Non-Cochrane · aetiology · PM41640576

Smoking and oral and pharyngeal cancer: a meta-analysis.

Possenti Irene, Miotti Stefano, Gallus Silvano, et al. · Oncology reviews · 2025 · PubMed · doi:10.3389/or.2025.1672607

Findings

127 findings

Population
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: middle or low income	RR 4.47 [2.48, 8.05] GRADE not reported 8 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal squamous cell carcinoma risk Case-control and cohort studies worldwide · Overall	RR 3.31 [2.07, 5.30] GRADE not reported 11 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: case-control	RR 3.82 [2.99, 4.89] GRADE not reported 36 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 126-374	RR 4.00 [2.89, 5.54] GRADE not reported 17 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: high (NOS 7 or more)	RR 3.70 [3.00, 4.58] GRADE not reported 11 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: hospital (case-control studies)	RR 3.93 [2.83, 5.46] GRADE not reported 21 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: women	RR 2.77 [1.89, 4.07] GRADE not reported 16 studies
General population	Current cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 5.15 [3.09, 8.57] GRADE not reported Studies not reported
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: adequate	RR 3.68 [2.93, 4.62] GRADE not reported 34 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Asia	RR 2.26 [1.91, 2.67] GRADE not reported 14 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Oceania	RR 6.44 [0.54, 76.97] GRADE not reported 2 studies
General population	Current cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 4.24 [2.96, 6.09] GRADE not reported 18 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Europe	RR 3.59 [2.63, 4.89] GRADE not reported 19 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 375 or more	RR 3.89 [2.82, 5.11] GRADE not reported 15 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Overall	RR 3.58 [3.03, 4.24] GRADE not reported 54 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: <126	RR 3.11 [2.38, 4.06] GRADE not reported 20 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: incidence (cohort studies)	RR 3.00 [2.35, 3.82] GRADE not reported 9 studies
General population	Current cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 3.52 [2.28, 5.43] GRADE not reported Studies not reported
General population	Current cigarette smokers	Never smokers	Hypopharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 4.21 [0.78, 22.59] GRADE not reported 2 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: low (NOS <7)	RR 3.64 [2.94, 4.50] GRADE not reported 43 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Africa Unresolved: the two extractors disagree on this row.	RR 4.63 [1.74, 12.31] GRADE not reported 1 study
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: high income	RR 3.60 [3.01, 4.31] GRADE not reported 42 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: South America	RR 10.02 [6.68, 15.03] GRADE not reported 3 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2010 or later	RR 4.06 [3.11, 5.23] GRADE not reported 15 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: non-adjusted (Asian studies)	RR 2.26 [1.91, 2.68] GRADE not reported 9 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: before 2000	RR 3.41 [2.49, 4.66] GRADE not reported 15 studies
General population	Current cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 3.37 [2.68, 4.24] GRADE not reported Studies not reported
General population	Current cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 3.39 [2.64, 4.35] GRADE not reported 25 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: mortality (cohort studies)	RR 3.51 [2.53, 4.86] GRADE not reported 9 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: adjusted (Asian studies)	RR 2.45 [1.31, 4.59] GRADE not reported 5 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: cohort	RR 3.29 [2.68, 4.05] GRADE not reported 18 studies
General population	Current cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.90 [2.39, 6.37] GRADE not reported Studies not reported
General population	Current cigarette smokers	Never smokers	Oropharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.20 [2.25, 4.55] GRADE not reported 5 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: men	RR 2.98 [2.27, 3.89] GRADE not reported 22 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: population (case-control studies)	RR 3.59 [2.23, 5.78] GRADE not reported 11 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2000-2009	RR 3.35 [2.50, 4.49] GRADE not reported 23 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: non-adequate	RR 3.42 [2.67, 4.38] GRADE not reported 20 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: North America	RR 5.01 [3.96, 6.35] GRADE not reported 11 studies
General population	Current cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sensitivity: trim-and-fill adjusted for publication bias	RR 3.00 [2.48, 3.63] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Europe	RR 1.59 [1.24, 2.04] GRADE not reported 18 studies
