Impact of body size and physical activity during adolescence and adult life on overall and cause-specific mortality in a large cohort study from Iran

Thursday, 21 August 2014: 11:00 AM
Ballroom C (Dena'ina Center)
Arash Etemadi, PhD , Tehran University of Medical Sciences, Tehran, Iran
Christian Abnet, PhD , National Cancer Institute, Bethesda, MD
Farin Kamangar, PhD , Morgan State University, Baltimore, MD
Sholom Wacholder, PhD , National Cancer Institute, Bethesda, MD
Farhad Islami, PhD , Tehran University of Medical Sciences, Tehran, Iran
Paul Brennan, PhD , International Agency for Research on Cancer, Lyon, MD
Paolo Boffetta, MD , Mount Sinai School of Medicine, New York, MD
Reza Malekzadeh, MD , Tehran University of Medical Sciences, Tehran, Iran
Sanford Dawsey, MD , National Cancer Institute, Bethesda, MD
INTRODUCTION:  Most of the information about the association between obesity and mortality comes from Western populations. The reports from the low and middle-income countries in Asia have not studied adolescent or early adulthood obesity, lifetime changes in body fatness, or physical activity.

METHODS:  The Golestan Cohort Study is a population-based cohort in northeastern Iran in which 50,045 people above the age of 40 have been followed since 2004. Participants were shown a validated pictogram to assess body size at ages 15, 30, and the time of recruitment, categorized from 1 (very thin) to 7 in men and 9 in women (very obese). Information on physical activity at these ages was also collected. Subjects were followed up annually, and cause of death was determined. Cox regression models were adjusted for age at cohort start, smoking, socioeconomic status, ethnicity, place of residence, education, and opium use. Models for body size were also adjusted for physical activity at the same age, and vice-versa.

RESULTS:  During a total of 252,740 person-years of follow-up (mean follow-up duration 5.05+1.25 years) through December 2011, 2,529 of the cohort participants died. The most common cause of death was cardiovascular diseases (n=1318, 52.1%), followed by cancer (n=543, 21.5%). Larger body sizes at ages 15 or 30 in both sexes were associated with increased overall mortality. Cancer mortality was more strongly associated with adolescent obesity, and cardiovascular mortality with early adulthood body size. Weight gain between these ages was associated with cardiovascular mortality. Obese adolescents who lost weight still had increased mortality from all medical causes in both sexes. Physical activity during adolescence and early adulthood had no association with mortality, but at cohort baseline higher levels of activity were associated with reduced mortality.

CONCLUSIONS:  Mortality in this Middle-Eastern population was associated with obesity both during adolescence and early adult life.