INSULIN AND RISK OF CARDIOVASCULAR-DISEASE - A METAANALYSIS

Background-Our purposes were to estimate the strength of the longitudi nal relationship between hyperinsulinemia and cardiovascular diseases (CVD) from the available literature and to identify study characterist ics that modify this relationship. Methods aad Results-Articles mere i dentified by means of a MEDLINE and Embase search and citation trackin g. Eligible studies were prospective population-based cohort studies a nd nested case-control studies on the relationship between, on the one hand, fasting or nonfasting insulin levels and, on the other hand, my ocardial infarction, death from coronary heart disease, and/or ECG abn ormalities. Data were extracted pertaining to insulin measurements, ty pe oi outcome studied, adjustment for confounding, sex, mean age of th e study population, follow-up period, insulin assay, and ethnic backgr ound (white or nonwhite). Associations of insulin and CVD were reexpre ssed in a uniform manner, an estimate of relative risk (RR) and 95% CI , to be used in meta-regression analyses. Twelve of 17 potentially eli gible articles provided sufficient information. Overall, a weak positi ve association was found. The meta-analysis resulted in an estimated s ummary RR (95% CI) of 1.18 (1.08 to 1.29) for differences in insulin l evel, equivalent to the difference between the 75th and the 25th perce ntiles of the general population in the Netherlands. Ethnic background and type of insulin assay modified the relationship between insulin a nd CVD with borderline significance, Conclusions-Hyperinsulinemia is a weak risk indicator for the occurrence of CVD. The relationship betwe en hyperinsulinemia and CVD tvas modified by ethnic background and by the type of insulin assay involved.