Changes

Future strand files will also be available at that site.

Future strand files will also be available at that site.

== Primary Phenotypes ==

=== Average cigarettes smoked per day, either as a current smoker or former smoker ===

=== Primary Phenotypes ===

==== Average cigarettes smoked per day, either as a current smoker or former smoker ====

Individuals who either never smoked, or on whom we have no data (e.g., someone was a former smoker but former smoking was never assessed) will be excluded from analysis.  Only cigarettes will be included in the 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 smoked, or on whom we have no data (e.g., someone was a former smoker but former smoking was never assessed) will be excluded from analysis.  Only cigarettes will be included in the 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.

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.   

There was some cross-study variability on this measure.  Some studies specified avg drinking during a specific window, such as the 12 months or last one month; most made no such specification. Two studies forced the respondent to select ranges.

There was some cross-study variability on this measure.  Some studies specified avg drinking during a specific window, such as the 12 months or last one month; most made no such specification. Two studies forced the respondent to select ranges.

== 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.

== Ordinal versus Quantitative Phenotypes ==

=== Ordinal versus Quantitative Phenotypes ===

For studies with ordinal measures, such as questions that force the respondent to report ranges (e.g., 0, 1-10, 11-20, 21-30 cigarettes per day), please use midpoint of the range. These midpoints should then be treated as if they were quantitative variables in all further analysis.

For studies with ordinal measures, such as questions that force the respondent to report ranges (e.g., 0, 1-10, 11-20, 21-30 cigarettes per day), please use midpoint of the range. These midpoints should then be treated as if they were quantitative variables in all further analysis.