General population	Former cigarette smokers	Never smokers	Hypopharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 1.80 [0.20, 16.00] GRADE not reported 2 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: population (case-control studies)	RR 1.35 [1.04, 1.75] GRADE not reported 10 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: high (NOS 7 or more)	RR 1.47 [1.20, 1.79] GRADE not reported 12 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: middle or low income	RR 2.38 [1.51, 3.77] GRADE not reported 8 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sensitivity: trim-and-fill adjusted for publication bias	RR 1.44 [1.25, 1.66] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: South America	RR 2.91 [1.44, 5.88] GRADE not reported 3 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: North America	RR 1.60 [1.35, 1.90] GRADE not reported 14 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: <126	RR 1.59 [1.06, 2.38] GRADE not reported 17 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: hospital (case-control studies)	RR 1.90 [1.55, 2.32] GRADE not reported 26 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: non-adequate	RR 1.49 [1.23, 1.80] GRADE not reported 17 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: adjusted (Asian studies)	RR 1.36 [0.87, 2.12] GRADE not reported 4 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal squamous cell carcinoma risk Case-control and cohort studies worldwide · Overall	RR 1.86 [1.16, 2.99] GRADE not reported 9 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: low (NOS <7)	RR 1.67 [1.45, 1.92] GRADE not reported 41 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2000-2009	RR 1.74 [1.35, 2.25] GRADE not reported 21 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Oceania	RR 1.93 [0.33, 11.42] GRADE not reported 2 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Africa Unresolved: the two extractors disagree on this row.	RR 3.57 [1.30, 9.83] GRADE not reported 1 study
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: women	RR 1.50 [1.17, 1.93] GRADE not reported 14 studies
General population	Former cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 1.34 [1.08, 1.67] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: case-control	RR 1.68 [1.44, 1.95] GRADE not reported 38 studies
General population	Former cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 1.66 [1.03, 2.67] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 1.48 [1.18, 1.86] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2010 or later	RR 1.70 [1.42, 2.04] GRADE not reported 15 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: before 2000	RR 1.44 [1.19, 1.74] GRADE not reported 17 studies
General population	Former cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 2.06 [1.36, 3.13] GRADE not reported Studies not reported
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: high income	RR 1.54 [1.37, 1.73] GRADE not reported 43 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: men	RR 1.28 [1.00, 1.65] GRADE not reported 20 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: mortality (cohort studies)	RR 1.89 [1.63, 2.20] GRADE not reported 6 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Asia	RR 1.41 [1.12, 1.78] GRADE not reported 12 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 375 or more	RR 1.49 [1.27, 1.76] GRADE not reported 19 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 126-374	RR 1.89 [1.62, 2.22] GRADE not reported 16 studies
General population	Former cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 1.41 [1.20, 1.66] GRADE not reported 23 studies
General population	Former cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 1.94 [1.41, 2.67] GRADE not reported 18 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: cohort	RR 1.48 [1.25, 1.76] GRADE not reported 15 studies
General population	Former cigarette smokers	Never smokers	Oropharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 2.31 [1.26, 4.23] GRADE not reported 4 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: non-adjusted (Asian studies)	RR 1.47 [1.11, 1.94] GRADE not reported 8 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: incidence (cohort studies)	RR 1.14 [0.99, 1.31] GRADE not reported 9 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Overall	RR 1.61 [1.44, 1.81] GRADE not reported 53 studies
General population	Former cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: adequate	RR 1.68 [1.45, 1.94] GRADE not reported 36 studies
General population	Ever cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 2.26 [1.91, 2.68] GRADE not reported Studies not reported
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Europe	RR 2.58 [1.88, 3.55] GRADE not reported 18 studies
General population	Ever cigarette smokers	Never smokers	Oropharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 2.94 [2.02, 4.29] GRADE not reported 12 studies
General population	Ever cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.28 [1.96, 5.49] GRADE not reported Studies not reported
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sensitivity: trim-and-fill adjusted for publication bias	RR 1.98 [1.73, 2.27] GRADE not reported Studies not reported
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: low (NOS <7)	RR 2.48 [2.16, 2.85] GRADE not reported 62 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: women	RR 2.05 [1.51, 2.77] GRADE not reported 17 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 126-374	RR 2.29 [1.86, 2.82] GRADE not reported 29 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: <126	RR 2.34 [1.86, 2.94] GRADE not reported 27 studies
General population	Ever cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.25 [2.46, 4.29] GRADE not reported Studies not reported
