Income as mediator of the effect of occupation on the risk of myocardial infarction: does the income measurement matter?

TY - JOUR

T1 - Income as mediator of the effect of occupation on the risk of myocardial infarction: does the income measurement matter?

AU - Andersen, Ingelise

AU - Gamborg, Michael

AU - Osler, Merete

AU - Prescott, Eva

AU - Diderichsen, Finn

N1 - Keywords: Adult; Aged; Denmark; Epidemiologic Methods; Female; Humans; Income; Male; Middle Aged; Myocardial Infarction; Occupational Diseases

PY - 2005

Y1 - 2005

N2 - AIM: To investigate whether the effect of occupational grade on the risk of myocardial infarction (MI) is mediated by income with different aspects of income taken into account. METHODS: Data were used from three prospective population studies conducted in Copenhagen. A total of 16 665 employees, 43% women, aged 20-75 years, with an initial examination between 1974 and 1992 were followed up until 1999 for incident (hospital admission or fatal) MI. Register based information on job categories and income was used. RESULTS: During follow up, 855 subjects were diagnosed with a MI: 708 men and 147 women (in total 47% fatal). The hazards by household and individual income showed a graded effect with a hazard ratio (HR) of 1.43 (95% CI 1.12 to 1.83) for the lowest household income group compared with the highest, whereas equivalent income showed an inverse "J shape" effect with a HR of 1.55 (95% CI 1.25 to 1.82) for the third income group compared with the highest. HR for unskilled workers as compared with executive managers was reduced from 1.55 (95% CI 1.24 to 1.93) to 1.42 (95% CI 1.12 to 1.81) after adjustment for household income. CONCLUSIONS: Occupation and income are not mutually exclusive, but at least partly explained by or mediated through the other on the risk of MI. The mediating effect of income is independent of the choice of an income indicator. Income is not a big contributor to inequality in MI; probably because of the rather even income distribution in Denmark.

AB - AIM: To investigate whether the effect of occupational grade on the risk of myocardial infarction (MI) is mediated by income with different aspects of income taken into account. METHODS: Data were used from three prospective population studies conducted in Copenhagen. A total of 16 665 employees, 43% women, aged 20-75 years, with an initial examination between 1974 and 1992 were followed up until 1999 for incident (hospital admission or fatal) MI. Register based information on job categories and income was used. RESULTS: During follow up, 855 subjects were diagnosed with a MI: 708 men and 147 women (in total 47% fatal). The hazards by household and individual income showed a graded effect with a hazard ratio (HR) of 1.43 (95% CI 1.12 to 1.83) for the lowest household income group compared with the highest, whereas equivalent income showed an inverse "J shape" effect with a HR of 1.55 (95% CI 1.25 to 1.82) for the third income group compared with the highest. HR for unskilled workers as compared with executive managers was reduced from 1.55 (95% CI 1.24 to 1.93) to 1.42 (95% CI 1.12 to 1.81) after adjustment for household income. CONCLUSIONS: Occupation and income are not mutually exclusive, but at least partly explained by or mediated through the other on the risk of MI. The mediating effect of income is independent of the choice of an income indicator. Income is not a big contributor to inequality in MI; probably because of the rather even income distribution in Denmark.

U2 - 10.1136/jech.2005.036848

DO - 10.1136/jech.2005.036848

M3 - Journal article

C2 - 16286499

SN - 0143-005X

VL - 59

SP - 1080

EP - 1085

JO - Journal of Epidemiology & Community Health

JF - Journal of Epidemiology & Community Health

IS - 12

ER -