Distribution of risk factors of disease by having/not having a pet^a).

a)Combines categories no/not wanted and no/impossible to keep. b)One unit of pure alcohol (12 g) was equal to a 12-cl class of wine, a single 4-cl measure of spirits, or a 33-cl bottle of beer. c)Value 2 as a cut-off point apportions the respondents into two portions that are equally as large as possible. d)Calculated by dividing weight in kilograms by the square of height in meters.