Fifteen-year longitudinal trends in walking patterns and their impact on weight change

Abstract

Background: Although walking is the most popular leisure-time activity for adults, few long-term, longitudinal studies have examined the association between walking, an affordable and accessible form of physical activity, and weight gain.

Objective: The objective was to evaluate the association between changes in leisure-time walking and weight gain over a 15-y period.

Design: Prospective data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study of 4,995 men and women aged 18-30 y at baseline (1985-1986) from 4 US cities and reexamined 2, 5, 7, 10, and 15 y later. Sex-stratified, repeated-measures, conditional regression modeling with data from all 6 examination periods (n = 23,633 observations) was used to examine associations between walking and annualized 15-y weight change, with control for 15-y nonwalking physical activity, baseline weight (and their interaction), marital status, education, smoking, calorie intake, and baseline age, race, and field center.

Results: Mean (+/- SE) baseline weights were 77.0 +/- 0.3 kg (men) and 66.2 +/- 0.3 kg (women), weight gain was approximately 1 kg/y, and the mean duration of walking at baseline was <15 min/d. After accounting for nonwalking physical activity, calorie intake, and other covariates, we found a substantial association between walking and annualized weight change; the greatest association was for those with a larger baseline weight. For example, for women at the 75th percentile of baseline weight, 0.5 h of walking/d was associated with 8 kg less weight gain over 15 y compared with women with no leisure time walking.

Conclusion: Walking throughout adulthood may attenuate the long-term weight gain that occurs in most adults.

FIGURE 1

Percentage of sample to gain, maintain, or lose weight across 15 y of the Coronary Artery Risk Development in Young Adults (CARDIA) Study (n = 23,633 observations across 4995 individuals; 1985–1986 to 2000–2001). *P for trend < 0.0001 by examination year.

FIGURE 2

Percentage of sample to fall within the different walking-score categories, ranging from 0 (no walking) exercise units (EU) to 144 EU (≥4 h of walking/wk over 12 mo at 3 metabolic equivalents) across 15 y of the Coronary Artery Risk Development in Young Adults (CARDIA) Study (n = 23,633 observations across 4995 individuals; 1985–1986 to 2000–2001). *P for trend < 0.0001 by examination year. An EU of 72 approximates 2 h of walking/wk, and an EU of 36 approximates 1 h of walking/wk.

FIGURE 3

Predicted cumulative weight change in men and women based on coefficients from the longitudinal, repeated-measures conditional regression model across 15 y of the Coronary Artery Risk Development in Young Adults (CARDIA) Study (n = 23,633 observations across 4995 individuals; 1985–1986 to 2000–2001). Sex-stratified, longitudinal, repeated-measures conditional regression model predicted annualized weight changes with control for total physical activity score (nonwalking), age, marital status, education (referent or ≥high school), smoking (referent or never smoked), and calorie intake; the interaction term was walking by baseline weight. Men: walking score of 144 (referent, 0), 25th percentile baseline weight for men (β = −0.07 kg/y; 95% CI: −0.23, 0.09; P = 0.4), 50th percentile baseline weight (β = −0.15 kg/y; 95% CI: −0.29, −0.02; P = 0.03), and 75th percentile baseline weight, BMI equivalent to overweight (β = −0.25 kg/y; 95% CI: −0.40, −0.10; P = 0.001). Women: 25th percentile baseline weight for women (β = −0.12 kg/y; 95% CI: −0.29, 0.05; P = 0.2), 50th percentile baseline weight (β = −0.28 kg/y; 95% CI: −0.43, −0.14; P = 0.001), and 75th percentile baseline weight, BMI equivalent to overweight (β = −0.53 kg/y; 95% CI: −0.68, −0.38; P < 0.001). Values may appear inconsistent because of rounding. Bars for 0 exercise units (EU) are identical across sex and baseline weight because of regression parameterization.