Associations among 25-year trends in diet, cholesterol and BMI from 140,000 observations in men and women in Northern Sweden

Background: In the 1970s, men in northern Sweden had among the highest prevalences of cardiovascular diseases (CVD) worldwide. An intervention program combining population- and individual-oriented activities was initiated in 1985. Concurrently, collection of information on medical risk factors, lifestyle and anthropometry started. Today, these data make up one of the largest databases in the world on diet intake in a population- based sample, both in terms of sample size and follow-up period. The study examines trends in food and nutrient intake, serum cholesterol and body mass index (BMI) from 1986 to 2010 in northern Sweden. Methods: Cross-sectional information on self-reported food and nutrient intake and measured body weight, height, and serum cholesterol were compiled for over 140,000 observations. Trends and trend breaks over the 25-year period were evaluated for energy-providing nutrients, foods contributing to fat intake, serum cholesterol and BMI. Results: Reported intake of fat exhibited two significant trend breaks in both sexes: a decrease between 1986 and 1992 and an increase from 2002 (women) or 2004 (men). A reverse trend was noted for carbohydrates, whereas protein intake remained unchanged during the 25-year period. Significant trend breaks in intake of foods contributing to total fat intake were seen. Reported intake of wine increased sharply for both sexes (more so for women) and export beer increased for men. BMI increased continuously for both sexes, whereas serum cholesterol levels decreased during 1986 - 2004, remained unchanged until 2007 and then began to rise. The increase in serum cholesterol coincided with the increase in fat intake, especially with intake of saturated fat and fats for spreading on bread and cooking. Conclusions: Men and women in northern Sweden decreased their reported fat intake in the first 7 years (19861992) of an intervention program. After 2004 fat intake increased sharply for both genders, which coincided with introduction of a positive media support for low carbohydrate-high-fat (LCHF) diet. The decrease and following increase in cholesterol levels occurred simultaneously with the time trends in food selection, whereas a constant increase in BMI remained unaltered. These changes in risk factors may have important effects on primary and secondary prevention of cardiovascular disease (CVD)