Table 3.

Evidence-based Reviews of Smoking and ALS^a

Author year of publication	Study Population	Study Design	Number of Subjects (case/controls)	Case ascertainment	Adjustment variables	OR (95% CI)
Kamel et al, 1999 (202)	Two- centers study	Case- control	110/256	ALS Clinic	age, gender, education, region	1.70 (1.00 – 2.80)
Nelson et al, 2000 (201)	Population basedb	Case- control	161/321	Multiple case ascertainment sources	age, gender, education, alcohol	2.00 (1.30 – 3.20)
Weisskopf et al, 2004 (200)	Mortality surveillance c	Cohort	291/638,849 (women)	National Death Index	age, alcohol, education	1.67 (1.24 – 2.24)
Weisskopf et al, 2004 (200)	Mortality surveillance c	Cohort	330/459,360 (men)	National Death Index	age, alcohol, education	0.69 (0.49 – 0.99)
Fang et al, 2006 (208)	Constructio n workersd	Cohort	160/280,558	Registry	age, area of residence	0.80 (0.60 – 1.10)
Sutedja et al, 2007 (204)	Single center study	Case- control	364/392	ALS clinic	education, occupation, age	1.6 (1.00 – 2.50)
Gallo et al, 2009 (203)	Multicentere	Cohort	118/517,890	Death certificates	age, gender, education, center of recruitment	1.89 (1.14 – 3.14)
Okamoto et al, 2009 (207)	Multicenter	Case- control	153/306	ALS clinic	age, gender	1.00 (0.60 – 1.30)
Schmidt et al, 2010 (154)	Military veterans	Case- control	241/597	Registry	age, gender, race, education	0.90 (0.56 – 1.46)
Alonso et al, 2010 (206)	Cohortf	Case- control	1143/11,371	Death certificates	age at diagnosis, gender, diagnostic classificatio n	1.04 (0.80 – 1.34)
Wang et al, 2011 (205)	Cohortg	Case- control	832/1,119,080	Death certificates, registries	age, gender, physical activity, education, body mass index	1.42 (1.07 – 1.88)
de Jong et al, 2012 (209)	Population based incidence cohort	Case- control	494/1,599	Multiple sources (ALS clinics, rehabilitation centers, patient support associations)	age, gender, education	1.38 (1.02 – 1.88)

^aStudies of more than 100 ALS patients unless they are population-based

^bThree counties of western Washington state (King, Pierce, and Snohomish) in the US

^cParticipants were recruited by American Cancer Society in 50 States; families with at least one member over the age of 45 and other family members over the age of 30 were invited to participate (Cancer Prevention Study II cohort). Vital status of the study participants has been determined by automated linkage with the National Death Index through December 31, 1998.

^dSwedish Construction Workers Cohort

^eSubjects (aged 35–70) recruited from the general population residing in a given geographical area from 1991 to 2001, in 23 centers across 10 European countries (European Prospective Investigation into Cancer and Nutrition cohort)

^fGeneral Practice Research Database, a computerized clinical database in the United Kingdom

^gStudy population comprised of participants in the following: the Nurses’ Health Study, the Health Professionals Follow-up Study, the

Cancer Prevention Study -II Nutrition Cohort, the Multiethnic Cohort, and the National Institutes of Health American Association of

Retired Persons Diet and Health Study (NIH-AARP)