
65-74 | 27516 | 374.7 | 3340 | 488.7 | 1.30 | ||
75-84 | 23406 | 529.7 | 2118 | 641.3 | 1.21 | ||
2005 | 35-44 | 943 | 5.3 | 203 | 7.6 | 1.43 | |
45-54 | 5803 | 33.2 | 1334 | 56.9 | 1.71 | ||
55-64 | 15510 | 123.4 | 2721 | 199.1 | 1.61 | ||
65-74 | 24627 | 331.7 | 3011 | 408.6 | 1.23 | ||
75-84 | 24598 | 519.7 | 2066 | 564.3 | 1.09 | ||
Female | 2000 | 35-44 | 957 | 5.2 | 222 | 7.3 | 1.40 |
45-54 | 3941 | 24.8 | 746 | 32.8 | 1.33 | ||
55-64 | 10304 | 96.0 | 1289 | 95.3 | 0.99 | ||
65-74 | 18663 | 213.1 | 1885 | 194.1 | 0.91 | ||
75-84 | 18299 | 272.5 | 1315 | 224.2 | 0.82 | ||
2005 | 35-44 | 907 | 5.2 | 184 | 6.1 | 1.17 | |
45-54 | 4230 | 24.0 | 914 | 33.5 | 1.40 | ||
55-64 | 10947 | 82.6 | 1489 | 87.8 | 1.06 | ||
65-74 | 17883 | 207.1 | 1899 | 184.5 | 0.89 | ||
75-84 | 19816 | 288.3 | 1632 | 253.2 | 0.88 |
Differences in smoking habits between Black and White people in the US
Males | Females | |||
---|---|---|---|---|
White people | Black people | White people | Black people | |
Among the whole population
| ||||
Ever smoked (100 cigarettes) | 49.9% | 42.8% | 38.2% | 28.7% |
Current smokerb
| 23.7% | 27.0% | 18.5% | 18.9% |
Among ever smokers
| ||||
Current smokerb
| 47.5% | 63.0% | 48.4% | 66.0% |
Age of starting to smoke (mean, yrs) | 16.9 | 18.4 | 17.9 | 19.2 |
Among current smokers
b
| ||||
Number smoked per day (mean) | 16.1 | 11.4 | 13.9 | 10.0 |
Methods
Selection of studies
Data extraction
-
study design (prospective cohort, hospital case-control, population case-control)
-
study location and timing
-
sexes, races and age groups studied
-
whether current or ever smokers were studied
-
other inclusion criteria
-
cases - definition, number studied
-
controls (for case-control studies) - definition, matching to cases, number studied
-
at risk population (for cohort studies) - definition, number studied
-
questions asked relating to mentholation of cigarettes (and brands of cigarettes smoked) and the variables used to quantify exposure
-
statistical methods used for analysis
-
adjustment variables considered
-
availability of results by histological type, and
-
main conclusions reached by the authors.
Relative risk estimates
Summary of study characteristics, strengths and weaknesses
Meta-analyses
Checking
Results
Studies identified
Study descriptions and results
American Health Foundation multicentre case-control study
Histological type of lung cancer | Years of use of mentholated cigarettes | ||||||
---|---|---|---|---|---|---|---|
No. of | Neverb
| 1-14 | 15+ | Everc
| |||
Gender | Cases | Adjusteda
| RR | RR (CI) | RR (CI) | RR (CI) | |
Any | Male | 588 | Nod
| 1.00 | 0.98 (0.72-1.33) | 0.87 (0.64-1.20) | 0.92 (0.73-1.17) |
Yes | 1.00 | 1.14 (0.82-1.59) | 0.98 (0.70-1.38) | 1.06 (0.82-1.37) | |||
Female | 456 | Nod
| 1.00 | 0.56 (0.38-0.83) | 0.55 (0.38-0.80) | 0.56 (0.42-0.75) | |
Yes | 1.00 | 0.82 (0.52-1.28) | 0.76 (0.53-1.16) | 0.78 (0.57-1.08) | |||
Combined | 1044 | Nod
| 1.00 | 0.79 (0.62-1.01) | 0.72 (0.57-0.92) | 0.76 (0.63-0.91) | |
Yesd
| 1.00 | 1.02 (0.78-1.33) | 0.88 (0.68-1.14) | 0.94 (0.77-1.15) | |||
Squamous cell carcinoma | Combined | 268 | Yes | 1.00 | 1.17 (0.78-1.78) | 0.92 (0.60-1.42) | 1.04 (0.75-1.44) |
Small cell carcinoma | Combined | 131 | Yes | 1.00 | 0.80 (0.43-1.48) | 0.86 (0.49-1.51) | 0.83 (0.53-1.30) |
