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Serious psychological distress was assessed using a set of questions from the six-item Kessler (K6) scale (https://pubmed.ncbi.nlm.nih.gov/22351472/) that asks sampled adults to assess the frequency of six characteristics (sadness, nervousness, restlessness, hopelessness, feeling that everything was an effort, and worthlessness) experienced within the previous 30 days.
* Any tobacco use was defined as use either “every day” or “some days” of at least one tobacco product among individuals (for cigarettes, users were defined as persons who reported use either “every day” or “some days” and had smoked ≥100 cigarettes during their lifetime).
** Any combustible tobacco use was defined as use either “every day” or “some days” of at least one combustible tobacco product: cigarettes; cigars, cigarillos, filtered little cigars; pipes, water pipes, or hookah (for cigarettes, users were defined as persons who reported use either “every day” or “some days” and had smoked ≥100 cigarette during their lifetime).
*** Current cigarette smokers were defined as persons who reported smoking ≥100 cigarettes during their lifetime and now smoked cigarettes “every day” or “some days.”
**** Reported smoking cigars, cigarillos, or little filtered cigars at least once during their lifetime and now smoked at least one of these products “every day” or “some days.”
^ Reported smoking tobacco in a regular pipe, water pipe, or hookah at least once during their lifetime and now smoked at least one of these products “every day” or “some days.”
^^ Reported using electronic cigarettes at least once during their lifetime and now used e-cigarettes “every day” or “some days.”
^^^ Reported using chewing tobacco, snuff, dip, snus, or dissolvable tobacco at least once during their lifetime and now used at least one of these products “every day” or “some days.