Reduced mortality among whole grain bread eaters in men and women in the Norwegian County Study

Objective: To study whether mortality is reduced among whole grain eaters in Norway. Design: Non-interventional, prospective, baseline 1977-1983, followed for mortality through to 1994. Setting: Three Norwegian counties. Subjects: A total of 16933 men and 16915 women; systematic screening of all residents aged 35 - 56 y at baseline, not disabled and free of cardiovascular disease (79% response rate). Predictor variable: We combined self-report of type and number of bread slices (white, light whole grain, dense whole grain) to form a whole grain bread score, with range 0.05 (1 slice per day, made with 5% whole grain flour) to 5.4 (9 slices per day, made with 60% whole grain flour). Results: Norwegian whole grain bread eaters were less likely to be smokers, were more physically active, had lower serum cholesterol and systolic blood pressure, and ate less total and saturated fat as a proportion of energy intake than white bread eaters. After adjustment for age, energy intake, sex, serum cholesterol, systolic blood pressure, smoking, body mass index, physical activity at leisure and work, and use of cod liver oil or other vitamin supplements, hazard rate ratios (HRR) for total mortality were inverse and graded across whole grain bread score categories (category 5 vs category 1 HRR: 0.75, 95% confidence interval 0.63-0.89 in men and 0.66, 0.44-0.98 in women). Conclusion: Protection by whole grain intake against chronic disease is suggested in Norway, where four times as much whole grain is consumed as in the United States.