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · HPV serology: positive	RR 1.35 [0.90, 2.02] GRADE not reported 4 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: non-adjusted (Asian studies)	RR 2.20 [1.76, 2.77] GRADE not reported 20 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: case-control	RR 2.55 [2.21, 2.94] GRADE not reported 62 studies
General population	Ever cigarette smokers	Never smokers	Pharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.25 [2.56, 4.14] GRADE not reported 30 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Sex: men	RR 2.47 [1.91, 3.19] GRADE not reported 29 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: incidence (cohort studies)	RR 1.83 [1.54, 2.17] GRADE not reported 13 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Endpoint: mortality (cohort studies)	RR 2.69 [2.13, 3.40] GRADE not reported 6 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · HPV serology: negative	RR 3.28 [1.77, 6.08] GRADE not reported 4 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2000-2009	RR 2.48 [1.96, 3.13] GRADE not reported 23 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: middle or low income	RR 2.38 [1.86, 3.05] GRADE not reported 26 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Oceania	RR 3.87 [0.38, 39.30] GRADE not reported 2 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: 2010 or later	RR 2.43 [2.09, 2.83] GRADE not reported 33 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: hospital (case-control studies)	RR 2.47 [2.03, 3.00] GRADE not reported 33 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of study: cohort	RR 2.15 [1.81, 2.54] GRADE not reported 18 studies
General population	Ever cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 2.18 [1.89, 2.52] GRADE not reported 47 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Overall	RR 2.45 [2.19, 2.75] GRADE not reported 80 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Number of cases: 375 or more	RR 2.92 [2.42, 3.51] GRADE not reported 21 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Year of publication: before 2000	RR 2.46 [1.91, 3.17] GRADE not reported 24 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustment for betel quid or tobacco chewing: adjusted (Asian studies)	RR 2.53 [1.95, 3.28] GRADE not reported 14 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Africa	RR 2.19 [0.88, 5.45] GRADE not reported 3 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Study quality: high (NOS 7 or more)	RR 2.32 [1.94, 2.78] GRADE not reported 16 studies
General population	Ever cigarette smokers	Never smokers	Oral cavity cancer risk Case-control and cohort studies worldwide · Overall	RR 1.92 [1.54, 2.39] GRADE not reported Studies not reported
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: North America	RR 2.47 [2.06, 2.96] GRADE not reported 15 studies
General population	Ever cigarette smokers	Never smokers	Hypopharyngeal cancer risk Case-control and cohort studies worldwide · Overall	RR 3.95 [2.56, 6.08] GRADE not reported 8 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: Asia	RR 2.33 [1.97, 2.77] GRADE not reported 34 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: non-adequate	RR 2.40 [2.01, 2.86] GRADE not reported 38 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal squamous cell carcinoma risk Case-control and cohort studies worldwide · Overall	RR 2.28 [1.71, 3.03] GRADE not reported 17 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Adjustments: adequate	RR 2.46 [2.13, 2.84] GRADE not reported 42 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Income group: high income	RR 2.46 [2.16, 2.79] GRADE not reported 52 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Geographic area: South America	RR 5.12 [2.85, 9.19] GRADE not reported 4 studies
General population	Ever cigarette smokers	Never smokers	Oral and pharyngeal cancer (OPC) risk Case-control and cohort studies worldwide · Type of controls: population (case-control studies)	RR 2.72 [2.03, 3.66] GRADE not reported 22 studies
General population (adults)	Current cigarette smoking by intensity (cigarettes per day)	Never cigarette smokers	Oral and pharyngeal cancer 20 cigarettes/day	RR 4.78 [3.64, 6.27] GRADE not reported 20 studies
General population (adults)	Current cigarette smoking by intensity (cigarettes per day)	Never cigarette smokers	Oral and pharyngeal cancer 10 cigarettes/day	RR 2.88 [2.37, 3.50] GRADE not reported 20 studies
General population (adults)	Current cigarette smoking by intensity (cigarettes per day)	Never cigarette smokers	Oral and pharyngeal cancer 6 cigarettes/day	RR 1.98 [1.74, 2.25] GRADE not reported 20 studies
General population (adults)	Current cigarette smoking by duration (years)	Never cigarette smokers	Oral and pharyngeal cancer 20 years	RR 5.10 [3.27, 7.96] GRADE not reported 10 studies
General population (adults)	Current cigarette smoking by duration (years)	Never cigarette smokers	Oral and pharyngeal cancer 7 years	RR 2.01 [1.62, 2.51] GRADE not reported 10 studies
General population (adults)	Current cigarette smoking by duration (years)	Never cigarette smokers	Oral and pharyngeal cancer 10 years	RR 2.64 [1.96, 3.57] GRADE not reported 10 studies
General population (adults)	Former cigarette smoking by time since quitting (years)	Current cigarette smokers	Oral and pharyngeal cancer 10 years since quitting	RR 0.51 [0.42, 0.64] GRADE not reported 22 studies
General population (adults)	Former cigarette smoking by time since quitting (years)	Current cigarette smokers	Oral and pharyngeal cancer 18 years since quitting	RR 0.21 [0.17, 0.33] GRADE not reported 22 studies