Large cell carcinoma | Combined | 106 | Yes | 1.00 | 1.99 (0.73-5.41) | 0.84 (0.27-2.61) | 1.28 (0.56-2.91) |
Adenocarcinoma | Combined | 400 | Yes | 1.00 | 0.98 (0.68-1.42) | 0.95 (0.66-1.36) | 0.96 (0.73-1.28) |
Kaiser Permanente prospective study
Duration of mentholated cigarette use (years) | ||||||||
---|---|---|---|---|---|---|---|---|
0 | 1-9 | 10-19 | 20+ | Any | ||||
Gender | Age | No. of casesa
| Adjusted | RR | RR (CI) | RR (CI) | RR (CI) | RR (CI) |
Male | < 50 | 6 (3) | No | 1.0 | - | - | - | 2.2 (0.5-11.1) |
50-64 | 82 (24) | No | 1.0 | - | - | - | 1.1 (0.7-1.8) | |
65-74 | 60 (22) | No | 1.0 | - | - | - | 1.7 (1.0-2.9) | |
75+ | 20 (6) | No | 1.0 | - | - | - | 1.7 (0.6-4.3) | |
All | 168 (55) | Ageb
| 1.00 | - | - | - | 1.40 (1.01-1.94) | |
All | 160 (51)c
| Age, othersd
| 1.00 | - | - | - | 1.45 (1.03-2.02) | |
All | 158 (57)e
| Age, othersd
| 1.00 | 1.10 (0.65-1.87) | 1.32 (0.84-2.08) | 1.59 (0.96-2.63) | - | |
Female | < 50 | 11 (2) | No | 1.0 | - | - | - | 0.3 (0.1-1.6) |
50-64 | 61 (19) | No | 1.0 | - | - | - | 0.8 (0.5-1.4) | |
65-74 | 50 (10) | No | 1.0 | - | - | - | 0.6 (0.3-1.1) | |
75+ | 28 (7) | No | 1.0 | - | - | - | 0.9 (0.4-2.1) | |
All | 150 (38) | Ageb
| 1.00 | - | - | - | 0.71 (0.50-1.00) | |
All | 138 (34)c
| Age, othersd
| 1.00 | - | - | - | 0.75 (0.51-1.11) | |
All | 132 (42)c
| Age, othersd
| 1.00 | 0.72 (0.38-1.39) | 1.01 (0.61-1.69) | 0.70 (0.40-1.23) | - | |
Combined | < 50 | 17 (5) | Genderb
| 1.00 | - | - | - | 0.73 (0.26-2.04) |
50-64 | 143 (43) | Genderb
| 1.00 | - | - | - | 0.95 (0.67-1.35) | |
65-74 | 110 (32) | Genderb
| 1.00 | - | - | - | 1.12 (0.74-1.69) | |
75+ | 48 (13) | Genderb
| 1.00 | - | - | - | 1.17 (0.62-2.21) | |
All | 318 (93) | Gender, ageb
| 1.00 | - | - | - | 1.02 (0.80-1.29) | |
All | 298 (85)c
| Gender, age, othersb,d
| 1.00 | - | - | - | 1.09 (0.85-1.41) | |
All | 290 (99)c
| Gender, age, othersb,d
| 1.00 | 0.93 (0.62-1.40) | 1.17 (0.84-1.65) | 1.10 (0.76-1.60) | - |
Los Angeles County case-control study
Pack-years of mentholated smoking | |||||||
---|---|---|---|---|---|---|---|
Gender/Race | No of cases | 0 | 1-15 | 16-31 | 32+ | Anya
| |
Adjusted | RR | RR (CI) | RR (CI) | RR (CI) | RR (CI) | ||
Male/Both | 202 | No | 1.00 | 0.63 (0.42-0.95) | 1.40 (0.69-2.84) | 2.60 (1.33-5.08) | 0.92 (0.65-1.31) |
Age, raceb
| 1.00 | 0.62 (0.41-0.93) | 1.35 (0.67-2.73) | 2.52 (1.29-4.92) | 0.90 (0.64-1.28) | ||
Age, race and othersc
| 1.00 | 0.87 (0.57-1.37) | 1.21 (0.56-2.62) | 1.48 (0.71-3.05) | 1.00 (0.68-1.48) | ||
Female/Both | 135 | No | 1.00 | 0.90 (0.52-1.57) | 0.83 (0.36-1.96) | 0.90 (0.38-2.15) | 0.89 (0.55-1.44) |
Age, raceb
| 1.00 | 0.87 (0.50-1.52) | 0.68 (0.29-1.60) | 0.72 (0.30-1.71) | 0.80 (0.49-1.29) | ||
Age, race and othersc
| 1.00 | 1.58 (0.77-3.22) | 0.51 (0.19-1.34) | 0.41 (0.15-1.11) | 0.88 (0.50-1.57) | ||
Both/White peopled
| 181 | No | 1.00 | 0.64 (0.41-1.00) | 1.35 (0.58-3.11) | 1.80 (0.87-3.75) | 0.86 (0.59-1.26) |
Age, genderb
| 1.00 | 0.68 (0.44-1.06) | 1.41 (0.61-3.25) | 1.78 (0.86-3.70) | 0.90 (0.61-1.31) | ||
Age, gender and othersc
| 1.00 | 1.01 (0.61-1.68) | 1.01 (0.41-2.47) | 1.06 (0.47-2.36) | 1.02 (0.66-1.58) | ||
Both/Black peoplee
| 156 | No | 1.00 | 0.71 (0.43-1.16) | 0.91 (0.44-1.89) | 1.56 (0.72-3.37) | 0.85 (0.55-1.32) |
Age, genderb
| 1.00 | 0.66 (0.40-1.08) | 0.77 (0.37-1.60) | 1.46 (0.68-3.16) | 0.78 (0.51-1.21) | ||
