title: Sleep duration, sleep quality, and obesity risk among older adults from six middle-income countries: findings from the study on global AGEing and adult health (SAGE).
abstract: OBJECTIVE
  Changes in sleep patterns often occur in older adults. Previous studies have documented associations between sleep duration, sleep quality, and obesity risk in older individuals, yet few studies have examined these trends in lower-income countries. The present cross-sectional study uses nationally representative datasets from six countries to examine these relationships.
  
  
  METHODS
  Two hypotheses related to obesity risk and sleep patterns were tested using data from the first wave of the World Health Organization's Study on global AGEing and adult health (SAGE). This longitudinal study draws on samples of older adults (>50 years old) in six middle-income countries (China, Ghana, India, Mexico, Russian Federation, and South Africa). Self-report data were used to measure sleep duration, sleep quality, lifestyle and sociodemographic information, while anthropometric measurements were collected to assess body mass index (BMI) and waist circumference (WC). Multiple linear regressions were used to examine the relationship between sleep patterns and obesity risk while controlling for lifestyle factors.
  
  
  RESULTS
  Shorter sleep durations in both men and women were significantly associated with higher BMI and WC measures (P < 0.05). Low sleep quality did not significantly contribute to increased obesity risk. Surprisingly, high sleep quality was significantly associated with increased male BMI and WC in China and India (P < 0.01).
  
  
  CONCLUSIONS
  This study documented an association between short sleep duration and increased obesity risk, which is important given the global increase of obesity-related diseases.
authors.affiliation: Department of Anthropology, University of Oregon, Eugene, Oregon.
authors.forename: Theresa E
authors.initials: TE
authors.lastname: Gildner
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Liebert
authors.forename: Paul
authors.initials: P
authors.lastname: Kowal
authors.forename: Somnath
authors.initials: S
authors.lastname: Chatterji
authors.forename: J
authors.initials: J
authors.lastname: Josh Snodgrass
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D005869:Ghana / Q000453:epidemiology; D006801:Humans; D007194:India / Q000453:epidemiology; D008019:Life Style; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D012306:Risk; D012737:Sex Factors; D012800:Siberia / Q000453:epidemiology; D012890:Sleep; D012893:Sleep Wake Disorders / Q000453:epidemiology*; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D013019:South Africa / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013997:Time Factors; D055105:Waist Circumference