What is the clinical evidence from this study?

Study design: Cohort. Population: Coronary events (n=33346). Intervention: Baseline risk factors (e.g., smoking, hypercholesterolaemia, diabetes). Primary outcome: First coronary event (fatal or nonfatal) (RR 2.29, 95% CI 2.09-2.52).

What does this research mean for the field?

Smoking is the strongest long-term risk factor for coronary events in both men and women, and ten standard risk factors explain nearly all the variation in coronary event risk over a 20-year follow-up. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

June 26, 2006Open Access

Population‐attributable risk of coronary heart disease risk factors during long‐term follow‐up: the Malmö Preventive Project

Key Result

Smoking was the strongest long-term risk factor for coronary events in both men (RR 2.29; 95% CI 2.09-2.52) and women (RR 3.16; 95% CI 2.50-3.98) over a mean 20-year follow-up.

Study Design

Type

Cohort (n=33,346)

Structured PICO

What is the population-attributable risk of coronary events from 10 baseline risk factors over long-term follow-up?

Population

33,346 individuals (22,444 males and 10,902 females) from the Malmö Preventive Project

Intervention

Presence of 10 baseline risk factors (including smoking, hypercholesterolaemia, diabetes, and hypertension)

Comparator

Absence of the respective baseline risk factors

Outcome

First coronary event (fatal or nonfatal)hard clinical

Smoking is the most important long-term risk factor for coronary events in both genders, accounting for a large population-attributable risk.

Main Result

Effect estimate: RR 2.29 (95% CI 2.09-2.52)

Abstract

AIMS: To calculate the population-attributable risk (PAR) of coronary events (CE) from 10 risk factors, during long-term follow-up. METHODS: We used both case-cohort and case-control analyses for calculation of PAR in relation to 10 baseline risk factors. First CE (fatal or nonfatal, n=3072) in 22,444 males and 10,902 females was recorded during a mean follow-up of 20 years by use of national registers. RESULTS: Using a Cox regression analysis in a case-cohort design, smoking (prevalence in men 49%, women 37%) was the strongest risk factor, RR 2.29 (95% CI 2.09-2.52; PAR 39%), followed by hypercholesterolaemia, RR 1.70 (95% CI 1.56-1.86; PAR 18%), and diabetes, RR 1.67 (95% CI 1.41-1.99; PAR 3%). For women the strongest risk factors were smoking, RR 3.16 (95% CI 2.50-3.98; PAR 44%), diabetes, RR 2.59 (95% CI 1.78-3.76; PAR 6%), and hypertension, RR 2.47 (95% CI 1.94-3.14; PAR 23%). In men, smoking was the strongest predictor both after 10 years RR 2.69 (95% CI 2.23-3.24) and 20 years RR 2.45 (95% CI 2.15-2.79), followed by hypercholesterolaemia (RR 2.16-1.63), hypertension (RR 2.04-1.51), and diabetes (RR 1.85 -1.47). The case-control design gave very similar results. Total PAR varied from 74% (fully adjusted Cox regression, case-control, in men) to 116% in women (case-cohort). CONCLUSION: Smoking is the most important long-term risk factor for CE in both genders, based on data from a population with a high proportion of smokers. Ten measured variables explained almost all variation in risk and could be used as a basis for intervention programmes.