The predictability of risk factors with respect to incidence and mortality of myocardial infarction and total mortality. A 12-year follow-up of the Oslo Study, Norway.

OBJECTIVES

To study the prognostic value of several risk factors on incidence and mortality of myocardial infarction (MI) and total mortality in men.

DESIGN

Prospective cohort study of 12 years' follow-up.

SETTING

All men in Oslo aged 40-49 and a 7% sample of men aged 20-39 were invited for screening.

SUBJECTS

Of all 30,025 invited men, of whom 25,015 were aged 40-49, a total of 16,209 men aged 40-49 attended the screening and risk factors were recorded for these men.

MAIN OUTCOME MEASURES

Incidence of first MI (non-fatal and fatal), mortality of MI, total mortality.

RESULTS

When examining the rate ratio of the fifth to the first quintile of risk factors we found that systolic and diastolic blood pressures were stronger predictors for mortality than incidence of MI. The rate ratios (95% confidence interval) of systolic blood pressure were 3.73 (2.56, 5.44) and 2.56 (2.01, 3.25) respectively. For diastolic blood pressure the corresponding rate ratios were 4.14 (2.84, 6.04) and 2.78 (2.18, 3.54). Small differences in the rate ratios for these end-points were found for total serum cholesterol and triglycerides. Daily cigarette smoking versus non-cigarette smoking was a stronger predictor for MI mortality than incidence, with rate ratios of 3.16 (2.45, 4.24) and 2.34 (2.00, 2.79) respectively. The Cox proportional hazards regression analysis confirmed the above results.

CONCLUSIONS

Total serum cholesterol and triglycerides predicted incidence and mortality of MI equally well. Whereas blood pressure and daily cigarette smoking predicted mortality of MI more strongly.