Seven year changes in physical fitness, physical activity, and lipid profile in the CARDIA study

PURPOSE: To relate seven year changes in physical fitness and physical acti vity in the young adult population to changes in the plasma Lipid profile a nd to examine the influence of weight change on those relationships. METHODS: The participants in this observational study were the 1177 black a nd white men and women, ages 18-30 at entry into the Coronary Artery Risk D evelopment in Young Adults (CARDIA) cohort, who completed a symptom-limited graded treadmill exercise test and had an overnight fasting blood draw at both the Baseline (1985-86) and Year 7 (1992-93) exams. CARDIA, a longitudi nal study of the relationships of lifestyle and physiological variables to the development of coronary heart disease risk factors, consists of populat ion based cohorts in Birmingham, Alabama, Minneapolis, Minnesota and Chicag o, Illinois and a cohort recruited from the membership of a large, pre-paid health care plan, broadly representative of the population, in Oakland, Ca lifornia. RESULTS: All race/gender groups experienced mean decreases in physical fitn ess and self-reported physical activity and increases in weight. Decreased fitness was associated with decreased high density lipoprotein cholesterol (HDL-C), and conversely, increased fitness was associated with increased HD L-C. The correlation coefficients of change in fitness with change in HDL-C ranged from 0.17 in white men and black women to 0.24 in white women (P < 0.001 for all race/gender groups). Change in fitness was minimally correlat ed with change in low density lipoprotein-cholesterol (LDL-C) in all groups (r ranged from -0.09 in black women to -0.20 in white women), triglyceride s (TG) in men and white women (r ranged from -0.10 to -0.15), and total cho lesterol (TC) in white men and women (r = -0.11 and -0.15, respectively). T he magnitude of these correlations was further reduced with adjustment for weight change. Correlations between change in activity and change in lipid and lipoprotein Values were generally weak or nonexistent, except for the s uggestion of a small, direct relationship with change in HDL-C in black and white women (r = 0.14 and r = 0.11, respectively). ALI of the weight chang e adjusted correlations were essentially unaffected by further adjustment f or baseline fitness or activity and other covariates. CONCLUSIONS: Decreased fitness during young adulthood is associated with un favorable changes in lipid profile, explained mostly by increased weight. L ack of association between change in activity and change in lipid profile o bserved in this study may be due, in part, to imprecision of activity measu rement. (C) 1998 Elsevier Science Inc.