Longitudinal physical activity and diet patterns in the 1958 British Birth Cohort.

PURPOSE: This study was conducted to investigate, in the 1958 British birth cohort, physical activity and diet frequency indicators in persons between the ages of 33 and 42 yr. We also assessed whether activity level in adulthood was influenced by activity or television viewing in adolescence or early adulthood and to examine change in diet quality and whether any change was related to change in activity level.
METHODS: Main outcome measures were frequency of leisure physical activity and consumption frequencies of fruit, salad or raw vegetables, fried food, chips, sweets, and biscuits, at 33 and 42 yr of age. A total of 9769 participants contributed data at both time points. Activity and television viewing frequency were measured in persons at 11, 16, and 23 yr of age.
RESULTS: Between the ages of 33 and 42 yr, tracking (Spearman correlation) coefficients for food items were similar for men and women and varied from 0.23 for fried food to 0.49 for fruit and, for physical activity, were 0.31 in men and 0.23 in women. From 11 to 42 yr, activity tracking was low; the longitudinal correlation coefficient was 0.09 for males, and 0.07 for females. Correlations between activity in adolescence and adulthood (33 or 42 yr) were generally low (0.002-0.20); those for television viewing in adolescence and activity in adulthood even lower (-0.08 to 0.02). Overall improvement in diet quality was very small, but those who increased their physical activity frequency showed greater improvements in diet quality than those who decreased their activity frequency.
CONCLUSIONS: Tracking of physical activity and diet in midadulthood is low to moderate, which may partly be caused by measurement methods. Television viewing has no influence on subsequent physical activity frequency. Improvements in physical activity and dietary habits appear to be related.