Age, gender and othersc
| 1.00 | 0.96 (0.54-1.70) | 0.69 (0.30-1.60) | 0.90 (0.38-2.12) | 0.89 (0.53-1.47) | ||
Both/Both | 337 | No | 1.00 | 0.72 (0.52-1.00) | 1.20 (0.70-2.06) | 1.81 (1.07-3.07) | 0.93 (0.70-1.23) |
Age, race and genderb
| 1.00 | 0.70 (0.51-0.97) | 1.04 (0.61-1.79) | 1.64 (0.97-2.76) | 0.87 (0.66-1.15) | ||
Age, race, gender and othersc
| 1.00 | 1.05 (0.72-1.54) | 0.92 (0.50-1.68) | 0.95 (0.53-1.70)f
| 1.00 (0.72-1.40) |
Percentage of mentholated smoking | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Gender/Race | No of cases | 0 | 1-19 | 20-74 | 75-100 | Anya
| |||||
Adjusted | RR | RR (CI) | RR (CI) | RR (CI) | RR (CI) | ||||||
Both/Bothb
| 337 | No | 1.00 | 0.87 (0.59-1.29) | 0.84 (0.55-1.29) | 1.09 (0.73-1.63) | 0.93 (0.70-1.23) | ||||
Age, racec and gender | 1.00 | 0.94 (0.64-1.39) | 0.73 (0.48-1.12) | 0.94 (0.63-1.41) | 0.87 (0.66-1.15) | ||||||
Age, race, gender and othersd
| 1.00 | 1.11 (0.71-1.72) | 0.90 (0.55-1.45) | 1.02 (0.65-1.63) | 1.01 (0.74-1.40) |
Cigarette smoker type | ||||||
---|---|---|---|---|---|---|
Exclusive regular | Exclusive menthol | Mixed menthol/regular | Any menthola
| |||
Gender/Race | No of cases | Adjusted | RR | RR (CI) | RR (CI) | RR (CI) |
Both/Bothb
| 337 | No | 1.00 | 1.17 (0.74-1.85) | 0.86 (0.64-1.17) | 0.93 (0.70-1.23) |
Age, racec and gender | 1.00 | 1.10 (0.70-1.74) | 0.83 (0.61-1.13) | 0.89 (0.67-1.18) | ||
Age, race, gender and othersd
| 1.00 | 1.04 (0.62-1.75) | 1.01 (0.71-1.42) | 1.02 (0.74-1.40) |
Slone Epidemiology Center study
Years of use of mentholated cigarettes | ||||||
---|---|---|---|---|---|---|
Never | 1-15 | > 15 | Ever a
| |||
Gender/Race | No. of Cases | Adjusted | RR | RR (CI) | RR (CI) | RR (CI) |
Male/Both | 435 | Nob
| 1.00 | 0.58 (0.39-0.86) | 0.62 (0.42-0.93) | 0.60 (0.45-0.80) |
Age, racec
| 1.00 | 0.61 (0.41-0.90) | 0.71 (0.48-1.06) | 0.66 (0.49-0.88) | ||
Age, race and othersd
| 1.00 | 0.67 (0.43-1.05) | 0.91 (0.57-1.46) | 0.77 (0.55-1.08) | ||
Female/Both | 208 | Nob
| 1.00 | 0.67 0.42-1.09) | 0.75 (0.51-1.11) | 0.72 (0.52-1.00) |
Age, racec
| 1.00 | 0.76 (0.47-1.23) | 0.89 (0.60-1.32) | 0.84 (0.60-1.16) | ||
Age, race and othersd
| 1.00 | 1.14 (0.66-1.95) | 1.00 (0.63-1.60) | 1.05 (0.72-1.55) | ||
Both/White people | 515 | Nob
| 1.00 | 0.69 (0.49-0.98) | 0.71 (0.50-1.01) | 0.70 (0.54-0.91) |
Age, genderc
| 1.00 | 0.71 (0.50-1.01) | 0.87 (0.61-1.24) | 0.78 (0.60-1.01) | ||
Age, gender and othersd
| 1.00 | 0.86 (0.59-1.28) | 1.01 (0.68-1.51) | 0.93 (0.69-1.24) | ||
Both/Black people | 128 | Nob
| 1.00 | 0.40 (0.21-0.74) | 0.50 (0.32-0.79) | 0.46 (0.31-0.69) |
Age, genderc
| 1.00 | 0.52 (0.28-0.97) | 0.69 (0.44-1.09) | 0.63 (0.42-0.94) | ||
Age, gender and othersd
| 1.00 | 0.60 (0.27-1.35) | 1.21 (0.64-2.26) | 0.91 (0.52-1.59) | ||
Both/Both | 643 | Nob
| 1.00 | 0.59 (0.43-0.79) | 0.60 (0.46-0.79) | 0.59 (0.48-0.74) |
Age, race and genderc
| 1.00 | 0.65 (0.48-0.88) | 0.76 (0.58-1.00) | 0.70 (0.57-0.88) | ||
Age, race, gender and othersd
| 1.00 | 0.80 (0.57-1.13) | 0.97 (0.70-1.34) | 0.89 (0.69-1.14) |
Proportion of smoking history | |||||
---|---|---|---|---|---|
None | 1-49% | 50% | |||
Gender/Race | No. of cases | Adjusted | RR | RR (CI) | RR (CI) |
Both/Both | 642 | Noa
| 1.00 | 0.86 (0.62-1.18) | 0.49 (0.37-0.63) |
Age, race and genderb