Included primary studies 101

Open in Studies

Study	Year	Also included by	Outcomes it informs here	Trial data
Werbrouck 2008 matched by author and year (probable)	NR	1 other review	not stated	not extracted yet
Yang 2014 matched by author and year (probable)	NR	1 other review	not stated	not extracted yet
Yang 2023 matched by author and year (probable)	NR	1 other review	not stated	not extracted yet
Zeng 2019 matched by author and year (probable)	NR	1 other review	not stated	not extracted yet
Adeyemi 2011 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Agudo 2012 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Akiba 1990 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Akiba 1994 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Anantharaman 2016 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Ansary-Moghadda 2009 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Applebaum 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Balaram 2002 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Berthiller 2016 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Blakely 2013 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Blot 1988 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Bundgaard 1995 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Carter 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Castellsague 2004 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Chandran 2005 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Chen 2001 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Choi 1991 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Christensen 2018 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Coleman 2020 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
D'Souza 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
De Stefani 1994 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
De Stefani 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Dikshit 2000 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Escribano Uzcudun 2002 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Franceschi 1990 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Freedman 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Freedman 2016 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Friborg 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Gallus 2003 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Garrote 2001 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Ghani 2019 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Gholap 2023 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Gunasekera 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Hashibe 2009 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Hayes 1999 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Horn-Ross 1997 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Hung 1997 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Ishan 2011 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Jacob 2018 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Jussawalla 1971 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Kabat 1989 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Kabat 1994 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Katanoda 2008 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Katoh 1999 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Kune 1993 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
La Vecchia 1990 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
La Vecchia 1999 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Lakhanpal 2014 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Liaw 1998 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Lissowska 2003 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Llewellyn 2004 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Maasland 2014 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Madani 2010 PMID:20105913	NR	this review only	not stated	not extracted yet
Mahapatra 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Marques 2008 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Marron 2010 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Marshall 1992 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Martinez 1969 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Maurya 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
McLaughlin 1995 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Merletti 1989 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Mezzoiuso 2021 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Morales 2020 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Moreno-Lopez 2000 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Muwonge 2008 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Naghibzadeh-Tahami 2024 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Nandakumar 1990 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Nordlund 1997 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Offermans 2014 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Oudjehih 2020 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Pednekar 2011 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Radoi 2013 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Radoi 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Rodriguez 2004 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Saito 2013 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Sankaranarayanan 1989 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Sapkota 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Schildt 1998 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Schlecht 1999 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Shewale 2021 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Smith 1998 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Smith 2010 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Subapriya 2007 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Sugimura 2006 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Szymanska 2011 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Takezaki 1996 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Takezaki 2000 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Toporcov 2015 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Tuyns 1988 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Varela-Lema 2010 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Vlajinac 2006 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Wang 2005 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Wasnik 1998 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Winn 1981 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Zavras 2001 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Zheng 1990 matched by author and year (probable)	NR	this review only	not stated	not extracted yet
Znaor 2003 matched by author and year (probable)	NR	this review only	not stated	not extracted yet

Overlap with other reviews

Reviews that include the same primary studies are not independent evidence. Shared counts match studies by PMID, DOI or NCT, and otherwise by author and year (a probable match). Only the non-Cochrane dental reviews have study lists, so overlap with Cochrane reviews is not counted yet.

Review	Shared studies	Jaccard
Relationship between preterm, low birth weight and early childhood caries: a meta-analysis of the case-control and cross-sectional study. (2020)	1	0.01
The Efficacy and Safety of Nutritional Supplements for Cancer Supportive Care: An Umbrella Review and Hierarchical Evidence Synthesis. (2026)	1	0.01
Assessment of genetic susceptibility in patients with oral squamous cell carcinoma: a systematic review and meta-analysis. (2026)	1	0.00
Adverse effects of removable orthodontic aligners: A systematic review with single-arm meta-analysis. (2026)	1	0.01

Review question

Element	Planned (methods)	Found (results)
Population	General population	General population in 115 studies (87 case-control, 28 cohort; over 40,000 cases)
Intervention	Cigarette smoking (current, former, ever; intensity, duration, time since quitting)	Current (n=54), former (n=53) and ever (n=80) cigarette smoking; intensity (n=43), duration (n=30), time since quitting (n=22)
Comparison	Never cigarette smokers (current smokers for time since quitting)	Never smokers; current smokers for time since quitting
Outcomes	Oral cavity and pharyngeal (excluding nasopharyngeal) cancer risk	Oral and pharyngeal cancer (64 studies oral cancer, 49 pharyngeal cancer, 36 combined only)
Study designs	Case-control and cohort studies	87 case-control and 28 cohort studies, 1969 to 2024
Timing	Not specified	Not specified