Changes

There was some cross-study variability on this measure.  Some studies specified avg smoking during a specific window, such as the last 12 months; most made no such specification.  One study allowed respondents to report packs.

There was some cross-study variability on this measure.  Some studies specified avg smoking during a specific window, such as the last 12 months; most made no such specification.  One study allowed respondents to report packs.

== Smoking Initiation ==

=== Smoking Initiation ===

Every study had some useable measure of whether a respondent has ever regularly smoked.  Almost all asked directly.  Some have necessary information for this variable (e.g., 100 cigs lifetime? Ever smoked every day for 2 weeks straight?).

Every study had some useable measure of whether a respondent has ever regularly smoked.  Almost all asked directly.  Some have necessary information for this variable (e.g., 100 cigs lifetime? Ever smoked every day for 2 weeks straight?).

Note that we’re among the first groups conducting such meta-analyses, and our analysis pipeline is currently restricted to continuous traits. Until methods are developed for binary traits, it is proposed that we analyze smoking initation as a continuous trait.

Note that we’re among the first groups conducting such meta-analyses, and our analysis pipeline is currently restricted to continuous traits. Until methods are developed for binary traits, it is proposed that we analyze smoking initation as a continuous trait.

Average drinks per week, either as a current drinker or former drinker. 

 

=== Average drinks per week, either as a current drinker or former drinker ===

Individuals who either never drank, or on whom we have no data (e.g., someone was a former drinker but former drinking was not assessed) will be excluded from analysis.  All types of liquor will be combined in the total estimate.  If preferable, repeated measures designs (longitudinal data) can use all assessments by scaling and correcting for covariates within waves of assessment, then averaging across assessments.   

Individuals who either never drank, or on whom we have no data (e.g., someone was a former drinker but former drinking was not assessed) will be excluded from analysis.  All types of liquor will be combined in the total estimate.  If preferable, repeated measures designs (longitudinal data) can use all assessments by scaling and correcting for covariates within waves of assessment, then averaging across assessments.   

== Secondary Phenotypes ==

== Secondary Phenotypes ==

Pack Years

=== Pack Years ===

Number of packs of cigarettes per day multiplied by the number of years the person has smoked, corrected for age.

Number of packs of cigarettes per day multiplied by the number of years the person has smoked, corrected for age.

Age of Initiation of Smoking

 

=== Age of Initiation of Smoking ===

The age an individual first became a regular smoker.

The age an individual first became a regular smoker.

Covariates

 

== Covariates ==

Appropriate covariates can often be study-specific.  We will depend on local investigators to determine the most appropriate covariates.  We list here some covariates that will likely be necessary.

Appropriate covariates can often be study-specific.  We will depend on local investigators to determine the most appropriate covariates.  We list here some covariates that will likely be necessary.

Main Effects

=== Main Effects ===

1. Age of assessment for current smokers/drinkers

*Age of assessment for current smokers/drinkers

a. At assessment for current smokers/drinkers  

**At assessment for current smokers/drinkers  

2. Age of smoking/drinking for former smokers/drinkers

**Age of smoking/drinking for former smokers/drinkers

a. Could be age at quitting

*a. Could be age at quitting

3. Age of assessment for Pack Years, Smoking Initiation, and Age of Smoking Initiation  

*3. Age of assessment for Pack Years, Smoking Initiation, and Age of Smoking Initiation  

4. Sex

*4. Sex

5. Date of birth (or year, or range)

*5. Date of birth (or year, or range)

6. Cohort

*6. Cohort

7. Height, weight, BMI, for drinking (a single beer has different effects on a 200 lb man versus a 100 lb woman)

*7. Height, weight, BMI, for drinking (a single beer has different effects on a 200 lb man versus a 100 lb woman)

8. Genetic principle components (or empirical kinships)

*8. Genetic principle components (or empirical kinships)

9. Adolescence versus adulthood (e.g., < 21 years of age versus >=21)

*9. Adolescence versus adulthood (e.g., < 21 years of age versus >=21)

10. Date of assessment (e.g., the calendar year of the assessment)?

*10. Date of assessment (e.g., the calendar year of the assessment)?

 

Interactions

=== Interactions ===

11. Sex X Adolescence interaction

*11. Sex X Adolescence interaction

12. Sex X Age interaction

*12. Sex X Age interaction

13. Sex X Weight/Height/BMI interaction

*13. Sex X Weight/Height/BMI interaction

14. Age X Adolescence interaction

*14. Age X Adolescence interaction