| 1.00 | 0.81 (0.59-1.12) | 0.63 (0.48-0.82) | ||
Age, race, gender and othersc
| 1.00 | 0.86 (0.59-1.24) | 0.89 (0.65-1.22) |
Analysis | Adjusted | RR (CI) |
---|---|---|
In current smokers | Age, race, gender and othersa
| 0.90 (0.62-1.31) |
In smokers of filter cigarettes | Age, race, gender and othersa
| 0.95 (0.58-1.58) |
In smokers with full information on cigarette type | Age, race, gender and othersa
| 0.70 (0.38-1.29) |
Assuming smokers smoked mentholated cigarettes where brand history unknown | Age, race, gender and othersa
| 0.95b
|
Assuming proportion of menthol use same when brand history not known as when brand history is known | Age, race, gender and othersa
| 0.88b
|
Second American Health Foundation multicentre case-control study
Gender | Race | No. of cases | Adjusted | RR (CI) |
---|---|---|---|---|
Male | White people | 799 | Nonea
| 0.79 (0.61-1.01) |
Othersb
| 0.83 (0.63-1.09) | |||
Black people | 164 | Nonea
| 0.72 (0.46-1.11) | |
Othersb
| 1.34 (0.79-2.29) | |||
Combined | 963 | Nonea
| 0.80 (0.65-0.99) | |
Racea
| 0.77 (0.62-0.96) | |||
Race, othersa,b
| 0.92 (0.72-1.17) | |||
Female | White people | 701 | Nonea
| 0.50 (0.37-0.68) |
Othersb
| 0.61 (0.44-1.06) | |||
Black people | 102 | Nonea
| 0.66 (0.38-1.16) | |
Othersb
| 0.79 (0.41-1.54) | |||
Combined | 803 | Nonea
| 0.52 (0.40-0.67) | |
Racea
| 0.53 (0.41-0.70) | |||
Race, othersa,b
| 0.66 (0.46-0.95) | |||
Combined | White people | 1500 | Nonea
| 0.66 (0.54-0.80) |
Gendera
| 0.65 (0.54-0.79) | |||
Othersa,b
| 0.76 (0.60-0.96) | |||
Black people | 266 | Nonea
| 0.70 (0.49-0.98) | |
Gendera
| 0.70 (0.49-0.98) | |||
Othersa,b
| 1.09 (0.72-1.65) | |||
Combined | 1766 | Nonea
| 0.68 (0.57-0.80) | |
Gender, racea
| 0.66 (0.56-0.79) | |||
Gender, race, othersa,b
| 0.83 (0.68-1.02) |
German case-control study
Lung health prospective study
Houston case-control study
Smoking habits | Cases | Adjusted | RR (CI) |
---|---|---|---|
Current smokers | 278 | Nonea
| 0.63 (0.43-0.93) |
Age, gender | 0.69 (0.46-1.03) | ||
Former smokers | 176 | Nonea
| 0.76 (0.50-1.17) |
Age, gender | 0.99 (0.62-1.56) | ||
Current and former smokers | 454 | Nonea
| 0.72 (0.54-0.95) |
Smoking statusa
| 0.69 (0.52-0.91) | ||
Age, gender, smoking statusa
| 0.81 (0.60-1.09) |
Study characteristics, strengths and weaknesses
Characteristics | 1. American Health Foundation study | 2. Kaiser Permanente study | 3. Los Angeles County study | 4. Slone Epidemiology Center study |
---|---|---|---|---|
Source | Kabat and Hebert (1991) [68] | Sidney et al. (1995) [51] | Carpenter et al. (1999) [69] | Brooks et al. (2003) [53] |
Study design | Hospital case-control | Prospective cohort | Population case-control | Hospital case-control |
Location | USA; New York, Chicago, Detroit, Philadelphia | USA; Oakland, California | USA; Los Angeles County, California | USA; New York, Philadelphia, Massachusetts, Maryland |
Timing | 1985-1990 | 1979-1985 followed to 1991 | 1991-1994 | 1981-2000 |
Gender | Both | Both | Both | Both |
Age | Unrestricted | 30 to 89 years at baseline | 40 to 84 years | 40 to 74 years |
Smoking | Current smokers | Current smokers (for 20+ years) | Ever smoked | Ever smoked (for 20+ years) |
Other inclusion criteria | None stated | None stated | Caucasian (non-Hispanic) or African-American people; no previous cancer | Menthol details for 60% of smoking history; no history of cancer |
