Myocardial infarction and future risk of cancer in the general population—the Tromsø Study

Abstract

The association between myocardial infarction (MI) and future risk of incident cancer is scarcely investigated. Therefore, we aimed to study the risk of cancer after a first time MI in a large cohort recruited from a general population. Participants in a large population-based study without a previous history of MI or cancer (n=28763) were included and followed from baseline to date of cancer, death, migration or study end. Crude incidence rates (IRs) and hazard ratios (HRs) for cancer after MI were calculated. During a median follow-up of 15.7 years, 1747 subjects developed incident MI, and of these, 146 suffered from a subsequent cancer. In the multivariableadjusted model (adjusted for age, sex, BMI, systolic blood pressure, diabetes mellitus, HDL cholesterol, smoking, physical activity and education level), MI patients had 46% (HR 1.46; 95% CI: 1.21-1.77) higher hazard ratio of cancer compared to those without MI. The increased cancer incidence was highest during the first 6 months after the MI, with a 2.2-fold higher HR (2.15; 95% CI: 1.29-3.58) compared with subjects without MI. After a 2-year period without higher incidence rate, MI patients displayed 60% (HR 1.60; 95% CI: 1.27-2.03) higher HR of future cancer more than 3 years after the event. The increased incidence rates were higher in women than men. Patients with MI had a higher short-and long-term incidence rate of cancer compared to subjects without MI. Our findings suggest that occult cancer and shared risk factors of MI and cancer may partly explain the association.

<p>Increased cancer risk after myocardial infarction: fact or fiction? A systemic review and meta-analysis</p>

“…Four studies with 221,994 MI patients were included to estimate the incidence rate of cancer among patients with MI history. 10,12,13,20 The pooled cancer incidence rate in MI patients was 9.5% (8.3%-10.7%, Figure 2), which was comparable to that in non-MI controls (11.1%; 95% CI=7.3%-14.8). Three studies reported the overall effect estimates in patients with MI.…”

“…Finally, five cohort studies met all inclusion criteria. [10][11][12][13]20 One of them was a single-arm cohort study regarding MI and only provided cancer incidence rate. The rest of the studies supplied overall or subgroup effect estimates (OR, RR, HR, or SIR) with 95% CI.…”

“…Three studies reported the overall effect estimates in patients with MI. 10,12,13 Pooled analyses of OR in the random-effects model showed that the increased cancer risk in patients with MI in comparison with controls had no statistical significance, and the heterogeneity among studies was high (OR=1.08; 95% CI=0.97-1.19, P=0.153; I 2 =90.8%; P for heterogeneity <0.01; Figure 3).…”

“…Subgroup effect estimates based on gender were presented in four studies. [10][11][12][13] Pooled analyses of OR in random-effects model demonstrated that the overall risk of cancer incidence in male patients with MI was nonsignificant (OR=1.04; 95% CI=0.99-1.10, P=0.124; I 2 =78.5%; P for heterogeneity <0.01; Figure 4A). However, female patients with MI had a significantly increased risk of incident cancer (OR=1.10; 95% CI=1.01-1.20, P=0.025; I 2 =82.9%; P for heterogeneity <0.01; Figure 4B).…”

“…10,11 However, the results were inconsistent or even conflicting. 12,13 In view of the high disease burden of MI and cancer, it is necessary to confirm whether MI is a new risk factor for incident cancer. Therefore, we conducted a systematic review and meta-analysis in accordance with the PRISMA guidelines and our predesigned protocol to clarify the association between MI and incident cancer.…”