A 1999 metastudy combined data from five studies from western countries. The metastudy reported mortality ratios, where lower numbers indicated fewer deaths, for fish eaters to be .82, vegetarians to be .84, occasional meat eaters to be .84. Regular meat eaters and vegans shared the highest mortality ratio of 1.00. The study reported the numbers of deaths in each category, and expected error ranges for each ratio, and adjustments made to the data. However, the "lower mortality was due largely to the relatively low prevalence of smoking in these [vegetarian] cohorts". Out of the major causes of death studied, only one difference in mortality rate was attributed to the difference in diet, as the conclusion states: "vegetarians had a 24% lower mortality from ischemic heart disease than nonvegetarians, but no associations of a vegetarian diet with other major causes of death were established."