Cases | 1044 (588M, 456F) | 318 (168M, 150F) | 337 (202M, 135F) | 643 (435M, 208F) |
Cases in mentholated cig smokers | 259 | 93 | 151 | 114 |
Definition of cases | Histologically confirmed, interviewed within 2 months of diagnosis | Incident | Histologically confirmed, interviewed within 7 months of diagnosis | Confirmed by pathology, interviewed within 12 months of diagnosis |
At risk | Not applicable | 5771M, 5990F | Not applicable | Not applicable |
Controls | 1324 (914M, 410F) | Not applicable | 478 (349M, 129F) | 4110 (2123M, 1987F) |
Definition of controls | Diseases unrelated to smoking | Not applicable | Licensed drivers (age < 65) and Medicare beneficiaries (age 65+) | Diseases unrelated to smoking |
Matching of controls | Age, gender, race, hospital, date of interview | Not applicable | Age, gender, race | No matching |
Menthol variable | Time used (< 1, 1-14, 15+ yrs) | Time used (0, 1-9, 10-19, 20+ yrs) | Pack-years menthol (0, 1-15, 16-31, 32+), % menthol (0, 1-19, 20-74, 75-100), cig type (regular only, menthol only, mixed) | Time used (0, 1-15, > 15 years), % years smoked (0, 1-49, 50-100) |
Adjustment for race | Yes | Yes | Yes | Yes |
Adjustment for smoking habits | Cigs/day, inhalation, duration | Cigs/day, duration | Total pack-years, years since quitting | Cigs/day, duration, years since quitting, time used filter cigarettes |
Adjustment for other variables | Age, gender, education, body mass index | Age, gender, education | Age, gendera
| Age, gender, year of interview |
Results by histological type | Squamous cell, small cell, large cell, adenocarcinoma | No | No | No |
Study qualityb
| 5 | 9 | 7 | 6 |
Characteristics | 5. Second American Health Foundation study | 6. German study | 7. Lung Health study | 8. Houston study |
Source | Stellman et al. (2003) [83] | Jöckel et al. (2004) [84] | Murray et al. (2007) [56] | Etzel et al. (2008) [85] |
Study design | Hospital case-control | Population case-control | Prospective clinical trial | Population case-control |
Location | USA; New York, Chicago, Hines, Detroit, Philadelphia | Germany; location not known | USA and Canada; 10 centres | USA; Houston |
Timing | 1984-1998 | Not known | 1986-1989 followed for 14 years | 1995-2005 |
Gender | Both | Both | Both | Both |
Age | Unrestricted | Unrestricted | 35 to 60 years at baseline | Unrestricted |
Smoking | Current smokers | Ever smokersc
| Current smokers | Ever smokers |
Other inclusion criteria | None stated | None stated | Mild or moderate airways obstruction, no defined exclusiond
| Black people |
Cases | 1766 (963M, 803F) | 1004 (839M, 165F) | 240M+F | 454M+F |
Cases in mentholated cig smokers | 328 | 50 | About 50 | 198 |
Definition of cases | Histologically confirmed, interviewed within 12 months of diagnosis | Incident | Cause of death | Histologically confirmed, newly diagnosed, untreated, with no prior chemotherapy, radiotherapy or recent blood transfusion |
At risk | Not applicable | Not applicable | 3698M, 2185F | Not applicable |
Controls | 1670 (1098M, 572F) | 1004 (839M, 165F) | Not applicable | 353M+F |
Definition of controls | Diseases unrelated to smoking | Population | Not applicable | Population |
