Journal of Cancer Epidemiology

Review Article

Smokeless Tobacco and Oral Cancer in South Asia: A Systematic Review with Meta-Analysis

Table 2

Epidemiological studies of chewing tobacco and oral cancer.


Authors	OR (95% CI)	Men OR (95% CI)	Women OR (95% CI)	Frequency/day**			Duration of use in years***
Authors	OR (95% CI)	Men OR (95% CI)	Women OR (95% CI)	Tobacco ≤ 5 OR (95% CI)	Tobacco 6–10 OR (95% CI)	Tobacco > 10/OR (95% CI)	Tobacco ≤ 10 yrs/OR (95% CI)	Tobacco 11–20 yrs/OR (95% CI)	Tobacco > 20 yrs/OR (95% CI)

Goud et al. [32]	8.5 (4.3–16.5)	n/a	n/a	8.2 (3.0–22.3)	4.7 (2.0–10.7)	18.4*	n/a	4.2*	10.2*
Nandakumar et al. [33]	12.9 (7.5–22.3)	3.6 (1.7–7.9)	25.3 (11.2–57.3)	9.3 (4.9–17.5)	12.8 (6.6–25.0)	16.6 (6.3–44.3)	n/a	n/a	n/a
Rao et al. [34]	3.6 (2.5–5.6)	3.6 (2.5–5.6)	n/a	n/a	2.8 (2.2–3.5)⁺	3.8*	1.2 (0.9–1.8)	3.9 (2.7–5.7)	4.1*
Khan et al. [35]	2.3 (0.7–7.4)	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Wasnik et al. [36]	7.9 (4.1–13.5)	n/a	n/a	2.1*	8.1 (3.7–17.9)	20.0 (8.1–48.9)	n/a	n/a	10.9 (5.9–20.0)
Dikshit and kanhere [37]	5.8 (3.6–9.5)	5.8 (3.6–9.5)	n/a	2.0 (1.0–3.8)	6.7 (3.7–12.1)	13.9 (7.1–27.2)	n/a	n/a	n/a
Znaor et al. [40]	5.0 (4.2–5.9)	5.0 (4.2–5.9)	n/a	5.0*	11.9 (8.9–15.9)⁺⁺	n/a	n/a	3.1 (2.5–3.8)⁺⁺⁺	9.5*
Gangane et al. [42]	10.0 (6.7–14.8)	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Subapriya et al. [41]	2.9*	n/a	n/a	n/a	n/a	n/a	2.9*	2.5*	2.7*
Basu et al. [43]	2.0 (0.9–4.4)	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Jayalekshmi et al. [45]	5.5 (3.3–9.0)	n/a	5.5 (3.3–9.0)	3.3 (1.7–6.4)	7.8 (4.4–13.9)	9.2 (4.5–18.7)	n/a	n/a	n/a
Jayalekshmi et al. [46]	5.4 (3.0–9.0)	5.4 (3.0–9.0)	n/a	1.9 (1.2–2.8)	n/a	n/a	n/a	n/a	n/a
Pednekar et al. [47]	1.4 (1.0–2.1)****	1.4 (1.0–2.1)	n/a	1.1 (0.9–1.4)	1.1 (0.9–1.4)	n/a	0.8 (0.4–1.7)	1.0 (0.7–1.4)	1.1 (1–1.4)
Madani et al. [48]	8.3 (5.4–13.0)	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Ray et al. [49]	3.9 (2.4–6.1)	2.8 (1.5–5.1)	6.4 (3.2–12.7)	n/a	n/a	n/a	n/a	n/a	n/a

OR: odds ratio, CI: confidence interval, *95% CI not reported and/or could not be calculated, **daily frequency in number of times tobacco is chewed in a day, ***total duration of habit in “years,” ****for cancer of lip, oral cavity, and pharynx only, n/a: not available, ⁺1–10/day, ⁺⁺>5/day, ⁺⁺⁺0–19 years, and nonchewers taken as reference category. Frequency/intensity OR are for both genders.