Homozygosity for the C 677 →T mutation of 5,10-methylenetetrahydrofolate reductase and total plasma homocyst(e)ine are not associated with greater than normal risk of a first myocardial infarction in northern Sweden

BACKGROUNDResults of several case–control studies have shown elevated total plasma homocyst(e)ine (TPH) and homozygosity for the point mutation C →T in the gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) to be associated with a greater than normal risk of atherosclerotic vascular disease. However, there have been few epidemiologic studies and the interpretation of the results is not clear-cut. OBJECTIVETo elucidate whether homozygosity for the point mutation C →T in the gene for MTHFR, and TPH are risk factors for a first myocardial infarction. DESIGNA prospective nested case–control study in Northern Sweden. METHODSAmong more than 36 000 persons screened, 78 cases satisfied the inclusion criterion of having developed, after sampling, a first myocardial infarction. For each case, two controls matched for sex and age were randomly selected. RESULTSWe found no statistically significant difference among the prevalences of the three possible MTHFR genotypes –/– (no mutation), +/+ (both alleles have the mutation), and +/– among cases and controls in univariate conditional logistic regression analysis. Mean levels of TPH in patients and controls were 12.2 ± 4.9 and 12.2 ± 3.5 μmol/l (means ± SD), respectively (NS). CONCLUSIONSIn this study neither homozygosity for the point mutation C →T in the gene for MTHFR nor TPH was related to a greater than normal risk of a first myocardial infarction for members of the population of northern Sweden. Further research is needed in order to show whether TPH is an independent risk factor for a first myocardial infarction.