Matching of controls | Age, gender, hospital, year of interview | Age, gender, region | Not applicable | Age, gender, race |
Menthol variable | Preference for menthol | Ever smoked mentholated cigs | Smoked mentholated cigs at baseline | Used mentholated cigarettes |
Adjustment for race | Yes | Subjects White people | Yes | Subjects Black people |
Adjustment for smoking habits | Pack-years | Total amount smoked | Baseline cigs/day | Current/former |
Adjustment for other variables | Age, gender, body mass index, education | Age, gender, region | Age, gender, FEV1, randomization group, education | Age, gendere
|
Results by histological type | No | No | No | No |
Study qualityb
| 6 | 5 | 8 | 6 |
Characteristic | Level | N (%) | Characteristic | Level | N (%) |
---|---|---|---|---|---|
Study design | Cases in mentholated cigarette smokers | ||||
Prospective cohort | 2 (25.0) | 50-124 | 4 (50.0) | ||
Hospital case-control | 3 (37.5) | 125+ | 4 (50.0) | ||
Population case-control | 3 (37.5) | ||||
Controls matched on age and gender | |||||
Country | Yes | 5 (62.5) | |||
USA | 7 (87.5) | No | 1 (12.5) | ||
Germany | 1 (12.5) | Prospective | 2 (25.0) | ||
First year of study | Menthol dose-response studied | ||||
1979 to 1985 | 3 (37.5) | Yes | 4 (50.0) | ||
1986 to 1995 | 4 (50.0) | No | 4 (50.0) | ||
Not known | 1 (12.5) | ||||
Race accounted for | |||||
Year of publication | Yes | 8 (100.0) | |||
1991 to 2000 | 3 (37.5) | ||||
2001 to 2008 | 5 (62.5) | Smoking adjusted for | |||
Yes | 8 (100.0) | ||||
Genders studied | |||||
Both | 8 (100.0) | ||||
Age adjusted for | Yes | 8 (100.0) | |||
Smoking groups used in analysis | |||||
Current | 4 (50.0) | Results by histological type | Yes | 1 (12.5) | |
Ever | 4 (50.0) | No | 7 (87.5) | ||
Cases studied | |||||
200-499 | 4 (50.0) | NOS study quality score | 7 to 9 | 3 (37.5) | |
500-999 | 1 (12.5) | 5 to 6 | 5 (62.5) | ||
1000+ | 3 (37.5) |
Study type
Location
Timing
Possible overlaps between the studies
Number of cases and power to detect an effect
Adequacy of the cases
Adequacy of the controls
Reliability of the data collected
Study | Data collected |
---|---|
American Health Foundation study [68] | Subjects were asked about lifetime history of brands of cigarettes smoked (up to 7 brands per person) and information was obtained on whether all brands reported were mentholated or not. If the brand name could not be recalled, the mentholation status was recorded. |
Kaiser Permanente study [51] | Subjects were asked about the brand of the cigarette currently smoked and on whether the brand was mentholated or not. The authors did not report that they had obtained information on which brands were mentholated, or that they had checked one answer against the other. |
Los Angeles County study [69] | Mentholated cigarette use was based on the question "On average over your lifetime, out of every 100 cigarettes you smoked, how many were menthol?" |
Slone Epidemiology Center study [53] | Subjects were asked about the most recent brand and the brand used for the longest period of time to determine the brand name and whether it was mentholated or not. The consistency of the brand name and menthol status was not checked. In some analyses, cigarettes smoked prior to 1956 were assumed not to be mentholated. |
