2.2. Other questionnaires and supplements taken
All participants completed questionnaires which gave information
about smoking habits, self-rated health, alcohol consumption,
physical activity, education and the kind of salt used. With
regard to salt used, both the kind and the amount of salt were
examined at follow-up. Participants were asked open questions on
what salt brands they had in their kitchen. Afterwards, the answers
were divided into 3 groups: always use iodized salt, never use
iodized salt, and sometimes use iodized salt. The amount of
household salt used was asked about in two questions: low, moderate
or high addition when cooking, and no, low, moderate or high
addition at the table. These answers were combined, with equal
weight, and finally the participants were divided into 5 groups
according to the amount of household salt used.