Table 5.
Odds ratios (ORs)a,b for laryngeal cancer and corresponding confidence intervals (95% CIs) on non-alcohol energy-adjusted vitamin C intake quintiles, in strata of selected covariates. International Head and Neck Cancer Epidemiology (INHANCE) consortium.
| II Quintile OR (95% CI) |
III Quintile OR (95% CI) |
IV Quintile OR (95% CI) |
V Quintile OR (95% CI) |
pstudiesc | |
|---|---|---|---|---|---|
| Age (years) | |||||
| <55 | 0.63 (0.44–0.92) | 0.44 (0.28–0.70) | 0.39 (0.25–0.61) | 0.48 (0.32–0.71) | 0.281 |
| ≥ 55 | 0.62 (0.43–0.88) | 0.55 (0.39–0.78) | 0.52 (0.41–0.67) | 0.53 (0.39–0.72) | < 0.001 |
| pstratad | 0.729 | ||||
| Sex | |||||
| Female | 0.76 (0.47–1.24) | 0.57 (0.34–0.95) | 0.42 (0.23–0.77) | 0.69 (0.35–1.34) | 0.002 |
| Male | 0.60 (0.41–0.86) | 0.52 (0.39–0.70) | 0.48 (0.39–0.61) | 0.48 (0.38–0.62) | 0.002 |
| pstratad | 0.716 | ||||
| Education | |||||
| ≤high school graduate | 0.56 (0.38–0.82) | 0.47 (0.32–0.70) | 0.53 (0.34–0.82) | 0.48 (0.35–0.67) | < 0.001 |
| ≥some college | 0.78 (0.52–1.17) | 0.57 (0.32–1.02) | 0.53 (0.35–0.80) | 0.58 (0.38–0.90) | 0.119 |
| pstratad | 0.325 | ||||
| Geographic regione | |||||
| Europe | 0.55 (0.33–0.9) | 0.36 (0.24–0.54) | 0.33 (0.24–0.44) | 0.36 (0.21–0.63) | < 0.001 |
| America | 0.80 (0.54–1.20) | 0.91 (0.68–1.22) | 0.76 (0.56–1.02) | 0.77 (0.57–1.04) | 0.459 |
| Asia | 0.82 (0.39–1.75) | 1.54 (0.81–2.92) | 0.50 (0.22–1.14) | 1.35 (0.67–2.69) | NE |
| pstratad | 0.006 | ||||
| Body mass index | |||||
| <25 kg/m2 | 0.71 (0.53–0.97) | 0.52 (0.34–0.79) | 0.38 (0.25–0.60) | 0.47 (0.3–0.74) | 0.005 |
| ≥25 kg/m2 | 0.60 (0.39–0.90) | 0.50 (0.33–0.75) | 0.57 (0.41–0.79) | 0.52 (0.34–0.79) | < 0.001 |
| pstratad | 0.210 | ||||
| Tobacco consumption | |||||
| Never user | 0.45 (0.18–1.08) | 0.38 (0.15–0.98) | 0.60 (0.27–1.34) | 0.68 (0.32–1.46) | 0.185 |
| Former user | 0.58 (0.41–0.82) | 0.64 (0.43–0.96) | 0.43 (0.29–0.62) | 0.66 (0.47–0.92) | 0.144 |
| Current user | 0.55 (0.41–0.73) | 0.59 (0.39–0.90) | 0.49 (0.35–0.68) | 0.55 (0.41–0.72) | < 0.001 |
| pstratad | 0.845 | ||||
| Alcohol consumptionf | |||||
| Never/light drinker | 0.65 (0.39–1.09) | 0.72 (0.45–1.16) | 0.61 (0.43–0.87) | 0.76 (0.54–1.08) | 0.227 |
| Moderate drinker | 0.51 (0.31–0.84) | 0.38 (0.24–0.61) | 0.43 (0.30–0.61) | 0.39 (0.28–0.54) | 0.004 |
| Heavy drinker | 0.55 (0.37–0.81) | 0.43 (0.28–0.65) | 0.35 (0.22–0.54) | 0.38 (0.25–0.59) | 0.831 |
| pstratad | 0.308 | ||||
| Tobacco and alcohol consumption combinedf | |||||
| Never/former user -Never/light drinker | 0.61 (0.34–1.06) | 0.53 (0.28–0.99) | 0.40 (0.23–0.71) | 0.71 (0.44–1.16) | 0.043 |
| Current user- Never/light drinker | 0.58 (0.31–1.09) | 0.73 (0.39–1.38) | 0.62 (0.39–0.99) | 0.79 (0.49–1.28) | 0.100 |
| Never/former user -Moderate drinker | 0.49 (0.28–0.86) | 0.55 (0.27–1.12) | 0.59 (0.34–1.00) | 0.63 (0.38–1.06) | 0.011 |
| Current user -Moderate drinker | 0.47 (0.31–0.72) | 0.41 (0.23–0.73) | 0.40 (0.24–0.66) | 0.42 (0.22–0.84) | <0.001 |
| Never/former user - Heavy drinker | 0.52 (0.29–0.94) | 0.49 (0.27–0.92) | 0.24 (0.11–0.51) | 0.55 (0.29–1.06) | 0.626 |
| Current user -Heavy drinker | 0.57 (0.34–0.95) | 0.70 (0.33–1.46) | 0.47 (0.20–1.08) | 0.48 (0.26–0.90) | 0.024 |
| pstratad | 0.907 | ||||
ABBREVIATIONS: MSKCC: Memorial Sloan Kettering Cancer Center; NE: Not estimable.
Estimated from multiple logistic regression models adjusted for age, sex, education, race/ethnicity, study center, cigarette smoking status, cigarette intensity, cigarette duration, cigar smoking status, pipe smoking status, alcohol drinking intensity and the interaction between cigarette intensity and alcohol drinking intensity, when appropriate.
The I Quintile category was considered as the reference one.
P for heterogeneity among studies. When the p-value was less than 0.1 within strata, we reported the mixed-effects estimates derived from the corresponding generalized linear mixed model.
P for heterogeneity across strata. When, for a single stratification variable, fixed- and mixed-effects models were estimated within different strata, likelihood ratio tests for heterogeneity across strata were based on comparable mixed-effects models and therefore we re-fitted one or more mixed-effects models to replace the original fixed-effects ones. We consistently reported the corresponding stratum-specific mixed-effects models instead of the fixed-effects ones.
Europe included Italy Multicenter, Switzerland and Milan (2006–2009) studies. North America included Boston, Buffalo, Los Angeles, MSKCC, North Carolina (2002–2006), and US Multicenter studies. Asia included Japan study only. As Asia included Japan study only, there was no possibility to assess heterogeneity among studies in the Asia stratum.
The never/light drinker category included never drinkers and subjects who drinks less than 1 drink per day; the moderate drinker category included subjects drinking between 1 (included) and 5 drinks per day; the heavy drinker category included subjects drinking 5 drinks per day or more.