Survey of serum lipid levels in Icelandic men aged 34-61 years. An epidemiological and statistical evaluation.

This report presents the results of serum beta-lipoprotein, total cholesterol and triglycerides determinations in a male population surveyed 1967--'68. This was the first stage (stage I) in a prospective health survey conducted by the Icelandic Health Association. The area of study was the city of Reykjavík with adjacent suburbs and communes. The population invited was 1/3 of each of 16 year-groups of males in the age-interval 34-61 years. The population was selected from the National Roster according to birthdays i.e. the 1st, 4th, 7th,.. of each month, the total number being 2.955. The response was 75.1%. B-lipoproteins were determined with the Hyland Beta-L Test, total cholesterol and triglycerides on Technicon AutoAnalyzer (i) according to Technicon Methodology N-24a, and a modification of the method of Kessler and Lederer respectively. Control sera were run in connection with cholesterol- and triglycerides determinations. Serum cholesterol levels were similar to the highest reported from other countries contrary to the triglycerides levels which are in the low range. The mean values and lower centiles are practically independent of age whereas the higher centiles are markedly age-dependent. A seasonal variation for the cholesterol weekly mean values was found. These values were highest in winter and lowest in summer, the difference estimated to be 30-40 mg%. No seasonal variation of triglycerides was found. Centile-flowdiagrams for these blood lipids are presented and the use of similar flowdiagrams is suggested as an aid to bridge a gap between the interpretation of cross-sectional and longitudinal studies.