Characteristics of the study sample (N = 18000).

Data are %.†Education was classified as: low (less than complete secondary education), middle (completed secondary education), high (incomplete or complete higher education).*Physical activity difficulty was assessed by the question ‘How easily can you go up 2 or 3 flights of stairs or go uphill without getting out of breath?’§Answers to the question ‘I feel that what happens in life is often determined by factors beyond my control’ were classified as: disagree/rather disagree (high), quite agree (middle), agree (low).‡Principal component analysis was used to generate the wealth index based on the possession of 10 household assets.¶Level of social support was based on a composite score (refer to text for details).#Death of a close relative was assessed by the question ‘During the last months, have you experienced the death of a close relative?’