Table 3.

Results From Modeling^a of Excess Odd Ratios for Cancers of the Oral Cavity, Pharynx, and Larynx According to Alcohol Consumption (Drink-Years and Drinks/Day), by Body Mass Index Category, Derived Using Case-Control Data From the International Head and Neck Cancer Epidemiology Consortium

Variable	Oral Cavity and Pharyngeal Cancer Cases and Controls					Laryngeal Cancer Cases and Controls
	Parameter Estimate		Effect Modification by BMIb			Parameter Estimate		Effect Modification by BMI
	βf	φ1f	BMI Times:c	ΔDeviance (no.)d	P Valuee	βf	φ1f	BMI Times:c	ΔDeviance (no.)d	P Valuee
Never Drinkers and Consumers of ≤10 Drinks/Day
Total	0.0113	0.248				0.0004	1.440
BMI
<18.5	0.0033	1.761	Both	0 (8)		4.54 × 10−5f	3.110	Both	0 (8)
18.5–24.9	0.0189	0.177	Drinks/day	14.0 (5)	<0.01	9.65 × 10−5	2.045	Drinks/day	12.5 (5)	0.01
25.0–29.9	0.0058	0.448	Drink-years	9.3 (5)	0.03	0.0005	1.342	Drink-years	12.8 (5)	0.01
≥30	0.0055	0.116	None	58.9 (2)	<0.01	0.0024	0.688	None	15.1 (2)	0.02
BMI (omitting <18.5)
18.5–24.9	0.0182	0.202	Both	0 (6)		0.0001	2.011	Both	0 (6)
25.0–29.9	0.0059	0.447	Drinks/day	11.4 (4)	<0.01	0.0005	1.330	Drinks/day	2.2 (4)	0.33
≥30	0.0055	0.126	Drink-years	1.6 (4)	0.46	0.0024	0.681	Drink-years	1.8 (4)	0.42
			None	43.5 (2)	<0.01			None	2.8 (2)	0.59
Never Drinkers and Consumers of ≤5 Drinks/Day
Total	0.0127	0.192				0.0007	0.946
BMI
<18.5	0.0122	0.657	Both	0 (8)		0.0136	−1.510	Both	0 (8)
18.5–24.9	0.0205	0.199	Drinks/day	10.3 (5)	0.02	0.0006	1.204	Drinks/day	1.3 (5)	0.72
25.0–29.9	0.0092	0.110	Drink-years	0.8 (5)	0.85	3.58 × 10−5	2.838	Drink-years	2.7 (5)	0.45
≥30	0.0041	0.271	None	37.5 (2)	<0.01	0.0032	0.057	None	3.4 (2)	0.76
BMI (omitting <18.5)
18.5–24.9	0.0193	0.244	Both	0 (6)		0.0006	1.179	Both	0 (6)
25.0–29.9	0.0093	0.110	Drinks/day	8.8 (4)	0.01	1.29 × 10−5	3.482	Drinks/day	0.8 (4)	0.69
≥30	0.0041	0.290	Drink-years	0.3 (4)	0.87	0.0038	−0.056	Drink-years	0.7 (4)	0.72
			None	34.9 (2)	<0.01			None	1.0 (2)	0.92

Abbreviations: BMI, body mass index; EOR, excess odds ratio.

^aModel: EOR = β_f d g_f (x), with g(x) = exp{φ₁ ln(x)}, where d is drink-years and x is drinks/day. The subscript (f) denotes separate effects for levels of BMI. Results were adjusted for study/center, education, age, sex, pack-years of smoking, cigarettes/day, years since cessation of smoking, and use of other tobacco products.

^bWeight (kg)/height² (m²).

^cEffect modification of BMI by alcohol drinking, including: “both,” modification of BMI by drink-years and of BMI by drinks/day, β_f d g_f (x); “drinks/day,” modification of BMI by drinks/day, β d g_f (x); “drink-years,” modification of BMI by drink-years, β_f d g(x); and “none,” no effect modification, β d g(x).

^dDeviance change relative to the 8-parameter model β_f d g_f (x) and (in parentheses) number of parameters in the EOR.

^eP value from a likelihood ratio test relative to β_f d g_f (x), which included BMI modification for drink-years and drinks/day.

^fModel convergence required a constrained β.