Second American Health Foundation study [83] | Details are not given in the methods, but the variable analyzed related to whether current smokers preferred mentholated cigarettes. |
German study [84] | Subjects were asked about their smoking history including brand names, with exposure to mentholated cigarettes derived from the brand names blinded for case-control studies. |
Lung Health study [56] | At baseline subjects were asked "Do you now smoke cigarettes?" followed by "What type of cigarettes are they? Are they plain or menthol?" Similar questions were asked at annual follow-ups but the answers were not used in the analyses related to risk of lung cancer. |
Houston study [85] | Smokers were asked to report their use of mentholated cigarettes, with ever use the endpoint used for analysis. |
Adjustment for potential confounding variables
Statistical methods used
Results by histological type
NOS study quality score
Meta-analysis of results for use of mentholated cigarettes
Use of mentholated cigarettes
RR (CI) | ||||||
---|---|---|---|---|---|---|
Study | Comparison | Males | Females | White people | Black people | Overall total |
American Health Foundation 1 [68] | Ever/never used M (in current smokers) | 1.06 (0.82-1.37) | 0.78 (0.57-1.08) | 0.94 (0.77-1.15) | ||
Kaiser Permanente [51] | Usual brand M or not (in current smokers for 20+ years) | 1.45 (1.03-2.02) | 0.75 (0.51-1.11) | 1.09 (0.85-1.41) | ||
Los Angeles [69] | Ever/never used M (in ever smokers) | 1.00 (0.68-1.48) | 0.88 (0.50-1.57) | 1.02 (0.66-1.58) | 0.89 (0.53-1.47) | 1.00 (0.72-1.40) |
Slone Epidemiology Center study [53] | Ever/never used M (in ever smokers) | 0.77 (0.55-1.08) | 1.05 (0.72-1.55) | 0.93 (0.69-1.24) | 0.91 (0.52-1.59) | 0.89 (0.69-1.14) |
American Health Foundation 2 [83] | Currently prefers/does not prefer M (in current smokers) | 0.92 (0.72-1.17) | 0.66 (0.46-0.95) | 0.76 (0.60-0.96) | 1.09 (0.72-1.65) | 0.83 (0.68-1.02) |
German [84] | Ever/never used M (in ever smokers) | 1.12 (0.68-1.83)c
| 1.12 (0.68-1.83) | |||
Lung Health [56] | Current brand M or not (in current smokers) | 0.96 (0.70-1.32) | ||||
Houston [85] | Ever/never used M (in ever smokers) | 0.81 (0.60-1.09)c
| 0.81 (0.60-1.09) | |||
(in current smokers) | 0.69 (0.46-1.03)c
| 0.69 (0.46-1.03) | ||||
(in former smokers) | 0.99 (0.62-1.56)c
| 0.99 (0.62-1.56) |
Number of Estimates | RR (95% CI) | Heterogeneity χ2(df), p | |||
---|---|---|---|---|---|
Fixed-effect | Random-effects | ||||
In ever smokers (or current smokers if not available)
| |||||
Overall | 8 | 0.93 (0.84-1.02) | 0.93 (0.84-1.02) | 4.43 (7), 0.73 | |
Study design | |||||
- prospective | 2 | 1.04 (0.85-1.26) | 1.04 (0.85-1.26) | 0.38 (1), 0.54 | |
- hospital case-control | 3 | 0.89 (0.78-1.00) | 0.89 (0.78-1.00) | 0.73 (2), 0.69 | |
- population case-control | 3 | 0.92 (0.76-1.13) | 0.92 (0.76-1.13) | 1.54 (2), 0.46 | |
NOS study quality score | |||||
- 7 to 9 | 3 | 1.03 (0.87-1.22) | 1.03 (0.87-1.22) | 0.41 (2), 0.84 | |
- 5 to 6 | 5 | 0.88 (0.79-0.99) | 0.88 (0.79-0.99) | 1.94 (4), 0.75 | |
Study size | |||||
- < 125 casesa
| 4 | 0.99 (0.85-1.15) | 0.99 (0.85-1.15) | 1.52 (3), 0.68 | |
- 125+ cases | 4 | 0.89 (0.79-1.00) | 0.89 (0.79-1.00) | 1.59 (3), 0.66 | |
Year of publication | |||||
- 1991 to 2000 | 3 | 1.00 (0.86-1.15) | 1.00 (0.86-1.15) | 0.81 (2), 0.67 | |
- 2001 to 2008 | 5 | 0.88 (0.77-0.99) | 0.88 (0.77-0.99) | 1.82 (4), 0.77 | |
