Abstract 21275: Greater Adiposity is Associated with Less Weight Gain in Younger Persons and Greater Weight Loss in Older Persons
Introduction: Cross-sectional studies indicate increasing prevalence of obesity among Americans. However, longitudinal data for body weight for persons of differing adiposity is sparse and it is not clear whether lower body mass index (BMI) protects individuals from later weight gain.
Hypothesis: Longitudinal trends in weight will differ according to adiposity as indicated by BMI. Methods: Subjects were 69,337 (3,922 female, 5,488 minority race/ethnicity) veterans aged 18 to 100 years enrolled at the Phoenix VA Health Care System with serial measured weights recorded at outpatient visits between January 1999 and February 2006. BMI categories (kg/m2) were <18.5 (n=808), 18.5 to <25 (n=17,537), 25 to <30 (n=28,174), 30 to <35 (n=15,499), 35 to <40 (n=5,101), and 40 or more (n=2,218). Random effects mixed models were fitted to sequential weights. Models included fixed effects for age, sex, race/ethnicity, BMI category, and time. Linear and quadratic time tested nonlinear change. Interactions between BMI category and time variables tested effect modification by adiposity.
Results: Time trends in weight were similar for men and women and are presented for all. Over 7 years, persons initially aged 61 to 65 years were weight stable while younger persons gained weight and older persons lost weight (p<0.0001). Among those under 60 years, weight gain was highest for those 18-25 (16.4+3.8 lb) and 26-30 (18.1+2.6 lb) years. Longitudinal changes in weight from 1999 to 2006 were inversely associated with adiposity: Among the large cohort aged 46 to 50 who overall gained 6.7+1.4 lb (p<0.001), gain was 14.6+5.8 lb in those with BMI<18.5 and decreased in a step-wise fashion with increasing BMI category to no change in those with BMI≥35 (p<0.001). Results were generally similar in the much smaller cohort under 30 years.
Conclusion: These results indicate that low or normal BMI in youth and middle age does not protect individuals from later weight gain and suggest the need to extend weight control efforts to the young and those with normal BMI.
- © 2010 by American Heart Association, Inc.