EFFECTS OF PERSISTENT PHYSICAL-ACTIVITY AND INACTIVITY ON CORONARY RISK-FACTORS IN CHILDREN AND YOUNG-ADULTS - THE CARDIOVASCULAR RISK IN YOUNG FINNS STUDY

The tracking of physical activity and its influence on selected corona ry heart disease risk factors were studied in a 6-year (original surve y in 1980, with follow-ups in 1983 and 1986) study of Finnish adolesce nts and young adults as part of the Cardiovascular Risk in Young Finns Study. The subjects in this analysis were aged 12, 15, and 18 years a t baseline. Physical activity was assessed with a standardized questio nnaire, and a sum index was derived from the product of intensity, fre quency, and duration of leisure time physical activity. Complete data on physical activity index from each study year were available on 961 participants. Significant tracking of physical activity was observed w ith 3-year correlations of the index ranging from 0.35 to 0.54 in boys and from 0.33 to 0.39 in girls. Tracking was better in older age grou ps. Two groups of adolescents (active and sedentary groups) were forme d at baseline according to high and low values of the index, respectiv ely. Approximately 57% of those classified as inactive remained inacti ve after a B-year follow-up. The corresponding value for active subjec ts was 44% (p c 0.01, active vs. inactive). The long-term effects of p hysically active and sedentary life-styles were studied by comparing g roups of young adults who had remained active or inactive in every thr ee examinations. Serum insulin and serum triglyceride concentrations w ere significantly lower in active young men. They had a more beneficia l high density lipoprotein to total cholesterol ratio and thinner subs capular skinfolds. Among young women, significant differences were see n in adiposity (subscapular skinfold) and in serum triglyceride concen tration. Physical activity was also related to less smoking in both se xes and, among young men, to tower consumption of saturated fatty acid s and to higher polyunsaturated to saturated fatty acids ratio of the diet. In regression analyses adjusted for the 6-year change in obesity , smoking status, and diet, the change in physical activity was invers ely associated with changes in serum insulin and triglycerides in boys . Independent association with triglycerides disappeared when insulin change was added to the model, suggesting that the effect may partly b e mediated through insulin metabolism. The authors conclude that the l evel of physical activity tracks significantly from adolescence to you ng adulthood. Physical inactivity shows better tracking than does phys ical activity, and subjects who are constantly inactive express a less beneficial coronary risk profile compared with those who are constant ly active.