Avoiding possible overlapb
| 6 | 0.93 (0.83-1.04) | 0.93 (0.83-1.04) | 4.31 (5), 0.51 | |
Males | 5 | 1.01 (0.88-1.15) | 1.01 (0.84-1.22) | 7.62 (4), 0.11 | |
Females | 5 | 0.80 (0.67-0.95) | 0.80 (0.67-0.95) | 3.25 (4), 0.52 | |
White people | 4 | 0.87 (0.75-1.03) | 0.87 (0.75-1.03) | 2.98 (3), 0.40 | |
Black people | 4 | 0.90 (0.73-1.10) | 0.90 (0.73-1.10) | 1.30 (3), 0.73 | |
In current smokers (or ever smokers if not available)
| |||||
Overall | 8 | 0.92 (0.84-1.02) | 0.92 (0.84-1.02) | 5.70 (7), 0.58 | |
Black people | 4 | 0.88 (0.70-1.10) | 0.88 (0.70-1.10) | 2.44 (3), 0.49 | |
In ever smokers specifically
| |||||
Overall | 4 | 0.91 (0.78-1.07) | 0.91 (0.78-1.07) | 1.60 (3), 0.66 | |
In current smokers specifically
| |||||
Overall | 5 | 0.91 (0.82-1.02) | 0.91 (0.81-1.03) | 4.76 (4), 0.31 | |
In former smokers specifically
| |||||
Total | 1 | 0.99 (0.62-1.56) | 0.99 (0.62-1.56) | - |
Meta-analysis of results for long-term use of mentholated cigarettes
RR (CI) | ||||||
---|---|---|---|---|---|---|
Study | Exposurec
| Males | Females | White people | Black people | Total |
American Health Foundation 1 [68] | 15+ years use of M (in current smokers) | 0.98 (0.70-1.38) | 0.76 (0.53-1.16) | 0.88 (0.68-1.14) | ||
Kaiser Permanente [51] | 20+ years use of M (in current smokers for 20+ years) | 1.59 (0.96-2.63) | 0.70 (0.40-1.23) | 1.10 (0.76-1.60) | ||
Los Angeles [69] | 32+ pack-years M (in ever smokers) | 1.48 (0.71-3.05) | 0.41 (0.15-1.11) | 1.06 (0.47-2.36) | 0.90 (0.38-2.12) | 0.95 (0.53-1.70) |
Slone Epidemiology Center study [53] | 15+ years of M (in ever smokers) | 0.91 (0.57-1.46) | 1.00 (0.63-1.60) | 1.01 (0.68-1.51) | 1.21 (0.64-2.26) | 0.97 (0.70-1.34) |
Number of Estimates | RR (95% CI) | Heterogeneity χ2(df), p | |||
---|---|---|---|---|---|
Fixed-effect | Random-effects | ||||
Overall | 4 | 0.95 (0.80-1.13) | 0.95 (0.80-1.13) | 0.95 (3), 0.81 | |
Males | 4 | 1.11 (0.88-1.39) | 1.13 (0.86-1.47) | 3.76 (3), 0.29 | |
Females | 4 | 0.78 (0.60-1.01) | 0.78 (0.60-1.01) | 2.84 (3), 0.42 | |
White people | 2 | 1.02 (0.71-1.46) | 1.02 (0.71-1.46) | 0.01 (1), 0.92 | |
Black people | 2 | 1.09 (0.66-1.81) | 1.09 (0.66-1.81) | 0.30 (1), 0.59 |
Can mentholation explain the higher lung cancer risk in US Black people?
Never smoked | Ex smoker | Current smoker | Total | ||||||
---|---|---|---|---|---|---|---|---|---|
Total | Total | Menthol | Non-menthol | Total | Menthol | Non-menthol | Total | ||
(1) | (2) | (3) | (4) | (5) | |||||
White people
| |||||||||
Frequency1
| 0.501 | 0.262 | 0.237 | 1.000 | |||||
Menthol proportionb
| 0.218 | 0.782 | 0.218 | 0.782 | |||||
(a) | Frequency by menthol | 0.501 | 0.057 | 0.205 | 0.052 | 0.185 | 1.000 | ||
(b) | Risk relative to never smokersc
| 1.00 | 9.36 | 9.36RR | 9.36 | 22.36 | 22.36RR | 22.36 | |
Black people
| |||||||||
Frequency1
| 0.572 | 0.158 | 0.270 | 1.000 | |||||
Menthol proportionb
| 0.835 | 0.165 | 0.835 | 0.165 | |||||
(a) | Frequency by menthol | 0.572 | 0.132 | 0.026 | 0.225 | 0.045 | 1.000 | ||
(b) | Risk relative to never smokersc
| 1.00 | 9.36 | 9.36RR | 9.36 | 22.36 | 22.36RR | 22.36 | |
Assumed value of RR | Black/White relative riskd
| ||||||||
1.0 | 0.980 | ||||||||
1.1 | 1.035 | ||||||||
1.2 | 1.088 | ||||||||
1.3 | 1.138 | ||||||||
1.5 | 1.234 | ||||||||
1.8 | 1.365 | ||||||||
2.0 | 1.445 |